Why do endangered whales keep getting entangled off New England?

The right whale's numbers have been particularly affected by fishing gear, according to an August study.

Stephan Savoia/AP/File
The head of a North Atlantic right whale peers up from the water as another whale passes behind in Cape Cod Bay near Provincetown, Mass., in April 2008. An August 2016 study found that the ability of the endangered whale species to recover is jeopardized by increasing rates of entanglement in fishing gear and a resultant drop in birth rates.

A 45-ton North Atlantic right whale, a rare breed whose numbers have been in decline recently, was found dead about 12 miles off of the coast of Maine over the weekend after it became entangled in fishing gear.

The case is the latest of three recent right whale entanglements – one of which also resulted in the whale’s death – that authorities with the National Oceanic and Atmospheric Administration say could inform future regulations. The agency is in the process of using the gear to sort out whether the fishermen who owned it were in compliance with regulations, according to NOAA Marine Mammal and Sea Turtle program coordinator David Gouveia.

"We're on par for the course with the averages for the year for entanglements," Mr. Gouveia told the Associated Press. "Overall, if you look at entanglements of all large whale species, we're a little bit above our average."

The incidents come as scientists point to entanglements as an increasing source of danger for the whales.

Between 1970 and 2009, 44 percent of diagnosed deaths were because of entanglements, according to a study published this August in the journal Frontiers in Marine Science. Between 2010 and 2015, entanglements accounted for a full 85 percent of right whale deaths. Meanwhile, deaths from entanglements and collisions with ships, another common hazard, increased over that five-year period, compared to the preceding two decades. The whales' birth rate also fell sharply from 2010 to 2015.

"Right whales need immediate and significant management intervention to reduce mortalities and injuries from fishing gear," concluded the study's authors, adding that an explanation for the decline in new births was necessary before the species' return from near-extinction could be considered a success story. "Failure to act on this new information will lead to further declines in this population's number and increase its vulnerability to extinction," they wrote.

Entanglements also harm the whale's population indirectly even if the whale doesn't die, according to one of the authors of the study, Scott Kraus.

"They are carrying heavy gear around, and they can't move as fast or they can't feed as effectively," Dr. Kraus told The Associated Press in an interview this month. "And it looks like it affects their ability to reproduce because it means they can't put on enough fat to have a baby."

Other whales whose numbers were once under pressure from commercial whaling and other environmental hazards have seen a resurgence in recent years. This month, federal authorities removed the humpback whale from the endangered species list, reported The Christian Science Monitor:

The clearance for the majority of humpback whales joins another conservation announcement ... which removed giant pandas from the endangered species list. Together, the changes mark a significant moment of progress for conservation efforts around the world after nearly half a century of protecting two of the most iconic symbols of the movement. But conservationists still warn that despite the hard-won victories, the species remain vulnerable.

The beaching of a humpback whale only weeks later in New Jersey put attention back on the hazards still faced by species in recovery, as the Monitor wrote then:

Generally speaking, the threats are well known: entanglement, weaponized sonar use, and ship collisions are common causes of whale fatalities. But to neutralize these threats, conservationists must either work with – or against – commercial interest groups and military organizations.

This report contains material from the Associated Press.

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