COSEWIC Assessment and Status Report on the Channel Darter Percina copelandi in Canada 2016

Channel Darter
Photo: Illustration by © Ellen Edmonson (NYSDEC).

Lake Erie populations - Endangered
Lake Ontario populations - Endangered
St. Lawrence populations - Special Concern
2016

Table of contents

List of figures

  • Figure 1. Channel Darter (Percina copelandi) © Ellen Edmonson (NYSDEC).
  • Figure 2. Global distribution of the Channel Darter (modified from DFO 2011). The thick black diagonal lines represent the divisions between DU1 (southwestern Ontario), DU2 (southeastern Ontario) and DU3 (Ottawa River / St. Lawrence) populations.
  • Figure 3. Unrooted Neighbor-joining tree of Ontario and Quebec populations of the Channel Darter based on Nei genetic distance (DA). Numbers at branch points represent percentage bootstrap support of each branching point from 1,000 pseudoreplications. The three designatable units (DUs) are contained within the dashed boxes.
  • Figure 4. Range of Channel Darter in the Lake Erie DU.
  • Figure 5. Range of Channel Darter in the Lake Ontario DU.
  • Figure 6. Range of Channel Darter in St. Lawrence DU.

List of tables

  • Table 1. Summary of recent fish surveys, 1995-2013, in known areas of Channel Darter occurrence and sources of the information. *Populations in bold were discovered since the publication of the previous COSEWIC report in 2002. Gear: a = backpack electrofisher, b = seine net; c = drift/kick net; d = boat electrofishing; e = trawl.
  • Table 2. Summary of occurrences of Channel Darter at 53 sample sites in the St. Lawrence DU. X=occurrence; 0=absent despite inventories directed on the species; (XXXX) =year of capture; FMN=data from the St. Lawrence ish Monitoring Network. The data from 1930-2009 is summarized in DFO (2013) and the 2010-2013 data is a recent unpublished compilation for which data are available at the Centre de données sur le patrimoine écologique du Quebéc.
  • Table 3. Matrix showing the relation between the Relative Abundance Index and the Population Trajectory Index in the calculation of the Population status (from Bouvier and Mandrak 2010).
  • Table 4. Relative Abundance Index and Population Trajectory Index for populations of Channel Darter in Quebec and Ontario (modified from Bouvier and Mandrak 2010 and Boucher and Garceau 2010). Certainty: 1 = quantitative analysis; 2 = CPUE or standardized sampling; 3 = expert opinion.
  • Table 5. Population Status Index for populations of Channel Darter in Quebec and Ontario (modified from Bouvier and Mandrak 2010 and Boucher and Garceau 2010). Certainty: 1 = causative study; 2 = correlative study; 3 = expert opinion.
  • Table 6. Threat status of each threat for populations of Channel Darter from Ontario and Quebec (modified from Bouvier and Mandrak 2010 and Boucher and Garceau 2010). The number in brackets refers to the level of certainty assigned to the Threat Status (1=causative studies; 2= correlative studies; 3=expert opinion).
  • Table 7. Global, national, and subnational heritage ranks of the Channel Darter Percina copelandi (NatureServe 2011).

List of appendices

  • Appendix 1. Threat Calculator results for Channel Darter (Percina copelandi) – Lake Erie populations (DU1).
  • Appendix 2. Threat Calculator results for Channel Darter (Percina copelandi) – Lake Ontario populations (DU2).
  • Appendix 3. Threat Calculator results for Channel Darter (Percina copelandi) –St. Lawrence populations (DU3).

Document information

COSEWIC
Committee on the Status
of Endangered Wildlife
in Canada

COSEWIC logo

COSEPAC
Comité sur la situation
des espèces en péril
au Canada

COSEWIC status reports are working documents used in assigning the status of wildlife species suspected of being at risk. This report may be cited as follows:

COSEWIC. 2016. COSEWIC assessment and status report on the Channel Darter Percina copelandi, Lake Erie populations, Lake Ontario populations and St. Lawrence populations, in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. xvi + 68 pp. (Species at Risk Public Registry website).

Previous report(s):

COSEWIC 2002. COSEWIC assessment and update status on report on the channel darter Percina copelandi in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. vii + 21 pp.

Phelps, A., and A. Francis. 2002. Update COSEWIC status report on the channel darter Percina copelandi in Canada, in COSEWIC assessment and update status on report on the channel darter Percina copelandi in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. 1-21 pp.

Goodchild, C.D. 1993. COSEWIC status report on the channel darter Percina copelandi in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. 24 pp.

Production note:

COSEWIC would like to acknowledge Jean-Sebastien Moore, Dominic Nowasad and John Mee for writing the status report on the Channel Darter, Percina copelandi, in Canada, prepared under contract with Environment and Climate Change Canada. This report was overseen and edited by Nick Mandrak, Co-chair of the COSEWIC Freshwater Fishes Specialist Subcommittee.

For additional copies contact:

COSEWIC Secretariat
c/o Canadian Wildlife Service
Environment and Climate Change Canada
Ottawa, ON
K1A 0H3

Tel.: 819-938-4125
Fax: 819-938-3984
E-mail: COSEWIC E-mail
Website: COSEWIC

Également disponible en français sous le titre Évaluation et Rapport de situation du COSEPAC sur le Fouille-roche gris (Percina copelandi), populations du lac Érié, populations du lac Ontario et populations du Saint-Laurent, au Canada.

Cover illustration/photo:

Channel Darter -- Illustration by © Ellen Edmonson (NYSDEC).


COSEWIC assessment summary

Assessment summary – November 2016

Common name:
Channel Darter - Lake Erie populations
Scientific name:
Percina copelandi
Status:
Endangered
Reason for designation:
This small-bodied species occupies nearshore lake and river habitats that are undergoing major shoreline modifications and the negative impact of the invasive Round Goby, having resulted in likely extirpation from large areas of Lake Erie and Lake St. Clair.
Occurrence:
Ontario
Status history:
The species was considered a single unit and designated Threatened in April 1993. Status re-examined and confirmed in May 2002. When the species was split into separate units in November 2016, the “Lake Erie populations” unit was designated Endangered.

Assessment summary – November 2016

Common name:
Channel Darter - Lake Ontario populations
Scientific name:
Percina copelandi
Status:
Endangered
Reason for designation:
This small-bodied species is limited to three small watersheds. The primary threat is the invasive Round Goby, which is now found throughout the Trent River and has resulted in declines in the abundance of this population. For the time being, populations along the Moira and Salmon rivers are largely unaffected by Round Goby. However, introductions upstream of dams via bait bucket transfers are considered likely.
Occurrence:
Ontario
Status history:
The species was considered a single unit and designated Threatened in April 1993. Status re-examined and confirmed in May 2002. When the species was split into separate units in November 2016, the “Lake Ontario populations” unit was designated Endangered.

Assessment summary – November 2016

Common name:
Channel Darter - St. Lawrence populations
Scientific name:
Percina copelandi
Status:
Special Concern
Reason for designation:
This small-bodied species is broadly distributed, but there is evidence of extirpation at some localities within its range. The species is subjected to a variety of threats related to the impact of the invasive Round Goby and pollution. The species may become Threatened if these threats are not effectively managed.
Occurrence:
Ontario, Quebec
Status history:
The species was considered a single unit and designated Threatened in April 1993. Status re-examined and confirmed in May 2002. When the species was split into separate units in November 2016, the “St. Lawrence populations” unit was designated Special Concern.

COSEWIC executive summary

Channel Darter
Percina copelandi

Lake Erie populations
Lake Ontario populations
St. Lawrence populations

Wildlife species description and significance

The Channel Darter is a small (less than 72 mm total length) bottom-feeding fish that inhabits lake and river habitats. It is one of 12 species of the darter subfamily (Etheostomatinae) found, and one of four species of the genus Percina, in Canada. It can be distinguished from other darters by dark pigmentation on its first (or spiny) dorsal fin, small M-, V-, W-, or X-shaped marks along the dorso-lateral surface, 8-10 oblong or squarish black blotches along the lateral line, and the presence of two spiny rays on its anal fin. Three designatable units are identified in Canada: Lake Erie populations (DU1); Lake Ontario populations (DU2); and, St. Lawrence populations (DU3).

Distribution

The Channel Darter has a wide, but discontinuous, distribution throughout eastern North America. In the United States, it is found in the east from the Lower Peninsula of Michigan through to Alabama, Arkansas, Oklahoma, Mississippi, Louisiana, and southeastern Kansas. In Canada, the species is found in low numbers and its distribution is discontinuous. In Ontario, the species is restricted to the Bay of Quinte drainage, the Ottawa River drainage, and in the Lake Erie and Huron-Erie corridor. In Quebec, the species is found in the St. Lawrence River and many of its tributaries distributed in four hydrographic regions: Ottawa and Montréal; Southwest St. Lawrence; Northwest St. Lawrence; and Southeast St. Lawrence. Range disjunctions of > 300 km separate the southwestern Ontario, southeastern Ontario and Ottawa River / St. Lawrence populations.

Habitat

The Channel Darter inhabits both river and lake habitats. Adult Channel Darter typically live in small to large rivers with moderate current and coarse bed material. In lakes, the Channel Darter is predominantly found on sand and gravel beaches with moderate wave action.

Biology

The Channel Darter feeds predominantly on benthic invertebrates such as mayfly, caddisfly, and midge larvae. It matures after one year and can live up to five years. Spawning takes place in spring and summer, when males select and defend territories composed of pebbles and cobbles in areas of moderate water flow. Females bury eggs in the substrate, where the males fertilize them. Individuals can reproduce several times, with different partners, throughout the reproductive season. There is no parental care of the eggs. Some evidence exists that the Channel Darter migrates towards deeper portions of lakes or pools to overwinter, but this migratory behaviour remains poorly studied.

Population size and trends

The Channel Darter is found at low abundances throughout its range, and evidence suggests that abundances are generally declining throughout the Canadian range of the species. The previous COSEWIC report on the species (2002) identified six extirpated populations in Quebec. Recent targeted sampling confirmed that four of those populations are likely extirpated, but specimens have since been captured at the other two. In Ontario, targeted sampling in Lake Erie failed to capture Channel Darter at five historical sampling locations in the nearshore habitat. Furthermore, extensive sampling failed to capture Channel Darter from Lake St. Clair at sites where the species was previously captured, with the exception of a single individual captured in 2012. Increased sampling effort led to the discovery of seven new populations in Quebec since the last report, and confirmed the presence of the species in all six new locations reported in the previous report. In Ontario, a new population was discovered in the Salmon River since the publication of the last report, and the presence of the species was confirmed in one of three new locations from the previous report. Newly discovered populations are more likely the result of increased sampling effort than species range expansion.

Threats and limiting factors

The most severe threats to populations appear to be the Round Goby. Altered flow regimes, and sediment and nutrient loading also constitute a moderate threat in many river populations. Threats related to intensive agriculture and urban development (sedimentation, shoreline modifications, altered flow regimes, excess nutrient, and toxic substances) are also prominent, especially in Lake Erie, Ottawa River and the rivers in the southwestern St. Lawrence River drainage.

Protection, status, and ranks

The Channel Darter is listed as Threatened under Schedule 1 of the Canadian Species at Risk Act (SARA). In Ontario, the species is listed as Threatened under the Ontario Endangered Species Act, 2007 (ESA). In Quebec, the species is listed as ‘Vulnérable’ under the Loi sur les Espèces Menacées ou Vulnérables. These listings prohibit harvest or capture without authorization. The species is ranked as Apparently Secure globally by NatureServe, and is not protected federally in the United States.


Technical summary – Lake Erie populations - DU1

Scientific name:
Percina copelandi
English name:
Channel Darter
Lake Erie populations
French name:
Fouille-roche gris
Populations du lac Érié
Range of occurrence in Canada (province/territory/ocean):
Ontario

Demographic information

Demographic information of the species
Summary itemsInformation
Generation time2 yrs
Is there an inferred continuing decline in number of mature individuals?Yes
Estimated percent of continuing decline in total number of mature individuals within 5 yearsUnknown
Percent reduction in total number of mature individuals over the last 10 years?Unknown
Percent reduction in total number of mature individuals over the next 10 years.Unknown
Percent reduction in total number of mature individuals over any 10 years period, over a time period including both the past and the future.Unknown
Are the causes of the decline clearly reversible and understood and ceased?No
Are there extreme fluctuations in number of mature individuals?No

Extent and occupancy information

Extent and occupancy information of the species
Summary itemsinformation

Estimated extent of occurrence

Present: 2918 km2

Recent Historical: 1828 km2

2918 km2

Index of area of occupancy (IAO)

Present: 180 km2

Recent Historical: 80 km2

1802
Is the total population severely fragmented?No

Number of locationsi

(Historically 6 locations, currently 3 or 4)

3-4
Is there an inferred continuing decline in extent of occurrence?No
Is there an inferred continuing decline in index of area of occupancy?No
Is there a continuing decline in number of populations?Yes
Is there an observed continuing decline in number of locations?Yes
Is there an observed continuing decline in area, extent, and quality of habitat?Yes
Are there extreme fluctuations in number of populations?No
Are there extreme fluctuations in number of locationsi?No
Are there extreme fluctuations in extent of occurrence?No
Are there extreme fluctuations in index of area of occupancy?No

i See Definitions and Abbreviations on the COSEWIC website and IUCN 2010 for more information on this term.

Number of mature individuals (in each population)

Number of mature individuals of the species
PopulationMature Individuals
Detroit RiverUnknown
St. Clair RiverUnknown
Lake Erie – Western BasinUnknown
Lake Erie – Central Basin (likely extirpated)Unknown
Lake Erie – Eastern Basin (likely extirpated)Unknown
Lake St. Clair (likely extirpated, but one specimen collected in 2012)Unknown
TotalUnknown
6 populations; 3 likely extirpatedblank 

Quantitative analysis

Quantitative analysis of the species
Summary itemsInformation
Probability of extinction in the wild is at least 20% within 20 years or 5 generations or 10% within 100 years.Unknown

Threats (actual or imminent, to populations or habitats)

Threats
Summary itemsInformation
Exotic speciesPollution

Rescue effect (immigration from outside Canada)

Rescue effect of the species
Summary itemsInformation
Status of outside population(s)?

United States: N4 (Apparently secure; NatureServe 2011)

Vulnerable or imperiled in 12 out of the 14 states where it is found.

Is immigration known or possible?Possible, but unknown
Would immigrants be adapted to survive in Canada?Yes
Is there sufficient habitat for immigrants in Canada?Yes
Are conditions deteriorating in Canada?Yes
Are conditions for the source population deteriorating?Yes
Is the Canadian population considered to be a sink?No
Is rescue from outside populations likely?Unlikely

Data-sensitive species

Data-sensitive information of the species
Summary itemsInformation
Is this a data-sensitive species?No

Status history

Status history
Summary itemsInformation
COSEWIC:The species was considered a single unit and designated Threatened in April 1993. Status re-examined and confirmed in May 2002. When the species was split into separate units in November 2016, the "Lake Erie populations" unit was designated Endangered.

Status and reasons for designation:

Status and reasons for designation
Summary itemsInformation
Status:Endangered
Alpha-numeric code:B1ab(iii,iv,v)+2ab(iii,iv,v)
Reasons for designation:This small-bodied species occupies nearshore lake and river habitats that are undergoing major shoreline modifications and the negative impact of the invasive Round Goby, having resulted in likely extirpation from large areas of Lake Erie and Lake St. Clair.

Applicability of criteria:

Applicability of criteria
Summary itemsInformation
Criterion A
(Decline in total number of mature individuals):
Not applicable. Unknown number of mature individuals.
Criterion B
(Small distribution range and decline or fluctuation):
Meets Endangered, B1ab(iii,iv,v)+2ab(iii,iv,v), because of small extent of occurrence, small index of area of occupancy, few locations, and observed decline in quality of habitat, number of locations and an inferred decline in the number of mature individuals.
Criterion C
(Small and declining number of mature individuals):
Not applicable. Unknown number of mature individuals.
Criterion D
(Very small or restricted total population):
Not applicable. Unknown number of mature individuals.
Criterion E
(Quantitative analysis):
Quantitative analyses have not been completed.

Technical summary – Lake Ontario populations - DU2

Scientific name:
Percina copelandi
English name:
Channel Darter
Lake Ontario populations
French name:
Fouille-roche gris
Populations du lac Ontario
Range of occurrence in Canada (province/territory/ocean):
Ontario

Demographic information

Demographic information of the species
Summary itemsInformation
Generation time2 yrs
Is there an inferred continuing decline in number of mature individuals?Yes
Estimated percent of continuing decline in total number of mature individuals within 5 yearsUnknown
Percent reduction in total number of mature individuals over the last 10 years?Unknown
Percent reduction in total number of mature individuals over the next 10 years.Unknown
Percent reduction in total number of mature individuals over any 10 years period, over a time period including both the past and the future.Unknown
Are the causes of the decline clearly reversible and understood and ceased?No
Are there extreme fluctuations in number of mature individuals?No

Extent and occupancy information

Extent and occupancy information of the species
Summary itemsinformation

Estimated extent of occurrence

Present: 1655 km2

Recent Historical: 667 km2

1655 km2

Index of area of occupancy (IAO)

Present: 392 km2

Recent Historical: 172 km2

3922
Is the total population severely fragmented?No
Number of locationsii4-9
Is there an inferred continuing decline in extent of occurrence?No
Is there a continuing decline in index of area of occupancy?No
Is there a continuing decline in number of populations?No
Is there an observed continuing decline in number of locations?No
Is there an observed continuing decline in area, extent, and quality of habitat?Yes
Are there extreme fluctuations in number of populations?No
Are there extreme fluctuations in number of locationsii?No
Are there extreme fluctuations in extent of occurrence?No
Are there extreme fluctuations in index of area of occupancy?No

ii See Definitions and Abbreviations on the COSEWIC website and IUCN 2010 for more information on this term.

Number of mature individuals (in each population)

Number of mature individuals of the species
PopulationN clones (index of mature individuals)
Moira River system (including tributaries: Skootamatta, Black)Unknown
Salmon River (likely two populations due to a dam blocking upstream movement of invasive species)Unknown
Trent RiverUnknown
Totalblank 
4 populationsUnknown

Quantitative analysis

Quantitative analysis of the species
Summary itemsInformation
Probability of extinction in the wild is at least 20% within 20 years or 5 generations or 10% within 100 years.Unknown

Threats (actual or imminent, to populations or habitats)

Threats
Summary itemsInformation
Exotic speciesblank 

Rescue effect (immigration from outside Canada)

Rescue effect of the species
Summary itemsInformation
Status of outside population(s)?

United States: N4 (Apparently secure; NatureServe 2011)

Vulnerable or imperiled in 12 out of the 14 states where it is found.

Is immigration known or possible?Possible but unknown
Would immigrants be adapted to survive in Canada?Yes
Is there sufficient habitat for immigrants in Canada?Yes
Are conditions deteriorating in Canada?Yes
Are conditions for the source population deteriorating?Unknown
Is the Canadian population considered to be a sink?No
Is rescue from outside populations likely?Unlikely

Data-sensitive species

Data-sensitive information of the species
Summary itemsInformation
Is this a data-sensitive species?No

Status history

Status history
Summary itemsInformation
COSEWIC:The species was considered a single unit and designated Threatened in April 1993. Status re-examined and confirmed in May 2002. When the species was split into separate units in November 2016, the "Lake Ontario populations" unit was designated Endangered.

Status and reasons for designation:

Status and reasons for designation
Summary itemsInformation
Recommended status:Endangered
Alpha-numeric code:B1ab(iii,v)+2ab(iii,v)
Reasons for designation:This small-bodied species is limited to three small watersheds. The primary threat is the invasive Round Goby, which is now found throughout the Trent River and has resulted in declines in the abundance of this population. For the time being, populations along the Moira and Salmon rivers are largely unaffected by Round Goby. However, introductions upstream of dams via bait bucket transfers are considered likely.

Applicability of criteria:

Applicability of criteria
Summary itemsInformation
Criterion A
(Decline in total number of mature individuals):
Not applicable. Unknown number of mature individuals.
Criterion B
(Small distribution range and decline or fluctuation):
Meets Endangered, B1ab(iii,v)+2ab(iii,v), because the species has a small extent of occurrence, small index of occupancy, a substantial reduction in the quality of habitat due to the invasion of Round Goby and an inferred reduction in the number of individuals.
Criterion C
(Small and declining number of mature individuals):
Not applicable. Unknown number of mature individuals.
Criterion D
(Very small or restricted total population):
Not applicable. Unknown number of mature individuals.
Criterion E
(Quantitative analysis):
Quantitative analyses have not been completed.

Technical summary – St. Lawrence populations - DU3

Scientific name:
Percina copelandi
English name:
Channel Darter
St. Lawrence populations
French name:
Fouille-roche gris
Populations du Saint-Laurent
Range of occurrence in Canada (province/territory/ocean):
Ontario and Quebec

Demographic information

Demographic information of the species
Summary itemsInformation
Generation time2 yrs
Is there an inferred continuing decline in number of mature individuals?Unknown
Estimated percent of continuing decline in total number of mature individuals within 5 yearsUnknown
Percent reduction in total number of mature individuals over the last 10 years?Unknown
Percent reduction in total number of mature individuals over the next 10 years.Unknown
Percent reduction in total number of mature individuals over any 10 years period, over a time period including both the past and the future.Unknown
Are the causes of the decline clearly reversible and understood and ceased?No
Are there extreme fluctuations in number of mature individuals?No

Extent and occupancy information

Extent and occupancy information of the species
Summary itemsinformation

Estimated extent of occurrence

Present – 53,215 km2

Recent Historical – 47,000 km2

>53,215 km2

Index of area of occupancy (IAO)

Present - 7,664 km2

Recent Historical - 5,620 km2

>7,664 km2
+ Does not include new records received after 2-Month Provisional Report.blank  
Is the total population severely fragmented?No
Number of locationsiii29
Is there an inferred continuing decline in extent of occurrence?No
Is there a continuing decline in index of area of occupancy?No
Is there a continuing decline in number of populations?Yes
Is there an observed continuing decline in number of locations?Yes
Is there an observed continuing decline in area, extent, and quality of habitat?Yes
Are there extreme fluctuations in number of populations?No
Are there extreme fluctuations in number of locationsiii?No
Are there extreme fluctuations in extent of occurrence?No
Are there extreme fluctuations in index of area of occupancy?No

ii See Definitions and Abbreviations on the COSEWIC website and IUCN 2010 for more information on this term.

