Five North Atlantic right whales have been found dead in the past week, and six in the last month. With just over 400 remaining and calving rates low, that’s a death toll the critically endangered population can’t afford.

“Panicking seems appropriate, yes,” said Peter Corkeron, who leads the large whale research program at NOAA’s Northeast Fisheries Science Center.

The whales' death toll is similar to that of the summer of 2017, when there was one death in early June, and then, later in the month, five deaths in the span of a week, all in the Gulf of St. Lawrence. That summer went on to become catastrophic for the whales, with a total of 12 documented fatalities in Canadian waters and another six in U.S. waters.

There are notable differences, as well, though. In 2017, some whales were hit by ships, but many of the deaths were due to whales getting tangled in fishing gear. This year, ship strikes seem to be the primary problem.

Large numbers of North Atlantic right whales have been sighted in the western Gulf of St. Lawrence in recent summers. Corkeron says that may be because of a subtle shift in where the animals are spending their time. Right whales have only started showing up in the Gulf of St. Lawrence in significant numbers in the past few years, a change in their migration patterns that researchers attribute to climate change.

But last year, most right whale sightings in the Gulf of St. Lawrence were clustered along its western edge. This year, the whales appear to be spread east-to-west, along an area that happens to be a busy shipping channel.

“From the whales' point of view, it's all the same place. It's like going to one coffee shop rather than another,” Corkeron said. “But, for how we manage killing them, it becomes really important.”

Canadian officials have put in place a speed limit for vessels over 20 meters in that area.

Corkeron says the damage done this year can’t be underestimated. There were only seven new calves sighted this year, and none last year, so this month has all but wiped out any progress the population had made.

And, Corkeron says, two of this month’s deaths are particularly worrisome. One whale, known as Punctuation, was a female in her forties who has produced several calves and was a grandmother. Another was a young female, close to reproductive age.

“Losing an adult female and a female who is about to reach adulthood is a huge problem, because now they're not going to have any more babies,” Corkeron explained. “If babies aren't born, then the rest of the species is just dead whales swimming.”

Corkeron says there is one silver lining to this situation: as long as human activities are what's killing right whales, that means we have the power to stop the deaths.