What has been described as the 'UK's biggest and best known example' of an unusual marine habitat has been found in a Scottish loch during surveys carried out by scientists from Heriot-Watt, Scottish Natural Heritage (SNH) and Scottish Association for Marine Science (SAMS).

Mounds of mud of up to 30cm high were recorded in Argyll's Loch Sween in surveys by scientists. Made by creatures called mud volcano worms, the mounds cover an area of about 1,630 acres (660ha).

"Rich beds" of sea pens were also found covering seabed in areas near Loch Linnhe in the Highlands and south of Arran ocean quahog clams were widely recorded and found in 'abundant' numbers at one site. Quahog clams are the world's longest living molluscs, with one dredged up off Iceland in 2007 aged between 405 and 410 years old. Maerl and horse mussel beds and northern sea fan and deep sponge communities were also found.

Scottish lochs and seabed were surveyed to better understand the state of marine wildlife and habitats and the studies formed part of work led by Marine Scotland to develop a network of Marine Protected Areas (MPAs). The results will also help inform future decisions about marine renewable energy development.

A range of techniques including remote video footage, sampling the seabed and diving were used to explore areas in the Firth of Clyde, Loch Sween, around Loch Linnhe and Orkney.

Thirty-three sites around the coast of Scotland are being considered as possible MPAs.