Fish can come back.

A research paper published in last Friday’s journal Science concludes that while fish stocks remain threatened by overfishing, collaboration among scientists and fisheries managers can reverse the trend.

Boris Worm, a marine ecologist with Dalhousie University in Halifax and other scientists published a report in 2006 citing evidence that if current trends continued, all commercially harvestable fish would be gone by 2048.

The Friday report in Science takes an entirely different view.

Fish stocks can be improved and there is plenty of evidence to suggest that controlling fishing effort can have a positive result, the report says.

“Marine ecosystems are currently subjected to a range of exploitation rates, resulting in a mosaic of stable, declining, collapsed, and rebuilding fish stocks and ecosystems. Management actions have achieved measurable reductions in exploitation rates in some regions, but a significant fraction of stocks will remain collapsed unless there are further reductions in exploitation rates,” it concludes.

The report offers new hope that fish stocks can be rebuilt and are being rebuilt, but with a strong warning that the effort will involve science and restraint.

The Vineyard is surrounded by what were once the best fishing grounds in this hemisphere. The Island is the gateway to Georges Bank, an ocean area larger than the state of Massachusetts that used to be one of the world’s richest fishing grounds. Though many of the stocks are depleted on the bank, the new report points to the restoration of sea scallops and the recovery of haddock as evidence that fisheries managers can come up with the tools to reverse decline.

The seven-page report in Science draws on a study by Mr. Worm and Ray Hilborn of the University of Washington, using an international team of 19 coauthors. The purpose of the paper was to examine current fish trends and exploitation rates and identify the tools necessary to rebuild stocks.

“Across all regions we are still seeing a troubling trend of increasing stock collapse,” said Mr. Worm of the report. “But this paper shows that our oceans are not a lost cause.”

The report states: “Most rebuilding efforts only begin after there is drastic and undeniable evidence of overexploitation. The inherent uncertainty in fisheries, however, requires that agencies act before it comes to that stage.”

Mike Fogarty, a Woods Hole National Marine Fisheries scientist and coauthor, said: “Even though we do recognize that sacrifices have been made by fishermen and shoreside communities toward recovery, the main message here is that applying these efforts can have positive results. Despite the short-term cost there can be a long-term benefit.”

Steve Murawski, NOAA fisheries chief scientist, said there is already evidence in New England waters that fisheries managers can bring back stocks. He said there is positive evidence in Australia and New Zealand as well. “Australia has a very aggressive program. They’ve got property rights, catch shares,” Mr. Murawski said, adding: “Alaska is an important example.”

Titled Rebuilding Global Fisheries, the Science report included evaluating catch data wherever scientists could find it. They gathered information from Europe, several places in Africa, Thailand and Australia, although information from the New England region was not used in the report. Computer models were used to predict the effects of exploitation worldwide.

“We were able to take a detailed look at information that had never been assembled before on a global basis,” Mr. Fogarty said.

It is a far bigger research project than the one that led to the 2006 Worm report.

“A lot of the scientists that were involved in that report didn’t include the latest information that was available. It painted a doomsday scenario. We know there is plenty of good evidences about resurrecting fisheries,” Mr. Murawski said, adding: “Striped bass and sea scallops were once at death’s doorstep, and we pulled them back. We want this to become a rule and not the exception.”

He said what is significant about this report is that it includes two groups of scientists talking to each other. “One group is idealistic and they want a more pristine environment and the other group is looking to allow harvesting,” he said.

Mr. Fogarty said the research was headed by the California-based National Center for Ecological Analysis and Synthesis. Funding came from the National Science Foundation and the University of California at Santa Barbara.