The National Oceanic and Atmospheric Administration is investigating a report of another dead North Atlantic right whale found off the coast of Virginia and has declared a new voluntary slow-speed zone in the mid-Atlantic to help protect four live whales spotted in the area.

This would be the first North Atlantic right whale to be found dead this year.

At least 17 of the endangered whales died in Canadian and U.S. waters in 2017, and scientists believe human activity, including shipping and fishing, was the primary cause.

The latest carcass appears to be entangled in fishing gear, based on a photograph received by the Virginia Aquarium Stranding Response Program on Wednesday night, NOAA said in an emailed statement Thursday.

The U.S. agency is asking mariners in the area — 86 nautical miles east-southeast of Virginia Beach — to slow down to 10 knots or less or to route around to avoid striking the four live North Atlantic right whales spotted there by a U.S. military ship on Tuesday.

The voluntary speed restriction zone will remain in effect until Feb. 7, the statement said.

There are only an estimated 450 North Atlantic right whales left in the world, according to NOAA. Of those, only about 100 are reproducing females and no new calves have been spotted yet this year in the calving grounds off Florida.

NOAA Fisheries has requested a drift analysis from the U.S. Coast Guard to try to determine the current location of the carcass and whether it can be towed to shore for a necropsy.

"At this point, we are not able to confirm the whale's sex or match its identity with the photo-ID catalog of known individuals that scientists maintain for the population," the statement issued by NOAA spokesperson Jennifer Goebel said.

The carcass has been positively identified as a North Atlantic right whale, however, and it "appears to be wrapped in line in a manner that, based on past observations of entanglements, suggests the whale was alive and swimming when it encountered the line," the statement said.​

Necropsies on seven of the carcasses found last year determined four whales died of blunt force trauma from collisions with ships, and the other three likely died from entanglements in fishing gear.

Earlier this week, Fisheries and Oceans Minister Dominic LeBlanc announced changes to the snow crab fishery in the southern Gulf of St. Lawrence to protect the North Atlantic right whale from entanglement.

The changes include reducing the number of fishing rope floating on the surface and mandatory reporting of all lost gear. The government also said it will most likely impose speed restrictions for vessels again this year, when the whales return to the gulf.

This female North Atlantic right whale found in the Gulf of St Lawrence on Sept. 15 was deemed a case of 'severe entanglement' by the federal Fisheries Department. (Shane Fowler/CBC)

Last summer, Transport Canada imposed a mandatory 10-knot speed limit in the western part of the Gulf of St. Lawrence for vessels 20 metres or longer to help reduce the risk of whale strikes, while also improving the chances of survival for any whales struck.

Other pending crab fishery measures relate to the number of traps that will be permitted this season and the possibility of using Coast Guard ice-breakers to start the season sooner.

During a news conference in Moncton, LeBlanc said the new management measures were effective immediately and others will be announced in coming weeks and months.

A running tally

Regina Asmutis-Silvia, the executive director of Whale and Dolphin Conservation North America in Cape Cod, said the protection measures LeBlanc presented this week won't stop whales from getting caught in fishing line.

"Maybe you can figure out where the gear came from, but it doesn't prevent that entanglement," she said.

"The closest one to come up to mitigation is limiting the amount of float line that is between the two buoys at the surface."

I don't want to be ready to say goodbye to this species but I've never been in a position where I really thought they were this close to extinction. - Regina Asmutis-Silvia , executive director of Whale and Dolphin Conservation North America

Without having a baseline measurement of how much line was used before, it's still not clear if this step will reduce risk, she said.

Asmutis-Silvia found out about the latest North Atlantic whale death online Thursday morning, describing it as "a huge loss."

She said there will either be drastic measures taken to save the North Atlantic right whale or a running tally to its extinction.

"I don't want to be ready to say goodbye to this species but I've never been in a position where I really thought they were this close to extinction," she said.

"It's scarily imminent," given the estimated four per cent loss of the population in less than a year and no new calves being seen.

"We are at a point where it is so incredibly devastating to the species that it's a running tally," she said. "There's no clock to start over with."

Measures being taken in U.S.

Meanwhile, in the United States, conservation and animal-protection groups launched a lawsuit last week against the National Marine Fisheries Service in that country, alleging it failed to protect right whales from entanglement in commercial fishing gear.

Kristen Monsell, oceans legal director for the U.S. Center for Biological Diversity, said more needs to be done to prevent whale deaths and injuries.

"It's just absolutely devastating to hear that and yet another reason on a very long list as to why the United States and the Canadian government need to take very strong and immediate action to reduce risk to right whales," she said Thursday.

Monsell applauded the Canadian government for its latest steps to protect the right whales, she said more needs to be done.

"They don't go nearly far enough and we are hoping to see more mandatory changes."

The lawsuit, filed in federal court in Washington, D.C., alleges the federal management of the U.S. lobster fishery violates the Endangered Species Act and the Marine Mammal Protection Act.