I agree that “no one should doubt that our seas need protection” (Nature 480, 151; 2011) and that establishing marine protected areas alone will not do the job (Nature 480, 14–15; 2011). A combination of measures is needed, including the elimination of overfishing subsidies. These incentives were introduced when fisheries seemed inexhaustible, but they inflate profitability and drive fishing beyond economic or sustainable levels.

The global community mandated the World Trade Organization (WTO) to discipline overfishing subsidies more than ten years ago, but the issues were still unresolved at their meeting last month. One reason is that WTO negotiators are trying to broker an all-inclusive deal that encompasses domestic and international, small- and large-scale fisheries. But this approach is hindered by national interests.

The answer is to split the world's fisheries into domestic and international ones. Domestic fisheries would operate within a country's economic exclusion zone and target fish stocks that spend all their lives there. This split is necessary because the incentives to eliminate overfishing subsidies differ according to whether a fishery is domestic or international.

For a domestic fishery, the heavy lifting should be on the home front; for an international fishery, global coordination would be needed, because unilateral action by one country will not eliminate overfishing. Categorizing fisheries in this way would make it easier to identify leverage points for eliminating overfishing subsidies.