In the Midst of Marine Collapse will We Save Our Last Ocean?

Mongabay.com, 5 July 2010

Imagine an ocean untouched by oil spills: a sea free of pollution, invasive species, dead zones, and over-exploitation; waters where marine animals exist in natural abundance and play ecological roles undimmed by mankind.

Such a place may sound impossible in today's largely depleted oceans, but it exists: only discovered in 1841, the Ross Sea spreads over nearly a million kilometers adjacent to the Antarctic continent.

Here killer whales, penguins, sea birds, whales, and giant fish all thrive. However, even with its status as the world's 'last ocean', the Ross Sea has not escaped human impact. Over the last 15 years commercial fisheries have begun to catch one of its most important species in the ecosystem to serve them up on the dinner plates of the wealthy.

"[The] Ross Sea is the last open ocean tract (i.e. not a reef) that still has a food web much like what one would expect the 'Garden of Eden' to have been like. That is: all the 'fruits' are still there, ready to be picked," explains marine ecologist Dr. David Ainley in an interview with mongabay.com, adding that "the reason why it has yet to be depleted by humans is that the Antarctic Treaty prohibits mineral/oil extraction, and its remoteness from civilization, the extensive sea ice that covers it for a lot of the year, and its reputation for harsh weather."

However, like many remote places on Earth during the last century, humans have begun moving into the Ross Sea, not for oil and mineral riches, but for fish.

"The fact that all the large fish have been taken from the rest of the world ocean brought industrial fishing to the Ross Sea," says Ainley. "Right now, while the fish are still plentiful, it's easy to quickly fill holds of vessels in just a few weeks."

Industrial fisheries mostly out of New Zealand are targeting the man-sized, slow growing Antarctic toothfish (Dissostichus mawsoni), or as it is known by its more palatable market name, the Chilean sea bass. Market-wise, the fish is lumped with a close-relative, the Patagonian toothfish, which has been largely depleted for consumption.

"These fish are the 'sharks' of the southern ocean, and thus play a critical role in the food web," Ainley says. "The removal of sharks from other oceans has had dire ecological consequences, in some cases leading to the disappearance of species with which the sharks have no direct contact. This is because the sharks (toothfish) keep the populations of smaller predators in check."

If the Antarctic toothfish are allowed to vanish due to overexploitation, Ainley says that the Ross Sea—now home to a unique species of killer whale, over a third of the world's Adelie penguins, and over a quarter of the world's emperor penguins—could no longer be considered an intact ecosystem, like stripping lions from the Serengeti or wolves from Alaska.

Economically, Ainley says, the Antarctic toothfish fishery is actually unviable: the cost of traveling and fishing in this remote sea actually outweighs the profit. But instead of giving up the catch, fisheries are now applying for sustainability certificates through the Marine Stewardship Council. If awarded—despite scientific concerns—the fisheries believe they can then up the already expensive price of $20-35 a pound for the species.

Full story: Mongabay.com