EU fishery ministers began difficult talks Tuesday on the vexed question of 2013 quotas as they sought to balance conflicting demands from environmentalists and fishermen alike.

The European Commission is proposing to cut quotas for some 47 fish species in the Atlantic and North Sea because many stocks are over-exploited.

In October, they agreed to maintain controversial fishing subsidies for the industry, opposed by environmental groups who say they only encourage overfishing of already stressed stocks.

The subsidies pay for modernising existing vessels or taking older boats out of the fleet and are jealously guarded by the main fishing powers -- France, Portugal and especially Spain.

"The negotiations are going to go on all day, into the night, to tomorrow and no doubt, tomorrow night as well," said Cyprus Agriculture, Natural Resources and Environment Minister Sofocilis Aletraris as he went in to chair the talks.

Environmentalists are pressing for reforms to allow stocks to recover above so-called Maximum Sustainable Yields (MSY), the EU benchmark, while major fishing groups claim ministers were caving in to Green demands.

Europeche, which represents EU national fishery organisations, said the planned quota cuts go beyond the scientific recommendations and put environmental over social and economic considerations.

To accept them would undercut the viability of companies and lead to job losses across the industry, Europeche said in a statement.

Spanish Agriculture Minister Miguel Arias Canete said the proposed quota cuts, some of more than 30 percent, were not justified by scientific research and would harm his country's fishing industry.

The Fisheries Committee of the European Parliament meanwhile approved measures to rebuild fish stocks above MSY levels, to ban the practice of fish discards and control subsidies.

The WWF said the vote would prove to be the cornerstone of a new EU Common Fisheries Policy (CFP) Basic Regulation, meeting all its five goals of reform.

The committee has shown "through this milestone vote that the European Parliament is listening to scientific advice and wants fish stocks to recover."

Small artisanal fishermen meanwhile said any quota cuts should not hurt those who practice traditional methods which harm the environment least.