Examination of entangled gray whale reveals it was a calf that died as a result of the entanglement

Washington State Stranding Response >> Examination of entangled gray whale reveals it was a calf that died as a result of the entanglement

 

An examination of a dead gray whale found entangled in crab gear off S Washington was completed late on Thursday, 4 May 2017 on a remote island at the mouth of the Columbia River. While the final examination was led by biologists with Cascadia Research, multiple organizations played key roles in the discovery, disentangling, towing, and examination of this whale including Washington Department of Fish and Wildlife, NOAA, SR3, Portland State University, U.S. Army Corps of Engineer, and Oregon State Police. The whale was initially reported already dead on Saturday morning, April 29th anchored in place 1/2 mi. off of the Seaview Beach Approach on the Long Beach Peninsula, WA. More detailed documentation became available Monday, 1 May showing the whale entangled in apparent commercial crab pot gear (pending identification by WDFW Shellfish team). WDFW Enforcement & Marine Mammal Investigations, NOAA Office of Law Enforcement, Cascadia Research Collective and SR3 responded on scene Tuesday, 2 May and the whale was towed to a remote location in the mouth of the Columbia River.

The examination (necropsy) revealed that the whale was a 20’ 7” male calf of the year. This is consistent with current timing which is when mothers with calves migrate north from their winter breeding and calving grounds in Baja to their feeding areas primarily in Arctic waters. Their migration is often close to shore and through areas with where many thousands of crab pots occur. The whale was entangled in numerous areas including through the mouth and showed bruising around these areas indicating it was alive when it became entangled had died as a result of the entanglement. The whale was in excellent body condition with a large and oily blubber layer and even fat reserves around the heart all indicating it had been in good health prior to experiencing a more sudden death. Many of the internal organs were decomposed likely as a result of rapid decomposition due to the insulating blubber layer.

Incidences of whale entanglement have increased in recent years along the US West Coast most dramatically with humpback whales off California and have been of growing concern. These have prompted increased efforts to identify solutions as well as help disentangle whales when encountered still alive. Other threats to whales including gray whales were also highlighted by a boat strike on a well-known adult gray whale in Puget Sound caught on video April 23rd. Fortunately that whale survived though the full extent of its injuries is not yet known.


Examination of dead whale underway on 4 May 2017. Photo by Cascadia Research.