June 4, 2021 — Entanglements in fishing gear, which have been among the leading causes of death of North Atlantic right whales, are likely also stunting their growth and causing the critically endangered species to reproduce less often, a new study found.
The research raises questions about the findings of a major report on the species released last month by the federal government and could have a significant impact on how it regulates the lobster industry, which has been the primary source of entanglements. The population of right whales has plummeted over the past decade by a quarter, with scientists estimating that fewer than 370 remain.
The long-term study, published Thursday in the journal Current Biology, estimated that a calf born in recent years was likely, when mature, to be about 3 feet shorter in length than those born in the 1980s. Entanglements have become more of a problem for whales in recent decades, as ropes have increasingly used synthetic materials and become stronger.
“Stunting of growth is a classic sign that a species is in trouble,” said Michael Moore, a senior scientist at the Woods Hole Oceanographic Institution and a coauthor of the study. “Smaller mothers are less capable of being successful breeders, because they have a smaller fuel tank and less lactation. That’s the biggest concern.”
He and other authors said the findings call into question a long-awaited report released last month by the National Marine Fisheries Service that found the lobster industry isn’t jeopardizing the survival of right whales. A federal judge last year ordered the agency to produce the report, known as a biological opinion, after rulingthat it had violated the Endangered Species Act by failing to reduce entanglements.