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Marine Turtle Newsletter 52:12-14, © 1991

Marine Turtle Newsletter-Online

Observations of Leatherback Turtles off the Cornish Coast

Roger D. Penhallurick
2 Chapel Terrace, Trispen, Truro, Cornwall TR4 9BA, Great Britain

The occurrence of turtles in British waters is still regarded, by those few who even think about them, as an exceptional rarity. Abundance is, of course, a relative thing, so that the sighting of 16 leatherback turtles off the coasts of Cornwall and the Isles of Scilly during 1988 (Penhallurick 1990; see Book Reviews, this issue) was quite unprecedented. The warm winter that followed raised hopes of a similar invasion in 1989, but it was not to be. However, another equally mild winter, with high sea temperatures favouring good numbers of jellyfish, has turned 1990 into the second best year for turtles on record.

The year began with an invasion of loggerhead turtles, particularly off the Irish coast, but south-west England was not excluded. One was stranded at Woolacombe Sand, north Devon, on 15 February. On 24 March, one less than a foot long [0.3 m] was stranded alive at Loe Bar near Helston, Cornwall, but later died at Gweek Seal Sanctuary (Postscript, Penhallurick 1990). Unknown to me then, was that another equally small loggerhead had been recovered alive from the rocks at Sennen near Land's End. It was found by a worker at the First and Last Inn and taken to Penzance Aquarium. It was not in good health, listed badly, and had an eye infection. It has improved since, feeding well on such fare as mackerel and squid.

More spectacular have been the leatherback sightings during the summer of 1990:

  1. 17 July: Tony Soper, a well-known British naturalist and TV personality, wrote in a letter to me that "At 1130 h on Tuesday 17 July I was motoring in the Island Cruising Club's yawl Speedwell through what seemed to be an endless shoal of jellyfish Rhizostoma octopus (syn. pulmo) a couple of miles SSW of Gribbin Head (near Fowey). Someone saw a fin and called "shark" so we turned and approached slowly, to find a leatherback turtle feeding on one of the jellyfish. It bit into the animal and tore out a chunk of flesh so violently that the jellyfish rotated like a top. We had a clear view of the keels on the carapace, which was about 1.75 m long, since the creature was only just below the surface. The turtle then came to the surface and showed its head clear of the water, then dived and swam away."
  2. 19 & 31 July: Steve Madge observed a leatherback about 0.5 mile offshore at Portwrinkle, south-east Cornwall, on the evening of 31 July. He wrote, "Asking local fishermen to look out for it, I was told that two Portwrinkle boatmen, Bert Pengelly and Tony Amor, had seen what I presume was the same animal off Portwrinkle on 19 July; they had it on and off around their boat for nearly an hour and reckoned it to be 6-8 feet [ca. 2.0-2.5 m] in length. They had kept quiet about it as they didn't want it chased about by other boats! There are masses of jellyfish (Chrysaora isoceles) in the area and according to local boatmen there had been unprecedented numbers of jellyfish throughout last winter as well."
  3. 20 July: A leatherback was sighted in the morning, one mile off Penare Point, between Pentewan and Mevagissey. It was about 5 feet [ca. 1.5 m] long, grey-black with white blotches (Dr. A. F. Stimson, The Natural History Museum, London, pers. comm.).
  4. 28 July: A leatherback was reported by a Falmouth coastguard about one mile south of Dodman Point. Length was estimated to be six feet [ca. 1.8 m], and breath four feet [ca. 1.2 m] (Stella Turk, pers. comm).
  5. 28 July: A. B. Griffiths of Penzance saw a turtle on his way to Scilly from MV Scillonia III about 5 miles west of Wolf Rock. It was just below the surface, very dark, about the size of a large "fertilizer bag". Species is uncertain, but leatherback seems most likely.
  6. 6 August: Stephanie Cairns of St. Dennis, when diving with a friend at a depth of 22 m on the wrecks of the Hathor and the Plympton on Lethegus Reef off St. Warna's Cove, St. Agnes, Isles of Scilly, watched a leatherback "heading south at a good speed". This is the first record I have of a leatherback seen at depth.
  7. 20 August: Angler Mr. Leslie Trenoweth of Truro was fishing about 5 miles south of Falmouth when, at about 1300 h, a leatherback turtle estimated to be about 8 feet [ca. 2.5 m] long surfaced in a swirl of water only a few feet from his cabin cruiser Alice Elizabeth. It remained alongside for a few minutes before diving and moving off; photos were taken. The turtle was accompanied by a foot-long [ca. 0.3 m] fish, probably a pilot fish Naucrates ductor.
  8. 18 September: Chris Mlynski found a dead leatherback turtle caught in his crabpot lines 2.5 miles southeast of Portloe. It had been trapped for 2-3 days, and had become so entangled that the front right flipper had to be severed to release it; the carcass subsequently stranded some 28 miles up the coast at Downderry. Overall length: 7 feet; carapace width: 39 inches. The tail was large, indicating a male. According to local fishermen, there were plenty of jellyfish (e.g., Rhizostoma pulmo) about.
  9. 19 September: A dead leatherback washed ashore on Perran Beach below Carn Haut, just south of the mine adit. Head, flippers, and tail were missing; skin was stripped from its back revealing the bony carapace. The carapace measured 150 cm long and about 85 cm wide.
  10. 26 & 28 September: John Hurr sighted a leatherback during the morning of the 26th about two miles north of Portreath while hauling in his crab pots. Then, on the 28th, in the same area, he saw a turtle estimated to be at least 2 m in length. He approached within 10 m of the creature, which was feeding on large jellyfish. Hurr wrote, "The turtle was slowly pushing the jellyfish in front of his mouth (in the manner of a water-polo player controlling a ball), keeping his prey steady with his flippers. Every so often he would lift his head and the remains of the jellyfish out of the water, open his mouth wide, take a deep breath and continue with his meal." Mr. Hurr and his crew watched the turtle for about 20 minutes, regretting only that no one had a camera on board.
  11. 8 October: A leatherback turtle, with a carapace estimated to be about six feet long, was found trapped in Barry Mundy's lobster pot lines set about three miles off Mullion. Not until the 12th was he able to enlist the assistance of local divers to release the animal, an operation which took nearly an hour, so entangled had it become. On its release, the turtle swam close around the boat a few times allowing the divers to touch it before it swam off, little the worse for wear apart from a skin break on one flipper. The turtle was accompanied by pilot fish and a number of smaller grey fish, most likely remoras (Remora remora), which attached themselves from time to time to the underside of the turtle. This is the first time I have heard of remoras associated with a turtle off Cornwall.

Penhallurick, R. D. 1990. Turtles off Cornwall, The Isles of Scilly and Devonshire. Dyllansow Pengwella, Cornwall, Great Britain. 95 p.