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Atlantic Wolfish

Atlantic Wolfish
DFO  R. Larocque

Whether you fish at sea, sail or harvest natural resources, whatever you do has an impact on hundreds of organisms from the tiniest unicellular alga to the immense blue whale. The ocean is vast. How many different habitats does it encompass? What are their geographic boundaries? What species depend on which habitat? What habitats may be affected by human activity in a given sector?

These are questions that interest researchers at the Maurice Lamontagne Institute. The area studied is vast, because it includes the estuary and Gulf of St. Lawrence, some 236,000 km2. The seabed has been described using a grid composed of 100 km2 cells. For each cell, the available information was collated; it includes such things as relief, , the nature of the seabed, slope and bathymetry, salinity and temperature, oxygen availability, proximity of the coast and protection from inclement weather. These data were then used to identify habitat categories with similar characteristics  so as to be able to assess their significance for each of the fish species inhabiting them. Ultimately, 13 major habitat categories were described: 4 in deep water and 9 in shallower water. Of these 13 categories, 4 are located in the southern gulf and 5 in the estuary and northern gulf.

This survey, built using the rich ministerial data base, also proposes a powerful environmental analysis and management method. This knowledge is used to delimit conservation areas and define the essential habitat of species at risk, including the spotted wolffish and the northern wolffish. In the case of these two species, catches have been collated so that the habitats they frequent and the environmental variables that explain their range could be collated. Researchers were also able to determine the other species with which the wolffish share these habitats. Another step forward could be taken if human activities were collated using the same analysis framework.  This survey therefore helps to achieve two objectives : the protection of the habitats of fish and species at risk and the formulation of notices that simultaneously take into account a number of ecosystem components.

A report on the classification of major habitat categories has been written and this data base is now available to the general public . The same method is currently being applied to describe, classify and map inshore and pelagic habitats (present in the water column) in this same area.

Fisheries and Oceans Canada ensures the protection of fish habitat particularly that of species at risk. This commitment is a key element of the international agreements to which Canada is a signatory. To preserve the health and productivity of marine habitats, this commitment is subject to a legislative framework pursuant to the Fisheries Act, the Oceans Act, the Species at Risk Act and the Canadian Environmental Assessment Act.

Jean-Denis Dutil
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