Fishes (marine)

Shark, Blue  | Prionace glauca  |  Atlantic population

Status: Special Concern

Last Examination and Change: April 2006 (New)

Canadian Occurrence: Atlantic Ocean

Status Criteria: Not applicable

Reason for Designation: This species is a relatively productive shark (maximum age 16-20 years, mature at 4-6 years, generation time 8 years, 25-50 pups every two years) but as an elasmobranch, populations are susceptible to increased mortality from all sources including from human activities. The species is considered to have a single highly migratory population in the North Atlantic, of which a portion is present in Canadian waters seasonally. The abundance index which is considered to best represent the whole population has declined 60% 1986-2000 but another index shows no long-term trend for the whole population 1971-2003. Indices of abundance in and near the Canadian waters show variable trends from no decline to 60% decline from the 1980s to early 2000s. There is evidence for a decline in mean length in longline fisheries in Canadian waters 1986-2003. The primary threat is bycatch in pelagic longline fisheries; although the threat is understood and is reversible, it is not being effectively reduced through management. Assessing the impact of bycatch on the population would benefit from better information on proportion of individuals discarded which survive. It appears that recent fishery removals from the North Atlantic have been several tens of thousands of tons annually.  Estimated Canadian removals, a small proportion of the total, have been declining since the early 1990s and recently have averaged around 600 t/yr.

Status History: Designated Special Concern in April 2006.

Find out more about this species on the Species at Risk Act Public Registry

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