An international study assessing the status of marine fisheries and ecosystems concludes that efforts to curb over-fishing are beginning to succeed in five of the 10 large marine ecosystems examined.
The report gives special kudos to the management of Alaska fisheries.
The paper appears in the July 31 issue of the journal Science. It provides new hope for rebuilding troubled fisheries, according to study leaders Ray Hilborn of the University of Washington, in Seattle, and Boris Worm of Dalhousie University, in Halifax, Nova Scotia, Canada.
Hilborn, Worm and 19 other co-authors concluded that Alaska and New Zealand have led the world in terms of management success by not waiting until drastic measures are needed to conserve, restore and rebuild marine resources.
The study is based on 166 fishery stocks, said Trevor Branch, a research scientist at the University of Washington and one of the co-authors.
"We think we can get that up to 300 (fishery stocks) or more," he said. "There's still a lot of work to be done, but I would say this is the most general overall paper planned from this group."
The two-year study examined current trends in fish abundance and exploitation rates - the proportion of fish taken from the sea - and to identify which tools managers have applied in efforts to rebuild depleted fish stocks.
Research showed that the rate of fishing has been reduced in several regions of the world, resulting in some stock recovery, and bolstered the argument that sound management can contribute to the rebuilding of fisheries elsewhere, the authors said.
"Yet there is still a long way to go," Hilborn said. "Of all fish stocks that we examined, 63 percent remained below target and still needed to be rebuilt."
While across all regions there is a troubling trend of increasing stock collapse, this paper shows that our oceans are not a lost cause, Worm said.
"The encouraging result is that exploitation rate - the ultimate driver of depletion and collapse - is decreasing in half of the 10 systems we examined in detail," he said. "This means that management in those areas is setting the stage for ecological and economic recovery. It's only a start, but it gives me hope that we have the ability to bring over-fishing under control."
The authors cautioned that their analysis was mostly confined to intensively managed fisheries in developed countries, where scientific data on fish abundance is collected. They also said that some excess fishing effort is simply displaced to countries with weaker laws and enforcement capacity.
While most fisheries that showed improvement are managed by a few wealthy nations, there are notable exceptions. In Kenya, for example, scientists, managers and local communities have teamed up to close some key areas to fishing and restrict certain types of fishing gear. This led to an increase in the size and amount of fish available, and a consequent increase in fishers' incomes, the study said.
According to Tim McClanahan of the Wildlife Conservation Society in Kenya, these local successes are inspiring others to follow suit.
Another co-author, Jeremy Collie of the University of Rhode Island, said researchers know more fish can be harvested with less fishing effort and less impact on the environment, if harvests are slowed down to allow over-fished populations to rebuild.
The authors said there is a range of management solutions available to help rebuild fish stocks. They have found that a combination of approaches, such as catch quotas and community management coupled with strategically placed fishing closures, ocean zoning, selective fishing gear and economic incentives, offer promise for restoring fisheries and ecosystems, provided that efforts are customized to the place and people involved.
The new study is a follow up to a 2006 paper in Science by Worm and others that highlighted a widespread global trend toward fisheries collapse. Results of that paper led to a public disagreement between Worm and Hilborn.
Subsequently the two scientists recognized a shared sense of purpose and collaborated on this more detailed assessment of world fisheries, with other fisheries scientists and ecologists, through the National Center for Ecological Analysis and Synthesis in Santa Barbara, Calif. The current paper is the result of this effort.
Margaret Bauman can be reached at margie.bauman@alaska
journal.com.
