Recovery Strategy for the Copper Redhorse in Canada [Final] 2012: Critical Habitat

Previous ToC Next

Critical habitat is defined in the Species at Risk Act (2002) section 2(1) as:

SARA defines habitat for aquatic species at risk as:

Critical habitat for the Copper Redhorse has been identified to the extent possible, based on the best available information. This critical habitat consists of aquatic grass beds in the St. Lawrence River, the littoral zone of the Richelieu River and the rapids below the Saint-Ours and Chambly dams (Figures 4 to 9). The grass beds provide rearing and feeding habitats while the rapids are used as spawning grounds. Critical habitat identified in the littoral zone of the Richelieu River is used for rearing and by adults to migrate to the spawning grounds. The critical habitat identified in the present recovery strategy is essential for the survival and recovery of the species but it is insufficient to reach the population objectives. The schedule of studies presented in Section 2.5.4 outlines the research deemed necessary to complete the identification of critical habitat in order to meet population and distribution objectives.

During two workshops held in 2009 and 2010 with the participation of the Ministère des Ressources naturelles et de la Faune du Québec, Fisheries and Oceans Canada reviewed the information and used the new data to identify habitat use by the Copper Redhorse in the St. Lawrence and Richelieu rivers (DFO, 2010a). In October 2010, the Copper Redhorse Recovery Team recommended, among other things, that the habitat used by the Copper Redhorse in the Rivière des Prairies and Rivière des Milles Îles be identified as critical habitat. These two rivers were not discussed during the workshops due to a lack of time. The identification of critical habitat in the recovery strategy is based on the information gathered during the two workshops (summarized below) and the Recovery Team recommendation.

Spawning habitat
In order to identify the critical spawning habitat of the Copper Redhorse, experts have studied the needs and probable behaviour of the species, the use of the rapids below the Chambly and Saint-Ours dams and the size of potential spawning habitat in the Richelieu River (DFO, 2010b). The spawning behaviour of the Copper Redhorse seems to involve two or more males for each female. The Copper Redhorse appears to use the same sites as the other redhorse species, and apparently experiences reduced levels of competition at these sites due to the late onset of spawning. Indications suggest that it possesses a certain capacity to adapt to environmental conditions and remains relatively faithful to spawning sites. The area required for spawning was estimated to be 1 m2 per female (trio) which corresponds to a minimum required area of 2,000 m2 for 2,000 females (to meet the objective of 4,000 mature individuals). This value was extrapolated from known data from other redhorse species. The size of the potential spawning sites in the Richelieu River is estimated at 583,064 m2 (Chambly: 488,364 m2 and Saint-Ours: 94,700 m2). This potential area has been calculated based on the location of the spawning grounds, the drifting of eggs, resting places for spawners and the variability of the substrate and hydraulic conditions. Thus, the critical spawning habitat identified in this recovery strategy appears sufficient to meet the objective of a recovered population of 4,000 Copper Redhorse spawners.

Rearing and migration habitat
The habitats frequented by young-of-the-year and sub-adults may be generally described as shallow littoral zones exposed to weak currents and with aquatic-grass beds. These habitats are relatively evenly distributed all along the Richelieu River and the size of the grass beds available in the Richelieu River remains unknown. This is why a bathymetric approach has been recommended to identify critical juvenile rearing habitat. Given the current hydrological conditions of the Richelieu River, restoration of lost grass beds would be problematic. The littoral zone frequented by juvenile Copper Redhorse is between 0 and 3 m deep. However, the critical habitat which has been identified in the Richelieu River covers the littoral zone which is 0 to 4 m deep in order to include the migration corridor used by spawners.

