All species of dolphins are at risk around south-west England unless Europe speeds up attempts to tackle dolphin deaths, an MP has warned.
It is thought dolphins are being caught in huge trawler nets
Hundreds of dead dolphins have been washed up on beaches in Devon and Cornwall in recent months, probably after being caught up in giant nets trawling for sea bass.
Torbay MP Adrian Sanders said if deaths continued at this rate, the results would be catastrophic.
"There's certainly some types of dolphin that could be threatened by the rate of catch.
"And certainly all species of dolphins are under threat if this continues for many more seasons," he told BBC Radio 4's Countryfile programme.
Since the start of January this year, at least 114 dolphins have been washed ashore in Devon and Cornwall, an increase of more than 27% on 2002.
Mr Sanders said it was thought the problem begins when dolphins follow the sea bass, one of their favourite foods, into the nets.
"When they need to go up for some air they can't get out of the net - they panic, they get tangled in the net and they suffocate horribly."
Mr Sanders said the dead dolphins were thrown back into the sea by fishermen.
Those found on beaches could be the "tip of the iceberg" as most corpses would sink the bottom of the ocean.
The problem could not be solved until it was confirmed that it was a bass fishing industry problem, he said.
To do this, observers must be put on boats - something which the UK Government has begun doing but the EU is dragging its heels over.
"There is principled agreement within the EU that observers should go on all boats across the EU fleet," he said.
"But the details are being worked up and it won't be until April, at the real end of this year's season, before there's an agreement.
"What we are arguing is many of these actions should have taken place 12 months ago, otherwise we're going to have another season of dolphin slaughter before anything is done."
Conservationists say UK fleets are not to blame for the problem.
They blame pair trawlers - which fishermen in Cornwall do not use - from Holland, Scotland and France which use huge nets to catch the sea bass.