Grass pickerel (Esox americanus vermiculatus) COSEWIC assessment and status report: chapter 13
Technical summary
Grass Pickerel
Brochet Vermiculé
Ontario, Quebec
Extent and area information
Area of occupancy (AO) (based on stream lengths in km).
- Severn River - Sparrow to Bass Lake - ca 26 km2
- Old Ausable Channel - 0.5 km2
- Lake St. Clair (incl. Walpole Island, Little Bear Creek, Sydenham River) - ca 260 km2
- Point Pelee ca 4 km2
- Long Point ca 140 km2
- Lower Grand River ca 1.9 km2
- Upper Niagara River tributaries, Welland River drainage, and Point Abino - ca 1.3 km2
- Twenty Mile Creek ca 1 km2
- Eastern Lake Ontario & upper St. Lawrence River (incl. Jones Creek, upper Gananoque) - ca 100 km2
- Lake St. Francis to Lac St-Louis. - ca 150 km2
Population information
Listed by location, there may be more than one population at locations 1, 3, 7, 9 and 10. There may be 3 populations at location 10 – Lac St-François, Coteau and Lac St-Louis. The number of mature individuals at any one location is not known, but would certainly not be large, perhaps in the 10s for the single population locations and in the 100s or low thousands for eastern Lake Ontario and the upper St. Lawrence.
- Severn River
- Old Ausable Channel
- Lake St. Clair (incl. Walpole Island, Little Bear Creek)
- Point Pelee
- Long Point
- Lower Grand River
- Upper Niagara River (including Welland River drainage)
- Twenty Mile Creek
- Eastern Lake Ontario & upper St. Lawrence River (incl. Jones Creek, upper Gananoque)
- Lake St. Francis to Lac St-Louis
Threats (actual or imminent threats to populations or habitats)
- urbanization and agriculture practices through effects on reduction in flow and channelization and pollution through herbicides
- siltation
- removal of vegetation
- low water levels caused by water extraction, and drought
- diversion of cold or cool water into pickerel habitat
- destruction and degradation of wetland habitat
Rescue effect (immigration from an outside source)
Only neighbouring populations – see below for status of other US locations
Pennsylvania (S4)
Ohio (S?)
Michigan (S5)
Quantitative analysis
Not applicable
Existing status
National
Canada – N4
Regional
Missouri – S?, Nebraska – S4, New Hampshire – S4, New Jersey – S5, New York – S4, North Carolina – S5, Ohio – S?, Oklahoma – S5, Pennsylvania – S4,
Rhode Island – S5, South Carolina – S?, Tennessee – S5, Texas – S3, Vermont – S4, Virginia – S4, Washington – SE, West Virginia – SU, Wisconsin – S4
Canada: Ontario – S3, Quebec – S4
Wild Species 2000 Canadian Endangered Species Council 2001)
Ontario – 3, Quebec – 2
Committee on the Status of Endangered Wildlife in Canada (COSEWIC) – Special Concern (May 2005)
Status and reasons for designation
Reasons for Designation: A subspecies known from 10 locations between Lake St. Louis, Quebec and Lake Huron, Ontario. Its usual habitat is shallow water with abundance of aquatic vegetation. An overall decline of approximately 22% in the area of occupancy has been observed. This decline appears to be related to degradation and loss of habitat due to channelization and dredging operations in wetland habitats where this species occurs.
Applicability of criteria
Criterion A (Declining Total Population): Not Applicable – although some decline has occurred in about 22% of the Area of Occupancy at 3 of 10 locations, and there are indications of continuing decline in these areas, threshold values are not met.
Criterion B (Small Distribution, and Decline or Fluctuation): The area of occupancy (683 km2) is below the minimum threshold for Threatened, and decline has occurred at 3 of 10 locations and is continuing to occur. Therefore qualifies for threatened B2a,b(ii-v).
Criterion C (Small Total Population Size and Decline): Not Applicable -- Total population size is unknown but presumed to be >10 000. Therefore, does not qualify under this criterion.
Criterion D (Very Small Population or Restricted Distribution): Not Applicable -- Number of individuals unknown but presumed to be >10 000. Area of occupancy and number of extant locations are greater than threshold limits.
Criterion E (Quantitative Analysis): Not Applicable.
Page details
- Date modified: