Preliminary results from necropsies performed on two North Atlantic right whales on the Magdalen Islands this week suggest one of them was involved in a collision with a ship.

The other whale was too decomposed and determining a cause of death was not possible.

The carcasses of seven right whales have been found in the Gulf of St. Lawrence since June 6.

Necropsies performed on two of the other dead whales at the start of July also found evidence of collisions with ships.

Another carcass showed evidence of a "chronic entanglement."

Toxic algae not ruled out

Josiane Cabana of Quebec's marine mammal rescue network told CBC's French-language service, Radio-Canada, that scientists have not ruled out toxic algae as a contributing factor in the deaths.

Whale necropsy

One of the whale carcasses showed evidence of a collision with a ship. (Gilbert Boyer)

"We know that red algae affects co-ordination," she said. "It can have a numbing effect and make them more susceptible to collisions."

The final results of the two new necropsies conducted July 9 and 10 will be known in six to eight weeks.

Sightings on the rise

Cabana said an increased presence of right whales in the Gulf of St. Lawrence has been noted.

"Something is really happening in terms of the distribution of the whales," she said.

Dead right whale

Seven North Atlantic right whales have died since June 7. (Department of Fisheries and Oceans)

Last year, right whales were observed off the Magdalen Islands, between Anticosti Island and the Mingan Archipelago, and off Percé in Quebec's Gaspé Peninsula.

Two right whales were also seen near Tadoussac, Que.

According to Cabana, an observation station on the Mingan Archipelago regularly sees right whales in a nearby shipping lane.

"It is a whale that swims very slowly that remains for a long time on the surface and is then very difficult to spot. Their basic behaviour makes them more susceptible to collisions," Cabana said.

DFO introduces safety measures

The federal Department of Fisheries and Oceans is calling on vessels to reduce their speed between the Magdalen Islands and the Gaspé Peninsula until Sept. 30.

whale rescue, Bay of Fundy

Fishing line entanglements are a constant threat to right whales. (International Fund for Animal Welfare)

Fisheries and Oceans Canada also closed part of the snow crab fishery two days early on Wednesday as part of efforts to save the remaining population of endangered North Atlantic right whales, which number around 500.

The DFO, however, is pausing efforts to assist whales found entangled in fishing line in order to conduct a safety review of its procedures.

The pause comes after a New Brunswick man died earlier this week while helping set a whale free from fishing lines.