Green campaigners are urging Europe's fisheries ministers to impose a total fishing ban on waters west of Ireland, harbouring rare cold-water coral reefs.
As ministers from each of the EU countries negotiate over fishing quotas at the annual December council, WWF warned that the final deal will be decisive for the survival of the reefs and the communities they support.
"Located between 400 and 1,600 meters depth, they support a wealth of marine wildlife, including commercial fish stocks," said Stephan Lutter, WWF International Marine Policy Officer.
"However, they are extremely vulnerable to bottom trawling and other destructive fishing gear. In certain areas of the North-East Atlantic, up to 50% of the reefs have been reported to be damaged or lost already.
"In 2006, the Irish government proposed the inclusion of four sites at Porcupine Bank and Bight - an area of approximately 2,500 sq km - in the Natura 2000 network of European protected areas.
"To protect these ecosystems, the European Commission has recommended an overall fishing ban in the area for all EU fleets."
WWF is calling on the European Fisheries Ministers gathered in Brussels this week to confirm the ban, Mr Lutter said.
Fisheries Minister Michelle Gildernew has welcomed early proposals that Total Allowable Catch for prawns in waters fished by Northern Ireland's fishermen will remain the same.
But the commission has also proposed 25% cuts in days at sea for both prawn and whitefish.