The findings, based on nearly 50 years of data, offers a bleak outlook for some of the most commercially valuable trophy fish species, and further debunks a notion that oceans are limitless blue frontiers teeming with boundless life.

Fishing industry experts in Hawai'i were critical of the study and say they will examine it closely.

"The study is very simplistic," said Paul Dalzell, senior scientist for the Western Pacific Regional Fishery Management Council. "It ignores changes in fishing over time in terms of fishing technology. It ignores that we have very good stock assessments for the western and central Pacific."

While some fish populations have been in decline, none are anywhere near 90 percent gone, he said. "While the picture isn't entirely rosy, it is not as gloomy as it is painted in this study," Dalzell said.

Sean Martin, president of the Hawai'i Longline Association, today said the study "sounds out of whack to me."

"I believe it is off the mark and misleading," he said. "In the study, they didn't use any north Pacific data. They specifically excluded it in this report."

He said that decision was made because that broad expanse of ocean, which is used by the Hawai'i-based fleet, was already "industrially exploited" before fishing management and data collection.

There about 100 boats in the Hawai'i fleet. Last year, they caught 17 million pounds of big eye, yellow fin and albacore tuna. The year before, they caught 15 million pounds.

The study, which appears in tomorrow's issue of Nature magazine, was done by scientists Ransom A. Myers and Boris Worm.

"Although it is now widely accepted that single populations can be fished to low levels, this is the first analysis to show general, pronounced declines of entire communities across widely varying ecosystems," they wrote. "Most scientists and managers may not be aware of the true magnitude of change in marine ecosystems."

Myers, a marine biology professor at Dalhousie University in Canada, and Dalhousie research fellow Worm found that it generally takes less than 15 years for giant commercial fishing operations to kill 80 percent of a new fishing ground's abundance.

They also found that marine life can recover from such commercial operations if smaller, fast-growing species are given a chance to fill in for the overfished predators, whose average weights also are declining sharply.

The data cover Japanese fishing between 1952 and 1999 for the most widespread type of fishing gear ­ longlines ­ used on the open ocean to catch tuna, marlin and swordfish. Longlines float for miles with baited hooks dangling below, causing lots of other unintended catches.

Just after World II, as large-scale fishing fleets began spreading globally, no marine fish stocks were known to be overfished and the Japanese caught 10 fish per 100 hooks.

Now, they are lucky to catch one per 100, Myers said. The report uses other research to verify the results and expand them to other species.

Michael Sissenwine, head of fisheries science at the National Oceanic and Atmospheric Administration, said fishing can cause big reductions in populations quickly, but he cautioned against drawing larger conclusions.

"There's nothing that assures us that the data they are using is representative of all populations in the world," he said, adding that fishing typically reduces a species' population by at least 50 percent.

"We shouldn't on the other hand conclude that a substantial reduction is a problem," he said. "The point is we shouldn't be thinking we can have fisheries and leave the ecosystem in a pristine state."