Number of mature individuals (in each population)

Number of mature individuals of the species
PopulationN clones (index of mature individuals)
Little Rideau CreekUnknown
Ottawa RiverUnknown
Lake Saint-LouisUnknown
Gatineau RiverUnknown
Blanche River (Gatineau)Unknown
Blanche River (Thurso)Unknown
Petite-Nation RiverUnknown
Saumon RiverUnknown
Rouge RiverUnknown
Ruisseau CalumetUnknown
Pointe-au-ChêneUnknown
Richelieu RiverUnknown
Châteauguay RiverUnknown
Yamaska RiverUnknown
Saint-François RiverUnknown
Lake Saint-FrançoisUnknown
Lake Saint-PierreUnknown
St. Lawrence River, downstream of Lake Saint-PierreUnknown
Nicolet RiverUnknown
L’Assomption RiverUnknown
Bayonne RiverUnknown
Du Loup RiverUnknown
Grande Yamachiche RiverUnknown
Batiscan RiverUnknown
Jacques-Cartier RiverUnknown
Sainte-Anne RiverUnknown
Bécancour RiverUnknown
Du Sud RiverUnknown
Du Chêne RiverUnknown
Total (29 populations)Unknown

Quantitative analysis

Quantitative analysis of the species
Summary itemsInformation
Probability of extinction in the wild is at least 20% within 20 years or 5 generations or 10% within 100 years.Unknown

Threats (actual or imminent, to populations or habitats)

Exotic species, Pollution

Rescue effect (immigration from outside Canada)

Rescue effect of the species
Summary itemsInformation
Status of outside population(s)?United States: N4 (Apparently secure;
NatureServe 2011) Vulnerable or imperiled in 12 out of the 14 states where it is found.
Is immigration known or possible?Possible, but unknown
Would immigrants be adapted to survive in Canada?Yes
Is there sufficient habitat for immigrants in Canada?Yes
Are conditions deteriorating in Canada?Yes
Are conditions deteriorating for source populations?Unknown
Is the Canadian population considered to be a sink?No
Is rescue from outside populations likely?Unlikely

Data-sensitive species

Data-sensitive information of the species
Summary itemsInformation
Is this a data-sensitive species?No

Status history

Status history
Summary itemsInformation
COSEWIC:The species was considered a single unit and designated Threatened in April 1993. Status re-examined and confirmed in May 2002. When the species was split into separate units in November 2016, the "St. Lawrence populations" unit was designated Special Concern.

Status and reasons for designation:

Status and reasons for designation
Summary itemsInformation
Status:Special Concern
Alpha-numeric code:Not applicable
Reasons for designation:This small-bodied species is broadly distributed, but there is evidence of extirpation at some localities within its range. The species is subjected to a variety of threats related to the impact of the invasive Round Goby and pollution. The species may become Threatened if these threats are not effectively managed.

Applicability of criteria:

Applicability of criteria
Summary itemsInformation
Criterion A
(Decline in total number of mature individuals):
Not applicable. Unknown number of mature individuals.
Criterion B
(Small distribution range and decline or fluctuation):
Not applicable. All thresholds exceeded.
Criterion C
(Small and declining number of mature individuals):
Not applicable. Unknown number of mature individuals.
Criterion D
(Very small or restricted total population):
Not applicable. Unknown number of mature individuals.
Criterion E
(Quantitative analysis):
Quantitative analyses have not been completed.

Preface

The Channel Darter in Canada was last assessed by COSEWIC in 2002 and was assigned the status of Threatened. Following the proclamation of the Species at Risk Act (SARA) in 2003, Channel Darter was included on Schedule 1 of SARA, which required Fisheries and Oceans Canada (DFO) to undertake action towards the recovery of the species (DFO 2010; DFO 2011). As a consequence, much new information has been collected on the species since the publication of the last report. The present report includes new information on the population structure of the species that follows from an increase in the number of targeted sampling studies and genetic analyses. Those studies have provided evidence for the existence of three designatable units within the Channel Darter distribution in Canada, discovered new populations, and revisited many historical sites whose status was unknown in the last report. New population extirpations are also documented. However, quantitative estimates of abundance and trends are still lacking. New studies have also improved our knowledge of the Channel Darter habitat requirements and have allowed a better characterization of the threats faced by the species.

COSEWIC history

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) was created in 1977 as a result of a recommendation at the Federal-Provincial Wildlife Conference held in 1976. It arose from the need for a single, official, scientifically sound, national listing of wildlife species at risk. In 1978, COSEWIC designated its first species and produced its first list of Canadian species at risk. Species designated at meetings of the full committee are added to the list. On June 5, 2003, the Species at Risk Act (SARA) was proclaimed. SARA establishes COSEWIC as an advisory body ensuring that species will continue to be assessed under a rigorous and independent scientific process.

COSEWIC mandate

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) assesses the national status of wild species, subspecies, varieties, or other designatable units that are considered to be at risk in Canada. Designations are made on native species for the following taxonomic groups: mammals, birds, reptiles, amphibians, fishes, arthropods, molluscs, vascular plants, mosses, and lichens.

COSEWIC membership

COSEWIC comprises members from each provincial and territorial government wildlife agency, four federal entities (Canadian Wildlife Service, Parks Canada Agency, Department of Fisheries and Oceans, and the Federal Biodiversity Information Partnership, chaired by the Canadian Museum of Nature), three non-government science members and the co-chairs of the species specialist subcommittees and the Aboriginal Traditional Knowledge subcommittee. The Committee meets to consider status reports on candidate species.

Definitions (2016)

Wildlife species
A species, subspecies, variety, or geographically or genetically distinct population of animal, plant or other organism, other than a bacterium or virus, that is wild by nature and is either native to Canada or has extended its range into Canada without human intervention and has been present in Canada for at least 50 years.
Extinct (X)
A wildlife species that no longer exists.
Extirpated (XT)
A wildlife species no longer existing in the wild in Canada, but occurring elsewhere.
Endangered (E)
A wildlife species facing imminent extirpation or extinction.
Threatened (T)
A wildlife species likely to become endangered if limiting factors are not reversed.
Special concern (SC)
(Note: Formerly described as “Vulnerable” from 1990 to 1999, or “Rare” prior to 1990.)
A wildlife species that may become a threatened or an endangered species because of a combination of biological characteristics and identified threats.
Not at risk (NAR)
(Note: Formerly described as “Not In Any Category”, or “No Designation Required.”)
A wildlife species that has been evaluated and found to be not at risk of extinction given the current circumstances.
Data deficient (DD)
(Note: Formerly described as “Indeterminate” from 1994 to 1999 or “ISIBD” [insufficient scientific information on which to base a designation] prior to 1994. Definition of the [DD] category revised in 2006.)
A category that applies when the available information is insufficient (a) to resolve a species’ eligibility for assessment or (b) to permit an assessment of the species’ risk of extinction.

The Canadian Wildlife Service, Environment and Climate Change Canada, provides full administrative and financial support to the COSEWIC Secretariat.


Wildlife species description and significance

Name and classification

Class:
Actinopterygii
Order:
Perciformes
Family:
Percidae
Subfamily:
Etheostomatinae
Genus:
Percina
Species:
Percina copelandi (Jordan, 1877)
Synonyms:
Rheocrypta copelandi - Jordan 1877a:9
Cottogaster copelandi - Jordan & Evermann 1896-1900: 1045
Hadropterus copelandi - Hubbs and Lagler 1958:107
Common Name:
English: Channel Darter
French:
fouille-roche gris (Page et al. 2013) (formerly dard gris)

The family Percidae is a diverse collection of freshwater fishes with a Holarctic distribution (Sloss et al. 2004). Darters (subfamily Etheostomatinae) are a North American clade and are the most diverse group of percids (Sloss et al. 2004; Near et al. 2011). The darter clade includes approximately 250 species (12 in Canada; Page et al. 2013), which is more than 20% of the entire North American freshwater fish fauna (Scott and Crossman 1973). There are four well-supported (i.e., reciprocally monophyletic) and commonly recognized genera of darters: Ammocrypta, Crystallaria, Etheostoma, and Percina (Near et al. 2000; Page 1983, 2000; Simons 1992; Near et al. 2011; Smith et al. 2011; Page et al. 2013). The estimated age of the most recent common ancestor of all darters is between 34 and 40 million years, which places the origin of the darters some time during the Late Eocene or Early Oligocene (Near et al. 2011; Smith et al. 2011). Most extant darter species, however, are thought to have originated in the last 15 million years. For example, the estimated age of the Percina genus is between 17.8 and 20.9 million years (Near et al. 2011). Hence, most darter diversification probably occurred during the Pliocene. A general mechanism for the extreme diversification of darter species has yet to be elucidated (Near and Peck 2005).

The genus Percina, with 45 species, is the second largest genus of darters (Page et al. 2013). The most recent phylogenetic analyses of Percina suggest that former groupings of species into subgenera or other hierarchical groupings (e.g., Bailey et al. 1954; Page 1974, 1981, 2000; Bailey and Etnier 1988; Bart and Page 1992) do not reflect monophyletic relationships (Near 2002; Near et al. 2011). Hence, Near et al. (2011) suggested 11 new or revised “species clades” within Percina that reflect monophyletic groupings. Under this new classification, the Channel Darter (Figure 1) is one of eight members of the Etnieperca clade and one of three members, along with the Pearl Darter (Percina aurora) and the Coal Darter (Percina brevicauda), of the Cottogaster clade. Those two other species are not found in Canada and Channel Darter is, thus, the only member of that clade found in Canada. There are no recognized Percina copelandi sub-species.

Figure 1. Channel Darter (Percina copelandi) © Ellen Edmonson (NYSDEC).
Channel Darter (see long description below)
Long description for figure 1

Image of the Channel Darter, lateral view. Body colouration can range from yellow to olive with brown speckles that run along the dorsal portion of the body. The ventral regions are pale. A series of characteristic small brown, round, or oblong blotches also run along the side of the Channel Darter’s body and can be joined by a thin line. The fins are generally clear and sometimes show light speckles.

Morphological description

Adults typically reach a maximum of 62 mm total length (TL) (Page and Burr 2011), although specimens measuring up to 72 mm TL have recently been captured (Holm et al. 2009). Body colouration can range from yellow to olive with brown speckles that run along the dorsal portion of the body (Holm et al. 2009, Figure 1). The ventral regions are pale. A series of characteristic small brown, round, or oblong blotches also run along the side of the Channel Darter body and can be joined by a thin line (Scott and Crossman 1973). The fins are generally clear and sometimes show light speckles (Scott and Crossman 1973). Males in breeding conditions can show a darker colouration, especially around the head (Scott and Crossman 1973; Holm et al. 2009).

The geographical range of the Channel Darter overlaps that of other morphologically similar darters. The Channel Darter can be distinguished from most Canadian darters by the small M-, V-, W-, or X-shaped marks along its mid-side (Holm et al. 2009). The Johnny Darter (Etheostoma nigrum) and Tessellated Darter (E. olmstedi), however, can also display such marks. The Channel Darter differs from those two species by the presence of two anal spines, compared to only one for the Johnny Darter and Tessellated Darter (Scott and Crossman 1973). The Channel Darter can also be confused with the River Darter (Percina shumardi). The Channel Darter has dark pigmentation at the base and side of the spiny dorsal fin, while River Darter has a small anterior black spot and a large posterior black spot on the dorsal fin (Holm et al. 2009; Bouvier and Mandrak 2010).

Population spatial structure and variability

In Canada, the Channel Darter appears to be absent from a 300 km stretch of the St. Lawrence River between Lake Ontario (Bay of Quinte drainage) and Lake St. Louis. Both parts of the range were probably re-colonized from the same glacial refugium (Mississippian) (Mandrak and Crossman 1992). The Channel Darter likely initially colonized glacial Lake Maumee (now Erie) from the Mississippian refugium through the Fort Wayne outlet, ca. 14,000 YBP (Mandrak and Crossman 1992). Fish species in the Erie basin could then subsequently disperse eastward into the Ontario basin through the Buffalo outlet (see Mandrak and Crossman 1992 for summary of postglacial lakes and outlets in the Great Lakes basin) and later via Niagara Falls. The species would have then been readily able to disperse through the Ontario basin. Its presence in the Champlain watershed indicates that it likely dispersed through the Mohawk outlet, which drained early glacial Lake Iroquois into the Champlain basin, ca.12,500 YBP (Mandrak and Crossman 1992). Mandrak (1990) hypothesized that a species, Eastern Sand Darter (Ammocrypta pellucida), with a disjunct range and postglacial dispersal history similar to Channel Darter, may have been more widespread in eastern Ontario until the end of the Hypsithermal warm period (ca. 6,000 YBP) when, as a result of the climate cooling, the original postglacial range contracted to suitable microhabitats. This would be consistent with disjunct patterns exhibited by other Prairie plant and animal species. Many of these microhabitats have been degraded in recent times (see Threats section), likely leading to further disjunction. There is also evidence for Eastern Sand Darter populations in the vicinity of Prince Edward County and Bay of Quinte in southeastern Ontario may have been isolated prior to a secondary colonization of the St. Lawrence River basin following the recession of the Champlain Sea from that basin (see Designatable Units section; R. Walter et al., University of Windsor, unpubl. data).

A recent study combining mitochondrial DNA (cytochrome b) and 10 microsatellite markers described genetic structure of 10 populations distributed across Ontario and Quebec (Kidd et al. 2011, Reid et al. 2013). A total of 67 mitochondrial DNA haplotypes were identified; 12 unique haplotypes were associated with western Lake Erie and the Huron-Erie corridor populations, 24 unique haplotypes were associated with Bay of Quinte drainage populations, and 19 unique haplotypes were associated with Ottawa River - St Lawrence system populations. However, 80% of unique haplotypes were associated with individual populations and only 6 haplotypes were shared across multiple populations. Only two haplotypes were found across all populations. This pattern could reflect a complex pattern of postglacial re-colonization, or postglacial diversification. Analysis using individual-based clustering (STRUCTURE 2.3), pairwise genetic distances (Nei’s measure, POPULATIONS 1.2.28), and microsatellite data revealed both regional- and local- scale population structure. At a range-wide scale, population genetic structure reflected the disjunct distribution of Channel Darter populations (Figures 2, 3). Significant structuring between sampled populations within each region was also identified. Genetic subdivisions suggest that dispersal among rivers is limited. Currently, dispersal among many populations is limited by anthropogenic and natural barriers (dams and waterfalls). Similar to Channel Darter, populations of Eastern Sand Darter (R. Walter et al., University of Windsor, unpubl. data) in Prince Edward County show greater genetic affinity to southwestern Ontario than to the closer St. Lawrence populations, hypothesized to be the result of early isolation of Prince Edward County populations and subsequent secondary colonization of the St. Lawrence River drainage (R. Walter, University of Windsor, unpubl. data) (see Designatable Units section).

The range disjunction observed in the Canadian distribution of the species does not qualify as severely fragmented according to the COSEWIC definition. There is good evidence that each portion of the range is large enough to support viable populations (Venturelli et al. 2010) (see Table 4).

Figure 2. Global distribution of the Channel Darter (modified from DFO 2011). The thick black diagonal lines represent the divisions between DU1 (southwestern Ontario), DU2 (southeastern Ontario) and DU3 (Ottawa River / St. Lawrence) populations.
Image of map (see long description below)
Long description for figure 2

Map showing the global distribution of the Channel Darter. The species has a wide but discontinuous distribution throughout eastern North America. In the United States, it is found in the east from the Lower Peninsula of Michigan through to Alabama, Arkansas, Oklahoma, Mississippi, Louisiana, and southeastern Kansas. In Canada, its distribution is disjunct and restricted to southern Quebec and Ontario.

Figure 3. Unrooted Neighbor-joining tree of Ontario and Quebec populations of the Channel Darter based on Nei genetic distance (DA). Numbers at branch points represent percentage bootstrap support of each branching point from 1,000 pseudoreplications. The three designatable units (DUs) are contained within the dashed boxes.
Image of map (see long description below)
Long description for figure 3

Diagram illustrating an unrooted neighbour-joining tree of the Ontario and Quebec populations of the Channel Darter based on Nei genetic distance.

Designatable units

All Canadian populations of the Channel Darter are found within the Great Lakes-Upper St. Lawrence National Freshwater Biogeographic Zone. Within this range, the Channel Darter consists of three designatable units (DUs) that satisfy the discreteness and significance criteria of the COSEWIC (2009) guidelines: Lake Erie (Lake Erie and Huron-Erie corridor); Lake Ontario (Bay of Quinte drainage); and, St. Lawrence populations.

First, the three DUs are disjunct from one another in Canada; each is separated from the nearest other by a minimum 300 km stretch of uninhabited area (Figure 2). The portion of the range between the southeastern Ontario populations and the St. Lawrence populations is separated by the section of the St. Lawrence River between Lake Ontario and Lake St. François. In Canada, there are no historical records of Channel Darter captures in this section of the St. Lawrence River itself, only in American tributaries. Local extirpations along the north shore of Lake Erie have increased the degree of spatial separation between southwestern and southeastern Ontario populations. The discreteness of DUs is further supported by microsatellite DNA data that provided support for grouping populations based on geography (Figure 3, Kidd et al. 2011, Reid et al. 2013). Genetic subdivisions between populations within DUs indicate that dispersal among rivers is limited and, between DUs, unlikely under contemporary time frames.

Southwestern Ontario populations include (and were historically dominated by) the only Canadian populations found in large lakes of the scale of the Laurentian Great Lakes. In other parts of its national and global distribution, it is completely or largely dominated by riverine populations. Differences in the physical (i.e. flow regimes) and biological (e.g. benthic invertebrate community) characteristics between these two environments can be inferred to affect morphology and life history and have resulted in distinct adaptations. Second, the disjunctions likely represent a natural consequence of different postglacial colonization histories for the three DUs and, thus, represent part of the historical legacy of the Channel Darter in Canada. Similar disjunctions are found in Eastern Sand Darter (Ammoycrypta pellucida)(Reid and Dextrase 2014; Ginson et al. 2015; R. Walter, University of Windsor, unpubl. data), both of which have southeastern Ontario populations that are more closely related to southwestern Ontario populations than the closer Quebec populations. This is hypothesized to be the result of early isolation of Bay of Quinte populations and subsequent secondary colonization of the St. Lawrence River drainage (R. Walter, University of Windsor, unpubl. data). Finally, loss of the southeastern Ontario DU would result in an extensive gap in the range of the species in Canada (from two smaller gaps of about 300-400 km each to a single large one of more than 700 km).

Consequently, this report recognizes three Designatable Units:

  • DU 1 – Lake Erie
  • DU 2 – Lake Ontario
  • DU 3 – St. Lawrence

Special significance

Channel Darter is not a species of economic or social importance. It is not restricted to Canada and is widely distributed in the United States. Its ecological role is not well known, but it could be a prey item for other species. The genus Percina comprises 45 other species (Near et al. 2011), four of which are found in Canada (Page et al. 2013). Channel Darter contributes to the aquatic biodiversity of Canada and may be considered a sentinel species because it appears to be easily affected by human activities. Channel Darter is the only member of the Cottogaster clade found in Canada (Near et al. 2011).


Distribution

Global range

The Channel Darter has a wide, but disjunct, distribution throughout the eastern United States and southeastern Canada (Figure 2; Page and Burr 2011; NatureServe 2011). In the United States, it is found across 15 different states along the eastern margin of the lower peninsula of Michigan, south to Alabama, Arkansas, Oklahoma, and southeastern Kansas (Page and Burr 2011). Individuals have been captured in Lake Champlain bordering New York and Vermont.

Canadian range

In Canada, the distribution of the Channel Darter is disjunct and restricted to southern Quebec and Ontario (Figures 4-6). In Ontario, the Channel Darter is currently distributed in four distinct areas in the eastern portion of the Great Lakes basin: Lake St. Clair drainage; Lake Erie drainage (Figure 4); Bay of Quinte drainage (Figure 5); and, Ottawa River drainage (Figure 5). Historical sampling suggests that Channel Darter distribution was always limited to these four areas, although presence/absence at specific sites has changed in recent decades. In Quebec, the Channel Darter is currently distributed in the St. Lawrence River and several of its tributaries (Figure 6). Its distribution encompasses four different hydrographic regions: Outaouais and Montréal; southwestern St. Lawrence; southeastern St. Lawrence; and, northwestern St. Lawrence.

Figure 4. Range of Channel Darter in the Lake Erie DU.
Image of map (see long description below)
Long description for figure 4

Map of the range of the Lake Erie designatable unit of the Channel Darter, which includes the Lake St. Clair and Lake Erie drainages. Symbols indicate records of Channel Darter, with colour indicating the time period in which the records were made.

Figure 5. Range of Channel Darter in the Lake Ontario DU.
Image of map (see long description below)
Long description for figure 5

Map of the range of the Lake Ontario designatable unit of the Channel Darter, which includes the Bay of Quinte drainage. Symbols indicate records of Channel Darter, with colour indicating the time period in which the records were made.

