Two of the dozens of North American right whales gathered off the coast of Portsmouth, N.H., are seen Sunday. Photo courtesy of New England Aquarium

Maine’s marine resources commissioner is “strongly urging” lobstermen to move their gear from an area in the Gulf of Maine where over 70 endangered North Atlantic right whales were spotted earlier this week.

“The ramifications of another entanglement in Maine gear could be devastating to your fishery,” Commissioner Pat Keliher said in an emailed announcement Friday afternoon.

Officials directly linked the death of a whale to a Maine lobsterman’s gear for the first time in October.

For several years, scientists have warned entanglements in fishing gear and boat strikes are the most common causes of premature right whale deaths, but they could not prove any of the problematic gear belonged to Maine fishermen until the fall.

Lobstermen have leaned on the absence of data when calling out how regulations meant to protect the whales come at a great cost to them and threaten to put them out of business.

The group of right whales gathered at Jeffreys Ledge — a long, underwater ridge that attracts marine life — is unusually large and represents more than 15% of the remaining global population. Surveyors noticed the group on Sunday.

A “large amount” of fixed fishing gear was also spotted in the area, according to the National Oceanographic and Atmospheric Administration.

Keliher, who last week got into a heated argument with lobstermen over a separate issue, asked them to “eliminate the risk” and move gear “until surveys indicate that the whales have moved on.” A slow zone for boaters — no more than 10 knots — is also in place.

“I cannot predict what will happen if Maine gear entangles a right whale, however it is possible that resulting federal regulatory restrictions on the Maine lobster fishery could be catastrophic — including extensive additional prohibitions on the use of traditional gear,” Keliher said.