Gravel chub (Erimystax x-punctatus) COSEWIC assessment and status report: chapter 11

Range of Occurrence in Canada:

Thames River

extent of occurrence (EO) (km²)

(Historic - Polygon Method) - Current <2000

specify trend (decline, stable, increasing, unknown) :

Not Applicable

are there extreme fluctuations in EO (> 1 order of magnitude)?

No

area of occupancy (AO) (km²)

Historic- actual aquatic habitat <20; using 1 km² grid <100; - Current : 0

specify trend (decline, stable, increasing, unknown) :

Extirpated

are there extreme fluctuations in AO (> 1 order magnitude)?

No

number of extant locations :

0

specify trend in # locations (decline, stable, increasing, unknown) :

Not Applicable

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 :

Decline

generation time (average age of parents in the population) (indicate years, months, days, etc.) :

2–3 yr?

number of mature individuals (capable of reproduction) in the Canadian population (or, specify a range of plausible values) :

0

total population trend: specify declining, stable, increasing or unknown trend in number of mature individuals :

Not Applicable

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)?

No

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

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

0

specify trend in number of populations (decline, stable, increasing, unknown) :

Not Applicable

are there extreme fluctuations in number of populations (>1 order of magnitude)?

No

does species exist elsewhere (in Canada or outside)?

Yes – in the U.S., but not in the Great Lakes watershed that could colonize the Thames River

status of the outside population(s)?

States adjacent to lakes Erie and St. Clair. NY – S1; OH – S3; PA – S1

is immigration known or possible?

Unknown

would immigrants be adapted to survive here?

Unknown

is there sufficient habitat for immigrants here?

No