Plans to create huge offshore wind farms put the jobs of hundreds of British trawler crews at risk, according to the National Federation of Fishermen's Organisations.
The turbines - at sites in the North West, the Wash and the Thames Estuary - would add hours to fishing trips and disrupt breeding grounds, the organisation said.
Fishing fleets are already facing tough times ahead
It also claimed they had been planned without proper consultation of the fishing industry, which has already said it is under threat because of reduced quotas.
Licences for hundreds of turbines are to be issued by the government, in a move aimed at meeting its own target for renewable energy.
It is hoped they will generate as much energy as about six nuclear power stations and have been broadly welcomed by environmental groups as a clean source of power.
Doug Beveridge, NFFO assistant chief executive, told BBC News Online: "We're well aware that we don't have a monopoly on the marine environment, but the disruption of offshore wind farms to us has never been assessed by the government."
The crews likely to be worst affected by the wind farms would be those operating from small boats, Mr Beveridge said.
Many such vessels can travel at only two or three knots and diverting them around a wind farm could add up to six hours to a day at sea, he added.
Hundreds of turbines could be built about five miles off the coast
Mr Beveridge said that unless those crews were allowed to travel through the sites many would not be able to continue.
He said: "The proposed developments... will put fishermen, especially those operating on inshore fishing grounds, out of business and devastate fishing
The fishing organisation also questioned claims that wind farms would help replenish fish stocks, by providing somewhere for algae and other plants to grow.
Mr Beveridge said it was unlikely that such food would grow in any great quantities.
The NFFO added: "It has been claimed that offshore wind farms will provide habitat and shelter for fish, yet studies have shown that vibration and electromagnetic radiation will interfere with the behaviour and migration of fish stocks."
Concerns have also been raised by the RSPB, which said seabirds could suffer.