The guardians of Antarctica's marine wealth gather in Germany will meet on Sunday for a fresh round of talks on creating the world's largest ocean sanctuary.
Two plans of unprecedented scope are on the table, aimed at protecting vast, pristine waters and 16,000 species from human predation.
But whether one scheme, both -- or none -- gets approval is unclear, given Russian and Chinese concerns that the restrictions are too draconian.
One proposal, floated by the United States and New Zealand, would cover 1.6 million square kilometres of the Ross Sea, the deep bay on Antarctica's Pacific side.
The other, backed by Australia, France and the European Union (EU), would protect 1.9 million sq. Km of coastal seas off East Antarctica, on the frozen continent's Indian Ocean side.
The three-day meeting in Bremerhaven, Germany, gathers 24 nations plus an EU delegation in the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR).
The CCAMLR is a treaty tasked with overseeing conservation and sustainable exploitation of the resources of the Southern Ocean.
It aims to fill a gap left by the Antarctic Treaty that came into force in 1961, which addressed the land of the continent but not its surrounding waters.
For nearly all of its 32 years, the CCAMLR -- pronounced "cam-lar" -- has barely flickered on the world's political radar.
But that is now changing as the world's fish stocks reel from decades of plundering and industrial trawlers venture ever farther to feed the planet's surging population.
High-profile campaigns about overfishing have also pushed the issue of the Antarctic's oceans higher up the agenda.
"Fishing has so accelerated on many parts of the globe that 85 percent of fish stocks are over-exploited," said Andrea Kavanagh, in charge of the Southern Ocean Sanctuaries campaign at the US green research group Pew Environment.
"Creating those protecting areas would more than double the amount of protected oceans in the world."
Robert Calcagno, director of the Monaco Oceanographic Institute, said the waters around Antarctica were a vital link in the ecological web.
"The Southern Ocean is of major importance, given its wealth of biodiversity, including fish that can live in waters below zero degrees (Celsius, 32 degrees Fahrenheit)," he said.
"It is also connected to the world's ocean current system, and has massive stocks of krill," he said, referring to the tiny shrimp that is a vital protein source for whales, penguins and seals.
