THE WORLD’S WATERS are dangerously overfished, threatening the health and livelihood of millions across the planet

THE WORLD’S WATERS are dangerously overfished, threatening the health and livelihood of millions across the planet.

A new study from consulting firm California Environmental Associates, part of which appeared in the journal Science last week, estimates that “over 40 percent of fisheries have crashed or are overfished, producing economic losses in excess of $50 billion per year.” If you’ve heard more encouraging numbers before now, that’s because these new figures include estimates of what’s happening to unmonitored stocks, from which fishermen draw 80 percent of the world’s harvest, not just those stocks that authorities closely assess. One indication of fishery depletion, the report notes, is that people are spending more effort — traveling farther, sinking more hooks, staying on the water longer — to catch fewer and fewer fish. Unsurprisingly, the problem is worst in middle- and low-income countries, where regulation is more often spottily enforced or nonexistent.

Just because many fisheries are strained, however, doesn’t mean they are beyond repair. At the root of the problem is that too many fishermen face incentives to take too many fish out of the water to secure immediate benefits. With few controls and many boats on the water, captains aren’t punished for pulling in full net after full net, but they do worry that competition will limit their ability to catch as many fish in the future. Changing those expectations to reduce overfishing in the short term can result in more fish available for catching in the long term, since fish populations would have time and space to rebound and grow. The study estimates that 64 percent of unmonitored areas could, in fact, provide a bigger harvest on a sustainable basis if properly regulated.

The best way to do that is to give fishermen a direct stake in the long-term health of a stock. U.S. fishery managers, for example, have increasingly introduced “catch share” systems in which regulators divvy up fishing rights among local captains. This system caps the number of particular species that fishermen can catch, and it eliminates the perilous race to fish when authorities limit fishing to just particular seasons.

Catch share-style programs might not be ideal solutions for every fishery, particularly in places where the government is weak. But even in places where institutions remain feeble, there is room for productive experimentation. Governments could consider devolving control over who can fish and how much to particular regions, towns or villages, institute cooperative fishery management or find other, inexpensive ways to offer those harvesting fish some sense of ownership over common, precious and currently overtaxed resources.