Figure 6. Range of Channel Darter in St. Lawrence DU.
Image of map (see long description below)
Long description for figure 6

Map showing the range of the St. Lawrence designatable unit of the Channel Darter, which encompasses four hydrographic regions: Outaouais and Montréal; southwestern St. Lawrence; southeastern St. Lawrence; and northwestern St. Lawrence. Symbols indicate records of Channel Darter, with colour indicating the time period in which the records were made.

Numbers refer to the following legend:

  1. Aux Ormes River
  2. Aux Orignaux River
  3. Au Saumon River
  4. Batiscan River
  5. Bayonne River
  6. Bécancour River
  7. Châteauguay River
  8. Du Chêne River
  9. Du Sud River
  10. Gatineau River
  11. Gentilly River
  12. Jacques-Cartier River
  13. L'Assumption River
  14. Lake Saint-François
  15. Lake St-Louis
  16. Lake Saint-Pierre
  17. Ottawa River
  18. Ottawa River watershed: Pointe aux Chênes, Rouge, Calumet
  19. Ouareau River
  20. Richelieu River
  21. Rivière aux Bleuets
  22. Rivière Aux Outardes
  23. Rivière des Anglais
  24. Rivière Chicot
  25. Rivière Niger
  26. Rivière Noire
  27. Rivière Trout
  28. Saint-Anne River
  29. Saint-François River
  30. Yamaska River
  31. Rivière Nicolet
  32. Rivière Henri
  33. Rivière aux Saumons
  34. Rivière du Nord

Recent reports have defined populations of Channel Darter based on watersheds (e.g., Boucher and Garceau 2010; Bouvier and Mandrak 2010). We follow this convention because it is plausible that many of the threats identified in the next section would affect a large proportion of watersheds simultaneously. For example, point-source pollution related to industrial activities or sewage outfall would introduce contaminants to many areas downstream of the source of pollution. Many threats to Channel Darter are also related to agricultural activities, whose diffuse source effects on water quality include increased sedimentation, turbidity, and nutrient loading that are all likely to affect many parts of a watershed simultaneously. Dams would also influence flow regimes in areas both upstream and downstream of the dam. Designating watersheds as locations is, therefore, consistent with the threat-based definition of a ‘location’ recognized by COSEWIC. There are two exceptions to this ‘one watershed, one location’ rule. First, Lake Erie was divided into three separate locations: the Western, Central, and Eastern basins. This was done because of the large size of the lake and because the Western Basin supports an apparently healthy population of Channel Darter while it appears extirpated in the other two basins. This suggests that the threats faced by one location do not necessarily affect the others in the same way and warrants separate location designation. Second, we separated the St. Lawrence River into four locations: Lake Saint-Louis, Lake Saint-François, Lake Saint-Pierre, and downstream of Lake Saint-Pierre. The large size of the St. Lawrence River makes it unlikely that threats are distributed equally. Furthermore, there is no record of Channel Darter capture in the river between those four ‘lakes’, suggesting that they are independent locations. Note that some locations were not recognized in the previous assessments (Boucher and Garceau 2010) either because they were combined into one (Lake Erie) or because data were not available to the authors at the time.

In the Lake Erie DU, six locations are recognized (from west to east): St. Clair River; Lake St. Clair; Detroit River; Lake Erie Western Basin (restricted to the Point Pelee area); Lake Erie Central Basin (likely extirpated); Lake Erie Eastern Basin (likely extirpated);

In the Lake Ontario DU, 4-9 locations are recognized, depending on whether Round Goby is a current (3) or future (9) threat: Trent River (1); Moira River system (including tributaries Skootamatta and Black rivers) (1-4); and, Salmon River (2-4).

 In the St. Lawrence DU, 30 locations are recognized: Little Rideau Creek;Ottawa River; Lake Saint-Louis; Gatineau River; Blanche River (Gatineau); Blanche River (Thurso); Petite-Nation River; Saumon River; Rouge River; Calumet; Pointe-au-Chêne; Richelieu River; Châteauguay River; Yamaska River; Saint-François River; Lake Saint-François; Lake Saint-Pierre; downstream of Lake Saint-Pierre; Nicolet River; L’Assomption River; Bayonne River; Du Loup River; Grande Yamachiche River; Batiscan River; Jacques-Cartier River; Sainte-Anne River; Bécancour River; Du Sud River; Du Chêne River.

Extirpated locations

Several locations were reported as extirpated by Phelps and Francis (2002). In Ontario, two specimens were collected in 1948 in an unnamed creek near Moira Lake, but no Channel Darter were collected when the site was revisited in 1997 (A. Dextrase, pers. comm.; Phelps and Francis 2002). Being part of the Moira River watershed, however, it is unclear whether this population should really be considered extirpated, given the Moira River appears to support a relatively abundant population. Phelps and Francis (2002) also reported six extirpated populations in Quebec: Rivière aux Bleuets, Rivière du Sud, Rivière Niger, Rivière Maskinongé, Rivière Chicot, and Port Saint-François. Rivière du Sud was re-sampled in 2005 and 2013, and a total of two and 29 specimens of Channel Darter were collected, respectively (Boucher and Garceau 2010; HydroNet 2013). Port Saint-François is just downstream of Lake Saint-Pierre, and Channel Darter was observed 1.6 km from that site in 2007 (M.-A. Couillard, pers. comm.). This population, therefore, cannot be considered extirpated. The status of the other four populations (aux Bleuets, Niger, Maskinongé, Chicot rivers) has not changed; as sampling in 1996, 2012, and 2013 failed to capture Channel Darter from these locations (Desrochers et al. 1996; Boucher and Garceau 2010; WSP 2013). In addition to these extirpated sites, Phelps and Francis (2002) reported nine sites that had not been re-sampled and whose status was uncertain. Of these nine sites, eight have since been re-sampled and the presence of Channel Darter was confirmed in: Rivière Chateauguay, Rivière Richelieu, Rivière au Saumon, Rivière du Chêne, and Rivière l’Assomption, Rivière aux Ormes, Rivière Henri, Rivière Bécancour (Table 2). Pointe-du-Buisson has not been sampled since 1942, therefore the status of this location is unknown.

New extirpations have also been reported since the publication of Phelps and Francis in Ontario (2002). Intensive targeted sampling of the shores of Lake Erie in 2005-2006 failed to capture Channel Darter at five historical sites: Holiday Beach andPelee Island in the western basin; Port Burwell, Rondeau Bay, and Port Dover in the eastern basin (Reid and Mandrak 2008). Therefore, the populations of the central and eastern basins of Lake Erie appear extirpated. However, Channel Darter was collected in the western basin in 2005-2006 (Reid and Mandrak 2008), from a bottom trawl in 2009 (M. Belore, unpubl. data) and using a seine net (over 50 individuals collected) in 2010 (S. Reid, pers. comm.). The population along the south shore of Lake St. Clair may also be extirpated. The last Canadian record of Channel Darter from Lake St. Clair dates back to 1996, and targeted sampling of historical sites in 2004-2005 and 2007-2010 yielded no captures (Bouvier and Mandrak 2010). A trawling survey conducted by the Michigan Department of Natural Resources conducted between 1996 and 2001 captured a total of six Channel Darter, but the report does not specify the year of captures (Thomas and Haas 2004). Additional sampling in 2011 yielded no captures (M. Belore, pers. comm.). There was a single specimen captured in 2012 (J. Barnucz, pers. comm.). It is unclear if a viable population of Channel Darter still exists in Lake St. Clair.

In summary, sampling since the publication of the last report confirmed the majority of the population extirpations reported by Phelps and Francis (2002). The only exception is Rivière du Sud, where 29 specimens were collected in 2013 (HydroNet 2013). In Ontario, intensive targeted sampling failed to capture the species at many historical nearshore collection sites in lakes Erie and St. Clair, indicating that lacustrine populations are experiencing more severe declines than riverine populations. A recent unpublished compilation of occurrence data from Quebec waterways summarizes data from collections made 2010-2013 (Table 2). Of the sampling sites reported, 22 confirmed continuing occurrence, five recorded new occurrences and nine failed to capture Channel Darter at sites that previously had the species. Sampling was not extensive enough to conclude that there were local extirpations, but indicate this potential.

Newly identified populations

In the last report, Phelps and Francis (2002) reported the discovery of Channel Darter in four new waterbodies in Ontario and six in Quebec (for details, see Appendix 1; Phelps and Francis 2002). Re-sampling has since occurred in all six new sites in Quebec and confirmed the presence of Channel Darter in all cases (Figure 6). In Ontario, two of the newly discovered locations (Lake St. Clair and St. Clair River) were sampled since the publication of the last report (Figure 4, 5). Targeted sampling yielded no recaptures in Lake St. Clair. Recent sampling also occurred in the St. Clair River and yielded no captures. This trawling survey, however, occurred in the fall when water temperatures were low, and failure to capture Channel Darter may be due to environmental conditions (J. Barnucz, pers. comm.). Channel Darter has been captured in trawls in the American portion of the St. Clair River (Burkett and Jude 2015). Channel Darter has also been captured from new waterbodies since the publication of the previous report in 2002. In Quebec, seven new populations have recently been discovered in Blanche River (Thurso), Sainte-Anne River, du Loup River, Grande Yamachiche River, Jacques-Cartier River, Calumet and Pointe-au-Chêne (Table 2) (Boucher and Garceau 2010; Levert 2013; ZIP du lac Saint-Pierre 2013; WSP 2014). In addition, Channel Darter has recently (2009-2010) been collected from two new tributaries, Miscou River and Huron River, in the watersheds of du Sud River and du Chêne River, respectively. In Ontario, a new population of Channel Darter was discovered in the Salmon River in 2003 (Reid et al. 2005). In summary, new populations of Channel Darter continue to be discovered, thus, extending the known range of the species. It should be noted, however, that these new discoveries are more likely the result of increased sampling effort rather than increases in abundance or population expansions (Figures 4-6).

Extent of Occurrence and Index of Area of Occupancy were estimated using observations made from 1980-1999 and in the following decade, 2000-present, for each DU:

  • DU 1 – Lake Erie (EOO 1980-1999=1,828 km2; 2000-present= 2,918 km2: IAO 1980-1999= 80 km2; 2000-present= 180 km2)
  • DU 2 – Lake Ontario (EOO 1980-1999= 667 km2; 2000-present= 1,655 km2: IAO 1980-1999= 172 km2; 2000-present= 392 km2)
  • DU 3 – St. Lawrence (EOO 1980-1999= 47,000 km2; 2000-present= >53,215 km2: IAO 1980-1999= 5,620 km2; 2000-present= 7,664 km2). N.B. Does not include new records received after 2-Month Provisional Report.

Search effort

Recent search effort for Channel Darter is summarized in Table 1, focusing mostly, but not only, on sampling done since the last report (Phelps and Francis 2002). Targeted surveys for Channel Darter have been increasing in frequency and intensity in recent years. Note that detailed effort data are often lacking and that many surveys were designed only to confirm the presence of the species and, therefore, such sampling stopped once a specimen was found (e.g., Garceau et al. 2007). In a few cases, detailed effort information is available and we refer the reader to the original report for details. This is especially true of recent surveys (e.g., Reid and Mandrak 2008). In general, the effort and gear used varied between surveys, making comparisons difficult. Recent efforts, however, have been using standardized survey methods across different geographical areas and should make future assessments of relative abundance easier. For example, DFO has been conducting trawl surveys using a new method in the Huron-Erie Corridor and the Ottawa River (J. Barnucz, pers. comm.). Finally, the table reports effort for each population, but many sites were often visited for each population. In most cases, Channel Darter was only captured at a subset of the sites visited. Whenever information was available on the number of sites visited, we included it in the table.

Table 1. Summary of recent fish surveys, 1995-2013, in known areas of Channel Darter occurrence and sources of the information.

*Populations in bold were discovered since the publication of the previous COSEWIC report in 2002. Gear: a = backpack electrofisher, b = seine net; c = drift/kick net; d = boat electrofishing; e = trawl.

Table 1.1 Summary of recent fish surveys, 1995-2013, in known areas of Channel Darter occurrence and sources of the information. Designatable unit 1.
AreaPopulationYear of surveyCD targeted?GearQuantitySourceEffort or CPUE data?
Bay of Quinte DrainageMoira system: Moira, Skootamatta and Black Rivers2001, 2003yesa, b61Reid et al. 2005no
Bay of Quinte DrainageSalmon River2001, 2003yesa, b65Reid et al. 2005no
Bay of Quinte DrainageTrent River2002-2010yesa>20 / yearCoker and Portt 2011 Reid (unpublished data)Yes. Details in report.
Table 1.2 Summary of recent fish surveys, 1995-2013, in known areas of Channel Darter occurrence and sources of the information. Designatable unit 2.
AreaPopulationYear of surveyCD targeted?GearQuantitySourceEffort or CPUE data?
Lake Erie DrainageDetroit River2010-2011yese79 in 2011J. Barnucz pers. comm.170 x ~2min trawls in 2011
Lake Erie DrainageWestern basin: Pelee Island, Point Pelee, Holiday Beach2010yesb>50S. Reid pers. commno
Lake Erie DrainageCentral Basin: Port Burwell, Erieau2005-2006; 2007-2008yesb, d0;0Reid and Mandrak 2008; Yunker et al. 20092 to 5 seine hauls per site (13 sites); see report
Lake Erie DrainageEastern basin: Port Dover, Rondeau Bay2005-2006; 2007-2008yesb, d0;0Reid and Mandrak 2008; Yunker et al. 20092 to 5 seine hauls per site (11 sites); see report
Lake St. Clair DrainageSt. Clair River2010yese0J. Barnucz pers. comm.blank 
Lake St. Clair DrainageLake St. Clair2005, 2007-2011nob0M. Belore pers. comm.>600 seine hauls
Table 1.3 Summary of recent fish surveys, 1995-2013, in known areas of Channel Darter occurrence and sources of the information. Designatable unit 3.
AreaPopulationYear of surveyCD targeted?GearQuantitySourceEffort or CPUE data?
Ottawa River DrainageLittle Rideau Creek2010noa2S. Reid pers. comm.no
Ottawa and Montreal DrainageOttawa River2011yese144S. Reid pers. comm.no
Ottawa and Montreal DrainageOttawa River west of Gatineau2006yesa, d0Pariseau et al. 2009no
Ottawa and Montreal DrainageLake St. Louis1999nob41J. Boucher pers. comm.no
Ottawa and Montreal DrainageLake St. Louis1997, 2005blank blank 0blank blank 
Ottawa and Montreal DrainageGatineau River1995, 2000, 2012, 2013blank blank ≥ 1Table 2no
Ottawa and Montreal DrainageGatineau River2011yesa183S. Reid pers. comm.no
Ottawa and Montreal DrainageBlanche (Gatineau)2011, 2012yesa48Levert 2013213 plots surveyed; details in report
Ottawa and Montreal DrainageBlanche (Thurso)1995, 2000, 2013blank blank ≥ 1Table 2blank 
Ottawa and Montreal DrainageBlanche (Thurso)2011, 2012yesa38Levert 2013277 plots surveyed; details in report
Ottawa and Montreal DrainagePetite-Nation River1995, 2000, 2013blank blank ≥ 1Table 2no
Ottawa and Montreal DrainagePetite-Nation River2011, 2012yesa62Levert 2013325 plots surveyed; details in report
Ottawa and Montreal DrainageSaumon River2011, 2012yesa78Levert 2013361 plots surveyed; details in report
Ottawa and Montreal DrainageRouge River1995, 2006blank blank ≥ 1Table 2no
Ottawa and Montreal DrainageCalumet2006blank blank ≥ 1Table 2no
Ottawa and Montreal DrainagePointe-au- Chêne2006, 2007blank blank ≥ 1Table 2no
Southwest St. Lawrence River DrainageRichelieu River2009-2011
2012
nob29, 58, 34
≥ 1
N. Vachon pers. comm.
Table 2
no
no
Southwest St. Lawrence River DrainageChâteauguay River (inc. trib : aux Outardes, Trout, des Anglais)2006yesa≥ 1 per stationGarceau et al. 200716 stations sampled (350 m each)
Southwest St. Lawrence River Drainagedes Anglais2012yesa11Ambioterra 2013blank 
Southwest St. Lawrence River Drainagedes Anglais2013blank blank ≥ 1Table 2no
Southwest St. Lawrence River DrainageYamaska River2010-2011
2013
yesa2
Garceau et al. 2011
Table 2
26 sites visited
no
Southwest St. Lawrence River DrainageRivière Noir2013 (x2)yes; noa  b12; 57WSP 2014; HydroNet 20136 stations sampled; 30 stations sampled
Southwest St. Lawrence River DrainageSaint-François River2008-2009, 2011; 2012; 2013yesa  b12; 0; ≥ 1M.-A. Couillard pers. comm.; ZIP du lac Saint- Pierre 2013no; details in report
Southwest St. Lawrence River DrainageRivière aux Bleuets***2013yesa  b0WSP 20146 stations sampled
Southwest St. Lawrence River DrainageRivière Niger***2013yesa  b0WSP 20143 stations sampled
Southwest St. Lawrence River DrainageRivière aux Saumon (at Richmond)2013yesa  b0WSP 20143 stations sampled
Southwest St. Lawrence River DrainageRivière aux Saumon (at Weedon)2013yesa  b1WSP 20147 stations sampled
Southwest St. Lawrence River DrainageRivière Maskinongé***1996; 2012yesa, b0Desrochers et al. 1996; Table 2no
Southwest St. Lawrence River DrainageLake Saint-François1996, 2004blank blank 0Table 2no
Southwest St. Lawrence River DrainageLake Saint-François2009nob1M.-A. Couillard pers. comm.no
Southwest St. Lawrence River DrainageLake Saint-Pierre2010nob7M.-A. Couillard pers. comm.no
Southwest St. Lawrence River DrainageDownstream of Lake Saint-Pierre2001, 2008, 2012blank blank 0Table 2blank 
Southwest St. Lawrence River DrainageBécancour-Batiscan1996blank blank ≥ 1Table 2blank 
Southwest St. Lawrence River DrainageGrondines-Donnacona2006blank blank ≥ 1Table 2blank 
Southwest St. Lawrence River DrainageNicolet River2012; 2013yes; noa  b0; 38ZIP du lac Saint-Pierre 2013; HydroNet 2013Details in report; 30 stations sampled
Northwest St. Lawrence River DrainageL'Assomption River2002; 2009; 2010; 2011;  2012yesa  b8; 10; 5; 77; 2M.-A. Couillard pers.comm.; CARA 2013no
Northwest St. Lawrence River DrainageOuareau River2009;  2011; 2012yesa  b10; 6; ≥ 1CARA 2013no
Northwest St. Lawrence River DrainageBayonne River
Rivière Chicot***
1996; 2012
1996; 2012
?
no
b
?
5; ≥ 1
0; ≥ 1
M.-A. Couillard pers. comm.
J. Boucher pers. comm.
no
no
Northwest St. Lawrence River DrainageDu Loup River2012; 2013yesa  b6; 3ZIP du lac Saint-Pierre 2013; WSP 2014Details in report; 7 stations sampled
Northwest St. Lawrence River DrainageGrande Yamachiche River2012, 2013yesa  b1; 0ZIP du lac Saint-Pierre 2013; WSP 2014Details in report: 4 stations sampled
Northwest St. Lawrence River DrainageBatiscan River2013yesa  b11WSP 201414 stations sampled
Northwest St. Lawrence River DrainageJacques-Cartier River2003; 2013yesa  b1; 0M.-A. Couillard pers. comm.; WSP 2014no; 11 stations sampled
Northwest St. Lawrence River DrainageSaint-Anne River2002; 2013?; yes?; a  b1; 2Boucher and Garceau 2010; WSP 2014no; 15 stations sampled
Southeast St. Lawrence River DrainageBécancour River2013yesa  b≥ 1Table 2no
Southeast St. Lawrence River DrainageAux Orignaux River2013yesblank 0WSP 20144 stations sampled
Southeast St. Lawrence River DrainageAux Ormes River2013blank a  b2WSP 20146 stations sampled
Southeast St. Lawrence River DrainageGentilly River2013yesa  b6WSP 20145 stations sampled
Southeast St. Lawrence River DrainageDu Sud River2005; 2013yes; noa2; 29M.-A. Couillard pers. comm.; HydroNet 2013no; 30 stations sampled
Southeast St. Lawrence River DrainageBras Saint-Nicolas2012; 2013yesa5; 2OBV de la Côte-du-Sud 2013; Paradis 2014  Details in report; 10 stations sampled
Southeast St. Lawrence River DrainageDu Chêne River2005, 2010; 2013yesa  b≥ 1; 6Table 2; WPS 20147 stations sampled
Southeast St. Lawrence River DrainageHenri River2013yesa  b2WPS 20143 stations sampled

Table 2. Summary of occurrences of Channel Darter at 53 sample sites in the St. Lawrence DU. X=occurrence; 0=absent despite inventories directed on the species; (XXXX) =year of capture; FMN=data from the St. Lawrence ish Monitoring Network. The data from 1930-2009 is summarized in DFO (2013) and the 2010-2013 data is a recent unpublished compilation for which data are available at the Centre de données sur le patrimoine écologique du Quebéc.

