The seventh dead North Atlantic right whale to undergo a necropsy in the Gulf of St. Lawrence last summer died after being entangled in fishing gear, according to newly updated results.
The two-year-old female whale was found tightly wrapped in heavy ropes and other fishing gear on Sept. 19 near Miscou Island, N.B., with deep cuts on its body, mouth, fins and in its blubber. A necropsy was launched, but investigators said early on it appeared to be a case of "severe entanglement."
At least 17 right whales died in Canadian and U.S. waters this summer and scientists believe human activity is the primary cause of death.
Necropsies on seven of the whales showed four died of blunt force trauma from collisions with ships, while two more appeared to die from being entangled in fishing gear.
Heavy snow crab fishing gear to blame
The 2017 Right Whale Incident Report was updated in late December to include findings on the seventh whale. The report says the whale died from acute entanglement in fishing gear and subsequent drowning.
It also states the animal was entangled in fishing lines attached to a heavy snow crab pot, and the heavy weight of the gear in relation to the small size of this particular whale caused scientists to believe it likely drowned.
It was the smallest of the seven whales examined.
Difficult to find cause of death
Pierre-Yves Daoust, a pathologist and professor at the Atlantic Veterinary College, previously told CBC it was difficult to determine exactly how these right whales died, because they decompose so quickly.
"The fact remains that human activities are a very important cause of this mortality this summer," Daoust told CBC in October.
Scientists at this year's North Atlantic Right Whale Consortium's annual meeting in late October said the species has a little over 20 years left, unless changes are made immediately.
A 10-knot speed limit was put in the Gulf of St. Lawrence in August to try and prevent further deaths.
Thicker, stronger rope to blame
But Amy Knowlton, who works at the New England Aquarium in Boston, Mass., said at the October meeting that rope was the main culprit for these deadly entanglements — and nothing has been done to address that problem.
Ropes used to catch lobster and crab, as well as for gillnetting, have become thicker and stronger in the last few years, she said, so these whales are unable to break free.
Knowlton said scientists are trying to work with industry partners to change the rope on the market, or eliminate it altogether.