The Department of Fisheries and Oceans says the death of a right whale in the Gulf of St. Lawrence does not appear to be the result of a recent vessel strike or entanglement in fishing gear.
A necropsy was conducted Friday on the shores of Miscou Island in New Brunswick, and the government said the results were inconclusive.
The nine-year-old male known as "Wolverine" was towed there after his carcass was discovered in the Gulf on Tuesday.
The whale was in an area previously closed to fishing activity as part of the 2019 management measures.
In recent years most right whale deaths have been attributed to being struck by ships or becoming entangled in fishing gear.
"The necropsy of the right whale did not reveal evidence of acute (recent) fishing gear entanglement or recent vessel strike. Further testing to investigate other possible causes of death is pending," the department said in a statement issued late Saturday, attributing the information to veterinarians from the Canadian Wildlife Health Cooperative.
"The Department will continue to work with the fishing industry in Atlantic Canada and Quebec as well as our marine mammal response partners to support the protection and recovery of the endangered North Atlantic right whale," they wrote.
Major efforts have been made to limit fishing gear when the whales are present, and there are now mandatory speed restrictions for vessels 20 metres or longer when travelling in the western Gulf.
No right whales died in Canadian waters last year, but 12 were found dead in the Gulf of St. Lawrence in 2017.
Necropsies on seven of those whales found four died from trauma consistent with vessel collisions, while two deaths were the result of entanglement in fishing gear.
There are estimated to be fewer than 420 of the North Atlantic right whales left, with deaths outpacing live births.
The right whale is one of the largest mammals in the sea.