We'd like to put the Ross Sea in perspective for Dr. Morgan and the readers of the NZ Herald. No doubt readers are familiar with, and proud of, Te Urewera and Fjordland National Parks. Together they comprise the largest area of native old-growth forest left on the North and South Island, respectively. Nearly all of the country's still extant native birds can be found there, including threatened species like kiwi, kokako, kaka, falcon and the unique whio or blue duck.
The motivation was to conserve the old growth trees and their greater ecosystem. By designating these national parks in the early 1950s, New Zealanders demonstrated that these trees were more valuable as part of an important, remnant ecosystem rather than being turned into lumber. These parks are priceless. The people of NZ would never allow the harvest of those ancient trees or any exploitation, despite the profit that could be made, and despite the fact that little trees would sprout when the old ones were taken away. The little trees just don't provide the same ecosystem services as the large, old ones.
Switch now to the Ross Sea. Few large intact marine ecosystems remain on Earth. In 2008 an independent analysis of human impacts on the world's oceans published in the prestigious journal Science classified the Ross Sea as the least affected large oceanic ecosystem left on Earth. It has no widespread pollution, no invasive species, no mining, and until recently, no large-scale commercial fishing. The Ross Sea truly is our most pristine marine ecosystem and our last chance to understand how a healthy, un-altered marine ecosystem functions.
The Ross Sea contains more than a quarter of the world's emperor penguins, more than a third of its Adélie penguins, and species of fish and invertebrates found nowhere else on Earth. Where many marine ecosystems have lost their top predatory fish to overfishing, the Ross Sea still has Antarctic toothfish. This fish, which grows in excess of two metres, is by far the most important predatory fish in the Southern Ocean. In an environment naturally devoid of sharks, the toothfish evolved to become the shark of the Antarctic.
Fifteen years ago, NZ fishing companies proposed to make the 4000 km round trip to start fishing toothfish in the Ross Sea. Using a stock model based on assumptions to drive management strategy, their current goal is to remove 50% of the largest, oldest fish. Whether or not this level of extraction is sustainable is not the point. Fishing at any level alters the ecosystem. That is the goal of fishing to remove fish, particularly the large ones, with the intention of allowing the smaller ones to grow faster, just as foresters propose for logging. But those old, big fish never return and small fish don't play the same role as big ones; hundreds of scientific papers support these facts. Where sharks, or other top predatory fish have been removed or reduced, ecosystems have become dramatically altered.
