Cod: Atlantic

Scrod, Whitefish

The Atlantic cod is a well known species that once sustained prodigious fisheries in the Northwest Atlantic, but declined dramatically from overfishing over many decades, but particularly in the late 1980s and early 1990s. Cod is distributed throughout the Atlantic with the highest densities in Canadian waters found off Newfoundland, in the Gulf of St. Lawrence and on the Scotian Shelf. Living near the ocean bottom, cod normally inhabit depths ranging from 10-50m, but can be found down to 400m. The species is largely sedentary, but does migrate to feed and spawn when cued by changes in water temperatures. Off Newfoundland, cod move from deep ocean waters in the winter to relatively warm shelf waters in the summer. In New England animals move into coastal waters in the autumn, then return to deeper waters during spring. Several different stocks have been identified in US and Canadian waters, but these populations are managed as two stocks: one centred in the Gulf of Maine and the other extending from Georges Bank southward.

Cod are not considered inherently vulnerable to fishing pressure, although history has shown otherwise, because they mature young (2-4 years of age) and are typically short lived. In the Gulf of Maine and George Bank stocks, there is evidence that selection via fishing has caused growth rates to increase, and age and size at maturity to decrease. These changes may negatively affect the condition of young and hence the number of individuals that successfully become a part of the adult population. Cod’s high fecundity –a large female can release up to 9 million eggs in a season- does not necessarily ensure that populations can rebound quickly from fishing pressure.

Both the Gulf of Maine and Georges Bank cod stocks are overfished, and overfishing is occurring. In Canada, 7/9 stocks are in ongoing decline while two stocks are considered depressed but stable. As of October 2003, the Gulf of Maine and Georges Bank stocks needed increases of 716% and 247% respectively, to rebuild to biomass at MSY. Therefore, the United States GOM and GB fisheries are ranked as a Critical Conservation concern. The status of Canadian cod stocks is ranked as poor, with the Canadian portion of the GB fishery considered to be in critical condition.

The trawl fishery for cod has substantial bycatch and discard of unmarketable and undersized catch. Trip limits, used to regulate catch, are also likely to cause otherwise market-worthy fish to be discarded as fishers try to maximize the value of each trip. While increasing the allowable mesh size may have decreased bycatch, the minimum legal size for cod has recently increased, which may have increased discarding. Trawling is also known to take small numbers of marine mammals and sea turtles, but observer coverage is only 5% and logbooks may underestimate true bycatch. A small hook and line fishery exists for cod and has shown very low rates of bycatch.

Otter trawling for Atlantic cod scrapes the ocean bottom causing: 1) sediment re-suspension and smoothing, 2) removal of non-target species and3) destruction of three-dimensional habitat. Recovery is slower in muddy and structurally complex (e.g. deep sea corals and sponges) habitats, while mobile sandy sediment communities are more robust. Trawlers targeting cod and other groudfish of the US East Coast encounter all of these types of substrate, and repeated trawling in many areas is believe to have caused significant adverse changes to seabed ecosystems. A small hook and line fishery exists for cod that does not damage habitat.

Removal of substantial fish biomass in Northwest Atlantic has shifted the ecosystem towards from a bottom fish community to a pelagic/invertebrate community. It is believe that predation of juvenile bottom fish by small and now abundant pelagic species may prevent recovery of the overfished species, resulting in a permanently altered system.

Canadian cod stocks are presently considered moderately well managed, after a history of poor management, although stocks show no sign of recovery. In Canada, the Department of Fisheries and Oceans (DFO) manages eight cod stocks and cooperates with the United States National Marine Fisheries Service (NMFS) to manage the transboundary Georges Bank stock. Canadian groundfish are managed through an individual transferable quota (ITQ) system. Additional management measures used in Canada include: regular stock assessments, mandatory dockside monitoring programs financed by fishermen’s organizations, prohibition on discarding undersized target species, gear restrictions, seasonal closures and no-take fishing zones to protect habitat, Canada Coast Guard monitoring of fishing vessels.

Contaminant levels do not warrant a consumption advisory.

No.