The high seas need to get fishy again

Closing the high seas to commercial fishing would create a ‘fish bank’, producing more fish – many of which then migrate closer to the coast and boost the catch there by 18%.

Nobody loves the United Nations (UN). It’s a bureaucracy, and its job is to make rules. But where else could you negotiate a treaty on The Conservation and Sustainable Use of Marine Biological Diversity of Areas Beyond National Jurisdiction (BBNJ for short)? That is to say, bringing the rule of law to the high seas before all the fish are gone.

All the ocean within 370km of land is now in some country’s “Exclusive Economic Zone” (EEZ), and protecting fish stocks within the zone is the task of more than 100 sovereign states with ocean coastlines. Some do it well; most don’t.

But out beyond is still the high seas, where nobody regulates the fishing. That’s half of the planet’s surface, containing 90% of the world’s biomass, but back in the ’80s, when UN members were negotiating the Convention on the Law of the Sea, hardly anybody was fishing that far out.

Well, they are out there now, taking as much as they want. Trawlers of up to 14 000 tons quarter the high seas, setting huge gill nets with a large “by-catch” of whales and turtles, dragging long-lines of up to 100km in length that bristle with hooks, and using bottom-trawling methods that damage the seabed.

Fish populations are generally denser close to the coasts because nutrients are richer, and the high seas account for only about one-tenth of the global fish catch. But it is a critical tenth, because the high seas act as a kind of nursery, especially for the larger species of fish.

Allowing large-scale commercial fishing to take over on the high seas is like sawing off the branch we’re sitting on. Happily, a majority of the world’s countries agree that it should be controlled.

Only 10 countries, all of them rich (Spain, Japan, Korea, etc.) account to 70% of fishing on the high seas, and even they aren’t really making money out of it. If it weren’t for large government subsidies, there would be hardly any fishing vessels operating that far out: the fuel costs along would be prohibitive. So there is probably a deal to be done here.

The initiative for a treaty to regulate high-seas fishing came from New Zealand and Mexico, but more than 70 countries have co-sponsored it, and negotiation on it opens at the UN in New York on Tuesday.

The treaty’s main achievement, if it succeeds, will be to create and supervise marine protected areas (MPAs) on the high seas in which no fishing would be permitted.

They need to be very large – advocates talk in terms of MPAs adding up to at least one-third of the entire high seas area – to allow entire ocean ecosystems to recover, from corals and sponges up to tuna, sharks and turtles.

Policing these MPAs once they are created would be a lot simpler than enforcing the rules closer to shore, because the high seas fishing fleets are big ships operating in relatively uncrowded waters. Satellites would quickly spot one fishing in the wrong area, and the fines would build up quickly. Meanwhile, smaller vessels fishing close to the coast might find that they were catching more fish.

Rashid Sumaila, director of the Fisheries Economics Research Unit at the University of British Columbia, estimates that closing all the high seas to commercial fishing would turn them into a “fish bank” that produces more and more fish, many of which then migrate to the EEZs and boosting the catch there by 18%.