Skull and Neck Lesions in a Long-Finned Pilot Whale (Globicephala melas): A Result of Ship Collision?

Abstract

Simple SummaryWe performed a routine necropsy on an adult male pilot whale stranded in a heavy boat traffic area of Denmark. On its outside, there was no visible damage or alterations, and similarly, the internal organs of the thorax and the abdomen also showed no significant changes that could explain the death of the whale. But to our surprise, we found extensive internal injuries after incisions in the head and neck regions: There were multiple fractured bones, muscle trauma and extensive bleeding including a fractured occipital bone with several fragments and bone pieces deeply embedded into the whale brain—injuries that very well, but not with certainty, could be caused by a ship collision. This case demonstrates the importance of performing full necropsies of whales to rule out other causes of death. Otherwise, ship collisions may be an overlooked issue with implications for population health.Necropsy on an adult male pilot whale stranded in Denmark in an area with heavy boat traffic revealed internal lesions in the head and neck region, while the exterior did not show any visible lesions. We found multiple fractured bones, muscle trauma and extensive hemorrhage including a fractured occipital bone with several fragments and bone pieces deeply embedded into the cerebrum of the brain. The brain was literally smashed while the third and partially fourth cervical vertebrae were almost pulverized surrounded by large amounts of blood and muscle contusion. The whale was likely killed due to a ship collision, and this particular case substantiates the value of always performing full necropsies including incisions in head and neck regions on all stranded whales—especially in areas with heavy boat traffic. This case demonstrates the importance of veterinarians performing full necropsies of whales to rule out other causes of death. Otherwise, ship collisions may be an overlooked issue having implications for population health.