Feds research whale mystery after more than a dozen dead whales wash up along East Coast

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Fourteen whales have washed up on Atlantic Coast beaches since Dec. 1, but marine mammal experts and some conservation groups urge caution before jumping to conclusions about why these animals and others died.

In total, at least 20 marine mammals from five species—including humpbacks, and an orca—have been found dead on beaches from Maine to Florida since Nov. 28.

The deaths have prompted concerns as photos and stories of the whales and marine mammal rescue teams circulate online. On Wednesday, held a conference call with reporters to try to address swirling questions and rumors.

Final results of their investigations aren't yet available. Based on preliminary reports, it's likely a variety of human activities may be responsible for some of the deaths.

Here's what is known so far:

How unusual is it to have so many dead whales?

Whale deaths overall have been unusually high for years, with an upward trend in deaths along the East Coast, said Gilbert Brogan, a program manager with Oceana, a nonprofit ocean advocacy group.

The National Marine Fisheries Service is in the midst of three separate investigations into an increase in deaths among Atlantic Coast whales.

Fisheries service officials also noted that humpback whales are rebounding to some extent in the mid-Atlantic. Increasing populations can put the animals at greater risk of interactions with boats and .

How many whale deaths have there been?

Authorities can't say for certain how many whales die. They can only count animals that strand or wash up on beaches. It's unknown how many die at sea.

The special investigations focus on three whale species along the east coast—humpback, right and minke. Known deaths include:

  • 178 humpback whales in the Atlantic since 2016,—an average of 25 deaths a year—and the investigation is ongoing, said Sarah Wilkin, a NOAA marine mammal health and stranding response program coordinator.
  • 136 minke whales from Maine to South Carolina since 2017, an average of 25 a year.
  • Critically endangered North Atlantic right whale deaths averaged 10 known deaths a year between 2017 and 2019 and 1.3 a year in 2020-2022.

Total deaths a year from just the three species average about 51, about 4 whales per month. NOAA said humpback deaths are higher in winter.

Where did the whales die in recent weeks?

According to NOAA, whale rescue groups and news media reports, marine mammal deaths over the past seven weeks include five long-finned pilot whales in Massachusetts. They also include:

  • New York: A and a humpback
  • New Jersey: A sperm whale and four , including one preliminarily blamed on a vessel strike
  • North Carolina: Three humpbacks and a critically endangered North Atlantic right whale calf

Additionally, an orca washed up in Florida, the first killer whale ever reported in the Southeast.

Why do whales die?

For many reasons, including , but human activities increase the risks. Causes of death include:

Boat strikes can cause massive blunt force trauma, large gashes and internal injuries.

Fishing gear entanglements cause injury when wrapped around flippers and flukes, and lingering, painful death when ropes and lines wrap around mouths or heavy gear drags behind the whale. An entangled 4-year-old right whale seen off North Carolina is expected to die.

Plastics—A necropsy on a dead sperm whale in Nova Scotia in November found 330 pounds of plastic inside the whale's stomach, the Marine Animal Response Society reported.

Climate change alters the food chain. Warming waters off the northeast coast send whales and their prey into new areas where they encounter more vessels and fishing gear.

Could offshore wind energy farms be responsible?

Federal officials repeatedly stated Wednesday they have no evidence to show that location surveys or offshore wind facility construction have caused or could cause deadly impacts to and marine mammals.

Though some local conservation groups have expressed concerns, the officials said none of the systems used in the exploration or construction have been shown to affect, harm or potentially kill marine mammals.

Work now taking place offshore involves searching for locations to place wind facilities and bury electric cables, Bureau of Ocean Energy Management officials said.

The equipment being used does not produce the powerful, sound used in seismic air gun blasting for oil and gas exploration, said Erica Staaterman, a bureau bioacoustician. It produces a narrow one direction beam for a few milliseconds at a time.

Because they have evidence traveling vessels could harass marine mammals, wind companies are required to have observers and acoustic monitoring during construction activities.

While some question whether scientists are examining ear bones of the dead animals to look for sonar impacts, Wilkin said their large size and decomposition means that's not usually feasible.

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Citation: Feds research whale mystery after more than a dozen dead whales wash up along East Coast (2023, January 20) retrieved 28 January 2023 from https://phys.org/news/2023-01-feds-whale-mystery-dozen-dead.html
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