In a series called Deep Trouble, CBC News explores the perils facing the endangered North Atlantic right whale.

Scientists have determined a whale grandmother known as Punctuation died as a result of being hit by a ship, news that comes as another critically endangered North Atlantic right whale has been discovered dead in the Gulf of St. Lawrence.

The Department of Fisheries and Oceans announced the preliminary necropsy results late Wednesday, and also said another carcass was found, near Anticosti Island in Quebec, bringing the right whale death toll in Canadian waters this month to five.

Punctuation, a large female right whale that scientists have been tracking since she was first spotted in 1981, has given birth to eight calves. Two of those calves went on to have calves of their own.

Her carcass was spotted floating last week west of the Magdalen Islands, and was towed by a Canadian Coast Guard vessel to Petit Étang, N.S., where the necropsy was performed.

"Any loss of a right whale is detrimental to the population. It's an endangered whale. This one is especially hard because she's a very prolific female, she's had a lot of calves and losing females out of an endangered population is the worst," DFO biologist Stephanie Ratelle said Tuesday.

"I feel incredibly sad and horrible. I'll start crying if I keep going. Just especially because you know the history of these animals, she's had a lot of calves, she's had a history of entanglement and ship strike…. You get attached."

Punctuation did not survive getting hit by a ship a 3rd time

With around 413 right whales now left in the world, the slew of recent deaths accounts for one per cent of the population, prompting Transport Canada on Wednesday to impose new vessel speed restrictions in parts of the Gulf.

A team of more than two dozen, including biologists, veterinary pathologists and veterinary technicians, ​​​​​performed the necropsy on Punctuation. In their preliminary findings, the veterinarians found her fatal injuries were due to "sharp trauma" consistent with a vessel strike.

The final results of the massive job, which involves taking apart an animal about 10 times the weight of a full-grown elephant, won't be known for months.

Punctuation is seen here with her calf, swimming off the coast of Georgia in 2006. (New England Aquarium taken under NMFS/NOAA permit #655-1652-01)

It's not the first time Punctuation was hit by a ship. According the New England Aquarium, she had been struck at least twice before. She had also been entangled in fishing gear at least five times.

Of particular concern is the fact that North Atlantic right whales don't live as long as one might expect for whales of similar size.

Barb Zoodsma, a right whale biologist with the U.S. National Oceanic and Atmospheric Administration, has told CBC News the longest living right whale that researchers know of only lived to be 75 years old.

"We also look to other species that they're closely related to. Bowhead whales can live to be 100 or 200 years old," she said.

But right whale females, on average, are only living between 20 and 30 years and usually produce their first calf when they're about 10.

Veterinary pathologists perform a necropsy on Wolverine. The nine-year-old North Atlantic right whale was the first to be found dead this year in the Gulf of St. Lawrence. (Gabrielle Fahmy/CBC)

Punctuation was the second right whale discovered dead this month in the Gulf.

DFO is still determining what will happen with the three latest carcasses, including the one discovered Wednesday. In a news release, the department said it's "working closely" with biologists and veterinarians to assess necropsy options.

DFO said Transport Canada is putting in place a precautionary speed restriction of 10 knots in the western Gulf of St. Lawrence for vessels 20 metres or more in length, in two designated shipping lanes north and south of Anticosti Island.

Those who fail to comply could face fines up to $25,000.

No right whales were recorded dying in Canadian waters last year, but 12 were found dead in the Gulf of St. Lawrence in 2017.

Necropsies on seven of them found four died from trauma consistent with vessel collisions, while two deaths were the result of entanglement in fishing gear.

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