In the chilly waters of the Southern Ocean, an annual drama is under way once more. The Japanese whaling fleet has set to sea again. So has a flotilla of vessels crewed by conservationists and activists, determined to keep the hunters from their prey.

Three Australian anti-whaling campaigners boarded the Shonan Maru No. 2 whaling ship on Sunday. After negotiations, the Japanese government has agreed to release them to an Australian customs ship. The incident came just days after the conservation ship Brigitte Bardot was smashed by a giant wave and seriously damaged while pursuing the ship Nisshin Maru, some 2,400 kilometres from the Australian coast. Sea Shepherd Conservation Society, a group based in Friday Harbour, Washington, that operates the stricken vessel, is counting the cost of its principles. This isn't the first time: in January 2010, the group's powerboat Ady Gil sank after a collision with the Shonan Maru No. 2. The skirmishes and confrontations continue, with campaigners maintaining their high-risk pursuit and their attempts to foul the propellers of the whaling ships with ropes, and the whalers responding with water cannon. Surely there is a better way?

Perhaps. On page 139 of this issue, three environmental scientists outline a plan to introduce tradable quotas for whale catches. Under the scheme, conservationists could buy (and retire) the quotas from whalers, giving industry a way to profit from the animals without killing them. In return, anti-whaling campaigners could be more certain that their actions were reducing the slaughter. Theoretically, such a scheme would allow both sides to benefit with no loss of face. As the researchers say, it could “open the door to reducing mortality without needing to battle over whether whaling is honourable or shameful”. And both the number of whales killed and the associated costs would go down.

The article's authors — Christopher Costello and Steven Gaines of the University of California, Santa Barbara, and Leah Gerber of Arizona State University in Tempe — use the per-animal profit of whaling ships to decide that about US$13,000 would be a fair price to buy the life of a minke whale, and $85,000 should secure a fin whale. “Whale prices should therefore be within reach of conservation groups and even some individuals,” they suggest.

The idea first surfaced in 1982, to little effect. But perhaps, three decades on, its time has come. Market approaches to environmental problems are now common, with carbon offsets bought by individuals to neutralize their greenhouse-gas emissions. Such systems have even been shown to be effective, reducing sulphur dioxide pollution from US power plants.

To put a price on the head of a whale would be a different matter, of course. Committed anti-whaling campaigners would have to put aside moral objections and accept such a scheme's tacit legitimation of whaling as an enterprise to be rewarded, as well as the de facto official approval for the heavily disputed notion that whales (and other animals) are a resource to be exploited. Pro-whaling nations would need to be persuaded that the scheme would have more strategic benefit than their continuing political efforts to lift, or find ways to work around, the current commercial whaling moratorium. Then there is the need for scrutiny and verification of the quota market, not to mention getting such a plan through the political quagmire that bogs down annual meetings of the International Whaling Commission, the body that would be best placed to put a market mechanism into action. (And what of the world's scientists, denied information from some of the 1,000 or so whales slaughtered each year for 'scientific purposes'? Nature suspects that they would manage.)

Still, with political will and goodwill, the idea could work. At the very least, it deserves proper consideration from all involved. As events in the Southern Ocean show, pro- and anti-whaling groups will both go to extraordinary lengths to pursue their agendas. To those in peril on the sea, the middle ground should seem just as secure as the moral high ground.