Overfishing has driven several species of deep-water fish in the Atlantic to the brink of extinction in a single generation, Canadian biologists have found.

Populations have plummeted so rapidly that two commercially fished species, the roundnose grenadier and onion-eye grenadier, and three other species, should be classified as critically endangered – a higher rating than for the giant panda and Bengal tiger.

Between 1978 and 1984, catch data from research trawl surveys showed the relative abundance of the five species declined between 87 per cent and 98 per cent in Canadian waters, the researchers found.




"They meet the IUCN [World Conservation Union] criteria for being critically endangered," Jennifer Devine of Memorial University in St. John's, N. L., and her colleagues wrote in Thursday's issue of the journal Nature.

"Conservation measures are necessary and lack of knowledge must not delay appropriate initiatives, including the establishment of deep-sea protected areas," the study's authors conclude.

Richard Haedrich
Richard Haedrich

During the federal election campaign, the Conservatives and Liberals have promised to extend protection to fish stocks beyond Canada's 200-mile limit, although other countries have warned the federal government to forget the idea.

Time running out to save fish

After the collapse of easy-to-catch species such as cod and tuna in the 1960s and 1970s, trawlers turned to the deep-sea grenadiers.

The roundnose and onion-eye grenadiers declined 99.6 and 93.3 per cent respectively over the 26-year survey.

Despite growing evidence of collapses, fish are caught between financial, political and environmental interests, said the study's lead author, Richard Haedrich of Memorial.

"The real concern is that you alter these productive fishery ecosystems to such an extent that they no longer produce what you're interested in."

The species, which also include the blue hake, spiny eel, and spinttail skate, live on or near the bottom of the North Atlantic Ocean, on the continental slope, a downward ridge between the coastal shelf and the extreme ocean.

The three other species were "bycatch" scooped up in the hunt for Greenland halibut and redfish. The declines occurred in about one generation, the data suggest.

The fish can live up to 60 years, grow to more than one metre in length and mature in their late teens, all traits that increase the vulnerability of the deep sea fish, the biologists said.

Some species spawn in clusters on the sea floor, increasing their susceptibility to overtrawling.