Adult feeding habitat
Adult feeding habitat was identified using modeling based on the telemetric monitoring of habitat use and on twelve habitat variables (for example: depth, current velocity, vegetation density). Habitat modeling was applied for the St. Lawrence River, Lake Saint-Louis and Lake Saint-Pierre. It was not applied to the Rivière des Prairies and Rivière des Mille Îles, but use of the lower stretches of these rivers was confirmed with recent telemetry and historic data. In the St. Lawrence River, between Beauharnois and Trois-Rivières, the size of the potential habitat for rearing and feeding does not seem to be a limiting factor in reaching recovery objectives. However, the size of the habitat currently being used, as confirmed by telemetry, and identified as critical habitat does appear limiting and is restricted to the fluvial reach between Montreal and Sorel. According to the model, habitat potential in the fluvial lakes is very high though use by Copper Redhorse remains marginal. However, the habitat available between Montreal and Sorel, which is smaller in size (between 25 and 35 km2 depending on flow rates), is highly frequented. Critical adult feeding habitat is consequently identified as habitat in the fluvial reach between Montreal and Sorel presenting the attributes that were used in the model listed in Table 3. This habitat will be insufficient to support a recovered population of 4,000 spawners who will require an estimated 260 km2 of adult feeding habitat (DFO, 2010a).

The Copper Redhorse’s identified critical habitat includes three features supporting specific vital functions of the life cycle: the grass beds, the littoral zone, and the rapids. Their attributes are listed in Table 3.

Table 3. Summary of the attributes and functions of critical habitat
Functions Feature Location Attributes
Spawning, incubation (May, June, July) Rapids Richelieu River, downstream of Saint-Ours and Chambly dams Depth between 0.75 to 2 m
Weak to moderate current (0.2 to 0.6 m/s)
Heterogeneous substrate consisting of fine to coarse gravel, rocks and sometimes blocks embedded in clay.
Rearing and feeding Littoral zone Richelieu River, from the Chambly basin to the river mouth 0 to 4 m deep
Minor slopes (less than 20 degrees)
Weak to moderate current (less than 0.5 m/s)
Presence of vegetation
Relatively fine substrate (mixture of clay-silt-sand)
Migration Littoral zone Richelieu River, from the Chambly basin to the river mouth 0 to 4 m deep
Adult feeding Grass beds St. Lawrence River, between Montréal and Sorel
Rivière des Prairies
Rivière des Milles Îles
0 to 4 m deep
Weak to moderate current (less than 0.5 m/s)
Relatively fine substrate
Medium to high vegetation density, composed primarily of Vallisneria americana and Potamogeton sp.
Abundance of gastropods and dreissenids

Spawning habitat
Spawning critical habitat includes the only two known spawning grounds of the Copper Redhorse, located in the Richelieu River, below the Saint-Ours dam (Figure 4) and in the Chambly rapids (Figure 5). The spawning grounds are used by the Copper Redhorse during the months of May, June and July. The attributes of these spawning grounds are listed in Table 3.

Figure 4. Critical spawning habitat of the Copper Redhorse at the Saint-Ours dam.

map

Figure 5. Critical spawning habitat of the Copper Redhorse at the Chambly dam.

map

Rearing and migration habitat
Critical habitat in the Richelieu River includes the littoral zone of the river, with a depth of 0 to 4 m, from the Chambly basin to the mouth of the river (Figure 6 and Figure 7), where submerged aquatic vegetation can be found (Table 3). The Richelieu River is the only watercourse in which larvae and young-of-the-year Copper Redhorse have been observed. Juvenile redhorse (less than 100 mm), such as the Copper Redhorse, are confined to the grass beds of the littoral zone. Critical habitat for the growth of juveniles corresponds to the grass beds, which present the attributes listed in Table 3, in the littoral zone of the Richelieu River (with a depth of 0 to 4 m). These grass beds, which play a key role during the rearing stage (growth, food and shelter), are not only important habitat for juveniles, but also for adults who frequent the river or use it as a migration corridor. Adults migrating between the St. Lawrence River and the spawning grounds use the littoral zone, with a depth of 0 to 4 m, in the Richelieu River.

