OTTAWA -- An endangered right whale has been found dead in the Gulf of St. Lawrence.

Fisheries and Oceans Canada says the carcass was discovered during a surveillance flight.

The department says it is working with the Marine Animal Response Society, the Quebec Marine Mammal Emergency Response Network and the National Oceanic and Atmospheric Administration to find the whale.

The hope is to recover the carcass so tests can be done to determine how it died.

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 Department of Fisheries and Oceans has rules to help protect the whales, including mandatory speed restrictions for vessels 20 metres or longer when travelling in the western Gulf.

The right whale is one of the largest mammals in the sea.

They typically migrate from the North Atlantic to give birth off the coasts of Georgia and Florida from December through March.

They then head back north to feed off Canada's East Coast during the summer months.