Blood, guts and suspiciously mangled fins: inside a porpoise autopsy

On a steel table at London Zoo sleuths are trying to solve a tricky whodunit: what is killing cetaceans?

Some of the causes of death of harbour porpoises include starvation, bycatch (being accidentally caught in fishing gear), or bottlenose dolphin attack. Often, however, other underlying factors contribute, including pollution — chemicals, plastic entanglement, shipping noise

The corpse lies on the stainless steel table. Next to it, a tray of sharp blades, pliers, and what look like garden implements. The body — dark-skinned above, but pale underneath — was found on the beach at Barmston, Yorkshire, in March, with its dorsal fin mysteriously missing. It’s a harbour porpoise — and I’m here for its autopsy.

For about 15 years, I have volunteered for Devon Wildlife Trust’s Marine Strandings Network, taking photos of dozens of marine mammals, from decomposing dolphins to scarred porpoises. Each one is a crime scene — teeth marks suggest a bottlenose dolphin attack; a missing tail fluke may be due to stray fishing gear; gashes could be caused by a boat propeller.