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Researchers are trying to figure out a mystery: Why are so many humpback whales, right whales, and other large mammals dying off the US east coast? One possible explanation is a change in food habits. And while theories are floating around that blame growing wind energy, scientists say there’s no evidence to support that theory.
Since Dec. 1, there have been at least 18 reports of large whales washed ashore in the Atlantic Ocean, according to the Marine Mammal Stranding Network. The losses of the population are already under the watch, due to the ongoing unexpected deaths.
“Unfortunately, there has been a period of several years where we have raised the filaments of large whales, but we are still worried about this pulse” in the deaths that have been happening for weeks now, as Sarah Wilkin, coordinator for the safety of marine mammals. and the Stranding Response Program said on a recent call with reporters.
Scientists are particularly concerned about recent spikes in deaths, Wilkins said, because the increase appears over a “relative geographic area” and over a short period of time.
Here is a look at what is happening and the possible causes;
What species of whales see spikes in death?
In the Far East, two species of whales — the humpback and the North Atlantic right whale — have each experienced a spike in deaths of six or seven years, according to the National Oceanic and Atmospheric Administration.
The agency declared an unusual mortality event, or UME, for both species of whales. It defines a UME as an unexpected spill that “involves the significant removal of any marine mammal population” and requires an immediate response.
As of 2016, 180 humpbacks have been reported stranded along the coast of US states from Florida to Maine. At least seven wires have already been reported for 2023, including four in New Jersey — matching the state’s total for 2022.
For right whales, more than 20 percent of the population has been affected by the UME, which has been documented since 2017, an alarming statistic for an endangered species that is estimated to have approximately 300 whales left. In the UME figure, whales that were found dead, injured, or ill were found.
On the West Coast, NOAA tracked UME gray whales. As of early 2019, 303 gray whale sightings have been reported in the U.S. If Mexico and Canada are included, the number rises to 608. More than a third of those deaths occurred in the first year of the UME; when the numbers fell sharply.
All three cetacean species in question have previously been driven close to extinction. And while gray and humpback whales are rebounding, right whales remain an endangered species, with more deaths than births each year.
What about disturbances in the wind from the countryside?
Even in the morning on the unexpected humpback tour, they were moved by questions about the damage caused to the whale farms by the winds. Those questions have grown in recent waves, with concerns about the energy of remote wind waves, which require the use of powerful devices to map the ocean floor.
The questions have only increased in the past two months, as crews are doing surveys of New York and New Jersey to learn more about the sea area, as well as to learn where they could locate the facilities and where they could run the cables.
The New Jersey-based group Clean Ocean Action has called to stop the ocean wind projects and research on the potential harm caused by whales. Local and state officials have joined that effort along with many others members of Congress.
But officials from NOAA and other agencies are pushing back against suggestions that wind farms somehow contribute to whale deaths.
“There are no known connections between any of this wind activity and any wandering whale of any kind,” Benjamin Laws, deputy chief of the permit and conservation division of NOAA’s fisheries, said in a briefing call.
The type of equipment used in the area is not as problematic as for projects such as marine exploration and oil and gas, said Erica Staaterman, a bioacoustician at the Bureau of Ocean Energy Management’s Center for Marine Acoustics.
“Those in oil and gas are called seismic air guns, and they’re specifically designed to penetrate kilometers into the sea floor. So they’re very bright sources of deep energy,” Staaterman said. On the other hand, he added, the tools used to prepare upwind sites are “high-resolution geophysical sources, and you’re typically smaller in the amount of acoustic energy they send into the water column.”
“And many of these at very short intervals of time interspersed with long silences,” Staaterman said, adding that some instruments also produce “a very narrow band of sound” rather than burning in all directions.
“I just want to be clear,” Laws stated, “that there is no evidence to support any suggestion that anyone has been using the instrument to develop the winds. [to perform surveys] directly to the death of the whale. “
So why kill the whales?
Overall, experts say human interactions are the main factors in whale deaths, through ship strikes or entanglements with fishing lines and gear.
Special prey this winter, with animals that typically prey on whales reportedly approaching shore, NOAA officials say. That tradition leads humpbacks and other whales to follow suit, and it grows stronger where whales and ships share the same waters.
And, as Wilkin notes, whale population growth may be a factor. “When whale abundance increases, we will find more whales in different areas,” he said.
For right whales, the agency says human trafficking is the leading cause of death. About half of the humpback whales that died recently had some degree of necropsy, NOAA says. Of that number, about 40 percent showed evidence of vessel impact or involvement.
The causes of the death of whales can be determined in only a fraction of cases, due to the difficulty of investigating a dying whale in the wild, from its enormous size to the various states of decomposition that can occur.
For the UME affecting gray whales in the Pacific Ocean, the cause is still undetermined, although the researchers note that the dead whales examined, many of them showed “evidence of emaciation”.
One thing permanent UMEs have in common on both sides of the coast is their broad scale: while historically some UMEs have been very local, track maps show that humpback, gray and right whales have occurred up and down the Atlantic and Pacific coasts. .
This is a sharp contrast with previous cluster deaths, such as 14 humpback whales that died from biotoxins in 1987 – all in the area around Cape Cod, Mass. In this case, the deaths were attributed to xitoxin, which was produced. Red algae can accumulate in the tides and in the mackerel – which the whales then eat.
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