A 41-foot gray whale that washed ashore in Washington state on April 1 is believed to have been killed by a vessel strike, scientists said.
The male whale was found in the shallows of Fox Island in the southern Puget Sound and moved to a remote site on April 3, where a thorough examination could take place to determine the cause of death. The necropsy was conducted by scientists primarily from the Cascadia Research and the Washington Department for Fish and Wildlife on April 4.
“The examination revealed the adult male had been killed by blunt-force trauma likely from a vessel strike though its poor nutritional condition likely contributed to both it being in Puget Sound and potentially also made it more vulnerable to the vessel strike,” research biologist John Calambokidis, from the Cascadia Research Collective, told Newsweek.
“The whale had been sighted alive in shallow waters on 27 March in the sound and appeared in poor condition then and died sometime between then and when it was discovered dead on 1 April.”
Gray whales can grow to about 48 feet long, weighing in at roughly 90,000 pounds.
They are found mainly in the shallow coastal waters of the North Pacific Ocean and make one of the longest annual migrations of any mammal, traveling 10,000 miles per round trip on average. In some cases, this exceeds 14,000 miles.
According to the National Oceanic and Atmospheric Administration, gray whales, along with blue whales, fin whales and humpback whales, are very vulnerable to vessel strikes during these migrations along the West Coast. Many use areas along the coast for feeding, which brings them in to areas with heavy shipping traffic.
Gray whales are also known for their curiosity towards boats, which may increase the chances of vessel strikes.
Calambokidis said that, in a normal year, there are typically around six gray whale strandings. However, since 2019, gray whale deaths have been elevated across the entire eastern North Pacific range. In 2019, the NOAA recorded 122 gray whale strandings across Alaska, Washington, Oregon and California.
In 2022, the NOAA recorded 15 gray whale strandings in Washington alone, and many of the beached whales examined were in a poor nutritional condition.
As a result of this increase, an Unusual Mortality Event has been declared in the region. “While the full reason behind the Unusual Mortality Event are not understood it does appear to be related to an increase in the gray whale population prior to the event and a decreased availability of prey creating nutritional deficiencies in a portion of the population,” Calambokidis said.
