MICHAEL FIELD
19/03/2011
DISRUPTED: A researcher says New Zealand fishing has caused an Adelie penguin population explosion at Cape Royds on Ross Island.
It is creating an explosion in penguin populations while cutting the number of killer whales.
US penguin researcher David Ainley, in California, said pushing an ecosystem so far out of kilter would have long-term impacts wrecking the world's last pristine ocean and the only natural laboratory for studying climate change.
New Zealand is leading the hunt for toothfish (dissoctichus mawsoni) in the Ross Sea, the world's southernmost fishing grounds, taking around 3000 tonnes and earning $18 million a year. A late-maturing, slow-growing, long-lived species that can grow up to 2m long, toothfish fetches around $US70 ($95) a kilogram.
Toothfish have now largely disappeared from McMurdo Sound. Scientists had been catching, tagging and releasing 200 to 500 adult toothfish a year for the past 40 years. Recently they have been lucky to catch one or two fish.
Ainley said the fishing caused an Adelie penguin population explosion at Cape Royds on Ross Island. He saysid Toothfish were the main predator of the penguins. Ross Sea killer whales, which ate the toothfish, had declined and Weddell seals and skuas had also been affected.
Ainley said the Ross Sea had provided 50 years of comprehensive climate data and was the best place in the world to work out what was happening with global climate change.
But the fishing had altered the ecosystem.
''It confuses everything. Now it is no longer easier to separate climate effects from fishing effects. Fishing has destroyed the science.''
There should be no commercial fishing in the Ross Sea, he said.
''It is far more valuable to society as a reference area for looking at climate change and its effects, and not just the last place on earth to catch toothfish for a while.''
Toothfish fishery was based on luxury, he claimed. ``There are very few people on earth who can afford to eat toothfish. It's just going to the top one per cent of the population.''
Peter Bodeker, chief executive of the Seafood Industry Council, said the Ross Sea has been managed on ''a conservative basis'' for 14 years by the Commission for the Conservation of Antarctic Marine Living Resources.
''The fishery makes up a relatively small part of human activity in an area that has seen continuous human habitation for some 50 years,'' he said.
While there were 15 relatively small fishing vessels there for three months each year, the place was also visited by numerous transportation vessels, aircraft, tourism operations, coast guard and naval vessels.
''It is unreasonable to single out New Zealand fishing activity, given that the area is governed by a regional entity that annually allows fishing by vessels from a wide range of countries,'' Bodeker said.
- Fairfax Media
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