HALIFAX, Nova Scotia (AP) – Many fish stocks throughout the world could face near-extinction by 2050 if more isn’t done to stem the increasing strain on most species, especially those in deep waters, says a report to be released Friday.

The article, to be published in Science Magazine, says authorities must try to contain a trend that has trawlers venturing further offshore and destroying habitats as they search for large species.

The paper, called the Future for Fisheries, describes measures that should be taken to “bring fisheries back from the brink and reduce the danger of extinction for many species.”

The world’s fisheries have become so stretched because boats have been moving into deeper water to find larger, high-priced fish, such as tuna and groupers, as smaller species become fished out, the article states.

Daniel Pauly, one of the article’s authors, said that over the last 50 years the international fishery has moved into deeper waters – a trend that could foreshadow stock losses similar to what happened to cod in Canada.

“You have one fishery collapsing after the other,” he said in an interview from his office at the University of British Columbia. “The parts of the world that were not fished are now fished… This is a very powerful trend.”

Pauly and his colleagues suggest there are things that can be done to prevent further erosion of stocks, and for the first time have linked the availability of cheap oil to the expansion of the world’s fisheries.

The scientists argue that boats will continue to ply deep waters further offshore if there is a ready supply of inexpensive fuel.

But economists and geologists have predicted that fuel prices will rise, possibly making the fishery prohibitive for large trawlers that are heavily dependent on fuel.

“If fuel energy becomes as scarce and expensive in the next decades as suggested by a number of independent geologists, then we should expect the most energy-intensive among industrial fisheries to fold,” the article says.

The authors argue this might protect stocks that are now under threat and could lead to the creation of reserves or protected areas with little or no fishing.

Fish stocks might also be helped internationally if heavy fishery subsidies are reduced if not eliminated, something that could lead to a significant reduction in the number of boats on the water, says Pauly.

“If you don’t subsidize so much, then most of the fisheries can rebuild because there’s less fishing effort on them,” he said.

The article also states that agencies and governments have to introduce regulatory reforms to protect resources that are already under threat. Pauly argues that more marine protected zones should be created, fishing effort should be reduced and gear that destroys habitats should be restricted.

Without such measures, the scientists contend many fisheries will be exhausted in the next four decades and marine geography will be stripped of valuable nutrients and plankton.

“I’m not too optimistic,” said Pauly. “If we chose ecology first, then that bleak ending will not happen. If we continue what we have, then we’re in trouble.”

AP-ES-11-20-03 1839EST