Table 2.1 Summary of occurrences of Channel Darter at 53 sample sites in the St. Lawrence DU. St. Lawrence River.
Sample sites in the St. LawrenceWatercourseYears of confirmed Channel Darter occurrence

1930-1949
Years of confirmed Channel Darter occurrence

1950-1969
Years of confirmed Channel Darter occurrence

1970-1989
Years of confirmed Channel Darter occurrence

1990-2009
Years of confirmed Channel Darter occurrence

2010-2013
Lake St. FrançoisLake St. FrançoisRSIblank blank blank O (1996RSI, 2004RSI)
X (2009RSI)
blank 
Lake St. FrançoisLac St -LouisRSIX (1941)blank blank O (1997RSI, 2005RSI)
X (1999)
O (2011)RSI
Lake St. FrançoisPointe-du-BuissonX (1942)blank blank blank blank 
Lake St. FrançoisLachine RapidsX (1941)blank blank blank blank 
Lake St. PierreLake St. Pierreblank blank blank X (1995RSI, 2002RSI, 2006, 2007RSI)X (2010, 2012)MDDEFP
Lake St. PierreSt. Pierre archipelagoRSIblank blank blank O (1995RSI)
X (2001, 2003RSI)
X (2010)RSI
Lake St. PierrePort Saint-Françoisblank blank X (1972)O (1995)blank 
Downstream sectionBécancour-Batiscan sectionRSIblank blank blank X (1996RSI)
O (2001RSI, 2008 RSI)
O (2012)RSI
Downstream sectionGrondines-Donnacona sectionRSIblank blank blank X (1997RSI)
X (2006RSI)
blank 
Table 2.2 Summary of occurrences of Channel Darter at 53 sample sites in the St. Lawrence DU. Montreal and Ottawa drainage.
Sample sites in the St. LawrenceWatercourseYears of confirmed Channel Darter occurrence

1930-1949
Years of confirmed Channel Darter occurrence

1950-1969
Years of confirmed Channel Darter occurrence

1970-1989
Years of confirmed Channel Darter occurrence

1990-2009
Years of confirmed Channel Darter occurrence

2010-2013
Des Sept drainageBlanche River (Gatineau)blank blank blank X (1995, 2000)X (2011, 2012, 2013)Uni. Ottawa
Des Sept drainageGatineau Riverblank blank blank X (1999, 2002, 2003 2004)X (2013)MDDEFP
Du Lièvre drainageBlanche River (Thurso)blank blank blank blank X (2011, 2012, 2013)Uni. Ottawa
Rouge/Petite-Nation/Saumon drainageCalumet Creekblank blank blank X (2006)blank 
Rouge/Petite-Nation/Saumon drainagePetite Nation Riverblank X (1964)blank X (1995, 2000)X (2011, 2012, 2013)Uni. Ottawa
Rouge/Petite-Nation/Saumon drainagePointe-au-Chêne Riverblank blank blank X (2006, 2007)blank 
Rouge/Petite-Nation/Saumon drainageRouge Riverblank blank blank X (1995, 2006)blank 
Rouge/Petite-Nation/Saumon drainageSaumon River (or Kinonge River)blank blank blank X (1995, 2007)X (2011, 2012, 2013)Uni. Ottawa
Ottawa River drainageOttawa Riverblank blank XX (2006)blank 
Table 2.3 Summary of occurrences of Channel Darter at 53 sample sites in the St. Lawrence DU. Northwest St. Lawrence River drainage.
Sample sites in the St. LawrenceWatercourseYears of confirmed Channel Darter occurrence

1930-1949
Years of confirmed Channel Darter occurrence

1950-1969
Years of confirmed Channel Darter occurrence

1970-1989
Years of confirmed Channel Darter occurrence

1990-2009
Years of confirmed Channel Darter occurrence

2010-2013
Batiscan-Champlain drainageBatiscan Riverblank blank X (1973)blank X (2013)Génivar
Bayonne drainageBayonne Riverblank blank X (1971)X (1996)X (2012)MDDEFP
Bayonne drainageChicot RiverX (1941)blank X (1971)O (1996)O (2012)MDDEFP
Bassin versant L’AssomptionRivière L’Assomptionblank blank X (1981, 1987)X (1991, 2002, 2009)X (2010, 2011, 2012)CARA
L’Assomption drainageL’Assomption Riverblank blank X (1981)X (1990, 2002, 2009)X (2011, 2012)CARA
Du Loup/Yamachiche drainageRivière du Loupblank blank blank blank X (2012ZIP lac Saint-Pierre, 2013Génivar)
Du Loup/Yamachiche drainageGrande Yamachiche Riverblank blank blank blank X (2012)ZIP lac St-Pierre
O (2013)Génivar
Jacques-Cartier drainageJacques-Cartier Riverblank blank blank X (2003)O (2013)Génivar
Sainte-Anne drainageBlanche Riverblank blank blank X (2002)blank 
Sainte-Anne drainageNoire Riverblank blank blank blank X (2013)Génivar
Table 2.4 Summary of occurrences of Channel Darter at 53 sample sites in the St. Lawrence DU. Southwest St. Lawrence River drainage.
Sample sites in the St. LawrenceWatercourseYears of confirmed Channel Darter occurrence

1930-1949
Years of confirmed Channel Darter occurrence

1950-1969
Years of confirmed Channel Darter occurrence

1970-1989
Years of confirmed Channel Darter occurrence

1990-2009
Years of confirmed Channel Darter occurrence

2010-2013
Châteauguay drainageAllen Creekblank blank X (1976)blank blank 
Châteauguay drainageChâteauguay RiverX (1941, 1942, 1944)blank X (1976, 1987)X (2006)X (2012)MDDEFP
Châteauguay drainageDes Anglais Riverblank blank X (1976)X (1996, 2006, 2009)X (2010, 2011, 2012, 2013)Ambioterra
Châteauguay drainageAux Outardes River (East)blank blank X (1976)X (1996, 2002, 2006)blank 
Châteauguay drainageTrout RiverX (1941)blank X (1976)X (1996, 2006)X (2010)Ambioterra
Richelieu drainageRichelieu Riverblank blank blank X (1991, 1993, 1994, 1997, 1999, 2001, 2003, 2006, 2009)X (2010, 2011, 2012)MDDEFP
Saint-François drainageAux Bleuets Riverblank blank X (1977)O (1992, 1996)O (2013)Génivar
Saint-François drainageLake Elgin outlet (or Maskinongé River) drainageX (1934)blank blank O (1996)O (2012)MDDEFP
Saint-François drainageNiger RiverX (1931)blank blank O (1996)O (2013)Génivar
Saint-François drainageSt. François RiverX (1944)blank blank X (1998, 2003, 2008, 2009)X (2011MDDEFP, 2013MDDEFP+Odanak)
O (2012)ZIP lac St-Pierre
Saint-François drainageAux Saumons River (Richmond/Melbourne)X (1932)blank blank X (2009)O (2013)Génivar
Saint-François drainageAux Saumons River
(Weedon/Lingwick)
blank blank X (1977)blank X (2013)Génivar
Yamaska drainageNoire Riverblank X (1964)X (1987)X (1995)X (2013)Génivar, Hydronet
Yamaska drainageYamaska Riverblank X (1969)X (1971)X (1995)X (2010)MDDEFP
X (2012)MDDEFP
Table 2.5 Summary of occurrences of Channel Darter at 53 sample sites in the St. Lawrence DU. Southeast St. Lawrence River drainage.
Sample sites in the St. LawrenceWatercourseYears of confirmed Channel Darter occurrence

1930-1949
Years of confirmed Channel Darter occurrence

1950-1969
Years of confirmed Channel Darter occurrence

1970-1989
Years of confirmed Channel Darter occurrence

1990-2009
Years of confirmed Channel Darter occurrence

2010-2013
Bécancour drainageBécancour Riverblank X (1964)blank blank X (2013)MDDEFP
Bécancour drainageAux Orignaux Riverblank blank X (1975)blank O (2013)Génivar
Bécancour drainageAux Ormes RiverX (1941)blank blank blank X (2013)Génivar
Bassin versant BécancourGentilly RiverX (1941)blank blank blank X (2013)Génivar
Côte-du-Sud drainageBras Saint-Nicolasblank blank O (1975), X (1980)X (1997), O (2003, 2005, 2007, 2010)X (2012, 2013)OBV Côte-du-Sud
Côte-du-Sud drainageDu Sud RiverX (1941)X (1964) O (1988)O (1991, 1992,1996, 1997, 2004)
X (2005)
X (2013)Hydronet
Côte-du-Sud drainageMiscou River (tributary of Du Sud River)blank blank blank X (2009)blank 
Du Chêne drainageDu Chêne Riverblank blank X (1971)X (2007)X (2010, 2013Génivar)
Du Chêne drainageHenri Riverblank blank X (1971)blank X (2013)Génivar
Du Chêne drainageHuron Riverblank blank blank blank X (2010)MDDEFP
Nicolet drainageNicolet RiverX (1944)blank blank blank O (2012)ZIP lac St-Pierre
X (2013)MDDEFP, Hydronet

Habitat

Habitat requirements

The following sections describe the general habitat requirements for the different life stages of the Channel Darter. Note that specific locations identified as critical habitats have been listed in the Recovery Strategy (DFO 2013).

Adult habitats

Adult Channel Darter are found in small, medium, and large river habitats where the current is moderate and on lakeshore beaches with clean coarse sand and fine gravel (Phelps and Francis 2002; Bouvier and Mandrak 2010; Boucher and Garceau 2010). Reid (2004) used electrofishing to collect a total of 347 Channel Darter from riffle and shoal habitats in the Salmon and Trent rivers. Reid et al. (2005) examined associations between riffle characteristics (width, depth, velocity, conductivity, median particle size) and occurrence of adult Channel Darter in five rivers in the Lake Ontario basin. While they failed to identify a statistically significant difference between sites with and without adult Channel Darter, they did note that most captures took place where riffles flowed into deep sand-bottomed run or pool habitats. The upstream limit of distribution in four of those rivers was associated with impassable barriers. In Quebec, Boucher et al. (2009) examined the habitat requirements of Channel Darter in the Richelieu and Gatineau rivers. In the Gatineau River, the sites where Channel Darter was captured had significantly higher water velocities and increased presence of periphyton. In the Richelieu River, capture sites were shallower, had higher water velocity, and increased presence of woody debris. The only variable associated with Channel Darter presence in both rivers was water velocity, and most individuals were captured at sites with intermediate water velocities of 0.39-0.48 m/s. Boucher et al. (2009) suggested that these intermediate water velocities could represent a compromise between prey availability and energy expenditures required at high velocities. Alternatively, it has also been suggested that moderate velocities may help maintain a fine-sediment-free substrate, perhaps for spawning (Scott and Crossman 1973). In their survey of beach habitat of Lake Erie, Reid and Mandrak (2008) captured most individuals on coarse sand-fine gravel beaches. Channel Darter was also collected from one site characterized as a fine-sand beach (Reid and Mandrak 2008). The habitat preference of Channel Darter in four tributaries of the Ottawa River (Gatineau, Blanche (Thurso), Petite-Nation, Saumon) over three seasons (spring, summer, fall) was also recently examined (Levert 2013). In all four tributaries, Channel Darter was found over heterogeneous, coarse substrates (gravel, pebbles and cobble), a shallow gradient, and water velocities ranging from 0.25 to 1 m/s. However, substrate type appeared to be the only fixed variable in determining the presence of Channel Darter in all four tributaries, suggesting habitat preference may be less specific than what was described in previous studies (e.g., Boucher et al. 2009, Bouvier and Mandrak 2010).

Note that most sampling has been conducted in the summer months and that comparatively little appears to be known about the overwintering habitat requirements of the Channel Darter. Reid (2004) reported decreasing catch-per-unit-effort (CPUE) in late summer-fall, with the number of fish collected per minute (electrofishing) 66% lower in August (water temperature 22°C) compared to the spawning season. CPUE in October (7°C) further decreased and was 90% lower than during the spawning season. This would suggest that Channel Darter move to other river habitats during the winter months. Alternatively, Channel Darter may be less active and, thus, more difficult to catch, in the winter season. Reid and Mandrak (2008) also noticed a seasonal shift in Channel Darter capture rates in Lake Erie. The trend, however, appears to be reversed in the lacustrine habitat, with more individuals collected in the fall (27 Sept-12 Oct, 2005-2006) during night seining than in the spring (5-21 Jun). While this suggests a seasonal shift in habitat, it also suggests that this shift occurs differently in lacustrine and riverine habitats. Alternatively, it raises the possibility that, after the spawning season is over, Channel Darter migrate from running water to slower moving and deeper habitats. Branson (1967) observed movement from the main stems of a river in Oklahoma to quieter leaf and debris filled backwaters for overwintering.

Spawning habitats

Channel Darter spawns in the spring and early summer when water temperatures range between 14 and 26°C (Comtois et al. 2004; Reid 2004). In general, suitable spawning habitats appear characterized by moderate water velocities and a coarse substrate (Reid 2004; Lemieux et al. 2005; Boucher et al. 2009). In Quebec, one particular spawning site in the Gatineau River has been identified and repeatedly visited over the years and yields insight into the spawning requirements of the Channel Darter (Boucher and Garceau 2010). In 1999, seven males and one female in spawning condition were captured between May 20 and June 21, in water temperatures varying between 14 and 19°C and depth of capture varying between 0.5 and 5 m (Comtois et al. 2004). In 2003, spawning females and heavily pigmented males were observed in the same area between July 14 and 27 (J. Boucher, pers. comm.). However, individuals in spawning condition constituted a very small proportion of the catch at that time (2-5 possibly ripe individuals out of a total of 137 captured; J. Boucher, pers. comm.), perhaps suggesting that the spawning season was reaching its end. This is consistent with the observations of Reid (2004) who collected males in spawning condition and ripe females in the Trent River throughout June 2003 when water temperatures increased from 14.5 to 25°C. No Channel Darter in spawning condition were captured after July 4 (water temperature: 27°C) in the Trent River and after July 1 (26°C) in the Salmon River, suggesting that Channel Darter preferentially spawn in waters with temperatures of less than approximately 26°C. This is further supported by the observation that spawning in the Cheboygan River, Michigan, occurred a month earlier than in the Trent River, but was associated with similar temperatures (Winn 1953). Reid (2004) measured a series of habitat variables at the sites on the Trent River where gravid Channel Darter were captured. Those measurements suggested that spawning occurs at sites with mean mid-column water velocities of 0.46 m/s (range 0-1.0), mean water depths of 0.49 m (range 0.23-0.77), and coarse substrate (21% gravel, 64% cobble). These spawning conditions are comparable those observed in four tributaries of the Ottawa River [Gatineau, Blanche (Thurso), Petite-Nation, Saumon], where 22 males with spawning colouration were observed from June 26th and July 17th at shallow depths (0.14 – 0.50 m), in water velocities of 0.076 to 3.5 m/s with coarse substrates and temperatures ranging from 17.5 and 23.9 °C (Levert 2013).

Together, these observations from a variety of locations all support the importance of a coarse substrate and a moderate water velocity. This is further supported by Winn’s (1953) observation that spawning ceased in the Cheboygan River, after water flow became interrupted. Winn (1953) also observed multiple spawning events directly at this location and noted that eggs were deposited in coarse to fine gravel, but not in fine sand. Males also appeared to defend breeding territories, which were often centered on a large rock (Winn 1953).

Young-of-the-year (YOY) and juvenile habitat

Limited information exists on the habitat requirements of juvenile Channel Darter. A literature review by Lane et al. (1996) noted that the presence of juveniles was associated with substrates such as gravel and sand and, to a lesser degree, silt. They also noted that juveniles were more common in streams than in lakes (Lane et al. 1996). Eggs and larvae were collected at a spawning site in the Gatineau River (Lemieux et al. 2005). The larvae collected emerged from the eggs as sampling was occurring and it is unclear whether the larvae would have moved later to a different habitat (Lemieux et al. 2005). Using electrofishing in the Salmon and Trent rivers, Reid (2004) failed to capture Channel Darter that were less than one-year old, and only two individuals out of a total of 54 individuals aged were one-year old. All other individuals were two to five years old. This suggests that smaller individuals were either less susceptible to capture with the electrofishing method, or that juveniles use different habitats than adults.

Residence

Channel Darter does not construct residences during its life cycle.

Habitat trends

There has been a net loss of Channel Darter habitat due to agricultural activities and urban development throughout the Canadian range of the species. Deforestation associated with agricultural and urban development, and shoreline modifications along lakeshores have increased sedimentation and decreased the availability of the coarse substrate preferred by Channel Darter (BAPE 2003; Vachon 2003; Reid and Mandrak 2008). The moderate water velocities required for Channel Darter spawning have been altered in many areas by dams and impoundments (Reid 2006; Boucher and Garceau 2010). Decreased water quality (e.g., Berryman 2008; ECCC 2017) and invasive species (Reid and Mandrak 2008) may also have made some habitats less available to Channel Darter. For example, in Lake Erie, harmful algal blooms have been increasing in frequency and the summer of 2010 saw an unprecedented bloom of toxic blue-green algae (Lake Erie Lakewide Management Plan 2011). This is especially worrisome because the western basin of Lake Erie, home to the only remaining population of Channel Darter in Lake Erie, was most severely affected (Lake Erie Lakewide Management Plan 2011). Habitat availability in the American distribution of the Channel Darter has also been decreasing (Rudolph et al. 2001; NatureServe 2011).

In Quebec, increased environmental awareness has led to the implementation of mitigation measures that may have beneficial effects for habitat availability over the longer term. For example, along the Yamaska River, concerted effort by industries in the small city of Granby led to a significant reduction in the concentration of PCBs (Berryman 2008). Regulations have also been put in place regarding management of the shoreline, but compliance was still low as of 2004 (Sager 2004). More rules regarding the use of manure as fertilizer and maximum number of animals per area may reduce the environmental impact of pork production, but the impacts of this industry are likely to remain important (BAPE 2003). Finally, Hydro-Québec is becoming aware of the impacts of alterations to flow regimes brought about by dams and has commissioned at least one study to explore ways to regulate flow in a way as to preserve Channel Darter spawning opportunities (Lemieux et al. 2005).

In Ontario, a variety of measures have also been put in place to improve water quality in the Great Lakes (e.g., Koonce et al. 1996). For instance, a partnership has been established between Environment Canada and the Ontario Ministry of the Environment and Climate Change to coordinate the development and implementation of remedial actions for several Areas of Concern (AOCs) around the Great Lakes (ECCC 2010). These AOCs cover parts of the Ontario range of the Channel Darter and include the Bay of Quinte, Detroit River, and St. Clair River. For example, in the Bay of Quinte, actions led to a reduction of phosphorus loadings in the bay by 16 500 kg and sediment loadings by 12 000 T (Environment Canada and Ontario Ministry of the Environment 2011a). Actions were also undertaken to increase monitoring of fish habitats and to implement stricter regulations for pulp and paper mills in the region (Environment Canada and Ontario Ministry of the Environment 2011a). The effects of these actions on Channel Darter habitat are unknown. In the Detroit River, provincial Municipal/Industrial Strategy for Abatement (MISA) regulations were implemented, which contributed to significant reductions in persistent toxic substances (Environment Canada and Ontario Ministry of the Environment 2011b). Large-scale natural shoreline protection and restoration programs were also implemented to increase fish habitat in several municipalities bordering the river (Environment Canada and Ontario Ministry of the Environment 2011b) and this could have a beneficial impact on Channel Darter, although it has not been quantified. The range of Channel Darter in Ontario also falls under the jurisdiction of a number of conservation authorities whose role is to deliver services and programs that protect and manage water resources in given watersheds. For example, Quinte Conservation has jurisdiction over the Moira and Salmon rivers watershed and is responsible for shoreline habitat restoration projects. Those watersheds are severely impounded and no plans are in place to remove dams (B. McNevin, pers. comm.). Quinte Conservation does not have projects specifically targeting Channel Darter habitat (B. McNevin, pers. comm.).

Together, these mitigation measures may lead to an increase in habitat availability in the future, but the combined impacts of intensive agriculture and urban development will likely continue to be important.


Biology

The biology of Channel Darter was previously summarized by Goodchild (1994) and Phelps and Francis (2002). However, new studies have clarified some aspects of Channel Darter biology, particularly regarding its reproductive biology (e.g., Reid 2004; Boucher et al. 2009).

Feeding and nutrition

Channel Darter is a demersal fish that feeds primarily on benthic invertebrates (Scott and Crossman 1973; Goodchild 1994; Lapointe 1997). Gut analyses from Lake Erie, ON, Cheboygan River, MI, and the Ohio River suggest that Channel Darter feed predominantly on chironomid larvae (midge larvae), small trichopteran larvae (caddisfly larvae), ephemeropteran naiads (mayfly larvae) and, occasionally, ostracods (Turner 1921; Winn 1953, Page 1983; Strange 1997). Zooplankton and pupae comprise the remainder of the diet, although the proportion of these prey items consumed varies depending on the geographical locality of Channel Darter and the composition of the local invertebrate community (Strange 1997). Algae, organic matter, and debris have also been reported as food items for Channel Darter (Turner 1921; Goodchild 1994), although it is unclear whether these items are consumed incidentally while feeding on invertebrates or are deliberately ingested.

Dispersal and migration

The migration and dispersal of Channel Darter remains poorly understood. Channel Darter is found in both riverine and lacustrine habitats often associated with coarse substrates with moderate flow or wave action (Phelps and Francis 2002; Reid and Mandrak 2008; Bouvier and Mandrak 2010; Boucher and Garceau 2010). In rivers, Reid et al. (2005) frequently caught Channel Darter on coarse substrates near sandy runs or pools. Within lakes, Trautman (1981) observed daily movements of Channel Darter, finding them mainly at depths greater than 3 m during the day and under 1 m at night. Seasonal movements of Channel Darter remain poorly understood (Reid 2004; Reid and Mandrak 2008), although Branson (1967) suggested that Channel Darter utilize deep, debris-filled backwater pools as overwintering habitats. Evidence for overwintering dispersal also comes from decreasing catch-per-unit-effort at riverine sampling sites from August to October (Reid 2004). This was associated with a concomitant increase in CPUE in deeper riverine habitats, perhaps suggesting that Channel Darter overwinter in deeper riverine environments (Reid 2004).

