143 marine mammals stranded in Cornwall in 2009

Seals, sharks and turtles also stranded

September 2010: Cornwall Wildlife Trust's Marine Strandings Network (MSN) has published its report for 2009. The report shows that, despite huge pressures, Cornwall and The Isles of Scilly still have a wealth of fascinating marine wildlife, from whales to sea potato urchins. The MSN examined and recorded 74 cetaceans (dolphins, whales and porpoises), 61 grey seals, 5 basking sharks and 3 turtles in the year. Numerous other marine species were added to the MSN's expansive database which holds a vast amount of information going back many years.

Cornwall Wildlife Trust believes that wildlife is a major draw for visitors and efforts to protect marine habitats and animals are vital for the county, ‘Conserving marine habitats is important not only for our fishing industry, but also for tourism and for those of us lucky enough to live here,' says Ruth Williams, Marine Conservation Officer for Cornwall Wildlife Trust.

Jan Loveridge, Co-ordinator of the Marine Strandings Network says: ‘One of the ways we can research the health of the seas around us is to monitor stranded marine animals. That's why the public, who report them to us and our volunteers, play such a vital role. Last year we received more than 1,000 calls to our hotline telling us about stranded animals. All of them were responded to by one of our trained team and were examined, photographed and recorded.'

Jan continues: ‘We retrieved 18 dolphins and porpoises that had recently died for post-mortem examination by pathologists at the Veterinary Laboratories Agency (VLA) in Truro, under the Defra-funded Cetacean Strandings Investigation Programme (CSIP). They are usually able to tell what caused the animals' death and run tests to check for such things as heavy metals, disease and parasites.

‘Among the findings were that three of the harbour porpoises were attacked by bottlenose dolphins, a species that we generally regard as playful and friendly. Another particularly tragic story was of a pregnant harbour porpoise that was carrying a full-term, 7kg foetus which was bent double in her uterus. She was not able to give birth to the calf and sadly they both died,' concludes Jan.

Trapped in fishing nets

STARVED TO DEATH: A mass was found in this starved grey seal's windpipe. Picture: Rebecca Allen,  MSN volunteer

‘Regrettably, accidental entrapment of cetaceans in fishing nets is still a cause for great concern,' adds Ruth Williams, ‘and once again bycatch was found to pose a real threat to dolphins and porpoises around Cornwall and the Isles of Scilly. The MSN even recorded a pregnant common dolphin wrapped in fishing net, and her tail had been cut off. That's why the trust has been working with local fishermen and other organisations to explore how we can work together to protect marine wildlife for the future.'

There were also 61 grey seals recorded, two of which were examined by the VLA. One had been hit by a boat and was so seriously injured that it had to be euthanased by the marine rescue organisation, British Divers Marine Life Rescue. The second was a very emaciated seal that was found to have a mass in its windpipe, which may have affected its ability to hold its breath to dive and to swallow food. The injury may have been caused by inhaling a fish bone, but as it would eventually have dissolved this could not be confirmed.

Again, net entanglement was a cause of serious injury and death among Cornish seals. One adult male was found on Hayle Sands and was identified by Cornwall Seal Group, with whom the MSN shares its seal records, as an animal they had been monitoring since 2002. Known as ‘DP52', this seal had lived with a necklace of net that was gradually biting into his neck for six years. Unfortunately, only a very limited amount of funding is available at the VLA for post-mortems on seals and this seal would have been too long dead to find the ultimate cause. Another seal, a juvenile female, was found at Newquay. Her head was tightly wrapped in a large amount of monofilament net and rope. Although it is not known whether she became entangled while playing with the rope or was bycaught, this sad case illustrates only too well the dangers to seals from fishing gear, whether the net is active or discarded only to become ‘ghost' net that continues to trap animals indefinitely.

Five basking sharks stranded in a year

Of the five basking sharks that were stranded, one became the second shark ever to undergo a necropsy under the CSIP. It was retrieved with the kind assistance of the Cornwall County Council Environmental Management team and the post-mortem discovered that the shark was suffering from gastritis and cystitis. External injuries also revealed that it probably stranded alive.

Two loggerhead turtles stranded alive in 2009 at Porthleven and Trebarwith Strand and were rehabilitated at the Blue Reef Aquarium in Newquay. These turtles were later released when fully fit in the warm waters of Gran Canaria. Regrettably, the remains of a 1.6 metre long leatherback turtle were found on Wanson Mouth beach. Among other things, these marine turtles feed on Portuguese Man-o-War and in 2009 these jellyfish-like animals were plentiful around Cornwall. More than 200 were reported to the MSN, which worked with the Cornwall County Council beach teams to safely remove them from our beaches.