On Saturday, 23 November 2024, biologists from Cascadia Research and Washington Department of Fish and Wildlife, with the assistance of a veterinary pathologist from the Washington Animal Disease Diagnostic Laboratory, examined a minke whale found dead in Commencement Bay earlier in the week. The carcass of the 17-foot juvenile female was first seen floating in Commencement Bay on 21 November, and was reported to the stranding network the following day when it was discovered on property owned by the Port of Tacoma. The detailed necropsy (animal autopsy) revealed good nutritional condition, evidence of recent feeding, and soft tissue trauma, suggesting blunt force trauma (consistent with vessel collision) as the cause of mortality. There was no evidence of disease, killer whale attack, or entanglement. Detailed examination of the bones on 26 November, conducted with the help of the MaST Center, revealed several broken vertebrae, confirming the preliminary diagnosis.
Ship strikes have been an increasing cause of death of large whales in Washington, especially since the early 2000s. This is particularly troubling because these known cases represent just a fraction of the true number of ship strike mortalities, as these occurrences are usually not observed, and carcasses often sink and are unable to be examined.
Minke whale strandings in Washington are infrequent. In the last 20 years, there have only been 4 other minke whale strandings in the state; the most recent was another subadult female in the San Juan Islands in October 2022 that was also killed by a ship (see https://www.seadocsociety.org/blog/necropsy-performed-on-dead-minke-whale). The skeleton of this whale will be cleaned, rearticulated, and displayed by the MaST Center (https://mast.highline.edu/) for education.