Spiny softshell turtle (Apalone spinifera) COSEWIC assessment and status report: chapter 12

Technical Summary

Apalone spinifera

Spiny Softshell Turtle – La tortue-molle à épines

Range of Occurrence in Canada:
Ontario and Quebec

Extent and Area information

Extent of occurrence (EO)(km²) :
55250 km²
specify trend (decline, stable, increasing, unknown) :
Stable?
are there extreme fluctuations in EO (> 1 order of magnitude)?
No
area of occupancy (AO) (km²) :
3000 km²
specify trend (decline, stable, increasing, unknown) :
Stable?
are there extreme fluctuations in AO (> 1 order magnitude)?
No
number of extant locations :
11
specify trend in # locations (decline, stable, increasing, unknown) :
decline (16 historic sites where species was extirpated)
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 :
Declining quality and extent

Population information

generation time (average age of parents in the population) (indicate years, months, days, etc.) :
18+ years
number of mature individuals (capable of reproduction) in the Canadian population (or, specify a range of plausible values) :
Ont: 1000 (approx)
total population trend:  specify declining, stable, increasing or unknown trend in number of mature individuals :
most likely declining from historic population
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)?
Yes

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

  1. Ontario ~ 800-1000
  2. Quebec ~ 100
specify trend in number of populations (decline, stable, increasing, unknown) :
Stable?
are there extreme fluctuations in number of populations (>1 order of magnitude)?
No

Threats (actual or imminent threats to populations or habitats)

  • recreational use of nesting areas by humans and potential consequences (disturbance during nesting, collisions with watercraft etc.);
  • poaching of eggs, high populations of egg predators, continued developmental pressure on nest sites.
  • decline in crayfish which are a major component of their diet
  • increased fragmentation of habitat and population by dams
  • incidental captures of adults by commercial and sport fisheries, and by trappers of other turtles.

Rescue Effect (immigration from an outside source)

does species exist elsewhere (in Canada or outside)?
yes
status of the outside population(s)?
Varied
is immigration known or possible?
Yes, for Quebec population
would immigrants be adapted to survive here?
Yes
is there sufficient habitat for immigrants here?
No

Quantitative Analysis

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