Inter-specific associations and interactions

Channel Darter has been sampled in Ontario from areas associated with Logperch (Percina caprodes) and Mimic Shiner (Notropis volucellus) (Goodchild 1994) and, in Quebec, with Johnny Darter, Trout-perch (Percopsis omiscomaycus), and White Sucker (Catostomus commersonii) (Lapointe 1997). In four tributaries of the Ottawa River (Gatineau, Blanche (Thurso), Petite-Nation, Saumon) Channel Darter was mainly found in the presence of Logperch, Fantail Darter (Etheostoma flabellare), and Longnose Dace (Rhinichthys cataractae) (Levert 2013). In Bras St. Nicolas (tributary of du Sud River), it was found with Cutlip Minnow (Exoglossum maxillingua), Rock Bass (Ambloplites rupestris), Spottail Shiner (Notropis hudsonius), and Mimic Shiner (OBV de la Côte-du-Sud 2013). It has been suggested that in the areas where Johnny Darter and Logperch co-occur with Channel Darter, inter-specific competition for spawning territories may occur along with potential hybridization between these species (Goodchild 1994). The reproductive behaviours of Channel Darter and Johnny Darter, however, differ substantially (Grant and Colgan 1984) making hybridization between these species unlikely.

Predators of Channel Darter remain poorly understood. However, Reid (2005) found Channel Darter in the Trent River, ON in areas alongside Smallmouth Bass (Micropterus dolomieu) and Rock Bass, two piscivorous species (Scott and Crossman 1973). Therefore, it is possible that these predators prey on Channel Darter, although evidence for this is lacking.

Channel Darter overlaps in range with invasive Round Goby (Neogobius melanostomus), in areas of the St. Clair River, Lake St. Clair, Detroit River, Lake Ontario (around the Bay of Quinte), and the St. Lawrence River (Bernatchez and Giroux 2000; Phelps and Francis 2002; Reid 2006; Reid and Mandrak 2008; Boucher and Garceau 2010). Round Goby is a competitor for food and habitat resources (including spawning habitat) with Channel Darter (Baker 2005; Reid and Mandrak 2008). Additionally, it has been suggested that Round Goby is a possible predator of Channel Darter eggs and young (French and Jude 2001; Boucher and Garceau 2010; Bouvier and Mandrak 2010). Reid and Mandrak (2008) noted that, within Lake Erie, CPUE was highest for Channel Darter in areas where Round Goby CPUE was lowest, suggesting that Round Goby displaces Channel Darter where these two species co-occur. Burkett and Jude (2015) attributed significant declines in Channel Darter CPUE and >80% decline in Channel Darter relative abundance in the St. Clair River to the impact of Round Goby. Further evidence of invasive Round Goby displacing native benthic fishes has been reported in Canada, including instances of the displacement of several additional darter species (Thomas and Haas 2004; Baker 2005).

Life cycle and reproduction

Most Channel Darter become sexually mature after one year (although some individuals may take two years; Page 1983; Etnier and Starnes 1993) and specimens have been aged from two to five years old (Reid 2004). Mature spawning fish in Ontario ranged 46-71 mm TL (Reid 2006), with males generally attaining greater lengths than females (Scott and Crossman 1973; Reid 2006). Spawning takes place in spring and summer months when temperatures range from 14.5°C to 26°C (Comtois et al. 2004; Reid 2004), but the duration of the spawning season is believed to vary according to latitude, with more southern populations having a longer breeding season (Hubbs 1985). Along with temperature, water flow is an important cue for Channel Darter spawning, with measured water velocities in spawning habitat ranging from 0.24 to 0.60 m/s in the Gatineau River (Comtois et al. 2004). The importance of water flow is further supported by observations by Winn (1953) that, when water flow was restricted to spawning habitats, Channel Darter breeding behaviour ceased. Winn (1953) observed the spawning and courtship behaviour of Channel Darter in the Cheboygan River, Michigan and estimated that males established spawning territories of approximately 1 m2. Males select breeding territories composed predominately of cobble and pebble ranging 30-67% of the total substrate present (Comtois et al. 2004, Lemieux et al. 2005) and often have a large boulder present within their territories (Winn 1953). Winn (1953) observed that when females approached a male’s territory, he would try to drive her into the centre of his territory. Spawning takes place between rocks or in gravel when the female partially immerses herself in the substrate and the male is positioned above her, cradling her body between his pelvic fins with both the male and females caudal fins depressed together (Winn 1953). The eggs are immediately fertilized within such “nests”. Winn (1953) excavated three “nests” and determined that they contained 4-10 mildly adhesive eggs that were approximately 1.4 mm in diameter. Winn (1953) also noted that female Channel Darter mate with several males during the breeding season and estimated that females could lay up to 357-415 eggs per mating season. However, due to the communal spawning behaviour of Channel Darter, the number of males present may limit the females ability to lay all of her eggs (Goodchild 1994). There is no parental care of the eggs (Winn 1953) and little is known about juvenile Channel Darter, except that young-of-year appear to be found in sand and gravel areas (Lane et al. 1996).

Physiology and adaptability

There is no information available on the physiology and adaptability of Channel Darter, although inferences may be drawn from investigations of congeneric species. In an investigation of the sensory physiology and behaviour of Logperch, Bergstrom and Mensinger (2009) showed that this Percina species suffers weight loss in competition with the invasive Round Goby. This competitive disadvantage may be compounded in situations of low light, as Logperch was found to be less active and to have shorter prey strike distances than Round Goby at low light intensities (Bergstrom and Mensigner 2009).

In a study of Leopard Darter (P. pantherina), Schafer et al. (2003) suggested that use of deeper, cooler waters by this species in late summer suggests that thermal refugia may be important habitats for long-term management. This implies that this species does not rely on physiological adaptability (i.e., plasticity) to cope with temperature change, but rather behavioural response and the presence of thermal refugia is of primary importance.


Population sizes and trends

Sampling effort and methods

The number of surveys targeting Channel Darter increased substantially since the publication of the last COSEWIC report (Phelps and Francis 2002; Table 1). However, quantitative data allowing an assessment of abundanceremain scarce. Indeed, many of the surveys conducted were designed to confirm the presence of the species, not to measure abundance, and sampling would often stop as soon as one or a few specimens were identified in the interest of protecting the species and its habitat (J. Boucher, pers. comm.). Some surveys (e.g., Reid and Mandrak 2008) include catch-per-unit-effort that can allow an evaluation of relative abundance. Comparison among populations is difficult because of the different gear used and the different habitat sampled in the different surveys (see Table 1).

All the available information on population abundance and trajectories (prior to 2010) was summarized and integrated in a series of reports published by DFO (Boucher and Garceau 2010; Bouvier and Mandrak 2010; DFO 2010). Those reports develop qualitative indices that allow an evaluation of the relative status of populations. We refer the reader to the original reports for details regarding the methods. In short, a Relative Abundance Index (RAI) was assigned to each known population of Channel Darter as Low, Medium, High, Extirpated, or Unknown. The index is calculated relative to the population with the highest estimated abundance (Trent River in Ontario) and is based on sampling parameters such as gear used, area sampled, sampling effort, and whether the study was specifically targeting Channel Darter. Further, the lack of standardized sampling design forced the authors to assume that sampling in different habitats (large river, small river, lakes) and using different gear types yielded comparative results. Finally, each RAI was assigned a level of certainty from 1 to 3, according to the following criteria: 1 = quantitative analysis; 2 = CPUE or standardized sampling; 3 = expert opinion. The RAI was also complemented by a similar assessment of Population Trajectory, with each population being assessed as Decreasing, Stable, Increasing, or Unknown. This was also based on the best available knowledge regarding trends in the number of individuals caught over time for each population. Note that, because the authors of the report did not have access to information on some populations, they were not included in these analyses. The level of certainty of these estimates was assigned using the same scheme as with the RAI. Finally, the information of the RAI and Population Trajectory were combined in a single index of Population Status, describing each population as being Extirpated, or of Unknown, Good, Fair, or Poor condition. This status was assigned to populations according to the matrix presented in Table 3. The level of certainty assigned to the Population Status estimate is the lowest level of certainty associated with either of the initial ranks. Also, note that, because it relies on the RAI, the Population Status index is also relative, and a ‘Good’ designation simply implies that the population is doing better than others, not that it is not at risk of extinction.

Table 3. Matrix showing the relation between the Relative Abundance Index and the Population Trajectory Index in the calculation of the population status (from Bouvier and Mandrak 2010).
Relative Abundance Index (RAI)Population trajectory

Increasing
Population trajectory

Stable
Population trajectory

Decreasing
Population trajectory

Unknown
HighGoodGoodFairFair
MediumFairFairPoorPoor
LowPoorPoorPoorPoor
UnknownUnknownUnknownUnknownUnknown
ExtirpatedExtirpatedExtirpatedExtirpatedExtirpated

Table 4. Relative Abundance Index and Population Trajectory Index for populations of Channel Darter in Quebec and Ontario (modified from Bouvier and Mandrak 2010 and Boucher and Garceau 2010). Certainty: 1 = quantitative analysis; 2 = CPUE or standardized sampling; 3 = expert opinion.

Table 4.1 Relative Abundance Index and Population Trajectory Index for populations of Channel Darter in Quebec and Ontario (modified from Bouvier and Mandrak 2010 and Boucher and Garceau 2010). Designatable unit 1 - Lake Erie populations.
PopulationRelative Abundance Index (RAI)CertaintyPopulation trajectoryCertainty
Detroit RiverUnknown3Unknown3
Lake Erie Western basin: Pelee Island, Point Pelee, Holiday BeachMedium2Decline2
Lake Erie Central/Eastern basin: Port Dover, Port Burwell, Rondeau BayExtirpated2NA2
St. Clair RiveraUnknown NAblank UnknownNA
Lake St. ClairLow2Unknown2
Table 4.2 Relative Abundance Index and Population Trajectory Index for populations of Channel Darter in Quebec and Ontario (modified from Bouvier and Mandrak 2010 and Boucher and Garceau 2010). Designatable unit 2 - Lake Ontario populations.
PopulationRelative Abundance Index (RAI)CertaintyPopulation trajectoryCertainty
Moira system: Moira, Skootamatta and Black RiversHigh2Unknown2
Salmon RiverHigh2Unknown2
Trent RiverHigh2Decline2
Table 4.3 Relative Abundance Index and Population Trajectory Index for populations of Channel Darter in Quebec and Ontario (modified from Bouvier and Mandrak 2010 and Boucher and Garceau 2010). Designatable unit 3 – St. Lawrence populations.
PopulationRelative Abundance Index (RAI)CertaintyPopulation trajectoryCertainty
Lake Saint-LouisaUnknown NAblank UnknownNA
Gatineau Riverblank blank blank blank 
Blanche River (Gatineau)aNot AssessedNANotAssessedNA
Blanche River (Thurso)aNot AssessedNANot AssessedNA
Petite-Nation RiveraNot AssessedNANot AssessedNA
Saumon RiveraNot AssessedNANot AssessedNA
Rouge RiveraNot AssessedNANot AssessedNA
CalumetaNot AssessedNANot AssessedNA
Pointe-au- ChêneaNot AssessedNANot AssessedNA
Richelieu RiverHigh2Stable2
Châteauguay RiverMedium2Decline2
Yamaska RiverLow3Decline3
Saint-François RiverHigh2Stable2
Lake Saint-FrançoisaUnknownNAUnknownNA
Lake Saint-PierreaUnknownNAUnknownNA
Downstream of Lake Saint-PierreaNot AssessedNANot AssessedNA
Nicolet RiverUnknown3Unknown3
L'Assumption RiverMedium2Stable3
Bayonne RiverMedium2Stable3
Du Loup RiveraNot AssessedNANot AssessedNA
Grande Yamachiche RiveraNot AssessedNANot AssessedNA
Batiscan RiverUnknown3Unknown3
Jacques-Cartier RiverUnknown3Unknown3
Saint-Anne RiverUnknown3Unknown3
Bécancour RiverUnknown3Unknown3
Du Sud RiverLow2Decline2
Du Chêne RiverUnknown3Unknown3

a Populations not evaluated in Bouvier and Mandrak (2010) or Boucher and Garceau (2010).

Some important surveys have been conducted in a few locations since the 2010 reports (Boucher and Garceau 2010; Bouvier and Mandrak 2010; DFO 2010). First, a trawling survey of the Huron-Erie corridor (i.e. St. Clair River, Lake St. Clair, and Detroit River) was conducted 2009-2013 by DFO. This survey, which uses a new trawling technique (J. Barnucz, pers. comm.), allowed the capture of over 100 specimens over the last three years, all from the Detroit River. A similar technique has also been applied to the Ottawa River where 125 specimens were captured in 2011 (S. Reid, pers. comm.). Second, the Richelieu River has been the focus of intensive annual sampling as part of a study on Copper Redhorse (Moxostoma hubbsi) recruitment (N. Vachon, pers. comm.). These surveys used seine nets in the fall from 1999 to 2011 (except 2000, 2002, 2005) and captured a total of 200 Channel Darter over the nine years where sampling occurred (N. Vachon, unpubl.data). In addition, multiple surveys have recently been conducted (2010-2013) in Quebec to confirm the presence or absence of Channel Darter at new and historical sites. For example, in 2012 “La Comité ZIP du lac Saint-Pierre” conducted multiple surveys in tributaries of the St. Pierre River, and from 2012 to 2013 “L’Organisme des Bassins Versants (OBV) de la Côte-du-Sud” conducted surveys within the du Sud River. The Quebec government (MDDEFP) also surveyed several tributaries in 2012 and 2013 including Bayonne, Nicolet, Bécancour and Gatineau rivers.

Abundance

Abundance in populations of Channel Darter, evaluated according to the RAI described above, is summarized in Table 4. In summary, the areas where Channel Darter is found in greatest abundance are in the Bay of Quinte drainage in Ontario, and in the Ottawa River and southwestern St. Lawrence River drainage (with the exception of the Yamaska River) in Quebec. Abundance also appears to be high in the Ottawa drainage including the Gatineau, Blanche (Thurso), Blanche (Gatineau), Petite-Nation, and Saumon rivers; however, the RAI for these populations have not yet been assessed. The areas where Channel Darter is found in lowest abundance appear to be the populations in Lake Erie, Lake St. Clair and connecting rivers. Abundance in the southeastern St. Lawrence River drainage also appears low, although lack of information precludes assessment of many rivers in that drainage. More information would also be necessary to make an assessment of abundance in the northwestern St. Lawrence River drainage. Sites that have been sampled in that region, however, appear to show moderate abundance of Channel Darter.

Fluctuations and trends

Trends in population abundance, characterized according to the methods described in the above section, are summarized in Table 4 for each population in each of the Designatable Units. The trends in abundance suggest that the situation of the Channel Darter in Canada has deteriorated since the last COSEWIC report (Phelps and Francis 2002). First, no population appears to be increasing in abundance. Second, five populations were judged to be declining in abundance. Most of the declines are for populations already showing low abundance, which is worrisome for the long-term persistence of those populations. Even abundant populations, however, appear to show signs of declines. Most notably, the Trent River population, which is deemed to be the most abundant Ontario population, shows signs of declining abundance (S. Reid, pers. comm.).

Burkett and Jude (2015) reported significant declines in Channel Darter CPUE and >80% decline in Channel Darter relative abundance from trawls undertaken in offshore habitats in 3-11 m depths of the St. Clair River, adjacent to the Canadian side, from 1994 to 2011.

The Population Status index, which combines the information of the RAI and the Population Trajectory index, is shown for each population in Table 5 for each population in each of the Designatable Units: lacustrine populations in Ontario, and populations in the southwestern St. Lawrence River drainage show poorer population status than the Ottawa River or populations from the southwest St. Lawrence River drainage (again with the notable exceptions of the Yamaska and Châteauguay rivers).

Table 5. Population Status Index for populations of Channel Darter in Quebec and Ontario (modified from Bouvier and Mandrak 2010 and Boucher and Garceau 2010). Certainty: 1 = causative study; 2 = correlative study; 3 = expert opinion.

Table 5.1 Population Status Index for populations of Channel Darter in Quebec and Ontario (modified from Bouvier and Mandrak 2010 and Boucher and Garceau 2010). Designatable unit 1 – Lake Erie populations.
PopulationPopulation statusCertainty
Detroit RiverUnknown3
Western basin: Pelee Island, Point Pelee, Holiday BeachPoor2
Central/Eastern basin: Port Dover, Port Burwell, Rondeau BayExtirpated2
St. Clair RiverbUnknownNA
Lake St. ClairPoor2
Table 5.2 Population Status Index for populations of Channel Darter in Quebec and Ontario (modified from Bouvier and Mandrak 2010 and Boucher and Garceau 2010). Designatable unit 2 – Lake Ontario populations .
PopulationPopulation statusCertainty
Moira system: Moira, Skootamatta and Black RiversFair2
Salmon RiverFair2
Trent RiverFair2
Table 5.3 Population Status Index for populations of Channel Darter in Quebec and Ontario (modified from Bouvier and Mandrak 2010 and Boucher and Garceau 2010). Designatable unit 3 – St. Lawrence populations.
PopulationPopulation statusCertainty
Little Rideau CreekUnknown2
Ottawa RiverGood2
Lake Saint-LouisbUnknownNA
Gatineau RiverbUnknownNA
Blanche River (Gatineau)bNot AssessedNA
Blanche River (Thurso)bNot AssessedNA
Petite-Nation RiverbNot AssessedNA
Saumon RiverbNot AssessedNA
Rouge RiverbNot AssessedNA
CalumetbNot AssessedNA
Pointe-au- ChênebNot AssessedNA
Richelieu RiverGood2
Châteauguay RiverPoor2
Yamaska RiverPoor3
Saint-François RiverGood2
Lake Saint-FrançoisbUnknownNA
Lake Saint-PierrebUnknownNA
Downstream Lake Saint-PierrebNot AssessedNA
Nicolet RiverUnknown3
L'Assomption RiverFair2
Bayonne RiverFair2
Du Loup RiverbNot AssessedNA
Grande Yamachiche RiverbNot AssessedNA
Batiscan RiverUnknown3
Jacques-Cartier RiverUnknown3
Saint-Anne RiverUnknown3
Bécancour RiverUnknown3
Du Sud RiverPoor2
Du Chêne RiverUnknown3

b Populations not evaluated in Bouvier and Mandrak (2010) or Boucher and Garceau (2010).

In the absence of quantitative estimates of abundance or trends, it is difficult to evaluate the probability of extinction of the Channel Darter. Nevertheless, an analysis evaluating the recovery potential of Channel Darter based on stochastic models was performed by Venturelli et al. (2010) and offers some insights regarding the factors liable to render the species more vulnerable. We do not provide details on the methods, but simply summarize the salient points of the results. The analysis determined that any actions that would reduce the survival of Channel Darter in its first three years of life, or that would reduce the fecundity of first- and second-time spawners, would be particularly damaging to the demographic recovery of the species. The authors suggested that for a lacustrine population to remain demographically sustainable (i.e., have a 95% probability of persistence over 250 years), it should be composed of more than 6,800 adults and have access to up to 125.2 ha of suitable habitat (Venturelli et al. 2010). This is assuming that the probability of catastrophic declines (declines in population size of more than 50%) is 5% or less. While current knowledge does not allow us to evaluate whether extant populations have those characteristics or not, the numbers provide guidelines for future recovery targets. The authors also calculated that, assuming the population sizes are currently at 10% of the target population size, it would take 23 years for them to reach 95% of the target population size if they suffered from no additional harm or did not benefit from recovery actions (Venturelli et al. 2010). This time could be reduced by half in cases where recovery actions such as habitat restorations are implemented such that survival is improved by 10% (Venturelli et al. 2010).

Rescue effect

Limited data are available on the dispersal propensity of Channel Darter. Its disjunct distribution in Canada, however, suggests that movement between watersheds is fairly rare. Significant genetic differences at microsatellite loci observed between watersheds further suggest that dispersal is limited (Kidd et al. 2011). The potential for a rescue effect to mitigate extirpations or population decline would appear limited.

The Channel Darter is more widely distributed in the United States than in Canada. The only area where the Canadian and American distributions are adjacent is on the shores of Lake Erie and in the Detroit and St. Clair rivers, and some rivers in Quebec (e.g.,Châteauguay River). The Channel Darter is present on the southern shore of Lake Erie in the states of Michigan, Ohio, Pennsylvania, and New York. In all of these states, the Channel Darter is ranked by NatureServe as equally imperiled, or, in the case of Michigan, as more imperiled than in Ontario (see Table 7). Furthermore, the threats impacting Channel Darter on the Canadian and American sides of Lake Erie are likely similar. It, thus, appears unlikely that a rescue effect from American populations would have a significant mitigating impact on extirpations or population declines in Canada, even if those populations would likely be adapted to survive in Canada.


Threats and limiting factors

We first summarize the available information on all potential threats to Channel Darter currently identified in the literature. We then report a threat analysis performed in a series of recent reports published by DFO that provide a qualitative assessment of the relative importance of each threat for different populations of Channel Darter (Table 6).Finally, we provide a summary of the threats calculated separately for the three designatable units (Appendix 1-3).

Table 6. Threat status of each threat for populations of Channel Darter from Ontario and Quebec (modified from Bouvier and Mandrak 2010 and Boucher and Garceau 2010). The number in brackets refers to the level of certainty assigned to the Threat Status (1=causative studies; 2= correlative studies; 3=expert opinion).

