HALIFAX -- Canadian officials are challenging American allegations that fishing gear from Canada is to blame for the entanglement of a North Atlantic right whale found dead off South Carolina.

Fisheries and Oceans Canada issued a statement Wednesday saying it had determined the gear, retrieved after a whale known as Cottontail was found dead on Feb. 27, likely came from an American inshore fishing boat.

The statement said Canadian officials believe the gear had been used somewhere between Long Island, N.Y., and South Carolina, and was mostly likely from the southern United States.

Canadian officials said they came to that conclusion after examining the gear with experts from the U.S. National Oceanic and Atmospheric Administration. As well, they pointed out that Cottontail was not spotted in Canadian waters in 2020.

"Over the past few years, Canada's fishing industry has demonstrated incredible adaptability and leadership when it comes to protecting North Atlantic right whales," Fisheries and Oceans Canada said.

"Our measures for protecting the North Atlantic right whales are world-class, and this is largely due to the hard work and co-operation of our harvesters and their organizations."

Experts estimate fewer than 400 North Atlantic right whales survive.

A spokeswoman for NOAA confirmed Thursday that the results of a draft report are at odds with the Canadian findings. "We came to different conclusions," said Jennifer Goebel, a public affairs officer with NOAA's Atlantic region. "We were told there was disagreement, but we have not seen the report from Canada."

She said NOAA's final report may arrive at a different conclusion once all of the evidence has been examined.

While it was agreed the gear could not have been used in the 2020 Canadian fishery, given its lack of compliance with the latest rules, the Americans concluded the gear could have been used in 2019 and 2018.

As well, the report stated the gear could not have been used off the coast of the southern United States because it doesn't match the gear type known to be used in that area.

NOAA's draft report also included a detailed description of the 1.5-centimetre floating line that was retrieved from Cottontail's body, as well as a description of the various knots and mending twine attached to the rope.

Though the rope had no identification tags or marks, NOAA experts concluded it was identical to the type of Canadian snow crab trap gear found on another entangled right whale, Ruffian, in 2017.

"Given all the similarities between the two cases and not matching any U.S. fishery, we feel the gear is consistent with Canadian snow crab (gear)," the report said.

Those who drafted the report, however, admit they are not experts on Canadian gear. "Our NOAA Fisheries gear team has extensive experience with fishing industries within our country and we recognize our knowledge of Canadian fisheries is limited," the report said.

"Any case, including this one, which is not identified to an individual fisher will remain an open case as additional information may change the conclusion."

The entanglement was first reported by an aerial search team on Oct. 19, 2020, as they were flying south of Nantucket, Mass. The New England Aquarium identified Cottontail, saying the 11-year-old male had rope over its head and hanging from both sides of his mouth.

About 27 metres of rope was removed from the whale's body, but the response team couldn't get it all, as Cottontail became evasive and agitated as night fell.

A signal from a tracking device indicated the whale was about 100 kilometres south of Yarmouth, N.S., on Oct. 31, 2020, but the crew aboard a Fisheries and Oceans aircraft could not see the whale as the aircraft zeroed in on the signal.

Cottontail was last seen alive off Florida's Treasure Coast on Feb. 18, 2021.

Conservationists worry that North Atlantic right whales are slipping closer to extinction as deaths in recent years have outpaced births.

The 2021 calving season, however, has proven to be the best in years. Survey teams dispatched last month to search by air for right whale mothers and newborn calves spotted 15 calves -- the most reported since 2015.

This report by The Canadian Press was first published April 1, 2021.