Three years ago, a study assessing the health of global fisheries caused a stir when it predicted that the populations of all commercially-fished ocean species would collapse by 2048.
The new study, published in the journal Science, confirms that an increasing number of fish populations are collapsing. But it finds that the steps taken around the world to reverse that trend are working. The rate at which fish are being taken out of the sea has dropped to a level that should allow fish populations to recover in five of the 10 regions studied.
"This means different regions are heading in different directions and some regions have indeed begun to eliminate overfishing," says Boris Worm at Dalhousie University in Canada. He's the lead author of both the new study and the controversial 2006 study. Worm and a group of 20 collaborators from around the world looked at what strategies had helped successfully rebuild fish populations.
For example, in the northeastern United States, populations of haddock and other fish had been devastated by overfishing, beginning the 1960s. But in the 1990s, federal fishing authorities took aggressive action. They limited how many days fishers could spend at sea. Certain areas were closed to fishing entirely. Authorities required fishers to use gear that let smaller fish escape. And they set limits on the number and size of fish that could be caught. Study co-author Mike Fogarty of the National Oceanic and Atmospheric Administration says these measures worked.
"Today we've witnessed a dramatic recovery of haddock to the highest levels we've seen since the 1930s, when actual population estimates were first available," he says.
And success stories can be found in the developing world as well. The study highlighted the experience in Kenya, where fish populations grew after fishers agreed to use different nets and not to fish in certain areas.
But Africa's fisheries face another threat, according to study co-author Tim McClanahan of the Wildlife Conservation Society.
"Most countries in Africa are selling fishing rights to industrialized nations which catch large amounts of seafood, essentially outcompeting local fishermen through the contracts signed by their own government representatives," he says.
The study shows that when industrialized nations tightened restrictions on fishing, seafood companies moved their fleets to the waters off developing countries with fewer restrictions. The study authors say better global oversight is needed so that one nation's efforts to rebuild its fish populations don't come at another nation's expense.