Antarctica is this planet’s only continent wholly protected from mining and other economic activity, save tourism — a place where nature, not commerce, rules. But protection ends at the water’s edge. While the land mass itself is pretty much a biological desert, Antarctic waters are full of life, especially krill, which has drawn the attention of international fishing fleets over the past decade. In fact, the Antarctic Ocean is one of the most intact marine ecosystems on the planet, and one of the most fragile. Now is the time to protect it for good.

The United States and New Zealand have put forward excellent proposals to create two major marine reserves. The proposals are under discussion at a meeting of the Commission for the Conservation of Antarctic Marine Living Resources (the international body that governs Antarctic waters) now under way in Bremerhaven, Germany. The proposals would protect some 600,000 square miles of ocean in the Ross Sea and an additional 733,000 square miles off the East Antarctic coast. All told, these marine reserves, where fishing would be prohibited, are about the size of all the marine reserves created so far around the world.

The biggest obstacle is Russia, which has expressed resistance to these reserves. It is joined by Ukraine, China and Japan. Their hope is to manage fishing in the Antarctic much as it is managed elsewhere, with limits and restrictions. But the state of fisheries around the globe makes it clear that the most effective antidote to declining fish populations is the creation of totally protected marine reserves.

The Obama administration has expressed strong support for the idea of such protections in Antarctica, and many delegates to the Bremerhaven meeting are hopeful that sooner or later the Russians and other opponents can be brought on board. But when it comes to protecting ecosystems, sooner or later often means later, which often means too late. The time to protect the Antarctic Ocean is now.