Fishing 'will not cause extinction'
No fish species in New Zealand or around the world is in danger of extinction caused by commercial fishing, an eminent fisheries scientist said in Nelson yesterday.
Ray Hilborn, professor of aquatic and fishery science at the University of Washington, said although claims that world fish stocks were in such decline that they would disappear by 2048 had received wide publicity, the evidence showed the opposite.
A three-year study he began in 2006 with other researchers showed that for those countries where there was available data on fish stocks, "the abundance of commercially harvested stocks are either stable or increasing, not declining".
"Two areas stood out as never being overfished, New Zealand and Alaska."
Professor Hilborn has had a close involvement with the New Zealand Fishing Industry Board and Seafood Industry Council since 1990 and helped develop this country's fish stock assessment models.
He said there were several widely held misconceptions about the sustainability of commercial fishing. In a speech at a lunch hosted by Sealord, he said that both research data and stock assessments showed an improving picture since 1980, and even in areas where the commercial fishery had collapsed and been closed, numbers were rapidly rising to the sustainable level, 30 per cent of the original stock.
"The areas that are traditionally the most overfished in the world – Europe, Eastern US, Eastern Canada, the site of the cod collapses and all that, we see stability, not decline."
The perception that the world's tuna stocks were disappearing was wrong, Prof Hilborn said.
"From all the data assembled since 1950, tuna are down about 25 per cent worldwide.
"Bluefin tuna are way down, no question about that, but tuna overall – pacific skipjack, pacific yellowfin – there's almost as many tuna in the world now as there were 60 years ago."
Studying the impact of fishing worldwide, New Zealand was "the best place we've looked at".
"On average, stocks are fished at less pressure than would produce maximum sustained yield and on average the abundance is well above the level that would produce maximum sustained yield."
There were also misconceptions about the value of marine reserves, he said.
While he did not argue against having some areas closed to fishing, he said this did not guarantee protection of marine ecosystems and could lead to a wider decline in fish stocks.
"What are the threats to marine ecosystems? Ocean acidification, warming oceans, sea level rise, unregulated fishing, exotic species, dead zones from pollution, illegal fishing.
"In a country like New Zealand or the United States, we have heavily regulated fishing and marine protected areas do not protect ecosystems from any of these threats.
"When you close some areas to fishing, you have more fish inside the protected area and you have fewer fish outside.
"Marine protected areas allocate higher abundance to people who don't consume fish – that would be divers, primarily, and marine ecologists at universities – and they take away fish from people who consume fish, that is recreational fishermen and commercial fishermen."
He said fishing was the most environmentally friendly way to produce food.
Agriculture required the ripping apart of natural habitat and replaced native species with exotics.
In contrast, fishing might change native habitat, but it didn't destroy it, was sustainable, and where there were good management systems such as New Zealand's, stocks were rebuilding, not declining.
Its energy use and carbon footprint was better than for livestock, and by many measures it had a lower environmental cost than organic vegetable growing.
"Fishing doesn't require large amounts of fresh water, fertiliser,current pesticides, or antibiotics, it doesn't cause dead zones, soil erosion or freshwater pollution," he said.
Professor Hilborn's five-week visit is to study the comparative impacts of fishing and agriculture, and is funded by the Seafood Industry Council (Seafic).
- © Fairfax NZ News
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