Some fish stocks that were on the verge of collapse are showing signs of recovery due largely to intensive management practices, according to new research that suggests limits on overfishing are saving imperilled fisheries.
The findings, being published Friday in the journal Science, blunt dire predictions made in a controversial paper in 2006 that warned of the complete collapse of commercial fish stocks around the globe if fisheries management didn't change.
'I'm far more hopeful than I was in 2006.'— Boris Worm, researcher
Boris Worm, a marine biologist at Dalhousie University in Halifax, co-wrote both the 2006 article and the new paper.
He said the new study presents a broader picture of the state of the world's fisheries, finding that in five out of the 10 ecosystems studied, the amount of fish being harvested has been reduced.
The discovery offers a glimmer of hope for marine scientists who have for years been pressing governments to bring in more stringent controls on fishing activity as they watched stocks dwindle to near collapse.
"I'm far more hopeful than I was in 2006," he said in an interview.
"We're not only saying this should be done, we're saying where it has been done it has yielded benefits and a number of ecosystems are recovering and a number of stocks are recovering."
Fish stocks rebound in U.S., Iceland
The paper cites New England, Iceland and New Zealand as good examples of how curbs on overfishing helped slow stock decline and actually increase in abundance.
Haddock on the U.S. side of Georges Bank on the East Coast have rebounded after years of continuous decline due to foreign and domestic overfishing.
The government introduced closures in 1994 and Worm said the lucrative stock is back to much healthier levels.
Stocks off California were also seen to be improving after restrictions were placed on the types of gear that can be used to fish, large areas were closed to certain fishing practices and overall catch rates were decreased.
"It's a tremendous success story," Worm said.
"It appears that those areas that are successful in fisheries management are employing a diverse suit of tools. They're not just relying on one thing."
The key measures include closed areas, restrictions on certain gear like trawls, caps on total catches, economic incentives and community management.
The paper, which claims to offer the most detailed fisheries assessment ever, comes years after Worm was publicly rebuked by some in the scientific community for his 2006 article.
Ray Hilborn, a professor of fisheries management at the University of Washington, alleged Worm and his co-authors used faulty data when assessing the health of international fish stocks and issuing the alarming predictions.
Hilborn, who called the report "bogus," later met Worm and the two agreed to work together to produce this latest research paper.
Most stocks remain overfished
He said that while the findings are heartening, the overall picture remains bleak for global fish stocks.
Of all the stocks they studied, 63 per cent are overfished and there is an increasing trend of stock collapse.
"There's definitely been a big change, but there's still a long way to go," he said from Anchorage, Alaska, adding that the new data suggests up to 30 per cent of stocks might be collapsed if current management practices persist.
Canada was one of several countries that lagged behind in changing management practices to address stock depletion and widespread changes in the ecosystem caused by fishing.
Worm said Canada, particularly the East Coast, has seen multiple groundfish collapses due to decades of overfishing and poor management practices.
The legacy is an ecosystem that has been dramatically altered and may never returned to its former composition, he said.
"Canada stands out as one of the most transformed ecosystems that we have data for, because it has largely shifted from a dominance of groundfish to now invertebrates and pelagic species," he said.
"It's an ecosystem that has been largely transformed by fishing."
The authors said of the 200 stocks they had data on, about one-third had not been overfished, a third had been overfished, and the remainder had been overfished but exploitation rates had gone down, giving them a chance to recover.