HALIFAX - A Canadian scientist renowned for his groundbreaking research and blunt warnings about the extinction of marine species around the world has been hospitalized with an inoperable brain tumour, according to friends.

Ransom Myers, a marine biologist who's been a vocal critic of Ottawa's management of Canadian fisheries, was admitted to the Queen Elizabeth II Health Sciences Centre in Halifax in November after a sudden diagnosis of a rare form of brain cancer.

Family and friends, who call him Ram, are saying little about the health of the 54-year-old, but a hospital spokesman said he was thought to be in critical condition.

Jeff Hutchings, a marine biologist who teaches with Myers at Dalhousie University in Halifax, said his colleague is best known for high-profile research on the shrinking populations of a variety of ocean species, including sharks, large predatory fish and cod.

Myers, who has published more than 100 peer-reviewed papers, has attracted international attention for both the unique methodology he uses in analyzing data and the dire predictions he has issued about the fate of oceans that are being stripped of their biodiversity.

"Ram has an uncanny ability to take disparate sets of data and bring it all together to address fundamentally important questions," Hutchings, who has published almost 20 papers with Myers, said Wednesday at Dalhousie.

"He has highlighted the demise and declines of marine fishes and brought it to the attention of people that previously hadn't been aware of it and that was groundbreaking."

In a study published in 2003, Myers, who holds the first Killam chair of Ocean Studies at Dalhousie, found that global industrial fishing had cut populations of large fish such as tuna, swordfish and marlin to a mere 10 per cent of 1950 levels.

In his usual plainspoken style, Myers said at the time that the world was in "massive denial" and spending its energy fighting over the few fish left instead of cutting catch limits before it was too late.

Hutchings, who met Myers in 1983 when they were both working in Newfoundland, said his colleague has never pulled punches in condemning the federal government's handling of the fishery, even when he was employed by them at the Department of Fisheries and Oceans.

"He's been outspoken within and outside DFO," he said. "I wrote a paper in 1997 and cited a letter of reprimand he had received from his directors at DFO . . . saying he was not supposed to speak on certain things."

At a federal committee looking into fisheries management in the late 1990s, Myers described incidents of censorship, intimidation and distortion within the department around the time the northern cod and other key stocks collapsed in 1992 off Newfoundland.

He also claimed that government officials tried to hide one of his scientific reports that suggested seals were not the reason for the cod collapse.

"He is a deeply, deeply honest person," said Boris Worm, a professor in the biology department who has written several papers with Myers. "He's incredibly inspiring in both his analytical abilities and asking clear questions and sifting through huge amounts of data to answer those questions.

"He has passion for the issues."

Colleagues praised Myers' unusual ability to analyze complicated data and produce clear pictures of what's happening in the world's oceans, while making such compelling arguments that governments are forced to listen.

After the release of one of his studies that contained grim findings about shark species in the Northwest Atlantic, a particular species of shark was listed as endangered.

"I think Ram's contribution really will ultimately be . . . his ability to communicate important issues about marine conservation biology to as broad an audiuence as possible," said Hutchings.

"His work absolutely and quite appropriately provokes. We've needed the scientifically driven provocations by Ram to force us to look very carefully at our oceans."

Myers, who has adult and young children, was recognized by Fortune Magazine as one of its Ten People to Watch in 2005, along with American senator Barack Obama and the three founders of Google.

Myers, who is originally from Mississippi, was the only Canadian to make the list and, according to friends, was more than amused to receive the honour.

"He laughed and laughed at it," said Worm. "He thought that was really funny."