Table 6.1 Threat status of each threat for populations of Channel Darter from Ontario and Quebec (modified from Bouvier and Mandrak 2010 and Boucher and Garceau 2010). Designatable unit 1 – Lake Erie populations .
PopulationTurbidity and sediment loadingContaminant and toxic substancesNutrient loadingShoreline modificationsAltered flow regimesBarriers to movementExotic species and diseasesIncidental harvest
Detroit RiverMedium (3)Medium (3)Medium (3)Medium (3)High (3)NAHigh (2)Low (3)
Western basin: Pelee Island, Point Pelee, Holiday BeachMedium (3)Unknown (3)Medium (3)High (2)NANAHigh (2)Low (3)
Central/Eastern basin: Port Dover, Port Burwell, Rondeau BayMedium (3)Unknown (3)Medium (3)High (2)NANAHigh (2)Low (3)
St. Clair River*Unknown (NA)Unknown (NA)Unknown (NA)Unknown (NA)Unknown (NA)Unknown (NA)Unknown (NA)Unknown (NA)
Lake St. ClairMedium (3)Low (3)Low (3)High (2)Unknown (3)NAHigh (2)Low (3)
Table 6.2 Threat status of each threat for populations of Channel Darter from Ontario and Quebec (modified from Bouvier and Mandrak 2010 and Boucher and Garceau 2010). Designatable unit 2 – Lake Ontario populations.
PopulationTurbidity and sediment loadingContaminant and toxic substancesNutrient loadingShoreline modificationsAltered flow regimesBarriers to movementExotic species and diseasesIncidental harvest
Moira system: Moira, Skootamatta and Black RiversLow (3)Low (3)Low (3)Low (3)Low (3)Medium (2)Low (3)Low (3)
Salmon RiverLow (3)Low (3)Low (3)Low (3)Low (3)Low (3)Low (3)Low (3)
Trent RiverMedium (3)Low (3)Low (3)Low (3)Medium (3)Medium (2)High (2)Low (3)
Table 6.3 Threat status of each threat for populations of Channel Darter from Ontario and Quebec (modified from Bouvier and Mandrak 2010 and Boucher and Garceau 2010). Designatable unit 3 – St. Lawrence populations.
PopulationTurbidity and sediment loadingContaminant and toxic substancesNutrient loadingShoreline modificationsAltered flow regimesBarriers to movementExotic species and diseasesIncidental harvest
Little Rideau CreekLow (3)Unknown (3)Unknown (3)Unknown (3)Unknown (3)Unknown (3)High (2)Unknown (3)
Ottawa RiverLow (2)Low (2)Low (2)Low (3)High (1)Medium (1)Unknown (3)Low (1)
Lake Saint-LouiscUnknown (NA)Unknown (NA)Unknown (NA)Unknown (NA)Unknown (NA)Unknown (NA)Unknown (NA)Unknown (NA)
Gatineau RivercUnknown (NA)Unknown (NA)Unknown (NA)Unknown (NA)Unknown (NA)Unknown (NA)Unknown (NA)Unknown (NA)
Blanche River (Gatineau)cNot AssessedNot AssessedNot AssessedNot AssessedNot AssessedNot AssessedNot AssessedNot Assessed
Blanche River (Thurso)cNot AssessedNot AssessedNot AssessedNot AssessedNot AssessedNot AssessedNot AssessedNot Assessed
Petite-Nation RivercNot AssessedNot AssessedNot AssessedNot AssessedNot AssessedNot AssessedNot AssessedNot Assessed
Saumon RivercNot AssessedNot AssessedNot AssessedNot AssessedNot AssessedNot AssessedNot AssessedNot Assessed
Rouge RiverNot AssessedNot AssessedNot AssessedNot AssessedNot AssessedNot AssessedNot AssessedNot Assessed
CalumetcNot AssessedNot AssessedNot AssessedNot AssessedNot AssessedNot AssessedNot AssessedNot Assessed
Pointe-au- ChênecNot AssessedNot AssessedNot AssessedNot AssessedNot AssessedNot AssessedNot AssessedNot Assessed
Richelieu RiverMedium (2)Medium (1)Medium (1)Medium (2)Low (3)Low (1)Unknown (2)Low (1)
Châteauguay RiverMedium (2)Medium (1)Medium (1)High (3)Low (3)Medium (1)Unknown (2)Low (1)
Yamaska RiverHigh (2)High (1)High (1)Low (3)Medium (3)Low (1)Unknown (2)Low (1)
Saint-François RiverMedium (2)Medium (2)Low (2)Low (2)High (2)High (2)Unknown (3)Low (1)
Lake Saint-FrançoiscUnknown (NA)Unknown (NA)Unknown (NA)Unknown (NA)Unknown (NA)Unknown (NA)Unknown (NA)Unknown (NA)
Lake Saint-PierrecUnknown (NA)Unknown (NA)Unknown (NA)Unknown (NA)Unknown (NA)Unknown (NA)Unknown (NA)Unknown (NA)
Downstream Lake Saint-PierrecNot AssessedNot AssessedNot AssessedNot AssessedNot AssessedNot AssessedNot AssessedNot Assessed
Nicolet RiverMedium (2)Medium (2)Medium (2)Medium (2)Unknown (2)Low (2)Unknown (3)Low (1)
L'Assomption RiverMedium (2)Medium (2)Medium (2)Medium (2)Low (2)Low (2)Unknown (3)Low (1)
Bayonne RiverMedium (2)Medium (2)Medium (2)Medium (2)Low (2)Low (2)Unknown (3)Low (1)
Du Loup RivercNot AssessedNot AssessedNot AssessedNot AssessedNot AssessedNot AssessedNot AssessedNot Assessed
Grande Yamachiche RivercNot AssessedNot AssessedNot AssessedNot AssessedNot AssessedNot AssessedNot AssessedNot Assessed
Batiscan RiverLow (2)Low (2)Low (2)Low (2)Unknown (2)Unknown (2)Unknown (3)Low (1)
Jacques-Cartier RiverLow (2)Low (2)Low (2)Unknown (3)Unknown (3)Unknown (2)Unknown (3)Low (1)
Saint-Anne RiverLow (2)Low (2)Low (2)Unknown (3)Unknown (3)Unknown (2)Unknown (3)Low (1)
Bécancour RiverMedium (2)Medium (2)Medium (2)Medium (2)Unknown (2)Unknown (2)Unknown (3)Low (1)
Du Sud RiverMedium (3)Medium (3)Medium (3)Medium (3)Medium (2)Unknown (2)Unknown (3)Low (1)
Du Chêne RiverUnknown (3)Unknown (3)Unknown (3)Unknown (3)Low (2)Low (2)Unknown (3)Low (1)

c Populations not evaluated in Bouvier and Mandrak (2010) or Boucher and Garceau (2010).

Table 7. Global, national, and subnational heritage ranks of the Channel Darter Percina copelandi (NatureServe 2011).
Rank LevelRankdJurisdictions
GlobalG4 (24 Sept 1996)blank 
NationalN3Canada
NationalN4United States
SubnationalS1Vermont
SubnationalS1S2Louisiana, Michigan
SubnationalS2Indiana, New York, Ohio, Pennsylvania, Virginia, Ontario
SubnationalS2S3Tennessee, West Virginia, Quebec
SubnationalS3Kansas, Missouri
SubnationalS4Arkansas, Kentucky

d 1 G4/N4/S4 – Apparently Secure: Uncommon but not rare; some cause for long-term concern due to declines or other factors; N3/S3 – Vulnerable: Vulnerable in the nation/state or province due to a restricted range, relatively few populations (often 80 or fewer), recent and widespread declines, or other factors making it vulnerable to extirpation; S2 – Imperilled: Imperilled in the state or province because of rarity due to very restricted range, very few populations (often 20 or fewer), steep declines, or other factors making it very vulnerable to extirpation from the state or province; S1 – Critically Imperilled: Critically imperilled in the state or province because of extreme rarity (often 5 or fewer occurrences) or because of some factor(s) such as very steep declines making it especially vulnerable to extirpation from the state or province. For more information on ranking see: NatureServe Explorer - Glossary.

Turbidity and sediment loading
Channel Darter appears to display a strong preference for gravel or coarse sand substrate for spawning and few individuals are captured in silt or fine sand habitats (Winn 1953; Reid et al. 2005; Reid and Mandrak 2008). Coarse substrate may be necessary for spawning and egg survival, and increased sedimentation and siltation could increase egg mortality (Winn 1953; Vachon 2003). Furthermore, it has been suggested that increased siltation and turbidity may reduce the availability of the Channel Darter’s preferred benthic prey (Goodchild 1994; Lapointe 1997; Phelps and Francis 2002). Correlative evidence for links between increasing sediment loading and turbidity and decreased Channel Darter abundance come from two studies in the United States. In the Ohio River, a decline in Channel Darter abundance appears to have coincided with increased sedimentation and turbidity caused by the construction of impoundments (Trautman 1981). In a study of the effect of siltation on fish communities in Missouri streams, Berkman and Rabeni (1987) found the benthic insectivore feeding guild (the guild to which Channel Darter would belong) to be the most heavily impacted by increased sediment loading. Agricultural practices and urbanization have led to increased sediment loading and turbidity over much of the Canadian range of the Channel Darter (Vachon 2003). For example, 47% of the Yamaska River drainage is agricultural land (Berryman 2008). Moreover, more than half of this agricultural land is made up of high intensity cultures like corn, which is cultivated in such a way that much of the land is tiled, which greatly increases runoff and erosion (Berryman 2008). Turbidity is also a problem along many stretches of the Yamaska River (Berryman 2008). While the Yamaska River is probably one of the most polluted rivers in Quebec, other rivers suffer from similar problems, albeit of smaller magnitude (e.g., Simoneau and Thibault 2009).
Alteration of flow regimes
Based on the evidence that all known Channel Darter spawning grounds are located in rivers with moderate water flow velocity and that spawning has been observed to cease when water flow stops (Winn 1953), alteration of flow regimes during the spawning period (May to July) would appear to pose an important threat to riverine populations of Channel Darter populations (little is known about spawning sites of lacustrine populations). Dams modify flow regimes and constitute a threat for some populations of Channel Darter, particularly in the Moira and Trent river populations in Ontario (Reid 2006; Bouvier and Mandrak 2010). For example, along the Trent-Severn Waterway, Reid (2005) observed temporary (1-2 h) drops in water levels (0.3-0.5 m) downstream of navigational dams. Those drops in water level caused large portions of shoals and nearshore habitats to be exposed. In October, portions of the river where Channel Darter were captured in the summer appeared completely dry. Another extreme dewatering event was observed on the Trent River in 2010 (S. Reid, pers. comm.) when extensive dewatering of tailwater habitats downstream of a dam stranded several Channel Darter individuals. The dewatering led to an investigation by OMNRF, DFO, and Parks Canada Agency, but no charges were laid under the ESA or SARA (S. Reid, pers. comm.). Exposure and dewatering of spawning habitats would result in mortality of eggs incubating in the gravel and could, thus, constitute an important threat to those populations. In Quebec, several rivers also have dams in place (e.g., Gatineau, Ottawa, Yamaska, Saint-François) and alteration of flow regimes could constitute an important threat. Severe dewatering was observed in in the Gatineau River below Farmers Rapid dam on September 26, 2016 (Simon Nadeau, pers. comm.).. In 2005, a study commissioned by Hydro-Québec focused on the Channel Darter spawning grounds adjacent to the power plant in the Farmers Rapids sector of the Gatineau River (Lemieux et al. 2005). The study did not report exposed or dry areas, but outlined the flow requirements and the critical periods for Channel Darter spawning. The report recommends flow-rate management plans compatible with the survival and spawning requirements of the Channel Darter (Lemieux et al. 2005). Another potential cause of flow alteration would be the modification of streams for agriculture activities. Although the creation and modification of streams is important, at least in Quebec (BAPE 2003), there is little information on its direct consequences for flow regime alterations in general, and its impact on Channel Darter in particular.
Shoreline modifications
Shoreline modifications can impact Channel Darter in both their riverine and lacustrine habitats, although effects on lacustrine populations appear more severe. In rivers, Channel Darter prefers habitats with moderate water-flow velocities and coarse substrate and only spawn during periods when the water temperature is between 14 and 26°C (Comtois et al. 2004; Reid 2004). Deforestation of riparian strips can lead to increased sedimentation, increased runoff of manure and fertilizers, and an increase in water temperature (Vachon 2003); effects that can potentially alter Channel Darter preferred habitats. In lakes, Channel Darter prefers nearshore habitats characterized by coarse sand substrate (Reid and Mandrak 2008). The construction of groynes, jetties, marinas, docks, and breakwaters modify shorelines and nearshore sediment transport (Edsall and Charlton 1996; Reid and Mandrak 2008), which can destroy Channel Darter habitat. Note that a major consequence of shoreline modification is increased sedimentation, a topic covered in a previous section. Lakes Erie and St. Clair have been subjected to extensive shoreline modifications. For instance, a large portion of the Lake St. Clair shoreline has been artificially hardened, filled, or dredged (EERT 2008; Bouvier and Mandrak 2010) and is no longer suitable habitat for Channel Darter. Reid and Mandrak (2008) noted that the extirpation of Channel Darter from two historical sites in Lake Erie might have been related to the construction of jetties that created large sand depositions. In Quebec, deforestation of riparian strips to increase cropland is a problem in the region where Channel Darter is found (FAPAQ 2002; BAPE 2003; Vachon 2003) and Quebec’s policies and regulations regarding shorelines and littoral zones have not been applied very extensively as of 2004 (Sager 2004).
Invasive species and disease
The Round Goby, an invasive species from the Ponto-Caspian region, is established in the Great Lakes and St. Lawrence River (Bernatchez and Giroux 2000; Corkum et al. 2004) and has recently colonized the Trent River (S. Reid, pers. comm.). Being a small benthic fish, it has been suggested that the Round Goby may compete with the Channel Darter for space and resources (Phelps and Francis 2002; French and Jude 2001). Fish eggs are commonly found in the stomachs of Round Goby and, thus, predation on Channel Darter eggs is also a risk (Corkum et al. 2004). Compelling evidence for the importance of this threat to Channel Darter comes from Reid and Mandrak (2008), who found that Channel Darter CPUE was highest when Round Goby CPUE was lowest in targeted sampling in Lake Erie. Burkett and Jude (2015) attributed significant declines in Channel Darter CPUE and >80% decline in Channel Darter relative abundance in the St. Clair River to the impact of Round Goby. In addition, a short time series of Channel Darter abundance during the current Round Goby invasion in the Trent River shows strong negative correlations (S. Reid, pers. comm.).
Barriers to movement
There is some evidence that Channel Darter use different habitats for spawning and for overwintering (Branson 1967; Goodchild 1994). Maintenance of movement potential between these habitats could be important. At a larger scale, exchange of migrants between populations may be important, and fragmentation could have detrimental demographic and genetic consequences. Dams are important barriers to movement and are found on many of the rivers inhabited by Channel Darter, both in Quebec (Boucher and Graceau 2010) and Ontario (Reid 2006). Other structures, such as poorly constructed culverts or bridges, can provide important obstacles to movement (Boucher and Garceau 2010). There is little direct evidence that such structures impact Channel Darter, but Reid et al. (2005) suggested that man-made structures in the Moira system might influence the current distribution of Channel Darter. Such barriers may also slow the spread of aquatic invasive species such as Round Goby.
Nutrient loading
Increased nutrient levels can lead to the development of algal blooms, which leads to depletion of dissolved oxygen (EERT 2008; Lake Erie Lakewide Management Plan 2011). While we could not find data specifically evaluating the impact of decreased oxygen levels of Channel Darter, it is assumed that their effects would be detrimental. In Quebec, excess fertilizer runoff in rivers from intensive agriculture is a well-documented problem (FAPAQ 2002). Many of the rivers inhabited by Channel Darter are in important areas of pork production, an industry with demonstrated impacts on aquatic environments (BAPE 2003). For example, it has been estimated that 67% of the phosphorus present at the mouth of the Yamaska River is of agricultural origin (Berryman 2008). In Ontario, the range of Channel Darter is also found in important agricultural areas where manure and fertilizer runoffs are common (EERT 2008). In addition, nutrient input from sewage treatment is observed (EERT 2008). In Lake Erie, harmful algal blooms have recently increased, probably because of increased temperature and increased nutrient loadings in at least two rivers (Lake Erie Lakewide Management Plan 2011).
Incidental catches
Federal and provincial regulations prevent the harvest of Channel Darter in both Quebec and Ontario. However, the distribution of Channel Darter overlaps with that of other small fishes targeted by the commercial baitfish fishery. Incidental captures could, thus, represent a risk for Channel Darter. This risk has been specifically evaluated in Quebec through a sampling program aiming to quantify the presence of species at risk in the commercial catches (Boucher et al. 2006). No specimens of Channel Darter were observed in the 41,500 fishes sampled (Boucher et al. 2006), suggesting that the threat associated with this activity is low. In Ontario, the risk associated with incidental catches has not been quantitatively evaluated, but is believed to be low as well (Bouvier and Mandrak 2010).
Contaminants and toxic substances
There is no direct evidence allowing for an evaluation of the effects of contaminants and toxic substances on Channel Darter. Areas surrounding Lake St. Clair, however, have increased levels of toxic substances that have been demonstrated to have an impact on the fish community as a whole (ECCC 2017). Both the St. Clair and Detroit rivers are Areas of Concern recognized by Environment and Climate Change Canada and the Ontario Ministry of the Environment and Climate Change. As such, they are being monitored and remediation actions are currently underway (ECCC 2017). Rivers in Quebec, such as the Yamaska, also have high levels of toxic substances where they flow close to urban areas (Berryman 2008).
Climate change
While climate change has been identified as a potential threat in previous reports (e.g., Bouvier and Mandrak 2010), the paucity of information on the topic makes its evaluation difficult. Some climate models predict a general drop in water levels in lakes and rivers in the range of the Channel Darter, which could severely impact habitat availability. For example, a recent habitat assessment of the Huron-Erie corridor estimated from climate models that the water levels in Lake St. Clair could decrease by as much as 1 m within the next 50 years and that variability in water levels could increase (Mackey et al. 2006). Because Lake St. Clair water levels show a great deal of natural fluctuations (by as much as 2 m), it is unclear what the consequences of decreased water levels and increased variation may be for fish habitats in general and for Channel Darter in particular (Mackey et al. 2006). Climate change, by increasing water temperatures, is also expected to favor the development of hypoxic (low oxygen) conditions in Lake Erie (Lake Erie Lakewide Management Plan 2011). Increased precipitation expected with climate change could also increase runoff of nutrients, further exacerbating hypoxic conditions.

Threat level

To evaluate the relative importance of these threats for each population of Channel Darter, a qualitative index was developed in a recent series of reports published by the DFO (Bouvier and Mandrak 2010; Boucher and Garceau 2010; DFO 2010). The methods used to develop this index is similar to that used for the indices of abundance discussed in a previous section. First, threat likelihood (i.e., whether the occurrence of a specific threat was documented for that particular population) was evaluated for each threat in each population. Second, threat impact (i.e., whether a specific threat is likely to have an impact for that particular population) was also evaluated for each threat in each population. The certainty of both was evaluated as follows: 1 = causative studies; 2 = correlative studies; and 3 = expert opinion. Threat likelihood and threat impact were then combined into a single index of Threat Status, which evaluates each threat as posing a High, Medium, Low, or Unknown risk to a particular population. The level of certainty assigned to the Threat Status estimates corresponds to the lowest level of certainty assigned to either of the initial indices. Only the Threat Status index presented for each population (Table 6), classified by drainage, but tables presenting values of threat likelihood and threat impact can be found in Bouvier and Mandrak (2010) and Boucher and Garceau (2010), along with further details regarding methods and full bibliographic information on the references used to evaluate the threats.

DU 1 – Lake Erie

The primary threats in this DU are invasion of Round Goby, shoreline modifications, and altered flow regimes, which have been assessed as high (Table 6). Threats associated with turbidity, altered flow regimes and barriers, nutrient loading, and contaminants/toxic substances have been assessed as medium across all locations where information is available (Table 6). The threats calculator ranked the overall threats for this DU as high with the invasive species category having a high impact ranking, the pollution category having a medium impact ranking, and the remaining evaluated categories having negligible rankings (Appendix 1).

DU 2 – Lake Ontario

The greatest threat in this DU is spatially restricted to the Trent River system where recent data clearly show that the invasive Round Goby population is rapidly growing resulting in declines in Channel Darter abundance (S. Reid, pers. comm.) and, therefore, a threat status of high (Table 6). Dams on the Moira and Salmon rivers have isolated upstream waters form Round Goby invasion. Other threats across this DU include those associated with turbidity, altered flow regimes and barriers, nutrient loading, and contaminants/toxic substances. These are geographically variable over the DU but have been assessed as low to medium threat status (Table 6). The threats calculator ranked the overall threats for this DU as medium with the invasive species category having a medium impact ranking and the remaining evaluated categories having negligible rankings (Appendix 2).

DU 3 –St. Lawrence

Threats are geographically variable across locations within this DU. Turbidity, altered flow regimes and barriers, nutrient loading, and contaminants/toxic substances are variable geographically over the DU and have been assessed as low to medium threat status (Table 6). The invasive Round Goby is now widespread in the St. Lawrence portion of this DU and Boucher and Garceau (2010) argued that it represents a major threat to Channel Darter. Yet, lack of specific information on Round Goby within this DU led Boucher and Garceau (2010) to rate this threat as unknown. We, therefore, conclude that the impacts of this invasive species are not as advanced as in other DUs, but that the threat is likely imminent. The threats calculator ranked the overall threats for this DU as high-medium with the invasive species category having a high impact ranking, the pollution category having a medium impact ranking, and the remaining evaluated categories having negligible rankings (Appendix 3).


