COSEWIC assessment and status report on the American Eel in Canada
- Assessment Summary
- Executive Summary
- Species information
- Population size and trends
- FEA2 - Eastern St. Lawrence(eastern Quebec)
- FEA3 - Maritimes (New Brunswick, Nova Scotia, Prince Edward Island, and the central and southern parts of Quebec's Gaspé Peninsula)
- FEA4 - Atlantic Islands (Newfoundland)
- FEA5 - Eastern Arctic (Labrador)
- Contribution of the St. Lawrence Eel Component – Landings Method
- Rescue effect
- Limiting factors and threats
- Special significance of the species
- Technical summary
- Information sources
- Biographical summaries of the report writers
- Collections examined
american eel anguille d’Amérique
Rangeof Occurrence in Canada: Accessible freshwater, estuaries, and sheltered salt water of Newfoundland, Nova Scotia, Prince Edward Island, New Brunswick, Quebec and Ontario to Lake Ontario and lower Niagara River. Continental shelves are also used by migrating juvenile and silver eels. The northern limit in Canadian waters is the Hamilton Inlet-Lake Melville estuary of Labrador.
Freshwater Ecological Areas (following the COSEWIC national system):
FEA1: Great Lakes-Western St. Lawrence (Ontario and western and central Quebec)
FEA2: Eastern St. Lawrence (eastern Quebec)
FEA3: Maritimes (New Brunswick, Nova Scotia, Prince Edward Island, and the central and southern parts of Quebec's Gaspé Peninsula)
FEA4: Atlantic Islands (Newfoundland)
FEA5: Eastern Arctic (Labrador)
|Extent and Area Information||FEA1||FEA2||FEA3||FEA4||FEA5||SPECIES|
|Extent of occurrence (EO)(km²) -based on polygons see text - Canadian Range||391,515||546,122||292,923||177,586||75,472||2,065,932|
|· Specify trend in EO||Decline||Decline?||Increase?||Stable ?||Stable ?||Decline|
|· Are there extreme fluctuations in EO?||No||No||No||No||No||No|
|Area of occupancy (AO) (km²)-based on Lake Ontario 0-10m area, Verreault et al. 2004 for Quebec, Museum records for Ontario, and Canadian waters outer limit (buffer of 370 km)||97 400||161 400||635 200||627 500||130 700||1 653 200|
|· Specify trend in AO||Decline||Decline?||Stable ?||Stable ?||Stable ?||Decline|
|· Are there extreme fluctuations in AO?||No||No||No||No||No||No|
|· Number of known or inferred current locations||Unknown||Unknown||Unknown||Unknown||Unknown||Unknown|
|· Specify trend in #||Decline||Decline?||Stable ?||Stable ?||Stable ?||Decline|
|· Are there extreme fluctuations in number of locations?||No||No||No||No||No||No|
|· Specify trend in area, extent or quality of habitat||Decline||Decline?||Stable?||Stable?||Stable?||Decline|
|Information for eel components||FEA1||FEA2||FEA3||FEA4||FEA5||SPECIES|
|Generation time (average age of parents in the component). Ranges refer to parental ages of eels reared in salt and fresh water, respectively||22||9-22||9-22||9-22||9-22||9-23|
|· Number of mature individuals||424,000 in 1997||Unknown||Unknown||Unknown||Unknown||Unknown|
|· Trends in components:||Decline||Decline?||Increase?||Unknown||Unknown||Decline|
· % decline over the last 10 years or 3 generations
Note: No data are available for changes over 3 generations of female fresh-reared eel, which is approximately 66 years. Data in this row are from Table 5. Reported landings in FEA3-5 declined by 26.2% over ~1 freshwater gen. and ~3 saltwater gen. Data from Ontario reflect the upper St. Lawrence/Lake Ontario part of FEA1. Data series from Quebec reflect the whole FEA1 population.
FEA 1 may supply ~27-67% of global spawn output (see text Contribution of the St. Lawrence eel population) - a > 90% decline in this area may indicate a loss of 25-60% of the global spawn. The calculations are based on unproven methodologies and may be an overestimate; for that reason a range of values is given.
See Table 5 1Landings 2ladder index *Elecrofishing densities over 1-2 generations, 3Electrofishing counts over 1 generation.
