About 30 fishermen signed up to the scheme to protect two offshore reefs, which are vulnerable to disturbance from mobile fishing gear such as scallop dredges.

The ground-breaking scheme is part of Devon Wildlife Trust's Lyme Bay Reefs Project.

The aim of the 10-year project is to protect marine life in two areas known as Lanes Ground and Sawtooth Ledges.

'Positive trends'

The trust said they were two of the most important wildlife areas in the 30-mile-long reef system, which lies up to six miles off shore between West Bay in Dorset and the Exe estuary in east Devon.

Trust marine conservation officer Jenny Glanville said that in the nine months since the agreement was signed, three of the five key species were up to 10 times more abundant in the protected zones compared with areas unaffected by the scheme.

She said: "While we are very pleased with these results it does not mean we can stop worrying about these reefs or protecting them.

"We need to see whether these positive trends continue over a period of time before we can say we have been completely successful."