Dozens of fishermen have been arrested in Brussels after violence broke out when protesters failed to convince the European Commission to subsidise them to soften the blow of soaring fuel prices.
The fishermen, mostly from France and Italy, occupied the commission's headquarters, setting off flares against police, who then charged them.
French fishermen say they will be out of work unless they obtain discounted diesel at $0.62 per litre as opposed to $1.23 per litre on the open market.
The price of marine diesel has risen by 30 per cent in the past four months.
The protesters also want the European Union to intervene by raising the amount of financial aid that a government may grant to its fisheries sector without attracting the scrutiny of EU internal market regulators.
A handful of demonstrators met Joe Borghe, the chief political adviser to the EU fisheries commissioner, to explain their grievances on Wednesday.
EU leaders will discuss the impact of high oil prices on Europe's fisheries sector at a summit in mid-June, Borghe said.
The sector also suffered from overcapacity and badly needed to restructure, he said, to the jeers of the fishermen.
Meanwhile, in France, truckers, taxi drivers and farmers also protesting against fuel costs blocked traffic on roads leading to Paris' Roissy airport, causing 7km of tailbacks.
A similar protest by more than a hundred truckers brought chaos to the ring road around the southern city of Toulouse.
While a number of ports, including Dieppe on the Channel coast, remain blocked by fishermen seeking more government aid.
The French government is due to hold talks with the various parties involved on June 10.