Adult feeding habitat
The critical adult feeding habitat which has been identified is located in the St. Lawrence River, between Montreal and Sorel and in the Rivière des Prairies and Rivière des Mille Îles. The critical habitat in the St. Lawrence River, located in a bounding area from the eastern tip of Île Notre-Dame (Figure 8) to the mouth of the Richelieu River (Figure 9), corresponds to gastropod-rich grass beds with the attributes described in Table 3. The potential locations of these grass beds were modeled using telemetry surveys and habitat variables; this model is illustrated in green in Figures 8 and 9. Critical habitat identified in the Rivière des Prairies and Rivière des Mille Îles, also corresponds to gastropod-rich grass beds with the attributes described in Table 3, within a bounding area extending from longitudes 73° 37′ 11″ W (des Prairies) and 73° 35′ 31″ W (des Milles Îles) to the river mouths. Potential locations of grass beds were not modeled in these rivers.

Figure 6. Critical rearing and migration habitat in the upstream reaches of the Richelieu River. Identified critical habitat for rearing corresponds to the littoral zone presenting attributes listed in Table 3, whereas critical habitat for migration is the littoral zone between 0 and 4 m depth (coloured in red), from the Chambly basin (upstream) extending to the river mouth.

map

Figure 7. Critical rearing and migration habitat in the downstream reaches of the Richelieu River. Identified critical habitat for rearing corresponds to the littoral zone presenting attributes listed in Table 3, whereas critical habitat for migration is the littoral zone between 0 and 4 m depth (coloured in red), from the Chambly basin (downstream) extending to the river mouth.

map

Figure 8. Bounding area (in black) in which critical adult feeding habitat corresponds to grass beds presenting the attributes listed in Table 3. Coloured in green are the areas thought to possess adult feeding critical habitat attributes in the Montréal region of the St. Lawrence River, based on a model. Stretches of the Rivière des Prairies and the Rivière des Mille Îles containing critical habitat begins at longitude 73° 35′ 31″ W in the Rivière des Mille Îles and at longitude 73° 37′ 11″ W in the Rivière des Prairies.

map

Figure 9. Bounding area (in black) in which critical adult feeding habitat corresponds to grass beds presenting the attributes listed in Table 3. Coloured in green are the areas thought to possess adult feeding critical habitat attributes in the Contrecœur region of the St. Lawrence River, based on a model.

map

The present recovery strategy includes the critical habitat identified to the extent possible, based on the best available information. The quantity and quality of habitat suitable for the growth of adults identified for the purposes of this recovery strategy do not appear sufficient to provide an adequate environment for a population containing 4,000 mature individuals. The fluvial lakes may offer adequate habitat for the Copper Redhorse, but their use by this species is not well documented. Studies need to be conducted to identify the entire critical habitat necessary to attain the population and distribution objectives (Table 4).

Table 4. Schedule of studies
Description of activity Results/rationale Timeline
Identify the grass beds in Lake Saint-Pierre, Lake Saint-Louis and in the de la Prairie basin which exhibit the necessary attributes of critical feeding habitat for adult Copper Redhorse. Identify feeding and growth areas for adults in order to meet population and distribution objectives 2016

Any activity that modifies the attributes presented in Table 3 of the features of identified critical habitat can cause its destruction. As habitat use varies in time, any human activity must be assessed on a case-by-case basis and mitigation measures have to be applied when available and be efficient. The activities described in Table 5 are not exhaustive and are taken from the General Threats described in section 1.5 of this recovery strategy. The absence of a specific human activity does not preclude, or fetter the department’s ability to regulate it pursuant to SARA. Furthermore, the inclusion of an activity does not result in its automatic prohibition because it is the destruction of critical habitat that is prohibited and not the activity itself.

Bank stabilization through the use of riprap or the construction of retaining walls leads to shoreline hardening which, in turn, modifies plant composition and water flow in the grass beds. The deforestation of banks prevents containment of runoff and results in soil erosion, leading to increases in water temperature. In-filling wetlands or grass beds and construction of certain types of docks or other structures within habitat areas lead to the modification or destruction of these habitats. Dredging and the deposition of sediments destroy streambeds, particularly through the disappearance of aquatic grass beds. In addition, many pleasure-boating activities may cause degradation of the substrate by augmenting turbidity, destroying aquatic vegetation and trampling substrates.

