The fishing and oil industries have been warned to keep away from the deep ocean waters north-west of Scotland where scientists have discovered new sea creatures.

Environmental groups say the waters around the tiny island of Rockall, far out in the north Atlantic, should be off limits for exploitation so its strange species and features can be investigated.

The Scottish Government announced yesterday that four species new to science had been found in the sea between 80 and 260 miles west of the Hebrides. They include a sea snail named Volutopsius scotiae, two kinds of clam - Thyasira scotiae and Isorropodon mackayi - and a worm, which is yet to be named.

Scientists from Marine Scotland are very excited by the finds, which they described as incredibly unusual. The worm, which was discovered inside one of the clams, is said to be the first found in the entire Atlantic.

Finding the clams and worm at a single site is described as "potentially hugely significant". This is because their presence could indicate a "cold seep", a phenomenon in which hydrocarbons leak into the water from a fissure in the seabed.

"The discovery of these new species is absolutely incredible," said Jim Drewery, the Marine Scotland scientist who oversaw the research. If the cold seep is confirmed, it would be the first to be discovered in the vicinity of Rockall. "The project we were undertaking was designed to provide advice that would help balance both commercial fishing and conservation interests in the Rockall area," he added. "The potential cold seep and its dependent community of marine life is a great find."

Lang Banks, director of WWF Scotland, said: "These latest discoveries underline the need for a precautionary approach in the management and use of our seas. Thankfully, the location where these species were found is not currently fished, and we hope it stays that way."

He argued it was necessary to go further, adding: "We now know enough to say that the area should certainly be put off limits to any future plans for oil and gas exploration."

Scottish Environment Secretary Richard Lochhead accepted the discoveries could trigger controls on fishing. "The area where these species were found is not currently fished and the confirmation of a cold seep is likely to result in the region being closed to bottom-contact fishing," he said. "We know that Scotland's seas are home to a diverse range of precious sea life and it is our responsibility to protect this fragile environment."