New research from Chris Costello and Steve Gaines of the University of California, Santa Barbara (under peer review for the journal Science) reckons that those unassessed fisheries are gravely depleted, with on average about half the fishy biomass they need to maintain their maximum annual yield (the usual definition of sustainability). Another analysis, using the same method, of around 1,500 fisheries last year reached similar results. Both suggest the least-known fisheries are the most damaged. This conflicts with the sunnier analysis of industrial fishing fleets, based largely on expensive studies of a few hundred fisheries, mostly in European and American waters. These are depleted but generally recovering, thanks to recent reforms.
That these turn out to be exceptional cases is unsurprising. The rapacious habits of fishermen and perverse effects of the subsidies some extract from governments are well known. Sometimes overfishing stems from ignorance and sometimes from short-termism, exacerbated by the belief that whatever they don’t take, others will. The cost is enormous. Besides harbouring millions of species, fisheries provide the primary source of protein for a billion people and livelihoods for hundreds of millions, most of them poor. The World Bank reckons that benefits (such as income and food) lost by overfishing between 1974 and 2008 amount to $2.2 trillion.
More happily, the new assessment reckons that only 2% of fisheries have so far collapsed—defined as a fall to less than a tenth of the historical biomass. Previous estimates were higher, at up to 30%. Yet incidences of collapse are rising, the researchers stress; and once collapsed, fisheries do not necessarily recover. Shoals of northern cod have not yet returned to the Grand Banks fishery off Newfoundland, which collapsed in 1992……
Above all, fishermen need better incentives to manage stocks properly. This has been tried in several ways. In Iceland and elsewhere they have a tradable share of a scientifically determined quota. Or they can be given long-term rights—akin to property rights—over an expanse of sea….
According to a 2008 study by Messrs Costello, Gaines and others, this approach works: fisheries where such rights are in force are only half as likely to collapse as the average fishery. Yet the spread of such schemes has been woefully slow; only a few hundred mainly rich-world fisheries have adopted them so far. Though sensible in theory, rights-based schemes are hard to get right in practice. Getting locals on board can be difficult and is a slow process at best. If the target species is especially valuable or slow-growing, overfishing (at least in narrow economic terms) is rational. That may make monitoring and enforcement impractically costly.
Rights-based fisheries are not the only answer to overfishing. In particular, a lot more of the sea needs protecting from any fishing at all. Yet there are few better ways to make fishermen control themselves.
Fisheries: Lost property, Economist, Feb. 25, 2012, at 71