Cornwall Wildlife Trust volunteers faced a tragic and emotional discovery on Good Friday (Friday 18th April), when they were called to Pentewan Beach near St Austell to examine a freshly deceased harbour porpoise. During the postmortem, it was revealed that the animal had been heavily pregnant – and both she and her near-term calf had died as a result of bycatch. 

Veterinary investigator for Cornwall Marine Pathology Team, James Barnett, who has two decades of experience conducting postmortem examinations on marine mammals, described the case as one of the most distressing he has seen. “In nearly twenty years of undertaking this work, I have rarely seen a female so close to term. It was quite emotional for all of us.” 

The porpoise displayed clear signs of entanglement in monofilament fishing net, also known as gillnets – a strong indicator of bycatch, which is the accidental capture of non-target species such as cetaceans. The postmortem was carried out as part of the Defra-funded collaborative Cetacean Strandings Investigation Programme.  

Rebecca Allen, Marine Conservation Officer at Cornwall Wildlife Trust, commented: 

“In 2024, we had 233 small cetaceans reported to Cornwall Wildlife Trust’s Marine Strandings Network. Sadly, this has become the norm in recent years – with an estimated 25 to 40% of those animals showing signs of bycatch. It’s an agonising death for the individuals, and this level of loss is not sustainable for these populations.” 

Over the last nine years, Cornwall Wildlife Trust has seen an increase in small cetacean sightings along Cornwall’s coastline. However, this rise in sightings has also led to more frequent interactions with fishing activities – a trend seen globally. Bycatch is estimated to kill more than 1,000 harbour porpoises every year in UK waters alone. 

Rebecca added, “We urgently need the government to take action, and work with fishers to turn this around. Many fishers are increasingly ready to use mitigation devices to help prevent the devastating impacts on cetaceans like this pregnant porpoise and its unborn calf. 

“Fisheries management is not keeping pace with our changing seas. We have already seen the Vaquita – another porpoise species, native to the Gulf of California – driven to the brink of extinction by bycatch. We cannot let that happen to our harbour porpoises.” 

One promising solution is the use of acoustic deterrent devices, or “pingers”, which emit sounds that alert porpoises to the presence of fishing nets, allowing them to avoid entanglement.  

Cornwall Wildlife Trust started research on pingers in 2008 and combined with further research into “banana pingers” in 2013, our trials have shown them to be effective – with both fishers and conservationists backing their use and working together to make progress on this issue.   

Nick West, chair of the Mevagissey Fisherman’s Association, whose members are part of the current government-led Clean Catch UK trial, says “it is deeply distressing to hear the news of a cetacean death and particularly within our district. In the four years the trial has been running, the devices have been undeniably effective” - with no bycatch being recorded or captured by cameras installed on the vessels using them daily. 

Frustratingly, local fishers have expressed strong support for the pingers but cannot currently obtain licenses to use them, meaning pingers are not widely available to inshore fishers outside of these limited trials. 

Nick added, “we have campaigned endlessly for these devices to become available for all our vessels, even offering to fund them ourselves. We have had full support for our need from Cornwall Wildlife Trust, Cornwall Inshore Fisheries & Conservation Authority, and the manufacturers of these units, along with secured funding for supply and administration, but have failed to secure the necessary license from the Marine Management Organisation that is required for these units to be legally used.” 

Cornwall Wildlife Trust is calling on decision-makers to provide access to proven mitigation technologies, and to work closely with the fishing industry to ensure a future where both wildlife and livelihoods can thrive. 

How to Report a Stranding:  

If you find a dead marine animal, please report it to the Cornwall Wildlife Trust’s Marine Strandings Network by calling the 24/7 hotline at 0345 201 2626.  

For more information about the Marine Strandings Network and how to get involved, visit Marine Strandings Network | Cornwall Wildlife Trust.