The New England Aquarium has spotted more than 75 endangered North Atlantic right whales in shipping lanes south of Massachusetts.
That's prompted the National Oceanic and Atmospheric Administration to issue voluntary speed restrictions for vessels transiting through those areas.
The aquarium said ship strikes are one of the leading causes of injury and death for the critically endangered species.
Researchers said it's not unusual for right whales to congregate in that part of the ocean during springtime, but that this year's group is one of the largest they've ever seen.
The aquarium said there are only about 370 North Atlantic right whales left.
