Severely entangled right whales seldom survive longer than 3 years, new research shows
North Atlantic right whales are suffering more than previously known from entanglements in rope and fishing gear, a new study found.
According to a study from the New England Aquarium and Duke University, most right whales that are severely injured in fishing gear entanglements die within three years. In fact, researchers found, only 44% of males and just 33% of females with severe injuries survived longer than 36 months.
“What we're showing is that [entanglements] have a much greater impact than the initial studies have suggested,” said lead author and New England Aquarium senior scientist Amy Knowlton. “We know things are bad, but it's even worse than we knew for the species.”
The study, published in Conservation Science and Practice, tracked the outcomes of 1,196 entanglements involving 573 right whales between 1980 and 2011 and found that right whales with severe injuries are eight times more likely to die than those with minor injuries. The conclusion: entanglements in rope and fishing gear are the leading cause of death for the critically endangered species — more than collisions with boats, illness, or anything else.
Experts say right whale entanglements typically occur in fixed fishing gear, specifically gillnets, lobster pots, and crab pots, a claim lobstermen contest.
Injuries from entanglements range from superficial wounds to catastrophic injuries, where the line wraps multiple times around a whale’s tail, mouth, or body, resulting in wounds down to the bone.
Researchers have long known that whales with severe entanglements are more likely to die than recover, Knowlton said, but until now there wasn’t a good metric to prove it.
“It's just more compelling evidence to show that we need to prevent all entanglements from happening,” she said, ”because the injuries that they endure are pretty debilitating for the species.”
Right whale conservation experts are pushing for urgent changes to the fishing industry as the species, with an estimated population of just 336 individuals, faces extinction.
“We need to really regulate this fishery dramatically and quickly and help the industry transition. It shouldn't all be on them to sort of cover the costs for this because … they're operating legally. So it's not a question of that,” Knowlton said. “The management needs to catch up to the story that right whales have been experiencing for decades.”