Finally, flood control structures and hydroelectric installations which modify water input into the critical habitats of the Copper Redhorse may alter or destroy these habitats. Structures which present obstacles to both upstream and downstream migration may destroy critical habitat.

Under SARA, critical habitat must be legally protected from destruction once it is identified. This will be accomplished through a s.58 Order, which will prohibit the destruction of the identified critical habitat unless permitted by the Minister of Fisheries and Oceans Canada pursuant to the conditions of SARA.

Table 5. Examples of activities likely to destroy critical habitat
Activities Pathway of effects Disrupted function Disrupted feature Disrupted attributes
Construction of dams Modification of hydraulic conditions Spawning Rapids
  • Depth between 0.75 and 2 m
  • Weak to moderate current (0.2 to 0.6 m/s)
  • Heterogeneous substrate (fine to coarse gravel, cobble)
Feeding
Rearing
Grass beds
Littoral zone
  • Depth from 0 to 4 m
  • Weak to moderate current (less than 0.5 m/s)
  • Minor slope (less than 20 degrees)
  • Relatively fine substrate
  • Moderate to high vegetation density
  • Abundance of gastropods and dreissenids
Obstacle to migration Migration Littoral zone
  • Depth from 0 to 4 m
Construction (dock, bridge, marina, etc.) Destruction of grass beds
Sedimentation
Feeding
Rearing
Littoral zone
Grass beds
  • Depth from 0 to 4 m
  • Weak to moderate current (less than 0.5 m/s)
  • Minor slope (less than 20 degrees)
  • Relatively fine substrate
  • Moderate to high vegetation density
  • Abundance of gastropods and dreissenids
In-filling Destruction of grass beds Feeding
Rearing
Littoral zone
Grass beds
  • Depth from 0 to 4 m
  • Weak to moderate current (less than 0.5 m/s)
  • Minor slope (less than 20 degrees)
  • Relatively fine substrate
  • Moderate to high vegetation density
  • Abundance of gastropods and dreissenids
Bank construction (retaining wall, rip-rap, etc.) Destruction of grass beds
Sedimentation
Feeding
Rearing
Littoral zone
  • Depth from 0 to 4 m
  • Weak to moderate current (less than 0.5 m/s)
  • Minor slope (less than 20 degrees)
  • Relatively fine substrate
  • Moderate to high vegetation density
  • Abundance of gastropods and dreissenids
Navigation Wave action from passing boats reducing grass beds
Destruction of aquatic vegetation
Feeding
Rearing
Littoral zone
Grass beds
  • Relatively fine substrate
  • Moderate to high vegetation density
  • Abundance of gastropods and dreissenids
Dredging and deposition of sediments Destruction of streambed Feeding
Rearing
Grass beds
  • Relatively fine substrate
  • Moderate to high vegetation density
  • Abundance of gastropods and dreissenids
Pleasure-boating activities Crushing and destruction of aquatic vegetation Spawning Rapids
  • Heterogeneous substrate (fine to coarse gravel, cobble)
Feeding
Rearing
Littoral zone
Grass beds
  • Relatively fine substrate
  • Moderate to high vegetation density
  • Abundance of gastropods and dreissenids

Despite the considerable effort made to gather information on such a rare species, knowledge gaps subsist and have been identified. This lack of knowledge must be addressed before the development of a comprehensive and adequate strategy for the recovery of the Copper Redhorse is possible.

There are other potential spawning grounds (Figure 3), though reproductive activity in these sites has never been confirmed. These potential spawning grounds need to be further assessed to ensure that they possess the requisite characteristics.

Information has been gathered on certain aspects of the growth, nutritional needs, and habitat of larvae and juveniles, which include young-of-the-year and fish that are one year old in the spring (between 25 mm and 60 mm). A fry rearing ground has also been identified in the Richelieu River. However, there is still a lack of knowledge about larvae (under 25 mm) and sub-adults, fish between one and ten years of age with lengths varying between 100 and 500 mm. Knowledge about these groups and their habitats is very fragmentary and is limited to a few captures.

