Postmortem computed tomography and pathology reveal multiple traumatic events in a stranded bottlenose dolphin Tursiops truncatus in Alabama, USA

This report describes a severely emaciated adult female bottlenose dolphin Tursiops truncatus found dead in September 2021 with numerous traumatic injuries. The animal stranded in coastal Alabama, USA, a hotspot in the Gulf of Mexico for trauma-related marine mammal strandings. A combination of traditional and advanced diagnostic techniques including postmortem examination, histopathology, and computed tomography revealed trauma from multiple events, including rib and vertebral fractures of varying chronicity and a more recent catfish barb penetrating the diaphragm with associated tissue necrosis. Tooth growth layer group analysis indicated this individual was ~40 yr old, despite a total straight length notably less than is typically reported for an adult female T. truncatus in the region. Advanced age was also supported by tooth wear, evidence of multiple pregnancies, fusion of sternal bones, and age-related changes in the heart and liver. This case illustrates a multifactorial cause of death in a coastal bottlenose dolphin and highlights the value of combining traditional postmortem examination with advanced imaging techniques to more accurately determine cause of death in the presence of multiple traumatic injuries.