Marine fisheries

Declines in several fish stocks have occurred in the Atlantic and Pacific oceans as well as in the Hudson Bay, James Bay, and Foxe Basin, as a result of overexploitation in combination with other stressors, such as increased temperature, decreased salinity, and increased acidity. Declining stocks include groundfish, such as Atlantic and Pacific cod, lingcod and rockfish, pelagic fish such as herring and capelin, and anadromous fish such as coho, chinook salmon, Atlantic salmon, and Arctic char.5 Management measures designed to reverse longterm fisheries declines have been largely unsuccessful. Depending on the fishery, Photo: netted fish © have been hampered by large-scale oceanographic regime shifts, loss of spawning and rearing habitat, and contaminants.5

Not all fisheries are in decline. For example, turbot, sablefish, and Pacific sardine are all increasing in the West Coast Vancouver Island Ecozone+ and pink and chum salmon are increasing in the Strait of Georgia.5

Map and graphs: population trends of marine fisheries at various locations in Canada. Click for graphic description (new window).
Source: adapted from Fisheries and Oceans Canada (DFO), 2010,5 Johannessen and McCarter, 2010,15 and Worcester and Parker, 201016

Fish length at age 5, Scotian Shelf

cm, 1970 to 2002
Graph: fish length at age 5, Scotian Shelf. Click for graphic description (new window).
Source: adapted from Fisheries and Oceans Canada (DFO), 20105


Size of fish is an important determinant of reproductive success. Since the 1970s, several species have been getting smaller, including Pacific herring in the Strait of Georgia and five species of groundfish in the Scotian Shelf. Smaller size is implicated as a factor hampering recovery of some fisheries.5




Global Trends

Over 30% of fish stocks are over-exploited, fully exploited, or depleted.29
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