Aboriginal traditional knowledge

The status of Aboriginal traditional knowledge for the Channel Darter was unknown at the time of writing (N. Jones, pers. comm.).


Protection, status, and ranks

Legal protection and status

The Channel Darter is listed as Threatened under Schedule 1 of SARA. In Ontario, the species is listed as Threatened under the ESA. In Quebec, the species is listed as ‘Vulnérable’ under the Loi sur les Espèces Menacées ou Vulnérables. The Channel Darter is not listed under the American Endangered Species Act, and it is neither a candidate nor is it proposed for listing.

In Quebec, a recovery strategy was published in 2001 (Équipe de rétablissement du fouille-roche gris 2001). The document recommended: (1) to improve knowledge of the species; (2) to protect known habitats; (3) to improve known habitats; and, (4) to restore perturbed habitats. In Ontario, no recovery strategy is yet in place for Channel Darter (S. Gibson, pers. comm.). Federally, a Recovery Potential Assessment document was published in 2010 (DFO 2010) and a Recovery Strategy was published in 2013 (DFO 2013). Those documents provide a full list of actions already under way, as well as actions that are planned for the future. Here, we only provide a summary of those actions. First, several studies have been undertaken since the publication of the previous report that significantly improve our knowledge of the species’ distribution, habitat requirements, and potential threats. These studies are cited in the present report. Second, several watershed- and ecosystem-based recovery strategies are now in place, notably in the Essex-Erie region (Lake St. Clair, Detroit River and Lake Erie populations; EERT 2008), Walpole Island (Lake St. Clair population; Bowles 2005), and the Outardes Est and Gatineau watersheds. Third, both provinces addressed the potential impact of commercial baitfish fishing (Boucher et al. 2006; Cudmore and Mandrak 2011). Fourth, efforts have been made to educate the public through an educational fact sheet produced by DFO (http://www.qc.dfo-mpo.gc.ca/publications/species-especes/fouille-channel-eng.asp).

The Recovery Strategy also identifies future actions and strategic direction for recovery (DFO 2013). The document recommends that actions be undertaken to address five categories of objectives: (1) Research; (2) Monitoring; (3) Management and Coordination; (4) Protection, Restoration and Stewardship; and, (5) Communication and Public Awareness. The Research objectives include plans to increase knowledge of the species’ biology, habitat and threats, but also to evaluate the potential of the species for re-establishment and captive breeding. For Monitoring, it is recommended that existing and historical capture localities be sampled regularly, but also that potential new sites be explored based on what is already known on the species’ habitat requirements. In terms of Management and Coordination, it is recommended that the different levels of government in Canada coordinate their efforts with those of NGOs and American agencies. Specific recommendations are also made regarding the planning and permitting of projects that may affect Channel Darter habitat and regarding the flow requirements of the species and how hydroelectric dams and navigable waterways could be managed to mitigate their impacts on the species. Several approaches are recommended for the protection and restoration of Channel Darter habitat and aim to encourage stewardship and Best Management Practices among the agricultural, waterpower, urban, and industrial sectors operating in watershed where the species is found. Finally, the need for communication with industry, municipalities and the public is stressed.

Non-Legal status and ranks

The Channel Darter is not listed in the IUCN Red List of Threatened Species. NatureServe (2011) gives a global rank of G4 to the species (i.e., the species is apparently secure). The species is not listed in the American Fisheries Society Endangered Species Committee list of imperilled freshwater and diadromous fishes of North America (Jelks et al. 2008). In Canada, the species is ranked as N3 (i.e., vulnerable), in Ontario as S2 (i.e., imperilled) and in Quebec as S2S3 (i.e., vulnerable to imperilled). Table 7 lists the NatureServe ranks of the species in all national and subnational jurisdictions where the species occurs.

Habitat protection and ownership

The protection afforded by the federal Fisheries Act is uncertain because the Channel Darter is unlikely to be considered to be of direct significance to Commercial, Recreational, or Aboriginal (CRA) fisheries. It may, however, receive protection if they can be demonstrated to be supporting a CRA fishery species.

Channel Darter received habitat protection due to its listing under the ESA in Ontario as of June 2013. In Quebec, the Règlement sur les habitats fauniques of the Loi sur la conservation et la mise en valeur de la faune can offer habitat protection on public lands, but it requires that the habitat characteristics of the species be identified and published in the Gazette Officielle du Québec, which has not been done yet for the species (J. Boucher, pers. comm.). Although the Channel Darter is listed as Threatened under Schedule 1 of SARA, critical habitat for the species will not be protected until an Order has been put in place for national parks and wildlife areas within 90 days after the federal Recovery Strategy is posted to the SARA Registry and for all other areas within 180 days. The Recovery Strategy (DFO 2013) identifies critical habitats for the species, which should receive appropriate protection.

Many provincial regulations and policy directly or indirectly protect Channel Darter habitat. COSEWIC (2009) reviewed these regulations with respect to Eastern Sand Darter (Ammocrypta pellucida) and these have been adapted to apply to Channel Darter. Several provincial laws and policies indirectly protect Channel Darter. In Ontario, fish habitat provisions of the Provincial Policy Statement (PPS) under the provincial Planning Act provides adjacent lands with policy-level protection. Channel Darter habitats may also be indirectly protected by the Lakes and Rivers Improvement Act when applications for the construction or maintenance of dams and dredging activities are reviewed. Channel Darter habitats may also be indirectly protected by several aspects of the Nutrient Management Act, Environmental Protection Act, Water Resources Act, and Source Water Protection Act. In Quebec, fish habitat protection is provided under the Loi sur la Conservation et la Mise en Valeur de la Faune and the Loi sur la Qualité de l’Environnement. Policy level indirect protection is also afforded through the ‘Politique de Protection des Rives, du Littoral, et des Plaines Inondables’ as well as a regulation framework dealing with municipal and urban planning.

Finally, parks protect a very small portion of the range of Channel Darter. The Channel Darter occurs in two federally protected areas in Ontario: Point Pelee National Park, and Trent-Severn Waterway National Historic Site (Mandrak and Brodribb 2006). Habitat protection is provided in those two sites by the Canada National Parks Act and by the Department of Transport Act (Historic Canals Regulations), respectively.


Acknowledgements and authorities contacted

The authors would like to acknowledge the help of many individuals who answered requests and gave access to data, all listed below. Special thanks go to a few of these people who spent significant amounts of time providing us information. Lynn Bouvier provided contact information for most of the authorities contacted. Julie Boucher answered almost daily e-mails at one point and always did so promptly. Erling Holm answered questions about the ROM records. Nicholas Mandrak and Scott Reid thoroughly reviewed an earlier version of the report, reviewed the list of collection sites, and pointed out some serious omissions. Jenny Wu prepared the maps and calculated the IAO and the EO.

Authorities contacted

Jason Barnucz, Aquatic Science Biologist, Great Lakes Laboratory for Fisheries and Aquatic Sciences, Fisheries and Oceans Canada, Burlington, Ontario, Canada

Megan Belore, Assessment Biologist, Ontario Ministry of Natural Resources and Forestry, Wheatley, Ontario, Canada

Julie Boucher, M.Sc., Biologiste, Ministère des Ressources Naturelles et de la Faune, Québec, Québec, Canada

Lynn Bouvier, M.Sc., Species at Risk Science Advisor, Fisheries and Oceans Canada, Burlington, Ontario, Canada

George Coker, Camm Portt and Associates, Guelph, Ontario, Canada

Marc-Antoine Couillard, M.Sc., Biologist, Ministère des Ressources Naturelles et de la Faune, Québec, Québec, Canada.

Alan Dextrase, Ph.D., Senior Species at Risk Biologist, Ontario Ministry of Natural Resources, Peterborough, Ontario

Scott Gibson, M.Sc., Biodiversity Conservation Policy Advisor, Ontario Ministry of Natural Resources, Peterborough, Ontario, Canada

Daniel Heath, Ph.D., Canada Research Chair and Professor, Great Lakes Institute for Environmental Research, University of Windsor, Windsor, Ontario, Canada.

Erling Holm, Assistant Curator of Fishes, Royal Ontario Museum, Toronto, Ontario, Canada

Neil Jones, Canadian Wildlife Service, Environment and Climate Change Canada, Gatineau, Québec, Canada.

Nicholas Mandrak, Ph.D., Associate Professor, University of Toronto Scarborough, Toronto, Ontario, Canada.

Simon Nadeau, Manager, Species at Risk, CITES, Aquatic Invasive Species, Marine Mammals, Atlantic Salmon, Ecosystem and Oceans Science - Fish Population Science, Fisheries and Oceans Canada, Ottawa, Ontario, Canada,

Brad McNevin, B.Sc., Regulations Officer/Fisheries Biologist, Quinte Conservation, Belleville, Ontario, Canada

Scott Reid, Ph.D., Aquatic Endangered Species Research Scientist, Ontario Ministry of Natural Resources and Forestry, Peterborough, Ontario, Canada.

Connie Smith, Species at Risk Biologist, Fisheries and Oceans Canada, Sudbury, Ontario, Canada

Shawn Staton, Team Leader, Fisheries and Oceans Canada, Burlington, Ontario, Canada

Ryan Walter, Ph.D, Postdoctoral Fellow, Great Lakes Institute for Environmental Research, Windsor, Ontario, Canada.

Chris Wilson, Ph.D., Research Scientist, Ontario Ministry of Natural Resources and Forestry Peterborough, Ontario, Canada.


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Holm, E., N.E. Mandrak, and M. Burridge. 2009. The ROM field guide to freshwater fishes of Ontario. Royal Ontario Museum, Toronto, Ontario, Canada. 462 p.

Hubbs, C. 1985. Darter reproductive seasons. Copeia 1985:56-68

HydroNet. 2013. Rivières échantillonnées au cours de l’été 2013, Province du Québec, présenté au ministère du Développement durable, de l’Environnement, de la Faune et des Parcs du Québec ,30 pp.

IUCN Standards and Petitions Subcommittee. 2010. Guidelines for Using the IUCN Red List Categories and Criteria. Version 8.1. Prepared by the Standards and Petitions Subcommittee in March 2010. Accessed April 2012. URL: http://intranet.iucn.org/webfiles/doc/SSC/RedList/RedListGuidelines.pdf.

Jelks, H.L., S.J. Walsh, N.M. Burkhead, S.Contreras-Balderas, E. Díaz-Pardo, D.A. Hendrickson, J. Lyons, N.E. Mandrak, F. McCormick, J.S. Nelson, S.P. Platania, B.A. Porter, C.B. Renaud, J. J. Schmitter-Soto, E.B. Taylor, and M.L. Warren, Jr. 2008. Conservation status of imperiled North American freshwater and diadromous fishes. Fisheries 33(8):372-407.

Kidd, A., S.M. Reid, and C.C. Wilson. 2011. Local and regional population genetic structure of the threatened Channel Darter in Ontario. Poster, Canadian Conference for Fisheries Research, Toronto, Ontario.

Koonce, J.F., W.-D.N. Busch and T. Czapla. 1996. Restoration of Lake Erie: contribution of water quality and natural resource management. Canadian Journal of Fisheries and Aquatic Sciences 53: 105-112.

Kraft, C.E., D.M. Carlson, and M. Carlson. 2006. Inland fishes of New York (Online) Version 4.0. Department of Natural Resources, Cornell University, and the New York State Department of Environmental Conservation. URL: http://fish.dnr.cornell.edu/nyfish/fish.html

Lake Erie Lakewide Management Plan. 2011. Annual Report. 4 pp. Catalogue No.: En161­7/2011E­PDF

Lane, J.A., C.B. Portt, and C.K. Minns. 1996. Nursery habitat characteristics of Great Lakes fishes. Canadian Manuscript Report of Fisheries and Aquatic Sciences 2338: v + 42 pp.

Lapointe, M. 1997. Rapport sur la situation du fouille-roche gris (Percina copelandi) au Québec. Ministère de l’environnement et de la faune. 55 pp.

Lemieux, C., S. Renaud, P. Bégin, and L. Belzile. 2005. Acquisition des connaissances – Rivière Gatineau Centrale des Rapides-Farmers et Secteur Wakefield. Report from GENIVAR Groupe Conseil Inc. presented to Hydro-Quebec Production, Direction Barrages et Environnement. 76 pp. + appendices.

Levert, C. 2013. Étude de l’habitat d’une espèce en péril au Canada, le fouille-roche gris (Percidae : Percina copelandi), dans quatre tributaire de la rivière des Outaouais. Thesis. Ottawa University. Ottawa, ON.

Mackey, S.D., J.M. Reutter, J.J.H Ciborowski, R.C. Haas, M. Charlton, and R. Kries. 2006. Huron-Erie corridor system habitat assessment – changing water levels and effects of global climate change. HEC Project Completion Report, 45 pp.

Mandrak, N.E. 1990. The zoogeography of Ontario freshwater fishes. MSc. Thesis, Department of Zoology, University of Toronto, Toronto, ON. 193 pp.

Mandrak N.E., and E.J. Crossman. 1992. Postglacial dispersal of freshwater fishes into Ontario. Canadian Journal of Zoology 70: 2247-2259.

Mandrak, N.E., and K.E. Brodribb. 2006. How well do parks protect fish species at risk in Ontario? pp. 205-220 In: G. Nelson et al. (eds). Protected areas and species and ecosystems at risk: research and planning challenges. Proceedings of the Parks Research Forum of Ontario Annual Meeting 2005. Parks Research Forum of Ontario, University of Waterloo, Waterloo, ON.

Minns, C.K. 1995. Allometry of home range size in lake and river fishes. Canadian Journal of Fisheries and Aquatic Sciences 52:1499-1508.

NatureServe. 2011. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.0. NatureServe, Arlington, Virginia. (Accessed: July 10, 2011).

Near, T.J. 2002. Phylogenetic relationships of Percina (Percidae: Etheostomatinae). Copeia 2002: 1-14.

Near T.J., C.M. Bossu, G.S. Bradburd, R.L. Carlson, R.C. Harrington. P.R. Hollingsworth Jr., B.P. Keck, and D.A. Etnier. 2011. Phylogeny and temporal diversification of darters (Percidae: Etheostomatinae). Systematic Biology 60: 565-595.

Organisme des bassins versants (OBV) de la Côte-du-Sud. 2013. Projet d’inventaire et de caractérisation des habitats utilisés par le fouille-roche gris (Percina copelandi) dans le Bras Saint-Nicolas, présenté à Pêches et Océans Canada, 43 pp.

Page, L.M. 1974. The subgenera of Percina. Copeia 1974: 66-86.

Page, L.M. 1983. Handbook of darters. Illinois Natural History Survey,

Champlain, Illinois. 271 pp.

Page L.M., and. B.M. Burr. 2011. Peterson field guide to freshwater fishes of North America North of Mexico, Second edition. Houghton Mifflin Harcourt, Boston, New York, 663 pp.

Page, L., H. Espinosa, L.T. Findley, C.R. Gilbert, R.N. Lea, N.E. Mandrak, R.L. Mayden, and J.S. Nelson. 2013. Common and scientific names of fishes from the United States, Canada and Mexico. 7th Edition. American Fisheries Society Special Publication 24. Bethesda, MD, USA.

Paradis, V. 2014. Projet sur l’utilisation des tributaires de la rivière du Sud par le fouille- roche gris (Percina copelandi). Organisme de bassins versants de la Côte-du-Sud. 39 pp.

Phelps, A. and A. Francis. 2002. Update COSEWIC status report on the Channel Darter Percina copelandi in Canada in COSEWIC assessment and update status report on the Channel Darter Percina copelandi in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa, Ontario, Canada. 21 pp.

Reid, S.M. 2004. Age-estimates and length distributions of Ontario channel darter (Percina copelandi) populations. Journal of Freshwater Ecology 19: 441-444.

Reid, S.M. 2006. River redhorse (Moxostoma carinatum) and channel darter (Percina copelandi) populations along the Trent-Severn Waterway. Proceedings of Parks Research Forum of Ontario Annual Meeting 2005. Parks Research Forum of Ontario, University of Waterloo, Waterloo, ON.

Reid, S.M. and A. Dextrase. 2014. First record of Ammocrypta pellucida (Agassiz, 1863) (Actinopterygii: Perciformes) from the Lake Ontario drainage basin. Checklist 10(5). DOI: http://dx.doi.org/10.15560/10.5.1201

Reid, S.M. and N.E. Mandrak. 2008. Historical changes in the distribution of threatened channel darter (Percina copelandi) in Lake Erie with general observations on the beach fish assemblage. Journal of Great Lakes Research 34: 324-333.

Reid, S.M., L.M. Carl, and J. Lean. 2005. Influence of riffle characteristics, surficial geology, and natural barriers on the distribution of the channel darter (Percina copelandi) in the Lake Ontario basin. Environmental Biology of Fishes 72: 241-249.

Reid, S.M., A. Kidd, and C. Wilson. 2013. Genetic information in support of COSEWIC evaluation of Channel Darter (Percina copelandi) designatable units. Unpublished report prepared for COSEWIC Freshwater Fishes Subcommittee. 8 pp.

Rudolph, N., B. Pence, and H. Jennings. 2001. Conservation assessment for Channel Darter (Percina copelandi). USDA Forest Service, Eastern Region, Allegheny and Huron-Manistee National Forests. 18 pp.

Sager, M. 2004. Enquête sur l'application de la politique de protection des rives, du littoral et des plaines inondables par les municipalités, Ministère de l'Environnement, Ministère des Affaires Municipales, du Sport et du Loisir, 30 pp. + annexes

Schaefer, J.F., E. Marsh-Matthews, D.E. Spooner, K.B. Gido, and W.J. Matthews. 2003. Effects of barriers and thermal refugia on local movement of the threatened leopard darter, Percina pantherina. Environmental Biology of Fishes 66(4): 391-400.

Scott W.B. and E.J. Crossman.1973. Freshwater Fishes of Canada. Fisheries Research Board of Canada Bulletin Vol. 184. Ottawa, ON. 966 pp.

Simoneau, M. et G. Thibault. 2009. État de l'écosystème aquatique du bassin versent de la rivière Richelieu: faits saillants 2005-2007, Québec, ministère du Développement durable, de l'Environnement et des Parcs, Direction du suivi de l'état de l'environnement, ISBN 978-2-550-56454-6 (PDF), 23 pp.

Strange, R.M. 1997. Food items of channel darter (Percina copelandi) collected from the Ohio River. Journal of Freshwater Ecology 12(2): 339-340.

Suttkus, R.D., B.A. Thompson, and H.L. Bart, Jr. 1994. Two new darters, Percina (Cottogaster), from the southeastern United States, with a review of the subgenus. Occasional Papers of the Tulane Museum of Natural History 4:1-46.

Thomas, M.V. and R.C. Haas. 2004. Status of Lake St. Clair fish community and sport fishery, 1996-2001. Fisheries Research Report. 2067. Michigan Department of Natural Resources, Fisheries Division. 27 pp.

Trautman, M B. 1981. The fishes of Ohio. Ohio State University Press. Columbus, Ohio. 966 pp.

Vachon, N. 2003. L'envasement des cours d'eau: processus, causes et effets sur les écosystèmes avec une attention particulière aux Catostomidés dont le chevalier cuivré (Moxostoma hubbsi). Société de l'aménagement de la faune de Montréal, de Laval et de la Montérégie, Longueuil, Rapport technique 16-13, vi + 49 pp.

Venturelli, P.A., L.A. Vélez-Espino, and M.A. Koops. 2010. Recovery Potential Modelling of Channel Darter (Percina copelandi) in Canada. Canadian Science Advisory Secretariat Research Document 2010/096. iii + 34 pp.

Winn, H.E. 1953. Breeding habits of the percid fish Hadropterus copelandi in Michigan. Copeia 1953: 26-30.

Wollnough, D.A. and J.A. Downing. 2009. Fish movement depends on waterbody size and shape. Ecology of Freshwater Fish 18:83-91.

WSP. 2014. Inventaire et caractérisation des habitats utilisés par le fouille-roche gris et le dard de sable dans 18 cours d’eau du Québec. Rapport de WSP à Pêches et Océans Canada. 39 pp. et annexes.

Yunker, G.B., K.D. Soper, and B. Locke. 2009. A habitat and fish biodiversity assessment of the nearshore Canadian waters of lakes Erie and St. Clair: A report funded by the Canada-Ontario Agreement Respecting the Great Lakes Basin Ecosystem. Ontario Ministry of Natural Resources, Lake Erie Management Unit. 23 pp + vi.


Biographical summary of report writers

At the time of writing the report, all three writers were working on graduate degrees under the supervision of Dr. Eric B. Taylor in the Department of Zoology, University of British Columbia. J.-S. Moore is a PhD candidate and works on the ecology and evolution of Arctic Char (Salvelinus alpinus) in the Canadian Arctic. He previously completed his BSc and MSc at McGill University, where he worked on Threespine Stickleback (Gasterosteus aculeatus) under the supervision of Dr. Andrew Hendry. D. Nowosad recently completed his MSc, which focused on the ecology and phylogeography of the Brassy Minnow (Hybognathus hankinsoni). He also has a BEd from UBC and a BSc from the University of Victoria. J. Mee received his PhD in 2011 for which he worked on an asexual species of dace that originated from hybridization between two sexual species of dace: Phoxinus eos, and P. neogaeus. He recently started a post-doctoral position with Dr. Sean Rogers at the University of Calgary, and previously received his MSc from the University of Toronto and BSc from the University of British Columbia.


Collections examined

Although no collections were examined directly for this report, the authors would like to acknowledge the help they received from Erling Holm, assistant curator of fishes, Royal Ontario Museum. Many of the records of capture of Channel Darter reported here are from his inventory of the ROM fish collection.


