Bycatch blamed for dolphin deaths

26th February

In the past two weeks Cornwall Wildlife Trusts Marine Strandings Network volunteers attended ten strandings, nine of which were common dolphins and one of which was a harbour porpoise. Volunteers along the south coast were called out to these strandings spread out between Downderry in the east to Penzance in the west. The Roseland peninsular was identified as a hotspot with three of the strandings recorded in the area.

Tom Hardy, Marine Conservation Officer for CWT says "Ten strandings in a ten day period is a cause for concern but when taking into account five of these were recorded over last weekend alone, it becomes a much more worrying trend."

So why are these dolphins being found on our beach? Tom Hardy explains: "The majority of the strandings showed signs of bycatch in fishing gear. This evidence of bycatch ranged from the very obvious marks such as amputation of the tail or the stomach being slit open, to help the animal sink and hide the evidence, to monofilament net marks across the body and the beak of the animal."

Cornwall Wildlife Trust does not rely solely on visual evidence but also delivers animals in suitable condition for post-mortem at the Veterinary Laboratory Agency in Truro. Only one of the recently stranded animals was in good enough condition to undergo a post-mortem which concluded that the injuries sustained were consistent with bycatch in fishing nets.

Tom continues: "By recording stranded cetaceans over the last 12 years, we have worked tirelessly to show the link between certain fishing methods and dead stranded cetaceans. In 2006 175 dead cetaceans were recorded and although this figure was lower in 2007 (81), this recent spate of strandings suggests the problem has not gone away."

Cornwall Wildlife Trust has been campaigning for protection of our dolphin populations and is currently working on appropriating funding for a project to introduce a pinger (an acoustic deterrent device) trial in inshore waters. Pingers have been shown to alert porpoises to the presence of a net and significantly reduce bycatch in certain fisheries. Cornwall Sea Fisheries officers are very supportive of this trial of pingers on smaller vessels operating in coastal waters.

Cornwall Wildlife Trust’s Marine Conservation Officer, Joana Doyle and cetacean expert, Nick Tregenza recently met with Jonathan Shaw, Minister for Marine, Landscape and Rural Affairs and Andrew George MP of West Cornwall and Isles of Scilly to discuss the ongoing problem of dolphin bycatch in fisheries around the Southwest. During this meeting the pinger trial proposal was presented to Jonathan Shaw and CWT have since officially approached DEFRA for funding to undertake this trial.

Please report all dolphin and marine animal strandings to Cornwall Wildlife Trust Marine Strandings Network on 0845 201 2626.

Joana Doyle Marine Conservation Officer