When it comes to fishing, most of the ocean is lawless. Fish in the high seas — the half of the world’s oceans that fall under the control of no single nation, because they’re more than 200 miles from a coastline — are being plundered with aplomb by fishing fleets that observe virtually no fish conservation rules.

Some very smart people think that might be a very stupid way of managing the world’s fisheries. They say it’s time for the world to ban fishing on the high seas.

Many of the world’s brawniest fish and shark species migrate through these open waters, where they are being targeted and overfished. Bluefin tuna are becoming so rare that a single fish sold last year for $1.8 million.

Last month, McKinsey & Company director Martin Stuchtey suggested during an ocean summit that banning fishing on the high seas would cause an economic loss of about $2 for every person on the planet. But he said the benefits of more sustainable fisheries, if such a ban was imposed, would be worth about $4 per person, creating a net benefit of $2 apiece. From Business Insider:

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Hard numbers reveal that today’s fishing industry is not profitable, and as fleets work harder chasing fewer fish, the losses grow and stocks are further depleted in “a race to the bottom,” the economist explained.

Stuchtey’s numbers were approximations. But the results of a study published in the journal PLOS Biology this week put some flesh on the economist’s back-of-the-envelope calculations. An economist and a biologist, both from California, modeled the effects of such a ban and concluded that the move could double the profitability of the world’s fishing industries — and boost overall fishing yields by 30 percent. It would also boost fish stock conservation and improve the sustainability of seafood supplies.

“The closure will probably result in short-term losses of protein from the sea,” Christopher Costello, a University of California at Santa Barbara environmental and resource economics professor who coauthored the paper, told Grist. “But the key point is that these short-term losses are likely to be followed by significant long-term gains because of the rebuilding of fish stocks.”

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The greatest human beneficiaries of such a ban would be residents of developing countries — nations that can’t afford the types of hulking vessels needed for high-seas fishing expeditions. The scientists say these developing nations would benefit from a rise in fish stocks in the waters they control, as would be the case for other countries.

The biggest potential losers, according to the researchers, would include Japan, China, and Spain, which operate large offshore fishing fleets. And that could make a high-seas fishing ban a difficult sell at the United Nations.

“Whether a country like Japan or China would stand to gain or lose is an empirical question that will require careful country-by-country analysis,” Costello said. “It may disadvantage a few politically powerful countries, while it advantages many smaller countries.”

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Global Ocean CommissionHigh seas are shown in dark blue. Click to embiggen.