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Science: Still Hope for Fisheries on the Brink
Researchers say that there is still hope for saving the world's fisheries from collapse—if we implement a combination of traditional approaches, such as catch quotas and community management, along with additional measures, such as strategically placed fishing closures, gear restrictions, ocean zoning, and economic incentives.
The future of the world's fisheries has been the subject of much debate in recent years, with some experts predicting a complete collapse and others hotly contesting this view. The conclusion that these fisheries can, in fact, still recover from high exploitation rates and plummeting fish stocks comes after a thorough assessment of global trends in their practices—possibly the most detailed and multi-faceted study on the subject to date.
Boris Worm from Dalhousie University in Canada, along with colleagues from various schools and organizations in the United States, the United Kingdom, Australia, New Zealand, Kenya, and Argentina, analyzed the current global trends in fisheries around the world, and they present their findings in the 31 July issue of the journal Science.
Their results reveal which management solutions work best for different fisheries, large and small, and they hope this data can be used to protect global fisheries and marine ecosystems from further depletion and collapse.
"What our results show is that, although the total number of collapsed [fish] stocks keeps increasing, different regions of the world are managed very differently," Worm said in an email interview. "Some, like Alaska, for example, see few collapses and display relative stability in both the ecosystem and the fisheries. Others, like Eastern Canada, have up to two-thirds of stocks collapsed and show dramatic changes in the composition of the ecosystem and their catches."
The group of researchers studied the "exploitation rates" of various fish stocks at different fisheries around the world, and found most were aimed at gaining the maximum sustainable yield—a goal that brings many fish stocks dangerously close to collapsing.
Worm and his colleagues say that some of the world's fisheries have already adjusted their exploitation rates, and are on their way to recovery. But, a large portion (at least 60%) of fish stocks worldwide still need help—and even lower exploitation rates are needed to reverse the collapse of some of the most vulnerable species.
The researchers recognize that rebuilding these collapsing fish stocks will require sacrificing short-term yields (and income) for conservation benefits, or at the very least, fishing some recoverable species while protecting others.
"Sixty-three percent of the stocks we examined are still lower than traditional target levels and need rebuilding," Ray Hillborn, a co-author of the Science report, said in an email interview. "Even when the ecosystems are fished at maximum sustainable levels, we expect 20 to 30% of the less productive species to be seriously depleted. If you want to save fish from depleting, you have to give up a lot of your potential yield. But, there are interesting options to try to prevent this tradeoff between yield and depleting unproductive stocks."
Unfortunately, most rebuilding efforts only begin after there is overwhelming evidence of overexploitation, and Worm and his colleagues insist that governments must take action to protect the fisheries before they reach that critical stage.
"The good news is that exploitation rates—a direct measurement of fishing pressure—is decreasing in half of the 10 ecosystems that we looked at in detail," Worm concluded. "This means that those regions are setting the stage for recovery. Other regions need to follow suit... It is possible to bring over-fishing under control. The tools are there and examples of recovery do exist. [This study] is only a start, but it suggests that the situation is not hopeless."
30 July 2009