Post mortems show nets cause most deaths

They are caught in large numbers in giant trawls strung between two large vessels - many in fishing grounds just off Plymouth and Cornwall.

Most of the boats involved are from other European Union (EU) countries.

Mr Morley said tests would take place at the Sea Fisheries Industry Authority facility at Hull.

It the new technique worked, the UK would press for it to be made compulsory across Europe, he said.

"If this net is not successful, we will be pressing for other forms of action and we certainly do not rule out seasonal closures or restrictions in this fishery," he said.

Where the bodies were found

Cornwall 46 Devon 28 Dorset 21 Hampshire 7 West Sussex 7 France 350

Mr Morley has said in the past that he could not act without firm evidence that pair-trawling was to blame.

"I have found it quite frustrating getting the information we require and I think we have a strong enough case to insist on EU action."

Mr Morley has raised the issue with the EU Agriculture Commissioner, Franz Fischler.

Mr Morley said the UK could not act alone.

Any new measures would have to apply to all EU vessels fishing in the Western Approaches and off the Cornish coast.

Dolphins have long been fishery victims

"If the gear trials are successful we will be pressing Franz Fischler to make this kind of net compulsory across the whole EU fleet," he said.

Between 1 January and 5 February this year, 109 sea mammals were found dead on the south coast of England.

It is thought many dolphins killed in nets are never washed ashore.

January's storms may have brought in a higher percentage than normal.

Slaughter witness

Last week, Devon fisherman Ernie Curtis told on a BBC documentary how he witnessed a Danish factory ship fishing among dolphins.

"We were out in the morning and came upon this Danish industrial boat and there were 100s of dolphins all around us and he didn't take a bit of notice.

"Obviously he must have had dolphins.

"They definitely know there's dolphins there - they see them the same as we do."