CONSERVATION ISSUES - DECEMBER 2007

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Two large thresher sharks were caught off Cornwall within a few weeks this autumn. The first was entangled in lobster pot ropes several miles south of Charlestown on 14th October and weighed 340 Kg gutted, so thought to be around 400 Kg entire, .and considered to be a record size for British waters. It however turned out to be quite a medium sized fish compared with a second one caught 3½ mile south of The Runnelstone on 21st November, which weighed in at 510 Kg (1122 lbs), making it one of the heaviest thresher sharks ever caught anywhere in the world. This female was 15 ft 10” long  and sold at Newlyn Market for £225.00 (50p per Kg).

A jellyfish invasion wiped out Northern Ireland’s only Salmon Farm, on November 21st, killing more than 100,000 fish, worth more than £1m. Billions of small jellyfish Pelagia noctiluca, sometimes called Mauve Stingers, flooded into the cages in Glenarm Bay. The jellyfish covered an area of up to 10 square miles and a depth of 35 ft.   

During an underwater research project examining the food web in 200 ft of water in Puget Sound on the east coast of America this summer, an Albino Ratfish was caught. Ratfish are usually brown or black with a smattering of white dots to blend in with the muddy sand in the sound, and they are far and away the most numerous species of fish in the sound. The near-by, university of Washington,  has a 7·2 million –specimen fish collection, and they have never seen an albino before. Albinos are found among mammals, fish, birds, reptiles and amphibians, but the condition is rare among sea life.  The only other albino sea creature in the Washington University is a Sea Cucumber collected in the 90s. This fish was almost pure white with a crystalline layer near the surface of the skin that gave it a silvery sheen. The searchers say that it must have stood out like a beacon on the bottom, and their main predator, the Spiny Dogfish, is very common in the sound, and they cannot understand how it had not been eaten before it arrived at near full size. .

There was only one reported sighting of Bottlenose Dolphins during November, that was of 6 off Tregantle in Whitsand Bay, East Cornwall on the 29th. However a report of about 5 unidentified dolphins off Downderry just along the coast, on the same day, was probably the same pod. There was also a sighting of 4 unidentified dolphins off Ladies Window, just west of Boscastle, on the 4th of the month which were probably also Bottlenose Dolphins. There was a sighting of 8 Risso's Dolphins near the Longships on the 2nd and another sighting of Risso's Dolphins off the Runnelstone on the 3rd, this could also be sightings of the same pod. There was also a single Risso's Dolphin seen off Gwennap Head on the 29th on November.

There were reports of Harbour Porpoises off Carn Gloose, The Runnelstone, Rospletha Head and Porthgwarra on different days, the largest group was of 5 off the Runnelstone on the 3rd. A Minke Whale was seen  about ½ a mile off Gwennap Head on the 29th, and the blow of another whale was seen from the lookout, 6Km to the southwest on the same day. A late Ocean Sunfish was seen off Sennen on the 3rd and there were about 20 Pearl Chain, Apolemia uvaria, pieces, seen off Pencarrow Head on the 11th Novemnber.

Strandings up to the end of November were 72 cetaceans, 45 seals, 23 birds 2 turtles and a Basking Shark. In comparison there were 175 cetaceans stranded during 2006, We are not yet into the busiest time of the year for stranded and by-catch cetaceans, but it looks like a big improvement. 

Conservation Officer: Raymond Dennis

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