Marine Environmental Monitoring


Leatherback turtles have been seen in increasing numbers over the past few years in UK waters. Unfortunately, many of the animals off the Welsh coast have been found entangled in fishing gear and ropes and eventually drown if not found quickly and released. The world's largest recorded Leatherback was found entangled in rope below Harlech Castle, North Wales in 1988 it measured 2.91 metres (113.5 inches) in total length and weighed 916 kg (2,106 lbs). The remains are exhibited at the National Museum and Galleries of Wales, Cardiff.

Virtually nothing is known about the movements of these unique turtles, however, amongst the dead stranded turtles found on the Welsh coast in 1997 was a 2.27 metre female that had been tagged. Subsequent investigations found she was from French Guiana, South America. There is great concern over the future of the world leatherback population, which appears to be in decline.

The International Union for Conservation of Nature and National Resources (IUCN) and The World Conservation Monitoring Centre (WCMC) has categorised the status of all seven species of marine turtles on the Red List of threatened animals, the leatherback turtle being *endangered.

If you find a dead turtle or observe one at sea around the Welsh & English coast please pass on your report to Marine Environmental Monitoring on 01239 683033.

*Endangered - when the reduction in population size is at least 50% in the last 10 years or 3 generations, whichever is longer.

In the event of a dead turtle being found on the UK coast a guide to taking measurements can be found here.


Several Basking sharks have been found live stranded over the years being left by fast receding tides or incidentally entangled in set nets. It would appear that this species might be able to survive extended periods out of the water.

This huge fish (up to 9 metres long) feeds exclusively on plankton and is no threat to humans and is present around the coast all year round, migrating closer-in during summer months. It has been fished for its liver oil but due to slow-breeding may become vulnerable to overfishing. It has no legal protection and recorded threats are vulnerable to overfishing and collision from boats. It is thought that its numbers are decreasing and its status should be kept under review.