More than 27,000 people have signed a petition calling on the Welsh government to withdraw plans to restart scallop dredging in Cardigan Bay.
Commercial scallop fishing came to an end in the bay five years ago when it became a special area of conservation.
Whale and Dolphin Conservation (WDC), which launched the petition, described scallop dredging as "a highly destructive fishing method".
The Welsh government said a public consultation was being carried out.
Mick Green, of WDC, said: "We are delighted so many people support our view that the current proposal to open up protected areas to scallop dredging is wrong.
"We hope that the Welsh government will take notice of the high level of opposition to these proposals and withdraw them."
A Welsh government spokesman said it was "currently considering the establishment of a viable and sustainable scallop fishery", which was "in line with the evidence provided by the Bangor University study".
The public consultation ends on 17 February.