Also landings in FEA 3-5 declined ~26%
|Ontario ~ 98.8% (Quinte trawl index)|
99.5% (Moses-Saunders ladder index)
Quebec ~15.1% (St. Nicholas index)
~63.9% (Quebec silver eel landings, ~1 generation
|Unknown||Rest. +74.8%* Miramichi ~43%*Margaree ~87.9%* Stewiake ~81.6%3 Elsewhere Unknown||Unknown||Unknown||Unknown|
|· Are there extreme fluctuations in number of mature individuals||No||Unknown||No||Unknown||Unknown||Unknown|
|· Is the total component severely fragmented?||No||No||Partly||Unknown||Unknown||No|
|· Specify trend in number of components / subcomponents||Decline||Stable||Stable||Stable||Stable||Decline (FEA1)|
|· Are there extreme fluctuations in number of components / subcomponents?||No||No||No||No||No||No|
· Loss of habitat (dams)
· Turbine mortality
· Change in oceanic currents
· Parasites - Anguillicola crassus
· Low pH
|Rescue Effect (immigration from outside source) Not Applicable||FEA1||FEA2||FEA3||FEA4||FEA5||SPECIES|
|Status of outside component(s)? USA:Rescue effect is not applicable since this is a catadromous, panmictic species, all components breed in one area (see text – Rescue Effect)||N/A||N/A||N/A||N/A||N/A||67.5% decline in reported US landings since 1970s|
|· Is immigration known or possible?||Yes||Yes||Yes||Yes||Yes||Yes|
|· Would immigrants be adapted to survive in Canada?||Yes||Yes||Yes||Yes||Yes||Yes|
|· Is there sufficient habitat for immigrants in Canada?||Yes||Yes||Yes||Yes||Yes||Yes|
|· Is rescue from outside components likely? – yes, but not really applicable – see note above||Yes||Yes||Yes||Yes||Yes||Yes|
|Quantitative Analysis||No Data||No Data||No Data||No Data||No Data||No Data|
NatureServe Status [NatureServe (2005) last revised in 1996; see also Table 7]
National US - N5
Canada - N5
Regional: US- AL- S5, AZ - SNA, AR - S4, CT - S5, DE - S5, DC - S4, FL - SNR, GA -S3S4, IL - S2, IN - S4, IA - S3?, KS - S2, KY - S4S5, LA ‑ S5, ME - S5, MD - S4,
MA -S5, MI - SNA, MS - S5, MO - SNR, NE - SNR, NY - SNA, NH - S5, NJ - S5, NM - SX, NY - S5, NC - S5, OH - SNR, OK - S3, PA - S5, RI - S5, SC - SNR, SD - 3?, TN - S3, TX - S5, VT - S3, VA - S5, WV - S2, WI - S1S2 .
N.B. the US is currently reviewing the status of this species for possible listing under the Endangered Species Act.
Canada: LB - S4, NB - S5, NF - S5, NS - S5, ON - S5, PE - S4S5, QC - S3
Wild Species 2000 (Canadian Endangered Species Council 2001)
National - N6
Provincial - N – 4*, QC -3, NB - 4, NS -4, PE - 4, LB - 4, NF - 4
*Dextrase indicated that this should be 2 (A. Dextrase, Ontario Ministry of Natural Resources, Peterborough, Ontario; annotated rank comments in relation to the data output for the Wild Species web site resulting from the November 2001 query for freshwater fish species).
First assessed in 2006 as Special Concern.
Status and Reasons for Designation
Alpha-numeric code: not applicable
Status: Special Concern
Reasons for Designation: Indicators of the status of the total Canadian component of this species are not available. Indices of abundance in the Upper St. Lawrence River and Lake Ontario have declined by approximately 99% since the 1970s. The only other data series of comparable length (no long-term indices are available for Scotia/Fundy, Newfoundland, and Labrador) are from the lower St. Lawrence River and Gulf of St. Lawrence, where four out of five time series declined. Because the eel is panmictic, i.e. all spawners form a single breeding unit, recruitment of eels to Canadian waters would be affected by the status of the species in the United States as well as in Canada. Prior to these declines, eels reared in Canada comprised a substantial portion of the breeding population of the species. The collapse of the Lake Ontario-Upper St. Lawrence component may have significantly affected total reproductive output, but time series of elver abundance, although relatively short, do not show evidence of an ongoing decline. Recent data suggest that declines may have ceased in some areas; however, numbers in Lake Ontario and the Upper St. Lawrence remain drastically lower than former levels, and the positive trends in some indicators for the Gulf of St. Lawrence are too short to provide strong evidence that this component is increasing. Possible causes of the observed decline, including habitat alteration, dams, fishery harvest, oscillations in ocean conditions, acid rain, and contaminants, may continue to impede recovery.
Applicability of Criteria
Criterion A: (Declining Total Population): Not Applicable. The Canadian segment of the population in the Great Lakes/Upper St. Lawrence Basin has declined by approximately 99% since the 1970s (based on landings, ladder indices, and test fishing indices), and is continuing to decline for reasons that are not well understood and may not be reversible. Decline has also been documented at four of five sites in the lower St. Lawrence and Gulf of St. Lawrence; however, the overall decline in Canadian waters is unknown
Criterion B: (Small Distribution, and Decline or Fluctuation): Not applicable – EO and AO exceed threshold values.
Criterion C: (Small Total Population Size and Decline): Not applicable - Total population size although unknown is undoubtedly well above the threshold value.
Criterion D: (Very Small Population or Restricted Distribution): Not applicable – the species is widespread and numerous, threshold values are exceeded.
Criterion E: (Quantitative Analysis): Not applicable – no data.
- Date Modified: