Why more dead whales are washing up on U.S. beaches : NPR

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People look at a dead gray whale at Ocean Beach in San Francisco, California, in May 2019, a year when 122 gray whales died in the United States, according to the National Oceanic and Atmospheric Administration. Last year, 47 of the whales died.

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Justin Sullivan/Getty Images

People look at a dead gray whale at Ocean Beach in San Francisco, California, in May 2019, a year when 122 gray whales died in the United States, according to the National Oceanic and Atmospheric Administration. Last year, 47 of the whales died.

Justin Sullivan/Getty Images

Researchers are trying to solve a mystery: Why are so many humpback whales, right whales, and other large mammals dying along the East Coast of the United States? One possible explanation is a change in eating habits. And while theories are circulating that blame the booming offshore wind industry, scientists say there is no evidence to support that idea.

Since Dec. 1, at least 18 reports have come in of large whales washing ashore along the Atlantic Coast, according to the Marine Mammal Stranding Network. The losses are affecting populations that were already under guard, due to ongoing increases in unexpected deaths.

“Unfortunately, it was a period of several years where we had elevated levels of large whales, but we are still concerned about this pulse” in deaths that has now been going on for weeks, as Sarah Wilkin, the coordinator for Mammal Health Maritime and Stranding Response Program, he said on a recent call with journalists.

Scientists are particularly concerned about the recent increase in deaths, Wilkins said, because the increase is being seen in a “relatively narrow geographic area,” and over a short period of time.

Here’s a look at what’s happening, and some of the possible reasons:

Which whale species are seeing a sharp rise in deaths?

On the East Coast, two species of whales — the minke whale and the North Atlantic right whale — have each suffered an increase in deaths over the past six to seven years, according to the -National Oceanic and Atmospheric Administration.

The agency declared an unusual mortality event, or UME, for both types of whales. It defines a UME as an unexpected break that “involves a significant death of any marine mammal population” and requires an immediate response.

As of 2016, 180 humpbacks have been reported to be stranded on the coast of the states of the United States from Florida to Maine. At least seven scalds have already been reported in 2023, including four in New Jersey — equal to the state’s total in 2022.

For right whales, more than 20 percent of the population was affected by the UME that was documented from 2017, alarming statistics for an endangered species that was last estimated to have 350 whales left. The UME figure includes whales found dead, injured or sick.

On the West Coast, NOAA has been tracking an involving UME gray whales. Since the beginning of 2019, 303 gray whales have been reported lost in the U.S. If Mexico and Canada are included, the overall number rises to 608. More than a third of those deaths occurred in the first year of UME; the numbers have dropped drastically since then.

All three whale species in question were previously hunted close to extinction. And while gray and humpback whales have made a comeback, right whales are still an endangered species, with more deaths than births each year.

What about disruption from offshore wind farms?

Even early in the humpback’s unexpected spawning, questions were being raised about the possible damage caused to whales by wind farms. Those questions grew during the current rise, as interest is increasing in offshore wind energy projects that require the use of powerful ocean floor mapping devices.

The questions have only increased in the past two months, as crews conduct surveys off New York and New Jersey to learn details about the seabed, both to learn where facilities might be located and where the – cables.

The New Jersey-based group Clean Ocean Action has he called for the wind projects in the oceans to be stopped and an investigation into potential harm to whales. Local and state officials should join that effortalong with several members of Congress.

But officials from NOAA and other agencies are pushing back on suggestions that wind farms may somehow contribute to whale deaths.

“There is no known connection between any of this offshore wind activity and any whale captures regardless of species,” said Benjamin Laws, deputy chief for the division of permits and conservation at NOAA Fisheries, in a briefing.

The type of equipment being used in the area is not as problematic as projects such as offshore oil and gas exploration, said Erica Staaterman, a bioacoustician at the Office of Management’s Center for Marine Acoustics. of Ocean Energy.

“Those in oil and gas are called seismic air guns, and they’re specifically designed to penetrate kilometers into the seabed. So they’re very high energy, very powerful sources,” Staaterman said. In contrast, she added, the tools used to prepare for offshore wind sites are “high-resolution geophysical sources, and they are typically smaller in the amount of acoustic energy they put into the sound column. water.”

“Many of them are used for very short periods of time with long periods of quiet in between,” Staaterman said, adding that some of the instruments also produce “a very narrow cone of sound,” rather than blasting in all directions. .

“I just want to be unambiguous,” said Laws, “there is no information to support any suggestion that any equipment being used in support of wind development [to perform surveys] can lead directly to the death of a whale”.

So, what is killing the whale?

In general, experts say human interactions are a major factor in whale deaths, through ship strikes or entanglement from ropes and other fishing gear.

That’s a particular threat this winter, when the animals that typically prey on whales have reportedly come close to shore, NOAA officials say. That movement leads humpbacks and other whales to follow along, creating more overlap where whales and ships share the same waters.

And as Wilkin notes, the growth of the whale population may be a factor. “As the abundance of whales increases, we will have more whales in different places,” she said.

For right whales, the agency says human interaction is the leading cause of death. About half of the humpback whales that died in the recent spike had some level of necropsy examination, NOAA says. Of that number, about 40 percent showed evidence of an attack or entanglement on a vessel.

The causes of whale deaths can only be determined in a fraction of cases, partly due to the difficulty of examining a whale that dies in the wild, from their enormous size to the various states of decomposition that may have occurred.

For the UME that affects gray whales in the Pacific Ocean, the cause is still undetermined, although the researchers note that of the dead whales that were examined, several of them showed “evidence of emaciation.”

One thing the ongoing UMEs on both sides of the coast have in common is their broad scale: While historically some UMEs have been very localized, tracking maps show that humpback whale strandings , grays and normals occurred up and down the Atlantic and Pacific coasts. .

That’s a stark contrast to previous groups of deaths, such as the 14 humpback whales that died of biotoxin in 1987 — all of them in an area around Cape Cod, Mass. In that case, the deaths were attributed to saxitoxin, which is produced by red tide algae and can accumulate in mackerel — which the whales then eat.

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