Rainer Froese (Nature 475, 7; 2011) attributes the lack of success of Europe's Common Fisheries Policy to collusion between fisheries advisers and industry. I disagree. The fundamental problem is economics.

The only way to rebuild depleted fish stocks is to catch and land fewer fish until the stocks have recovered. That means reduced earnings for fishermen, at least in the short term. Thus, any conservation measure that is likely to work is going to hurt, and is almost certain to be opposed.

The deal on offer in Europe and elsewhere is a trade-off between short-term losses and long-term gains (larger stocks leading to higher stability, catch rates and profits). Without some mechanism to make the deal more attractive to fishermen, it is always going to be a struggle to achieve sustainable levels of fishing.

Such a mechanism is conceivable: for example, through an up-front investment in a buy-back of fishing rights, to be paid for by future licence charges or resource rental taxes. These steps are necessary to prevent future pressure on conservation measures once fishing becomes more profitable again. Direct controls on fishing effort, such as limiting the number of days at sea, are also likely to be needed. They have many advantages, especially for the regrettably common situation of inadequate stock assessments, and for reducing discarding in mixed fisheries.

Economic deadlock has bedevilled fisheries management for more than half a century. It needs to be addressed directly for any progress to be made.