POINTE-DU-CHENE, N.B. -- The federal government is ordering large vessels to slow down in the Gulf of St. Lawrence as it tries to protect right whales who frequent the waters.

Ten of the endangered mammals have died in the gulf since early June.

Fisheries Minister Dominic LeBlanc and Transport Minister Marc Garneau were in Pointe-du-Chene, N.B., Friday to announce immediate temporary measures aimed at preventing further whale deaths.

Garneau said vessels of 20 metres or more will be required to slow to 10 knots while travelling in the western Gulf of St. Lawrence, from the Quebec north shore to just north of Prince Edward Island. The limits of that zone are subject to change, he said.

"These are reasonable measures to accomplish something very important," Garneau said. "I think that Canadians and the shipping industry and the fishing industry recognize that this is something most unusual and we need to take measures."

The measure will be enforced by Transport Canada and the Canadian Coast Guard. Ships that don't comply with the speed limit will be subject to a financial penalty of up to $25,000.

Smaller ships are being asked to voluntarily abide by the speed limit, which will remain in place until the whales have migrated from the areas of the gulf that pose the most concern.

The measure was designed in consultation with the fishing and shipping industries, who according to Garneau, have for the most part embraced the conservation effort.

"We do realize that there is some impact, but I think the marine industry also recognizes that we are trying to achieve something extremely important," he said.

Preliminary necropsy reports indicate some of the whales died of either entanglements with fishing gear, or from blunt trauma caused by ship collisions. LeBlanc said a full report is set to be released next month.

It's believed 80 to 100 right whales are currently in the gulf, LeBlanc said, and scientists expect the mammals to migrate south some time this fall.

The Fisheries Department has already taken steps to prevent further deaths, including shortening the snow crab season and asking fishermen in the gulf to report any whale sightings.

LeBlanc said the existing measures will be continuously reviewed based on aerial surveillance of the whales' migration patterns.

It's estimated there are only about 500 North Atlantic right whales still alive.