Gray whale necropsy April 4, 2023

A gray whale that was reported dead in the shallows of Fox Island in southern Puget Sound on 1 April 2023 was successfully relocated to a remote site on 3 April and an examination conducted by biologists primarily with Cascadia Research, WDFW and World Vets on 4 April. 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. 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 whale deaths along their entire range in the eastern North Pacific have been elevated since 2019 when an Unusual Mortality Event was declared with many of the examined whales being in poor nutritional condition like this most recent one. Even in normal years we typically see about a half dozen gray whale strandings in Washington each year. 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.