May 13, 2022 — As female North Atlantic right whales decline in size, they’re producing fewer calves, which could have grave consequences for the critically endangered species, according to a new study.
Scientists found in an earlier study that right whales have been shrinking, a phenomenon they attributed to frequent entanglements in fishing gear. The previous study found that entanglements place greater stress on the whales by forcing them to drag heavy fishing gear over long distances, which consumes their energy, reduces the fat reserves they need to reproduce, and makes them more susceptible to a range of diseases.
Some 85 percent of right whales have been entangled at least once, and of those, a majority have been entangled multiple times, scientists say. Entanglements and vessel strikes have been the leading cause of death and serious injuries to the whales, whose population has plummeted by about 30 percent over the past decade.
In the latest study, published on Thursday by the journal Marine Ecology Progress Series, scientists determined that the declining body length and girth of the whales have likely resulted in their low birth rates in recent years.