Something is killing gray whales. Is this a sign that the oceans are in danger?

Something is killing gray whales. Is this a sign that the oceans are in danger?
Something is killing gray whales. Is this a sign that the oceans are in danger?
Anonim

For thousands of years, gray whales in the eastern Pacific have made one of the longest annual migrations of all mammals - from the cold waters of the Arctic, then down past the densely populated shores and beaches of California, before finding refuge in the warm, shallow coastal zones of the Mexican Baja Peninsula. California. Only to turn around in a few weeks and head back north.

Beginning in December 2018, this magnificent migration took a fatal outcome for them.

The bodies of California gray whales have begun to be washed ashore along the sheltered Baja bays, where gray whales swim every spring to feed and mate. The first to die was a young male, washed ashore on the Arena island in the Guerrero Negro lagoon. Two days later, the decomposing body of a young female was found in the waves on a beach in the Ojo de Lièbre lagoon, a few miles south of the first.

Then, on January 4, 2019, three more young whales were found dead in the same lagoon, all severely decomposed.

“We've never seen anything like it before,” said Ranulfo Mayoral, the 56-year-old son of Pacico Mayoral, one of the first owners of the whale-watching ecotourism business in the region. "This is a safe place for whales. This is not where they die."

What Mayoral witnessed was the beginning of the whale extinction that for 2.5 years haunted millions of whale watchers and puzzled scientists along the west coast of North America. Gray whales are known for their endurance and resilience - "ocean jeeps," as National Oceanic and Atmospheric Administration biologist Wayne Perryman calls them - but something went wrong.

Scientists are now trying to figure out what is killing these 40-foot long marine mammals. What exactly is not entirely obvious.

Some scientists believe that there may be too many whales for the population to support itself. Others say this explanation for "overpopulation" and "natural causes" overlooks a range of hazards faced by gray whales, including ecosystem changes, ship strikes, entanglement in fishing gear, plastic pollution, disease, ocean acidification, and the disappearance of kelp. …

In addition, there is climate change that is melting ice sheets in the Arctic, altering ocean currents, warming water temperatures and potentially altering the food supply for whales and other animals.

Researchers, however, agree on one thing: science must identify the root cause. Gray whales are a conservation success story, surviving commercial whaling and recovering from near extinction thanks to wildlife laws. Their ups and downs are important indicators of the health of the oceans.

"Like other large predators, gray whales are the guardians of the North Pacific," says Sue Moore, assistant professor at the Center for Ecosystem Watch at the University of Washington. She notes that although their current populations are far from threatened with extinction, these whales have something to tell us that will have implications for all marine life, as well as for humans."

From 2019 to July 29 of this year, 481 whales washed ashore along North American beaches, including 69 whales in California.While it is possible that extinction is part of the natural cycle, if the trend continues, “well, this is the thing that keeps me awake at night,” said John Kalambokidis, senior research biologist and co-founder of the Cascadia Research Collective, a center for marine research. mammals located in Olympia, Washington.

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