The government has announced a unilateral ban on pair trawling for seabass effective immediately.
Over 300 cetacean carcasses found on region's beaches in 2002-03
The announcement was made by Fisheries Minister Ben Bradshaw at the Labour Party conference in Brighton on Monday.
The ban will be implemented within the 20km (12mile) limit of the UK's waters and will mainly affect French and Spanish fishermen.
Pair trawling is widely blamed for the high number of dolphin and porpoise deaths along the South West coast.
The method of fishing involves a large net attached to two boats and trawled through the water.
More than 300 cetacean carcasses were found on beaches in the region in the year 2002-2003.
It is estimated that about 10,000 dolphins and porpoises die each year around UK and French coasts, many of them after being caught up in bass nets.