Many questions still remain concerning the distribution range and habitat of immature Copper Redhorse, particularly about the downstream migration and survival of larvae, the presence of sites in the Richelieu River where juveniles congregate, habitat characteristics, and the threats to the habitat and survival of sub-adult fish.

The adult population is composed primarily of older fish and available knowledge indicates that the level of reproduction is low. The mechanisms of absorption and the physiological effects of contaminants (atrazine, other pesticides, pharmaceutical and personal hygiene products) originating in municipal, industrial, and agricultural waste have not yet been clearly delineated, though they are suspected of acting as hormone and reproduction disruptors. Studies conducted on the Spottail Shiner (Notropis hudsonius), a cyprinid common to the Great Lakes basin and exposed to the wastewater outfall from Montreal, have revealed a high prevalence of feminization14 in specimens.

It is possible that the methods used to gather information on the total distribution range skewed the results partially to the detriment of Lake Saint-Louis. The information obtained through an analysis of the commercial fishery in Lake Saint-Pierre is based on incidental catches, while research activity itself is concentrated on the portion of the population located in the Richelieu River and St. Lawrence River, downstream of Montreal. Moreover, no sampling program has been carried out in the Noire River and Yamaska River since 1995. Though these environments have been severely degraded and minimum water flow within them greatly reduced, neither the presence nor absence of the species in these rivers can be confirmed. Questions also remain concerning factors (e.g. inadequate grass beds) which could explain why some areas of potential summer habitat in the fluvial lakes are less frequented by Copper Redhorse.

When invasive exotic species such as the Tench, Round Goby, zebra mussel, European water chestnut and common water reed establish themselves in an environment, they bring changes to the physical environment and to the food chain. However, the effects of these introduced species on the Copper Redhorse population have not been sufficiently well documented.

Current knowledge on winter habitat remains fragmentary and is solely based on the telemetric monitoring of 11 fish during the winter of 2008.

Despite these knowledge gaps, the available information on the Copper Redhorse is significant and of high quality considering how rare the species is. Further efforts to collect more information should avoid manipulation of specimens as much as possible as this presents a threat to the survival of the species.

The Regulation respecting the Pierre-Étienne-Fortin Wildlife Preserve, R.Q.c. C-61.1, r.3.01.3.3, provides protection measures for the spawning ground at the Chambly rapids. The land on which the wildlife preserve is located is owned by Hydro-Québec and the municipality of Richelieu. According to sections 3 and 4 of the Regulation, “From 20 June to 20 July, no person may enter, stay in, travel about or engage in any activity in sectors B and C of the wildlife preserve” and “No person may, in the wildlife preserve, engage in an activity that may alter any biological, physical or chemical element of the habitat of the Copper Redhorse, the River Redhorse or the Channel Darter (Percina copelandi).” (c. C-61.1, r.46, sections 3 and 4). For critical habitat to be adequately protected, the preserve will need to be extended to include all the spawning grounds.

The Saint-Ours Canal National Historic Site on the Richelieu River, together with the bridge-dam and fish ladder, the adjacent west bank and l'île Darvard fall under the jurisdiction of the Parks Canada Agency. The tailrace of the dam is a known spawning ground, while the fish ladder represents a necessary stage in the migration of Copper Redhorse towards the Chambly spawning ground.

Environment Canada’s Canadian Wildlife Service owns several islands in the Contrecoeur archipelago which have been declared national wildlife areas under the Wildlife Area Regulations (C.R.C., c. 1609) of the Canadian Wildlife Act. The Îles de Contrecœur National Wildlife Area covers 312 hectares and includes eleven islands in the archipelago.

The Île Jeannotte and Île aux Cerfs, located downstream of the Chambly basin in the Richelieu River were acquired by the NCC. Ownership of Île aux Cerfs has since passed to the MRNF. The shoreline of these islands is thus protected from urban development. This also provides protection for the grass beds around the archipelago. Creation of a wildlife refuge on these islands is in the planning stage.

