Mystery Deaths of Gray Whales Washing Up On U.S. Coasts Alarm Scientists

Five gray whales were found washed up on beaches across Washington in June 2023 alone, concerning scientists.

This comes after a gray whale was found stranded on a beach near Ocean Shores in Washington on Tuesday, June 27, according to the Washington Department of Fish and Wildlife (WDFW) and the Cascadia Research Collective.

Members of both groups attended the scene, but the whale did not survive, local news KIRO 7 reported.

In June alone, four other gray whales were found dead on the Washington coast. This is part of what has been declared by the National Oceanic and Atmospheric Administration (NOAA) to be an "Unusual Mortality Event (UME)" along North America's west coast since 2019.

Outside of this mortality event, Washington would usually only see four to six gray whale strandings per year, meaning that this June, the state has experienced nearly a year's worth of strandings in a single month.

"It is certainly unusual to have this many dead whales over a small time frame," Culum Brown, a professor of marine biology at Macquarie University in Australia, told Newsweek. "There is no doubt grey whales are in trouble. Their population has nearly halved in less than 10 years. These guys are migratory (moving from Alaska to California) and feed on plankton so it is difficult to pinpoint what the issue might be."

Gray whales are large marine mammals, usually growing to between 42 and 49 feet long. These gentle giants migrate up the West Coast between Alaska and Mexico, heading south for the winter and back north again in the summer.

NOAA data shows that Washington has had 12 strandings in 2023 so far; in 2022, there were 15, while in 2021, there were 9, and in 2020 and 2019 there were 13 and 34, respectively.

Across the whole U.S., 30 gray whales have been stranded this year already. Last year saw 47 strandings, 2021 saw 55, 2020 saw 79, and 2019 had a staggering 122 gray whale strandings. An interactive NOAA map shows the distribution of dead whales up and down the west coast.

"It is likely to be a combination of direct impacts from humans (eg boat strikes, marine noise etc) and indirect effects that impact the abundance of food," Brown said. "Some of the recent dead whales were underweight which suggests that their plankton supply is declining. The most likely explanation for that is a change in distribution or abundance of their food sources particularly off the coast of Alaska. Now factor in that we just had three La Ninas in a row which is extremely unusual. La Nina results in shifts in currents and water temperature which obviously impacts plankton."

La Nina is a periodic climate event triggered by stronger trade winds, which push warm water across the Pacific towards Asia, leading to cold water upwelling from the nutrient-rich deep off the U.S. West Coast, according to the NOAA. These colder waters can alter the jet stream's path, leading to warmer weather and drought in the southern U.S. and cooler-than-normal temperatures in the north. Alaska tends to be colder than normal during La Nina, so this may have led to a decline in summer plankton.

"Gray whales are specialized feeders largely depending on crustaceans that are on the ocean floor. Climate change has led to changes in food abundance in some regions but other factors may also contribute to the overall decline such as disturbance in breeding grounds and during migration," Olaf Meynecke, a research fellow in marine science at Australia's Griffith University, told Newsweek.

Not all of the whales have been emaciated, however, with some others being killed by vessel strikes and entanglement in fishing gear, leading investigators to want to gather more information from the dead whales to figure out if all the strandings are truly connected.

These strandings have had a major impact on the gray whale population in the Pacific, which had rebounded after being decimated during decades of commercial whaling. Now, populations have dropped by nearly 40 percent over the past 7 years, with an NOAA report finding that the eastern North Pacific population has decreased from 27,000 whales to around 14,000 since 2016.

"[This decline] for a species of such slow reproduction rate certainly is alarming," Meynecke said.

Gray whale reproduction is very slow, with juveniles taking between 8 and 9 years to reach sexual maturity, and gestation taking 13.5 months. Females tend to only give birth every one to three years, meaning that the population is sluggish to recover from large losses.

There have also been a lot of strandings of other whale species in recent years, including huge numbers in Tasmania and New Zealand.

"We also have higher than usual strandings here on the east coast of Australia. At least seven large whales in the past four weeks have stranded," Meynecke said.

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