UH team rejects articles saying oceans are dying
Fishery scientists say the ecosystem is not doomed, as reported
The ocean ecosystems and fish populations aren't as endangered as some researchers claim, University of Hawaii-Manoa fishery scientists report.
The UH group disputes the grim picture presented in recent science journal articles that the ocean ecosystem is on the verge of collapse.
Those findings were based on "cherry-picked" information, John Sibert, manager of the Pelagic Fisheries Research Program at the School of Ocean and Earth Science and Technology, said by e-mail from Apia, Samoa.
"Our methods are more rigorous," he said.
"Recent claims of catastrophic reduction in the biomass of top-level predators and the collapse of oceanic food chains have attracted widespread attention and provoked alarm among the lay public," the scientists said in a paper appearing in today's Science magazine.
Some fish stocks have decreased significantly because of increased fishing but the situation isn't as grave as previously reported, the scientists said.
"Fishing impacts on an ecosystem are complex," Sibert, the lead author, said in a news release. "They cannot be reduced to sound bites.
"Management of ocean ecosystems in the 21st century will require comprehensive analysis and not the half-baked approaches used in some recent papers and so widely reported in media," he said.
"I agree with that 100 percent," Bruce Anderson, president of Oceanic Institute, a nonprofit marine research and development organization, said in an interview. "It is a complex issue and there are no simple answers or conclusions we can come to today."
More information is needed on the condition of fisheries to make better management conditions, Anderson said. "As it is, we have incomplete and fragmented information used for political purposes, which makes it difficult to reach general conclusions."
The paper in today's issue of Science is entitled, "Biomass, size and trophic status of top level predators in the Pacific Ocean." Sibert's co-authors are John Hampton of the Secretariat of the Pacific Community, Pierre Kleiber of the National Oceanic and Atmospheric Administration's Fisheries Service and Mark Maunder of the Inter-American Tropical Tuna Commission.
One reason their analysis has scientific credibility, Maunder said, "is because we considered all the available data for these stocks rather than picking and choosing the data that suits our cause, which is a stark contrast to several of the recent pessimistic fishery articles published in the journals Science and Nature."
The scientists analyzed all available data for Pacific tuna fisheries from 1950 to 2004 to estimate the impact fishing has had on these populations in the past half-century.
The situation varies considerably for tunas, sharks and other top predators, they said.
Fishing for yellowfin and bigeye tunas is at the maximum sustainable level but growing international fishing fleets threaten the species, the group said.
Because of this threat, the Western and Central Pacific Fisheries Commission and Inter-American Tropical Tuna Commission are recommending options to limit fishing for those tunas, the scientists said.
They include limits on catch and "fishing effort," time and area closures and restrictions on use of floating objects by the purse-seine fishery.
There appears to be broad support for "meaningful restrictions," Sibert said in his e-mail, "but there are some who oppose any constraints."
"The truth is, there are some fisheries that are still robust and are very healthy," Anderson said. "I believe the aku fishery in many Pacific Island areas seems to be very productive despite international fishing pressure.
"But other fisheries are severely depleted and certainly more information is needed to provide a comprehensive picture of what is going on in the Pacific area."
Oceanic Institute is involved with UH and others in trying to assess the condition of prized bottomfish (ehu, onaga and opakapaka) around the main Hawaiian Islands, Anderson said.
Some work has been done around Kahoolawe, a reserve where fishing is prohibited, with fish being tagged and tracked to see whether the reserve is effective in preserving the population, he said.
"We don't know where the fish go or how fast they grow or a lot of basic information necessary to manage the fishery. So we're hopeful we can get more information in the future to enable our resource managers to better manage the fishery."
Dr. Carl Walters of the Fisheries Centre at the University of British Columbia in Vancouver applauded the Pelagic Fisheries Research Program scientists for their research.
"It is refreshing and encouraging to see Science finally publish a comprehensive stock analysis carried out by competent and experienced fisheries assessment experts," he said.