Appendix 1. Threat Calculator results for Channel Darter (Percina copelandi) – Lake Erie populations (DU1).

Threats assessment worksheet

Species or ecosystem scientific name:
Channel Darter Percina copelandi, DU1 Lake Erie populations
Element ID:
-
Elcode:
-
Date:
21/10/2015
Assessor(s):
Dwayne Lepitzki, John Post, Jean-Sébastien Moore, Jim Grant, Sara Hogg, Marc-Antoine Couillard, Scott Reid, Isabelle Gauthier
References:
-
Overall threat impact calculation help:
Threat impactThreat impact (descriptions)Level 1 threat impact counts:
high range
Level 1 threat impact counts:
low range
AVery high00
BHigh10
CMedium12
DLow00
-Calculated overall threat impact:HighMedium
Assigned overall threat impact:
B = High
Impact adjustment reasons:
-
Overall threat comments:
3-4 locations (Detroit River, St. Clair River, Lake Erie [western - ok, central & eastern basins – likely extirpated], Lake St. Clair [likely extirpated]), no subpop estimates.
Threats assessment worksheet table.
#ThreatImpact (calculated)Impact (description)Scope (next 10 yrs)Severity (10 yrs or 3 gen.)TimingComments
1Residential & commercial developmentblank blank  blank blank blank 
1.1Housing & urban areasblank blank blank blank blank not applicable
1.2Commercial & industrial areasblank blank blank blank blank not applicable
1.3Tourism & recreation areasblank blank blank blank blank jetties, marinas and docks. Destruction of habitat. Not planned in the next 10 years. So not applicable.
2Agriculture & aquacultureblank blank blank blank blank blank 
2.1Annual & perennial non-timber cropsblank blank blank blank blank not applicable
2.2Wood & pulp plantationsblank blank blank blank blank not applicable
2.3Livestock farming & ranchingblank blank blank blank blank not applicable
2.4Marine & freshwater aquacultureblank blank blank blank blank not applicable
3Energy production & miningblank blank blank blank blank blank 
3.1Oil & gas drillingblank blank blank blank blank not applicable
3.2Mining & quarryingblank blank blank blank blank pipelines 4.2
3.3Renewable energyblank blank blank blank blank Windmills? Not applicable. Offshore windpower development plans for western Lake Erie put on hold.
4Transportation & service corridorsblank UnknownSmall (1-10%)UnknownHigh (Continuing)blank 
4.1Roads & railroadsblank NegligibleNegligible (<1%)UnknownModerate (Possibly in the short term, < 10 yrs)Ambassador Bridge twinning (abutments)? Pylons in the middle of the river. Siltation accounted for under 9. Habitat is not limiting for Channel Darter however populations at max capacity unknown. Bridge development is not going on now. Impact is unknown.
4.2Utility & service linesblank NegligibleNegligible (<1%)UnknownModerate (Possibly in the short term, < 10 yrs)pipeline close to St.Claire. timing unknown.
4.3Shipping lanesblank UnknownSmall (1-10%)UnknownHigh (Continuing)dredging. Shipping lanes through St.Claire river. Timing is high. Proportion of this DU exposed to dredging is ??? Lake St.Clair also. Found through trawling in 2m deep in St.Claire river area and Detroit. Possible that they’re using deeper habitat shipping lanes. In QC 7m deep (deeper than once thought). Habitat preference is unknown. Observations have declined in Lake Erie corridor (corresponding to Round Goby). Lack of data to quantify dredging threat level of impact.
4.4Flight pathsblank blank blank blank blank not applicable
5Biological resource useblank NegligibleNegligible (<1%)Extreme (71-100%)High (Continuing)blank 
5.1Hunting & collecting terrestrial animalsblank blank blank blank blank not applicable
5.2Gathering terrestrial plantsblank blank blank blank blank not applicable
5.3Logging & wood harvestingblank blank blank blank blank not applicable
5.4Fishing & harvesting aquatic resourcesblank NegligibleNegligible (<1%)Extreme (71-100%)High (Continuing)Incidental catch is unquantified but suspected to be low in bait catch.
6Human intrusions & disturbanceblank NegligibleNegligible (<1%)Negligible (<1%)Moderate (Possibly in the short term, < 10 yrs)blank 
6.1Recreational activitiesblank blank blank blank blank not applicable
6.2War, civil unrest & military exercisesblank blank blank blank blank not applicable
6.3Work & other activitiesblank NegligibleNegligible (<1%)Negligible (<1%)Moderate (Possibly in the short term, < 10 yrs)No immediate plans for research (catch) but if so, negligible.
7Natural system modificationsblank NegligibleNegligible (<1%)Extreme (71-100%)Low (Possibly in the long term, >10 yrs)blank 
7.1Fire & fire suppressionblank blank blank blank blank not applicable
7.2Dams & water management/useblank blank blank blank blank not applicable
7.3Other ecosystem modificationsblank NegligibleNegligible (<1%)Extreme (71-100%)Low (Possibly in the long term, >10 yrs)Altered flow regimes high in Detroit River but low elsewhere in this DU. Not dams. Round Goby compete with Channel Darter (affects habitat - food sources). Softening of shoreline planned so hardening shouldn’t get worse. Worst spots is along St.Clair River as well as Detroit River. Population hits and hardening is past so future projection (threat of hardening) is negligible. Long term deliterious impact projected into future from hardening is unknown. Erosion from wave action on Point Pelee is on opposite side of Channel Darter habitat.
8Invasive & other problematic species & genesBCHigh - MediumPervasive (71-100%)Serious - Moderate (11-70%)High (Continuing)blank 
8.1Invasive non-native/alien speciesBCHigh - MediumPervasive (71-100%)Serious - Moderate (11-70%)High (Continuing)Round Goby eat Channel Darter eggs. RG in Detroit River now. RG throughout range in this DU. Predation is the predominant threat and therefore the quantification of invasive threat from Round Goby is accounted for under 8.1 as opposed to splitting between 7.3 and 8.1.
8.2Problematic native speciesblank blank blank blank blank not applicable
8.3Introduced genetic materialblank blank blank blank blank not applicable
9PollutionCMediumPervasive (71-100%)Moderate (11-30%)High (Continuing)blank 
9.1Household sewage & urban waste waterCMediumPervasive (71-100%)Moderate (11-30%)High (Continuing)Household waste water or run off contributing to nutrient loading.
9.2Industrial & military effluentsblank UnknownLarge (31-70%)UnknownHigh (Continuing)Detroit River medium. St.Clair low. Lake Erie unknown. Impact, severity on Channel Darter is unknown from threat of toxic substances. General knowledge that toxins impact fish communities negatively. Overall negative. Industrilization in western part of Lake Erie impact on CD is unknown.
9.3Agricultural & forestry effluentsCMediumPervasive (71-100%)Moderate (11-30%)High (Continuing)Increase in nutrient loading and sedimentation into western lake erie. Large algal blooms related to use of fertilizers from agricultural areas (9.3). Lake St.Clair shallow and warm and intensive agriculture. Most Channel Darters exposed to effluent since water flowing out of St.Clair.
9.4Garbage & solid wasteblank blank blank blank blank not applicable
9.5Air-borne pollutantsblank blank blank blank blank not applicable
9.6Excess energyblank blank blank blank blank not applicable
10Geological eventsblank blank blank blank blank blank 
10.1Volcanoesblank blank blank blank blank not applicable
10.2Earthquakes/tsunamisblank blank blank blank blank not applicable
10.3Avalanches/landslidesblank blank blank blank blank not applicable
11Climate change & severe weatherblank Not Calculated (outside assessment timeframe)Pervasive (71-100%)UnknownLow (Possibly in the long term, >10 yrs)Climate change and general drop in water level combined with fluctuations in level as well as increases in water temperature. Threat impact is unknown. Climate change? No increases in storm but two years of warmer than average temperatures.
11.1Habitat shifting & alterationblank blank blank blank blank all combined into level 1 threat (above)
11.2Droughtsblank blank blank blank blank all combined into level 1 threat (above)
11.3Temperature extremesblank blank blank blank blank all combined into level 1 threat (above)
11.4Storms & floodingblank blank blank blank blank all combined into level 1 threat (above)

Appendix 2. Threat Calculator results for Channel Darter (Percina copelandi) – Lake Ontario populations (DU2).

Threats assessment worksheet

Species or ecosystem scientific name:
Channel Darter Percina copelandi, DU2 Lake Ontario populations
Element ID:
-
Elcode:
-
Date:
21/10/2015
Assessor(s):
Dwayne Lepitzki, John Post, Jean-Sébastien Moore, Jim Grant, Sara Hogg, Marc-Antoine Couillard, Scott Reid, Isabelle Gauthier
References:
-
Overall threat impact calculation help:
Threat impactThreat impact (descriptions)Level 1 threat impact counts:
high range
Level 1 threat impact counts:
low range
AVery high00
BHigh00
CMedium11
DLow11
-Calculated overall threat impact:MediumMedium
Assigned overall threat impact:
C = Medium
Impact adjustment reasons:
-
Overall threat comments:
4 locations (Moira [Skootamata, Black), Salmon, Trent rivers), no subpop estimates; distribution figs 2, 4, 5. biggest threat to this DU is Round Goby.
Overall threat impact calculation help:
#ThreatImpact (calculated)Impact (description)Scope (next 10 yrs)Severity (10 yrs or 3 gen.)TimingComments
1Residential & commercial developmentblank blank blank blank blank blank 
1.1Housing & urban areasblank blank blank blank blank not applicable
1.2Commercial & industrial areasblank blank blank blank blank not applicable
1.3Tourism & recreation areasblank blank blank blank blank not applicable
2Agriculture & aquacultureblank blank blank blank blank blank 
2.1Annual & perennial non-timber cropsblank blank blank blank blank not applicable
2.2Wood & pulp plantationsblank blank blank blank blank not applicable
2.3Livestock farming & ranchingblank blank blank blank blank not applicable
2.4Marine & freshwater aquacultureblank blank blank blank blank not applicable
3Energy production & miningblank blank blank blank blank blank 
3.1Oil & gas drillingblank blank blank blank blank not applicable
3.2Mining & quarryingblank blank blank blank blank not applicable
3.3Renewable energyblank blank blank blank blank not applicable
4Transportation & service corridorsblank blank blank blank blank blank 
4.1Roads & railroadsblank blank blank blank blank not applicable
4.2Utility & service linesblank blank blank blank blank not applicable
4.3Shipping lanesblank blank blank blank blank not applicable
4.4Flight pathsblank blank blank blank blank not applicable
5Biological resource useblank NegligibleNegligible (<1%)Extreme (71-100%)High (Continuing)blank 
5.1Hunting & collecting terrestrial animalsblank blank blank blank blank not applicable
5.2Gathering terrestrial plantsblank blank blank blank blank not applicable
5.3Logging & wood harvestingblank blank blank blank blank not applicable
5.4Fishing & harvesting aquatic resourcesblank NegligibleNegligible (<1%)Extreme (71-100%)High (Continuing)Incidental catch is unquantified but suspected to be low in bate catch.
6Human intrusions & disturbanceblank NegligibleNegligible (<1%)Negligible (<1%)Moderate (Possibly in the short term, < 10 yrs)blank 
6.1Recreational activitiesblank blank blank blank blank not applicable
6.2War, civil unrest & military exercisesblank blank blank blank blank not applicable
6.3Work & other activitiesblank NegligibleNegligible (<1%)Negligible (<1%)Moderate (Possibly in the short term, < 10 yrs)No immediate plans for research (catch) but if so, negligible.
7Natural system modificationsDLowPervasive (71-100%)Slight (1-10%)High - Moderateblank 
7.1Fire & fire suppressionblank blank blank blank blank not applicable
7.2Dams & water management/useDLowPervasive (71-100%)Slight (1-10%)High - ModerateNo new dams but existing ones have continuous negative impact on population persistence via fragmentation. Therefore, lower severity but continuous threat impact. Impact of dams may be mitigated.
7.3Other ecosystem modificationsblank blank blank blank blank Not a lot of activity in this DU wrt development. So not applicable.
8Invasive & other problematic species & genesCMediumLarge (31-70%)Moderate (11-30%)High (Continuing)blank 
8.1Invasive non-native/alien speciesCMediumLarge (31-70%)Moderate (11-30%)High (Continuing)Round Goby in the Trent but not in remaining habitat in this DU. Asian Carp? Grass Carp are present. Round Goby has not spread into the Moira and Salmon River. However in Trent, RG released at the top and coming up from Bay of Quinte facilitated by locks. Threat impact is estimated for 8.1 based on RG in the Trent. No consistent decline in CD in the Trent and, therefore, difficult to infer threat based on Round Goby (according to data). Severity is likely less than Lake Erie DU. Smallmouth Bass is likely controlling invasives but this is speculation.
8.2Problematic native speciesblank blank blank blank blank not applicable
8.3Introduced genetic materialblank blank blank blank blank not applicable
9Pollutionblank NegligibleNegligible (<1%)Negligible (<1%)High (Continuing)blank 
9.1Household sewage & urban waste waterblank NegligibleNegligible (<1%)Negligible (<1%)High (Continuing)No large urban centres in this DU. So negligible. Scope and severity minimal in comparison.
9.2Industrial & military effluentsblank blank blank blank blank Pulp mill in Trent is downstream from this DU so not applicable.
9.3Agricultural & forestry effluentsblank NegligibleNegligible (<1%)Negligible (<1%)High (Continuing)Land is going fallow in this part of Ontario. Practices are less intensive than in the past. Not industrial scale. So this threat is low if at all a threat. Nutrient loading is negligible in comparison to other 2 DU's.
9.4Garbage & solid wasteblank blank blank blank blank not applicable
9.5Air-borne pollutantsblank blank blank blank blank not applicable
9.6Excess energyblank blank blank blank blank not applicable
10Geological eventsblank blank blank blank blank blank 
10.1Volcanoesblank blank blank blank blank not applicable
10.2Earthquakes/tsunamisblank blank blank blank blank not applicable
10.3Avalanches/landslidesblank blank blank blank blank not applicable
11Climate change & severe weatherblank blank blank blank blank Not a huge problem in comparison to other DU's. Higher water levels combined with flow structures maintain water levels. Increased temperatures is negligible as well since this is warmer temperature areas to begin with.
11.1Habitat shifting & alterationblank blank blank blank blank all combined into level 1 threat (above)
11.2Droughtsblank blank blank blank blank all combined into level 1 threat (above)
11.3Temperature extremesblank blank blank blank blank all combined into level 1 threat (above)
11.4Storms & floodingblank blank blank blank blank all combined into level 1 threat (above)

Appendix 3. Threat Calculator results for Channel Darter (Percina copelandi) – St. Lawrence populations (DU3).

Threats assessment worksheet

Species or ecosystem scientific name:
Channel Darter Percina copelandi, DU3 St. Lawrence populations, ON and QC
Element ID:
-
Elcode:
-
Date:
21/10/2015
Assessor(s):
Dwayne Lepitzki, John Post, Jean-Sébastien Moore, Jim Grant, Sara Hogg, Marc-Antoine Couillard, Scott Reid, Isabelle Gauthier
References:
-
Overall threat impact calculation help:
Threat impactThreat impact (descriptions)Level 1 threat impact counts:
high range
Level 1 threat impact counts:
low range
AVery high00
BHigh10
CMedium11
DLow01
-Calculated overall threat impact:HighMedium
Assigned overall threat impact:
BC = High - Medium
Impact adjustment reasons:
-
Overall threat comments:
23-30 locations, no subpop estimates, distribution figs. 2, 6
Overall threat impact calculation help:
#ThreatImpact (calculated)Impact (description)Scope (next 10 yrs)Severity (10 yrs or 3 gen.)TimingComments
1Residential & commercial developmentblank blank blank blank blank blank 
1.1Housing & urban areasblank blank blank blank blank not applicable
1.2Commercial & industrial areasblank blank blank blank blank not applicable
1.3Tourism & recreation areasblank blank blank blank blank not applicable
2Agriculture & aquacultureblank blank blank blank blank blank 
2.1Annual & perennial non-timber cropsblank blank blank blank blank not applicable
2.2Wood & pulp plantationsblank blank blank blank blank not applicable
2.3Livestock farming & ranchingblank blank blank blank blank not applicable
2.4Marine & freshwater aquacultureblank blank blank blank blank not applicable
3Energy production & miningblank UnknownLarge (31-70%)UnknownModerate - Lowblank 
3.1Oil & gas drillingblank UnknownLarge (31-70%)UnknownModerate - LowFracking. Not sure when this will occur but southern Quebec lowlands (St. Lawrence River to Appalachian mountains - south of St. Lawrence). Supposed to stop.
3.2Mining & quarryingblank blank blank blank blank not applicable
3.3Renewable energyblank blank blank blank blank not applicable
4Transportation & service corridorsblank UnknownRestricted - Small (1-30%)UnknownHigh (Continuing)blank 
4.1Roads & railroadsblank UnknownRestricted - Small (1-30%)UnknownHigh (Continuing)roads and bridge work expected in part of range in this DU.
4.2Utility & service linesblank UnknownSmall (1-10%)UnknownModerate (Possibly in the short term, < 10 yrs)Pipeline going through one river with Eastern Sand Darter but not Channel Darter. Service lines may go through some of CD habitat.
4.3Shipping lanesblank UnknownSmall (1-10%)UnknownHigh (Continuing)Dredging in the St.Lawrence but low. Ottawa unknown.
4.4Flight pathsblank blank blank blank blank not applicable
5Biological resource useblank blank blank blank blank blank 
5.1Hunting & collecting terrestrial animalsblank blank blank blank blank not applicable
5.2Gathering terrestrial plantsblank blank blank blank blank not applicable
5.3Logging & wood harvestingblank blank blank blank blank not applicable
5.4Fishing & harvesting aquatic resourcesblank NegligibleNegligible (<1%)Extreme (71-100%)High (Continuing)Incidental captures. Trying to stop bait fishery. Banned at certain times of the year. Research is active and usually fatal when caught but impact is minimal since once a site is confirmed, catch is minimized at that site. As well, better identification should increase catch and release events.
6Human intrusions & disturbanceblank NegligibleSmall (1-10%)Negligible (<1%)High (Continuing)blank 
6.1Recreational activitiesblank blank blank blank blank not applicable
6.2War, civil unrest & military exercisesblank blank blank blank blank not applicable
6.3Work & other activitiesblank NegligibleSmall (1-10%)Negligible (<1%)High (Continuing)not applicable
7Natural system modificationsblank UnknownRestricted - Small (1-30%)UnknownHigh (Continuing)blank 
7.1Fire & fire suppressionblank blank blank blank blank not applicable
7.2Dams & water management/useblank UnknownRestricted - Small (1-30%)UnknownHigh (Continuing)Dams present in CD habitat without fish ladders. Causes isolation. Recolonization in smaller rivers is affected by isolation due to dams. Most of the impact wrt dams has occurred in the past. Positive impact to fish population above dams but negative below dams except that the habitat is better downstream and worse upstream due to predation from larger fish.
7.3Other ecosystem modificationsblank UnknownRestricted - Small (1-30%)UnknownHigh (Continuing)Phosphorus leaching into the habitat from agriculture. Most CD habitat in this DU occur in agricultural areas. Encroachment from blooming flora in the riparian zones is altering shoreline habitat.
8Invasive & other problematic species & genesBDHigh - LowLarge - Restricted (11-70%)Serious - Moderate (11-70%)High (Continuing)blank 
8.1Invasive non-native/alien speciesBDHigh - LowLarge - Restricted (11-70%)Serious - Moderate (11-70%)High (Continuing)Round Goby? Don’t find RG often in Qc rivers. So impact is unknown in this DU. It is in the St. Lawrence and in Ottawa and Richelieu. It does eat CD eggs. Future impact projected to be a high threat over the next 10 yrs given the impact in the southwestern Ontarion DU.
8.2Problematic native speciesblank blank blank blank blank not applicable
8.3Introduced genetic materialblank blank blank blank blank not applicable
9PollutionCMediumPervasive (71-100%)Moderate (11-30%)High (Continuing)blank 
9.1Household sewage & urban waste waterCMediumLarge (31-70%)Moderate (11-30%)High (Continuing)Concentration of developed areas is in CD habitat (QC, Montreal) and problems with Montreal sewage so threat is prevalent.
9.2Industrial & military effluentsblank UnknownRestricted (11-30%)UnknownHigh (Continuing)Some industrial effluents but less than SW Ont DU. Plans for possible bigger port in St. Lawrence. So this may be intensive over the next 10yrs.
9.3Agricultural & forestry effluentsCMediumPervasive (71-100%)Moderate (11-30%)High (Continuing)Yamaska River low agricultural but St. Lawrence and Ottawa River is mostly agricultural so high impact from nutrient loading
9.4Garbage & solid wasteblank blank blank blank blank not applicable
9.5Air-borne pollutantsblank blank blank blank blank not applicable
9.6Excess energyblank blank blank blank blank not applicable
10Geological eventsblank blank blank blank blank blank 
10.1Volcanoesblank blank blank blank blank not applicable
10.2Earthquakes/tsunamisblank blank blank blank blank not applicable
10.3Avalanches/landslidesblank blank blank blank blank not applicable
11Climate change & severe weatherblank Not Calculated (outside assessment timeframe)Pervasive (71-100%)UnknownLow (Possibly in the long term, >10 yrs)Higher water levels and higher temperatures. But this may be beneficial for the species since Canada is northern range.
11.1Habitat shifting & alterationblank blank blank blank blank all combined into level 1 threat (above)
11.2Droughtsblank blank blank blank blank all combined into level 1 threat (above)
11.3Temperature extremesblank blank blank blank blank all combined into level 1 threat (above)
11.4Storms & floodingblank blank blank blank blank all combined into level 1 threat (above)