Photo: DFO

A marine biologist says the recent deaths of four endangered North Atlantic right whales in the Gulf of St. Lawrence is alarming, given that the massive mammals are just arriving in Canadian waters.

Boris Worm, a biology professor at Dalhousie University in Halifax, says the sudden spate of deaths stands in sharp contrast to last season, when no right whales were lost to ship strikes or entanglements.

Worm says innovative measures taken last year — including real-time tracking of the animals — were key to helping the whales avoid collisions with boats or getting trapped in fishing gear.

He says it will be important to learn if Fisheries and Oceans Canada has made any changes to this year's mitigation measures.

The department says the cause of death for one of the whales was not linked to a ship strike or entanglement, but there is still work to be done to determine what happened to the others.

On Tuesday, the department reported that one dead whale had been spotted near New Brunswick's Acadian Peninsula, and another had been found west of Quebec's Iles-de-la-Madeleine — bringing the total number of right whale deaths this month to four.