River redhorse (Moxostoma carinatum) assessment and update status report: chapter 13
Moxostoma carinatum
river redhorse
chevalier de rivière
Range of Occurrence in Canada: southcentral Ontario and southern Quebec
Extent and Area Information
| Extent of occurrence (EO) (km2) | 150 000 km2 |
| specify trend (decline, stable, increasing, unknown) | Possibly stable in Ontario and decrease in Quebec |
| Are there extreme fluctuations in EO (> 1 order of magnitude)? | No |
| Area of occupancy (AO) (km2) For rivers with multiple extant sites (except Ottawa River), calculated as length of river between uppermost and lowermost sites multiplied by an average width of 0.10 km. For the Ottawa River, the average width was 1 km (pers. comm. Tim Haxton) Not determined for species from waterbodies with single site. |
Grand – 5 Trent – 5 Ottawa – 150 Mississippi – 3.5 Madawaska – 5 Richelieu– 10 Total – 178.5 |
| specify trend (decline, stable, increasing, unknown) | Possibly stable in Ontario and decrease in Quebec |
| are there extreme fluctuations in AO (> 1 order magnitude)? | unknown |
| number of extant locations Locations interpreted as discrete open circles on Fig. 3. |
~25 |
| specify trend in # locations (decline, stable, increasing, unknown) | In some watersheds, the species has likely disappeared (Ausable, Châteauguay, Yamaska) or suffered a large decline (St. Lawrence River) |
| are there extreme fluctuations in # locations (>1 order of magnitude)? | No |
| habitat trend: specify declining, stable, increasing or unknown trend in area, extent or quality of habitat | Stable in Ontario Declined in Quebec |
Population Information
| generation time (average age of parents in the population) (indicate years, months, days, etc.) | >5-10 years |
| number of mature individuals (capable of reproduction) in the Canadian population (or, specify a range of plausible values) | Unknown |
| total population trend: specify declining, stable, increasing or unknown trend in number of mature individuals | Unknown |
| if decline, % decline over the last/next 10 years or 3 generations, whichever is greater (or specify if for shorter time period) | Unknown |
| are there extreme fluctuations in number of mature individuals (> 1 order of magnitude)? | Unknown |
| is the total population severely fragmented (most individuals found within small and relatively isolated (geographically or otherwise) populations between which there is little exchange (i.e., < 1 successful migrant / year)? | Yes |
| list each population and the number of mature individuals in each | Unknown |
| specify trend in number of populations (decline, stable, increasing, unknown) | Decline |
| are there extreme fluctuations in number of populations (>1 order of magnitude)? | No |
Threats
- habitat degradation, pollution, siltation, habitat fragmentation by dams
Rescue Effect (immigration from an outside source)
| does species exist elsewhere (in Canada or outside)? | United States |
| status of the outside population(s)? | Michigan(S1), New York (S2?), Pennsylvania (S3) |
| is immigration known or possible? | Immigration from Michigan and New York populations to Ontario rivers improbable and from Pennsylvania possible |
| would immigrants be adapted to survive here? | Yes |
| is there sufficient habitat for immigrants here? | Unknown |
Quantitative Analysis
Not applicable
Current Status
COSEWIC: Special Concern (1987)
Special Concern (2006)
Special Concern (2006)
Status and Reason for Designation
| Status: Special Concern |
Alpha-numeric code: Not Applicable |
| Reason for designation: This freshwater fish species occurs in Ontario and Quebec, and although it has been collected at new locations in both provinces, sometimes in large numbers, this is thought to reflect the use of more effective sampling techniques such as boat electrofishing. It has likely disappeared historically from the Ausable, Châteauguay and Yamaska rivers, since the use of boat electrofishing has failed to collect it recently. Threats to the species include habitat degradation (pollution, siltation), stream regulation that affects water flow (dams) and habitat fragmentation (dams). The Canadian range is highly fragmented and rescue effect is improbable because of the precarious conservation status in adjoining U.S. states. |
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Applicability of Criteria
Criterion A (Declining Total Population):
Criterion thresholds not met.
Criterion thresholds not met.
Criterion B (Small Distribution, and Decline or Fluctuation):
Met criterion B2 (AO of 178.5 < 500 sq. km) and a) for severely fragmented but no continuing decline or extreme fluctuations.
Met criterion B2 (AO of 178.5 < 500 sq. km) and a) for severely fragmented but no continuing decline or extreme fluctuations.
Criterion C (Small Total Population Size and Decline):
Criterion thresholds not met because population sizes not known.
Criterion thresholds not met because population sizes not known.
Criterion D (Very Small Population or Restricted Distribution):
Criterion thresholds not met because number of mature individuals not known or AO (178.5 > 20 sq. km) and no. of locations (about 25 > 5) exceed minimum thresholds.
Criterion thresholds not met because number of mature individuals not known or AO (178.5 > 20 sq. km) and no. of locations (about 25 > 5) exceed minimum thresholds.
Criterion E (Quantitative Analysis):
Not available.
Not available.
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