The performance indicators presented below provide a way to define and measure progress toward achieving the population and distribution objectives. Specific progress towards implementing the recovery strategy will be measured against indicators outlined in subsequent action plans.

Performance indicators

The Species at Risk Act stipulates that “No person shall kill, harm, harass, capture or take an individual of a wildlife species that is listed as an extirpated species, an endangered species or a threatened species.” (subsection 32 (1)). Under subsection 83(4) of the Species at Risk Act, “Subsections 32(1) and (2), section 33 and subsections 36(1), 58(1), 60(1) and 61(1) do not apply to a person who is engaging in activities that are permitted by a recovery strategy, an action plan or a management plan and who is also authorized under an Act of Parliament to engage in that activity, including a regulation made under section 53, 59 or 71.

Fisheries
Although fishing for Copper Redhorse is prohibited in Quebec, incidental catches occur in the commercial and sport fisheries. The immediate release of this fish is mandatory, according to the Quebec Fishery Regulations (1990), SOR/90-214 of the Fisheries Act, R.S.C., 1985, c. F-14. As mentioned in the “Threats” section, the risk of accidental mortalities caused by commercial fisheries is very low. An outreach project aimed at commercial fishermen in Lac Saint-Pierre to assess Copper Redhorse bycatch, determined that no Copper Redhorse was incidentally caught by these fishermen (Comité ZIP du lac Saint-Pierre, 2010). The mortality risk owing to commercial fisheries in the river stretches upstream of the lake is not considered detrimental to the Copper Redhorse because the only permit for fyke nets will be bought back (P. Dumont, MRNF, personal communication) and gill nets used for fishing sturgeon and carp are unlikely to capture Copper Redhorse (Vachon and Chagnon, 2004; Chagnon, 2006c, b, a).

In accordance with subsection 83(4) of SARA, this recovery strategy authorizes fishermen to carry out sport or commercial fishing subject to the following conditions:

Furthermore, in accordance with subsection 83(4) of SARA, this recovery strategy authorizes fishermen to fish under the provisions of an aboriginal communal fishing licence, subject to the following conditions:

Research
Beginning in 2004, an artificial reproduction plan was implemented to counter the low rate of natural reproduction. The objective of the plan is to rebuild the reproductive stock by preserving at least 90% of the initial genetic diversity of the population over a period of 100 years (Bernatchez, 2004). Artificial reproduction is carried out by the MRNF at Park Canada facilities, with the support of DFO since 2009.

In accordance with subsection 83(4) of SARA, this strategy authorizes employees of the Ministère des Ressources naturelles et de la Faune du Québec, while performing their duties, to carry out activities related to the Copper Redhorse artificial reproduction programme, with the following conditions:

A protocol for the monitoring of redhorse young-of-the-year recruitment in the Richelieu River has been designed and implemented on an almost yearly basis. The objective of this project is to develop a performance index with which to evaluate present and future conservation and support measures. Certain preliminary trends have been detected in population abundance, young-of-the-year growth and the climatic and hydrological conditions of the environment (Vachon, 1999b, 2002, 2007). These efforts have also confirmed the short-term survival of juvenile Copper Redhorse introduced into the environment as part of the stocking program and have added to our knowledge of older juveniles.

In accordance with subsection 83(4) of SARA, this strategy authorizes employees of the Ministère des Ressources naturelles et de la Faune du Québec, while performing their duties, to carry out activities related to the recruitment monitoring programme, with the following conditions:

There is a lack of knowledge about subadults, fish between one and ten years of age with lengths varying between 100 and 500 mm. Knowledge about this group and its habitat is fragmentary and is limited to a few captures. A research effort on this segment of the population (objective 3 of this strategy) will be necessary to better protect it.

In accordance with subsection 83(4) of SARA, this strategy authorizes employees of the Ministère des Ressources naturelles et de la Faune du Québec, while performing their duties, to carry out activities related to the subadult monitoring program, with the following conditions:

One or more action plans will be published on the Species at Risk Public Registry by June 2017.


14 Feminization is the hormonally induced development of female sexual characteristics.

Previous ToC Next

Page details

Date modified: