Scientific Name: Prionace glauca
Other/Previous Names: Blue Shark (Atlantic population)
Taxonomy Group: Fishes
Range: Quebec, New Brunswick, Prince Edward Island, Nova Scotia, Newfoundland and Labrador, Atlantic Ocean
Last COSEWIC Assessment: November 2016
Last COSEWIC Designation: Not at Risk
SARA Status: No schedule, No Status
PLEASE NOTE: Not all COSEWIC reports are currently available on the SARA Public Registry. Most of the reports not yet available are status reports for species assessed by COSEWIC prior to May 2002. Other COSEWIC reports not yet available may include those species assessed as Extinct, Data Deficient or Not at Risk. In the meantime, they are available on request from the COSEWIC Secretariat.
The blue shark (Prionace glauca) is long and slender with distinctive blue coloration on dorsal and lateral surfaces. They are widespread and highly migratory with some evidence of movement between hemispheres although most tagging studies suggest that blue sharks are largely separated by hemispheres. The North Atlantic and North Pacific populations are considered as two designatable units because they are geographically isolated by the continental landmass of North America: there is no evidence of movement between ocean basins. The population structure is not well defined from a genetic point of view. In French this species is known as requin bleu.
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.
Your opinion is being sought to assist the government of Canada in making an informed decision on whether to add the Blue Shark (Atlantic population), Shortfin Mako (Atlantic population) and White Shark (Atlantic population)
to Schedule 1 (the List of Wildlife Species at Risk) of the Species at Risk Act (SARA). Your input on the impacts of adding these species to the List is important. This workbook has been developed to give you an opportunity to provide Fisheries and Oceans Canada with your feedback, advice, and other comments regarding adding these species to Schedule 1 of SARA (Schedule 1 identifies which species are legally protected under SARA).