Staff from the New York Marine Rescue Center in Riverhead...

Staff from the New York Marine Rescue Center in Riverhead responded to a rare pygmy sperm whale that beached itself in Brooklyn on Thursday.  Credit: New York Marine Rescue Center/Maxine Montello

The stranding and death of a pygmy sperm whale on a Brooklyn beach raises concerns an unknown factor may be troubling this rare squid-hunting species that much prefers the sea’s deep waters, experts said on Friday.

“It rarely occurs,” said Rob DiGiovanni, chief scientist with the Hampton Bays-based Atlantic Marine Conservation Society, by telephone. 

While 18 such whales, which can grow around 11 feet long and weigh more than 900 pounds, have stranded on New York shores in the past 41 years, this is the fourth such death in the past five years, he said.

“The frequency is different, but you also had an increase in the number of large whale strandings,” he said. “You definitely have a change in the ecosystem, not necessarily for the worse.”

New York’s now cleaner waters and fishing limits that helped revive the population of a vital prey fish, bunker or menhaden, are among the reasons cited for the return of dolphins and whales to these waters.

This adult whale died on Thursday morning on Plumb Beach, part of the Gateway National Recreation Area, officials said, before Riverhead’s New York Marine Rescue Center could euthanize it.

Alerted Wednesday, the center sent a team out to evaluate the pygmy whale, which had been pushed back into the waters, said Maxine Montello, the center’s rescue program director.

“We understand everyone has the best intentions,” Montello said, yet returning a dolphin or whale back to the sea risks lengthening their suffering as they may have stranded because they are ailing and unable to swim properly.

Pygmy whales are protected in this country by the Marine Mammal Protection Act, which requires people to stay 150 feet away or risk fines of as much as $100,000 and up to a year in prison.

With their melon-like heads, they look a little like grey-black Beluga whales.

One reason they are so uncommon, the National Oceanic and Atmospheric Administration says, is because they “spend very little time at the water’s surface and almost never approach vessels.”

"This incident underscores the importance of the stranding network as a source of data on little-known species and as an early alert system for what could be an emerging issue with a marine mammal population," Teri Frady, chief, research communications, NOAA Northeast Fisheries Science Center, said by email.

Death did not come easily to this pygmy.

Not only was it thin — though there was food in its stomach — it also had a “heavy parasite load,” DiGiovanni said, which suggests an underlying ailment that might be identified from tissue samples taken during the necropsy the Atlantic Marine Conservation Society performed.

“It does appear to be natural, not human-induced,” DiGiovanni said, as this whale evidently had not been hit by a boat, gotten entangled in fishing gear or ingested trash. 

 Slow swimmers, pygmy whales are known for “logging,” or resting on the sea’s surface. “Floating motionless to recharge their proverbial batteries, their backs and heads are visible, whilst their tails hang limply in the water,” says the Plymouth, Massachusetts-based Whale and Dolphin Conservation Society, nonprofit advocates.

“Once they are ready to move on, pygmy sperm whales sink like stones below the surface, unlike other cetaceans who prefer to roll,” it added.

Capable of diving 1,000 feet, they also eat fish, octopus, crab and shrimp.

Unlike all other whales, except the dwarf sperm whale, pygmy sperm whales use the same kind of technique squids deploy when threatened, squirting “dark, reddish-brown liquid” from an intestinal sac that helps them escape predators by clouding the water, NOAA says.

Correction: Plumb Beach is part of the Gateway National Recreation Area. An earlier version of this story used an incorrect noun to describe the area.

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