I will repeat my mantra: Wherever you see whatever you want to call an environmental problem, catastrophe, screw-up, it's occurring in an open access commons. That is, since nobody owns the resource, everybody exploits it as much as they can because they know if they leave something behind, the next guy is just going to take it. I live in hope that someday soon environmental activists will heed this lesson.

A new study, "Status and Solutions for the World’s Unassessed Fisheries," (sub required) published this week in the journal Science notes that only 20 percent of the global catch comes from formally assessed fisheries, missing 80 percent that is harvested mostly from smaller scale local fisheries. With regard to the assessed fisheries, the study notes:

A recent synthesis of global fisheries with formal assessments reveals that although 63% have a biomass below what would produce maximum sustainable yields (MSY), nearly half of these (45%) have lowered exploitation rates sufficient for recovery. A complementary analysis by the FAO found that 32% of 441 studied stocks are either overexploited (28%), depleted (3%), or recovering (1%).

So the researchers looked at thousands of unassessed fisheries and found...

...that small unassessed fisheries are in substantially worse condition than assessed fisheries, but that large unassessed fisheries may be performing nearly as well as their assessed counterparts. Both small and large stocks, however, continue to decline; 64% of unassessed stocks could provide increased sustainable harvest if rebuilt. Our results suggest that global fishery recovery would simultaneously create increases in abundance (56%) and fishery yields (8%-40%).

So what do? Establishing property rights would help a lot:

Our analysis suggests large potential conservation and food benefits from improving the management of the world’s unassessed fisheries. To realize these benefits requires successful approaches for fisheries reform. Limiting entry and using individual transferable quotas (emphasis added) have been shown to benefit data-rich fisheries within developed countries . These approaches, however, may prove more challenging to implement for unassessed fisheries in developing countries, because they inherently require strong governance, rule of law and monitoring. Rather, ap- proaches such as territorial user right fisheries (TURFs), fisheries cooperatives, TURFs coupled with no-take reserves (25), and co- management approaches are likely to be more broadly appropriate tools. In addition, coupling recent advances in data poor assessment with these management instruments will be critical to success.

Speaking of the rule of law, for a depressing glimpse of how politics screws up even fisheries successes in the U.S., see my blogpost, "Give a Man a Fishery and Soon You'll Have More Fish."