Stocks of breeding tuna, such as this one caught off P.E.I. in early October, are in serious jeopardy, says the report. (CBC)

The population of spawning Atlantic tuna is down 75 per cent, says a new report, and a U.S. ecologist warns drastic action is required to save stock.

European and Mediterranean stocks are already in trouble, and the report from the Blue Ocean Institute in New York suggests tuna on this side of the Atlantic could be going the same way.

Carl Safina, an ecologist at the institute, is critical of the International Commission on the Conservation of Atlantic Tuna, the group that's been managing this stock for almost 40 years.

"The tuna population is lower now than it was about 10 years ago when they started what they called a rebuilding scheme," Safina told CBC News on Wednesday.

An emergency meeting on bluefin tuna is being held in Morocco next month. Delegates from 43 countries, including Canada, will decide what the latest science means for future fishing.

Safina is hoping one of the countries at the Morocco session will call for a five-year ban on fishing bluefin tuna in the Atlantic.

U.S. fishermen have seen their catch plummet in the last five years, down to 10 per cent of their allowable quota. Safina believes these declines will hit Canada within three to five years if something isn't done.

While catches have been good off P.E.I.'s North Shore in the last few years, Safina believes Canadians are catching the last of the old, large fish.

"Behind those fish there is very little, essentially nothing," he said.

The institute's report shows breeding stock is, on average, down 75 per cent since the 1970s, despite lower catches.