CONSERVATION ISSUES - APRIL 2005

More than 45 dead porpoises - five times the usual number - have been found along the north east coast during the first two weeks of March, some with 12” bites on their torso, and experts believe that a Shortfin Mako Shark may be causing the carnage. Makos are closely related to The Great White, and can grow up to 12 ft, and have attacked humans. Decapitated seals have also been found along with remnants of other large fish, and the experts believe that the size of the bites, and the number of kills would be consistent with a large Mako Shark in the area. The bodies of the porpoises have been sent to the Natural History Museum, where autopsies will be carried out to establish the cause of death. A spokesman for the  Maritime and Coastguard Agency said: ‘We would advise all those using the water, including surfers, fishermen and divers, to be especially careful and vigilant. The warnings come as marine biologists report growing numbers of exotic fish and marine creatures in British waters. Global warming has pushed up water temperatures, resulting in regular sightings of the smooth hammerhead shark, which is not dangerous to humans. The once rarely seen red mullet, black bream and cuttlefish are now being caught in fishermen’s nets as far north as the Isle of Man.  Japanese and Portuguese oysters - previously imported into Britain and unable to live in the cold water  have started to breed in British waters, as have the compass jellyfish and leathery sea squirt which is originally from the Pacific.

With unusual good timing, these cases of shark attack on cetaceans and seals, occurred as the BBC Natural History Unit, Bristol, began work on a film that examines British shark fauna, and Ian Fergusson, a member of the IUCN Shark Specialist Group was engaged to analyse the pieces of evidence on behalf of the production team, and he did not consider that the Shortfin Mako, widely touted by the media, was the culprit. He said it was not supported by the facts, for the Mako has ragged, narrow, awl-shaped teeth, which tend to make distinctive tooth punctures, and the bites on the carcasses pointed toward a broad mouthed species with fairly small teeth, closely separated in the jaw, like the Greenland shark or Bluntnose Sixgill shark, both of which occur in cold water and both recorded in the North Sea. However on a dolphin carcass from Cornwall, the tooth array/count of the shark responsible was clearly visible and he attributed this one with good certainty to a Shortfin Mako (possibly two different Mako sharks involved, one smaller than the other).

There were 10 reported sightings of Bottlenose Dolphins during March, from August Rock, just off the Helford river on the south coast all the way up to Crooklets Beach at Bude on the north coast, but the largest pod of 30 or more was off Baggy Point north Devon on the 30th. Common Dolphins were seen on 4 occasions between Penlee Point and Gwennap Head off West Penwith. An interesting sighting of 60 or more heading west off Porthgwarra on the 9th. A big pod for close inshore. 7 other reports of unidentified dolphins were probably Bottlenose except a report of 2 and a baby off Porthgwarra which were thought to be Commons and a large pod a 100 or more off St Agnes probably also Commons. The only other dolphins seen were 10 Risso’s 3 miles off Portreath. Harbour Porpoises were reported 9 times in groups up to 7 in number. Grey Seal were seen on 6 different days in different places from Mount Batten off Plymouth all the way around the coast to Beeny Cliff near Boscastle where 47 were seen hauled out on rocks and the beach. The first Basking Sharks of the year turned up in March, the first off Porthgwarra on the 13th and another (or was it the same one) off Cadgwith on 18th. A Thresher Shark was seen in Fal Bay and a rare Slipper Lobster was caught about 100 miles off Penzance, kept alive in a bucket and taken to the Blue Reef Aquarium.  

There were several carcasses on beaches again in March,  15 Common Dolphins and 2 other unidentifired dolphins, 5 Harbour Porpoises, a Leatherback Turtle and 2 Grey Seals. There were 4 birds, a Gannet, a Guillemot and 2 Herring Gulls and many Cuttlefish bones were found at Porthpean.

Conservation Officer Raymond Dennis

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