Pighead prickleback COSEWIC assessment and status report: chapter 12

Technical Summary

Acantholumpenus mackayi (Gilbert)

Pighead Prickleback – Terrassier à six lignes

Extent and Area information

extent of occurrence (EO) (km²) :

Possible maximum of 10,000 km²

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

Unknown

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

Unknown

area of occupancy (AO) (km²) :

  • Total, probably much less than 10,000 km².
  • Tuktoyaktuk = approximately 29 km²;
  • Liverpool Bay > 200 km²  

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

Unknown

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

Possible seasonal shifts of occurrence, otherwise unknown

number of extant locations :

About 5 or 6 known in Canada.

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

Unknown.

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

Unknown.

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.) :

Roughly 9 to 10 years (mean reproductive age varies with sizes of dominant year  classes).

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

Based on data for one year, mature, trawlable fish: Tuktoyaktuk: 1600+

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) :

NA

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

Yes, year classes fluctuate.

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)?

3 sampled populations in Canada, with unknown boundaries; globally, well fragmented.

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

  • Tuktoyaktuk (1600+);
  • Liverpool Bay (?);
  • Phillips Bay (?)

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

Unknown

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

Unknown

Threats (actual or imminent threats to populations or habitats)

  • potential threats include oil exploitation, global warming, dredging of harbours

Rescue Effect (immigration from an outside source)

does species exist elsewhere (in Canada or outside)?

Known outside Canada in western Alaska and near Japan.

status of the outside population(s)?

Unknown.

is immigration known or possible?

Restricted.

would immigrants be adapted to survive here?

Unknown.

is there sufficient habitat for immigrants here?

Unknown.

Quantitative Analysis

Other Status  

COSEWIC: Special Concern - 1989

Status: Data Deficient            

Criteria met: N/A

Reasons for Designation: There are insufficient data on population size and distribution

Applicability of Criteria 

Criterion A (Declining Total Population): Not applicable; population declined catastrophically 100 years ago, but began increasing about 50 years (2 generations ago).

Criterion B (Small Distribution, and Decline or Fluctuation):  Not applicable; there is a small distribution in terms of breeding sites, but population is now increasing after catastrophic decline 100 years ago.

Criterion C (Small Total Population Size and Decline):  Not applicable; population did decline to very few individuals 50 – 100 years ago, but is now increasing.

Criterion D (Very Small Population or Restricted Distribution):  Meets D1 and D2 criteria for Threatened (less than 1000 breeding individuals at less than 5 sites)

Criterion E (Quantitative Analysis):  None done.

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