Private “catch shares” create incentives to protect fisheries
Population crashes of predatory fish such as salmon, cod, and bluefin tuna are becoming increasingly common, and some experts warn that most of the world’s commercial fisheries could collapse within decades. These declines highlight a puzzling reality of fisheries management: overfishing is decimating many fisheries, even though the fishing industry has clear incentives to preserve populations and thereby ensure future profits. So why the disconnect?
According to a new paper in Science, one answer may be tied to the traditional management approach of setting an overall limit on how much fish can be harvested, then turning fishermen loose to scoop up the largest possible share. Such a system sparks intense competition among individuals, which can lead to overharvesting, but provides no incentives for individual fishers to practice good stewardship. An alternative management strategy is to allocate private “catch shares,” or rights to a percentage of the total harvest, to individuals or cooperatives. Proponents of catch-share management say it circumvents the “race to fish” while creating incentives to help expand the size and health of the entire fishery. And the Science study shows that catch shares are indeed highly effective in reducing fisheries declines.
A team led by Christopher Costello of the University of California, Santa Barbara, assembled a database of 11,135 commercial fisheries worldwide. After controlling for a host of other variables, the researchers found that catch share–managed fisheries had suffered only half the number of collapses—defined as a decline to less than 10 percent of maximum harvest—as those under traditional management. “Switching to [individual catch shares] not only slows the decline toward widespread collapse, but it actually stops this decline,” the researchers concluded.
The potential of rights-based management was shown by extrapolating data on catch-share fisheries alongside data from a 2006 report on global fisheries collapse. In that study, led by Boris Worm of Dalhousie University, researchers found that 27 percent of the world’s fisheries had collapsed by 2003, with a trend toward 100 percent collapse by 2048. In contrast, Costello and colleagues write that, if all fisheries had adopted catch shares in 1970, only about nine percent would have collapsed by 2003—and this percentage would not increase in coming decades. ❧
Costello, C., S.D. Gaines, and J. Lynham. 2008. Can catch shares prevent fisheries collapse? Science 321:1678-1681.