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Spotted sucker (Minytrema melanops) COSEWIC assessment and status report: chapter 11

Technical Summary

Minytrema melanops

Spotted Sucker

Meunier tacheté

Range of Occurrence in Canada:
Ontario--Detroit River (including Canard), East Sydenham River, North Sydenham River, Lake St. Clair, St. Clair River, Thames River, Western Lake Erie basin

Extent and Area information

extent of occurrence (EO)(km²) :
6,600
specify trend (decline, stable, increasing, unknown) :
Stable
are there extreme fluctuations in EO (> 1 order of magnitude)?
No

area of occupancy (AO) (km²).
For rivers with multiple sites, calculated as length of river between uppermost and lowermost sites multiplied by average width.

specify trend (decline, stable, increasing, unknown) :
Stable
are there extreme fluctuations in AO (> 1 order magnitude)?
No
number of extant locations :
Seven
specify trend in # locations (decline, stable, increasing, unknown):
Increasing
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 :
Unknown

Population information

generation time (average age of parents in the population) (indicate years, months, days, etc.) :
3 yrs
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)
are there extreme fluctuations in number of mature individuals
(>1 order of magnitude)?
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)?
No, but degree of migration rate between localities unknown

List each population and the number of mature individuals in each :

specify trend in number of populations (decline, stable, increasing, unknown) :
unknown
are there extreme fluctuations in number of populations (>1 order of magnitude)?
no

Threats (actual or imminent threats to populations or habitats)

habitat degradation (pollution), siltation

Rescue Effect (immigration from an outside source)
Moderate
does species exist elsewhere (in Canada or outside)?
Yes
status of the outside population(s)?
Michigan (S3), Ohio (S?), Pennsylvania (S2)
is immigration known or possible?
Yes
would immigrants be adapted to survive here?
Yes
is there sufficient habitat for immigrants here?
Yes

Quantitative Analysis

Data Not Available

Existing Status     

      Nature Conservancy Ranks (NatureServe 2004)

Other

Status and Reasons for Designation

Status:  Special Concern

Alpha-numeric code: None apply

Reasons for Designation:

This freshwater fish species is restricted to southwestern Ontario.  The greatest threat to this species is habitat degradation through increased erosion and turbidity.  The species is also at risk in Pennsylvania, but not at risk in Michigan (where it is S3-vulnerable) making rescue effect moderate at best. 

Applicability of Criteria

Criterion A (Declining Total Population): This criterion does not apply because the total population trend is unknown and the EO and AO are stable.

Criterion B (Small Distribution, and Decline or Fluctuation):  Qualifies for Threatened based on EO (6,600 km²), AO (1,090 km²), and number of locations (7 waterbodies); but no continued decline, nor extreme fluctuations are demonstrable.

Criterion C (Small Total Population Size and Decline): The data are not available.

Criterion D (Very Small Population or Restricted Distribution): Not applicable – area of occupancy greater than 20 km².

Criterion E (Quantitative Analysis): The data are not available.

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