More pressure is being put on the European Commission (EC) to take action to reduce the number of dolphin deaths off Devon and Cornwall's coastline.
A pair trawling ban within 12 miles of the UK was introduced in 2004
MEP Neil Parish has presented evidence that dolphin numbers in the Bay of Biscay - a key migratory route to the South West - have declined.
The information has come from wildlife trusts, marine groups and the Biscay Dolphin Research Programme.
Mr Parish believes a ban on pair trawlers could reduce dolphin deaths.
Pair trawling is when nets are slung between two fishing vessels.
The practice was banned in 2004 for British trawlers within 12 miles (19km) of the UK coast, but other European boats can continue because they are outside the rules.
EC Environment Commissioner Stavros Dimas has had a meeting with the International Council for the Exploration of the Sea to discuss the matter.
Meanwhile, Mr Parish will talk to the local fisheries regional advisory council and will take a boat trip along dolphin migration routes in the summer.