Privatizing fish supplies? In the Ocean? The Economist explains how it is being done.

The Alaskan halibut and king crab fisheries illustrate how ITQs can change behaviour. Fishing in these waters had turned into a race so intense that the season had shrunk to just two to three frantic days. Overfishing was common. And when the catch was landed, prices plummeted because the market was flooded. Serious injury and death became so frequent in the king crab fishery that it turned into one of America's most dangerous professions (and spawned its own television series, "The Deadliest Catch").

After a decade of using ITQs in the halibut fishery, the average fishing season now lasts for eight months. The number of search-and-rescue missions that are launched is down by more than 70% and deaths by 15%. And fish can be sold at the most lucrative time of year--and fresh, so that they fetch a better price.

In a report on this fishery, Dan Flavey, a fisherman himself, says some of his colleagues have even pushed for the quota to be reduced by 40%. "Most fishermen will now support cuts in quota because they feel guaranteed that in the future, when the stocks recover, they would be the ones to benefit," he says.

Although governing authorities are important in setting up ITQs, so is policing of the system by the fishermen themselves. In the Atlantic lobster fishery a property-based system has arisen spontaneously, says Dr Worm. Families claim ownership over parcels of sea and keep others out. Anyone trying to muscle in on the action risks being threatened; their gear may be cut loose or their boat could vanish.