Scientists spotted a North Atlantic right whale entangled in fishing gear in the Gulf of St. Lawrence earlier this month.
It is the fifth right whale with attached fishing gear observed so far this year. The New England Aquarium said in four of those cases, the gear belonged to a Canadian fishery.
The Gulf of St. Lawrence has become a popular summertime feeding spot for right whales, as the species searches for their preferred prey, a tiny zooplankton called copepods.
"They're migrating longer distances to get to feeding habitats, where protective measures have not necessarily been put in place," said Amy Knowlton, a senior scientist with the New England Aquarium.
The entanglement numbers are concerning, she said, because some Canadian fishing grounds are closed when right whales are seen aggregating in effort to protect them. Knowlton and other scientists are calling on both Canadian and U.S. fisheries to do more to modify their gear and implement "ropeless" or "on demand" options.
"That's why we need to think about just managing how the gear is set up, and maybe how much gear there is," she said. "If we don't start to think in that way, if we think about only managing when we know right whales are present, I just don't think we'll ever solve this problem."
The National Oceanic and Atmospheric Administration has counted 115 dead, seriously injured or ill right whales since 2017 as part of an ongoing investigation into an elevated number of mortalities. About two-thirds of those cases involved entanglements with fishing gear, according to the New England Aquarium. There are fewer than 340 right whales remaining.
The right whale that a team from Dalhousie University in Nova Scotia and others spotted on July 15 was seen dragging fishing rope from his mouth and with fresh wounds on his tail.