A well-publicized story that forecast the collapse of most of the world's fish stocks is flawed and full of errors, an American fisheries scientist says.

Ray Hilborn, a fisheries scientist at the University of Washington in Seattle, said a study published in the journal Science — which said present trends could lead to the collapse of most stocks by 2048 — cannot be taken seriously.

"This particular prediction has zero credibility within the scientific community," said Hilborn, a professor of aquatic and fishery sciences. 

'The authors were just incredibly sloppy in how they used that data.'-Ray Hilborn, University of Washington

The study, written by a team led by Dalhousie University researcher Boris Worm, attracted international headlines with a dire warning, which said current trends of overfishing and climate change were putting most species at risk.

However, Hilborn said the research was based on faulty methodology, including how catch rates were interpreted.

"The authors were just incredibly sloppy in how they used that data," Hilborn told CBC News.

"One of the stocks they list as collapsed is the Georges Bank haddock stock, which is bigger now than it has been in 40 years. The catch is lower simply because the regulations are much tighter," said Hilborn.

Projection based on valid data: author

Replying to Hilborn's criticism, Worm said the study actually did not predict a collapse within 50 years.

"They treat this as a prediction, as if we said that it will collapse by 2050, which is different from what we actually said — which is, if the present trend that we're seeing worldwide continues, we would see widespread collapse of fisheries by 2050," Worm told CBC News.

"We're assuming — and this is not hidden anywhere — that the trends we observed over the last 50 years are just going to continue as they did."

Worm said the strongest criticism of the study has come from the U.S., which has some of the world's strongest legislation aimed at protecting fish stocks.

"The problem is that the global trend is still in the other direction. All of the data very clearly show that," Worm said. 

'The door is closing, slowly, but it's still open enough to turn this around, and this is absolutely what we should do.' -Dalhousie University's Boris Worm

Worm said he hoped the study would spark change in fisheries management.

"The door is closing, slowly, but it's still open enough to turn this around, and this is absolutely what we should do," Worm said.

"With every species that's lost, the opportunity for recovery diminishes."

Projection 'unimportant' in report, critic says

Meanwhile, Hilborn said there were parts of the Science study that are worthy, but were overshadowed.

"The sad part is that this 'no fish by 2048' was a very unimportant part of their paper. The more important parts of the paper have been neglected because of this rather outrageous claim," he said.

Hilborn does not dispute that some stocks — notably cod stocks off Newfoundland's northeast coast — have collapsed, but says many fisheries are actually healthy.

Hilborn called the projection a "good hook" for news coverage.

Worm said the projection succeeded in attracting international media attention, far more than a discussion on other issues — such as nutrient cycling and water quality — would have.

"I think we succeeded in transporting a larger message — it's not just about [the] fishery, it's about the big picture, to maintain an ocean that's healthy and that's providing benefits to us."

Worm, who said he truly hopes his study's projection is wrong, said he views criticism from Hilborn and others as part of the scientific process.