New report shows worrying increase in dolphin deaths in Cornwall

Tuesday 19th September 2017

Common dolphin stranded on Maenporth beach, photo by Emma Theobold

A worrying increase in dolphin deaths has been observed in Cornwall in the last year, highlighted by Cornwall Wildlife Trust’s 2016 Marine Strandings Network (MSN) report which has been released today.

The report, summarising the work of the vital marine conservation project in Cornwall and available to download off the Trust website, has highlighted an astounding 50% increase in cetacean (dolphins, porpoises and whales) deaths in 2016 compared with 2015.

A total of 205 animals stranded in Cornwall in 2016, compared with only 10 in 2015. Amongst the 205 recorded, 113 were short-beaked common dolphins and 61 were harbour porpoises. Of particular stranding interest in 2016 were both a female sperm whale which stranded and was post mortem on Perran Sands, north Cornwall, in July 2016, and a bottlenose dolphin which stranded on the Isles of Scilly and was recorded on the 30th November 2016. A minke whale also stranded further north at Compass Point near Bude on the 13th July 2016.

Abby Crosby, Marine Conservation Officer at Cornwall Wildlife Trust, says

“The Trust has been collecting data on marine mammal strandings for over 25 years, so we can clearly identify peak levels of strandings. Seeing this recent increase is extremely worrying and highlights the importance of ensuring this work continues into the future whilst we discover what is happening out at sea.”

Animals strand for a variety of reasons, from natural causes such as disease to bycatch and boat strike. Of the 205 that stranded during 2016, 31 were accessible and suitable for retrieval by the Trust’s MSN team for post-mortem examination on behalf of the Defra-funded Cetacean Strandings Investigation Programme (CSIP). Post-mortem examinations, together with in situ examinations concluded that accidental entanglement in fishing gear (also known as bycatch) was the cause of death for 23% of the animals. 

Of further interest, the cause of death of 16% of the animals examined was bottlenose dolphin attack, where smaller animals are attacked by larger bottlenose dolphins. One such incident was witnessed by members of the public in Mounts Bay in January 2016, with the carcass stranding soon after the event.

Abby Crosby continues,

“2016 was a busy year, but 2017 is proving just as challenging, if not worse, with over 200 dolphins being recorded to date to our 24 hour Marine Standings hotline. If we have another bad winter, we will easily overtake the 2016 total, which is a worry to all biologists conserving these special creatures in our waters.”

Data is used not only regionally but shared nationally to the Cetacean Strandings Investigation Programme (CSIP) to better understand the ecology of dolphins, porpoises and whales in our UK waters so we can work towards their management and protection. The Trust is calling the public to send in their sightings of any stranded, dead marine animals to our 24 hotline, 0345 201226. For more information please go to our Trust website www.cornwallwildlifetrust.org.uk/strandings and download our 2016 MSN report.