Fishermen in Newlyn claim fuel costs have doubled in 12 months
Fishermen from Cornwall and Devon have travelled to London to protest at the "crucifying" effect high fuel prices are having on the industry.
A group from the fishing port of Newlyn in Cornwall set off in the early hours.
Fishermen there claim the cost of diesel has doubled, eating away at profits. They say the situation is "beyond critical".
Fishing boats use red diesel, which has risen from around 30p a litre to 60p a litre in the last 12 months.
Sam Lambourne, who fishes out of Newlyn, said fuel costs used to represent 20% to 25% of the gross value of the catch, but now represent 65% to 70% of the gross value.
Fishermen said they were unable to raise the price of fish to cover the rising fuel costs because what they catch is sold at auction.
Tom McClure, skipper of the trawler Harvest Reaper, said: "The price of fuel is crucifying us at the moment. It's not just the initial running costs, fuel prices are so high they are eating into profits, which is eating into the maintenance of the boat.
"A boat is a tool for earning money, you've got to maintain that tool."
Elizabeth Stevenson, president of the National Federation of Fishermen's Organisations, said: "We are looking for some sort of aid which will allow businesses to get back on their feet, to put together a plan of how to change their fishing patterns, to make them profitable or even break even."
The fishermen from Newlyn joined others from around the UK and some from France, in the demonstration outside the Department for Environment, Food and Rural Affairs in London.
The protest was timed to coincide with a meeting between fishing industry
leaders and the fisheries minister Jonathan Shaw to discuss the issue.
Last month a similar protest at fuel prices was held by lorry drivers.