Lethal fishing hook penetration and line entanglement in an adult bottlenose dolphin (Tursiops aduncus)

The carcass of a 15-year-old female Bottlenose dolphin (Tursiops aduncus) was retrieved from the Port River near Adelaide, South Australia, Australia. The animal was emaciated with five thick nylon fishing lines emerging from the oropharynx attached to a tangle of nylon and monofilament fishing line that also contained wire and eight fishing hooks. The mouth had been cut by the line and a circumferential curvilinear superficial abrasion/indentation from fishing line encircled the entire distal rostrum. Dissection of the upper aerodigestive tract revealed a large fish hook embedded in the lower blowhole associated with an adjacent abscess at the base of the epiglottis. The stomach contained two unattached fish hooks, parts of a plastic squid lure and two heavy duty work gloves. Further examination revealed a severe necrotising pneumonia with microabscesses in the kidneys and adrenal glands with scattered thromboemboli in keeping with terminal disseminated intravascular coagulation. Death had resulted from septic complications of fishing hook impalement and line entanglement with inanition. The case provides a graphic illustration of the effects of entanglement and fishing hook penetration, as well as ingestion of non-degradable plastic materials, in a free living Bottlenose dolphin.