First real-time acoustic recording captures porpoise entanglement in fishing net
Researchers at the University of St Andrews accidentally recorded a porpoise bycatch event using passive acoustic monitoring on a gill net. The recording provides unprecedented detail on the animal's calls and escape attempts. The findings were published in Royal Society Open Science.
This incident marks the first time a porpoise entanglement has been captured in real time through passive acoustic monitoring, a technique typically used to track marine mammal presence via their vocalizations. The accidental recording, made while researchers monitored a gill net, offers a rare acoustic window into a bycatch event—a major conservation concern for small cetaceans. Because the data were collected without human observation, they provide an unfiltered sequence of the animal’s calls and escape attempts, potentially revealing behavioral responses to net entanglement that were previously inferred only from post-mortem studies. The peer-reviewed findings, published in Royal Society Open Science, underscore how existing monitoring tools can yield unexpected insights into lethal fisheries interactions, even when not designed for that purpose.
This recording could help fisheries managers and gear designers better understand how porpoises behave when entangled, potentially leading to more effective bycatch reduction strategies—such as acoustic deterrents or modified net designs. Conservation groups and policymakers may use such evidence to refine regulations, while fishing communities could face pressure to adopt new practices. The impact, however, depends on whether the findings translate into practical changes, and whether similar acoustic data can be gathered across different regions and species.