CONSERVATION ISSUES - JUNE 2008

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Grey Triggerfish are often found washed up dead on Cornish beaches, but very few are reported by divers. They seem to strand more often than other fish, and it is not known why this should happen. We would like reports of any sightings of Triggerfish either alive and swimming, or dead on the beach. Particularly interesting would be fish of 10 cm or smaller, which would indicate that they may be breeding in British Waters. Usual stranding reports are of up to half a dozen on a beach, but a report in September 2001 at Perranporth was of at least 30 and may be as many as 100 on the beach, the reliable beachcomber did not cover the beach to count them all, but could see 30 or more from one spot. Mike Harvey told me that he often brought them up alive in his crab pots from September to December along the south Penwith coast. They have small mouths with incisor-like teeth and feed on crustaceans and molluscs, in rocky areas close inshore, and the female excavates nest-pits, where her  eggs are guarded by the male, perhaps this is why they strand so often, being caught out by the ebbing tide.    

There have been an unprecedented number of loggerhead turtle strandings this year; 18 have been recorded so far on the UK coast. Strandings have been reported from Cornwall, to Wales and islands off Scotland. Loggerheads are categorised as endangered on the internationally recognised Red List of Threatened Species. They breed on the northwest Atlantic, Gulf of Mexico and Caribbean coasts. Determining why these rare turtles are arriving on UK shores can be very difficult unless a post mortem is carried out. To achieve this, a standard series if observations and tests are carried out by a cetacean expert at the Zoological Society of London. An external examination will reveal if the animal has suffered any trauma or damage, and a depleted fat layer and the wasting away of muscle can suggest starvation as a result of cold-shock.

Causes of death have predominantly been a result of cold-shock, in other words the animal, which is normally found in warmer waters, becomes lethargic and unable to feed and eventually starve to death. Plastic Bag and Balloon ingestion has also been found as the cause of death in a small number of cases. Turtles swallow plastics after mistaking then for jellyfish, one of their staple foods.

Of the 18 stranded loggerheads recorded this year, five were found alive, but only two have survived. “James” named after his scientific code number 2008/007, being the seventh loggerhead found this year, and “Dink”. These two are currently at home at Newquay Blue Reef Aquarium. They were warmed up steadily but slowly from 10C, the temperature of UK seas in January, to 25C, their preferred temperature. Several weeks later they started to eat and are well on the road to recovery and have made such good progress that they are being returned to the wild. They fly to the Canary Islands later this month. Once they reach the turtle rehabilitation centre in Gran Canaria they will be checked over, fitted with a microchip, and hopefully released within 24 hours.

People are being asked to look out for turtles, but if you find a live one, do not put it back into the sea, it would die. A turtle may appear to be dead as its metabolism has slowed down, so all turtles dead or alive must be reported to the stranding network as soon as possible on 01825 765 546.

There were 38 reported sightings of Basking Sharks during May, only 12 of those up to 29th May then the invasion began with 14 reports on the 30th and 12 reports on the 31st. They were seen all around the coast from Widemouth Bay near Bude on the north coast, to St Austell Bay on the south.

Bottlenose Dolphins were reported 24 times, 18 of those were of the pod ranging from Sennen to St. Ives and the other 6 reports were of a pod in the St. Austell Bay area. There were 2 reports of Common Dolphins on the south coast, small pods of 10 and 4. Risso’s Dolphins were reported twice, two were seen off Maenporth and one off St. Ives. Two reports of dolphins off Bude and The Minack were probably Bottlenose Dolphins.

Four of 5 sightings of Harbour Porpoises were on the south coast from Black Head to the Dodman and the other was off Godrevy. A Minke Whale was spotted off Porthcurno and an early Ocean Sunfish was seen off Gwennap Head on the 12th of the month, and two Cuttlefish were seen off St. Just in Roseland.     

Conservation Officer: Raymond Dennis

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