One of the giants of the deep is shrinking before our eyes, a new study says.
The younger generation of critically endangered North Atlantic right whales are average three feet (one meter) shorter than whales were 20 years, drone and aircraft data show in a study in Thursday’s journal Current Biology.
Diminishing size threatens the species’ overall survival because the whales don’t have as many offspring. They aren’t big enough to nurse their young or even get pregnant, study authors said.
According to the study, these marine mammals used to grow to 46 feet (14 meters) on average, but now the younger generation is on track to average not quite 43 feet (13 meters).
“This isn’t about ‘short’ right whales; it’s about a physical manifestation of a physiological problem, it’s the chest pain before the heart attack,” said Regina Asmutis-Silvia, executive director of Whale and Dolphin Conservation North America, who wasn’t part of the study. “Ignoring it only leads to an inevitable tragedy, while recognizing and treating it can literally save a life, or in this case, an entire species.”
There are only about 356 North Atlantic right whales left, down from 500 in 2010, said study co-author Amy Knowlton, a senior scientist at the New England Aquarium. Other estimates put the population around 400, though researchers agree the population is shrinking.
In the past, scientists and activists have concentrated solely on whale deaths. However, now they realize there’s a problem afflicting surviving whales that can still cause populations to further dwindle, said study co-author Michael Moore, marine mammals director at Woods Hole Oceanographic Institute. The authors were able to take pictures of 129 of the right whales and use a computer program to compare them to the right whales of similar age 20 years ago.
The issue emerged from a research trip several years ago when Knowlton and others saw a few small whales and a dead one. They figured the small whales were calves less than a year old because of their size, but checking showed the whales actually were about two years old. Whale calves typically double in size in two years, said study lead author Joshua Stewart, a National Oceanic and Atmospheric Administration researcher.