PARIS — Angry fishers handed out free fish in Belgium, blocked ports across France, and kept British ferries from crossing the English Channel on Wednesday to protest proposed E.U. cuts on commercial catches of cod, hake, and other dwindling varieties.

Dozens of fishing trawlers from Denmark, France, the Netherlands, and Britain sailed to the Belgian harbor of Antwerp in a unified show of opposition to proposed quotas that European Union ministers will debate next week in Brussels.

Hundreds of supporters in Antwerp left with free food — some 11,000 pounds of fresh fish handed out by demonstrating fishers.

Fishers warned that the livelihoods of 200,000 people are at stake.

"Europe's fishing industry is going to collapse," Pierre-George Dachicourt, president of France's national fishers' committee, known as CPMEM, said on Europe-1 radio.

Speaking from Antwerp, he said the proposed quotas would "ruin the rich tradition of fishing all along Europe's coasts."

In France, fishers staged blockades at ports from the English Channel to the Mediterranean. Among the ports affected were those at Marseille, France's second-biggest city, and Nice on the Mediterranean coast, as well as Ajaccio on the island of Corsica.

Near the Landes region of southwest France, dozens of fishing boats occupied an off-limit zone near a military base used for missile testing, said Alain Argelas, president of SAMAP, a local fishermen's union.

Ferry traffic between France and Britain was hobbled by blockades at the French ports of Dunkirk and Calais, ruining travel plans for thousands of would-be passengers — many of them day trippers seeking cheaper holiday shopping in France.

Ferry companies P&O and SeaFrance, which run regular shuttles between the English port of Dover and France's Calais, canceled a combined total of 44 sailings Wednesday.

Many freight voyages from Britain were completed overnight before the blockade began, officials said.

Scientists have pressed the European Union's head office to enforce bans on over-fishing, warning that some species could face extinction. The European Commission backed away from a total catch ban on cod fishing, for example. Instead, it proposed beefing up checks on fishers to ensure that quotas are not exceeded.

The E.U. proposals would also lay out further cuts to existing quotas and impose more restrictions on the number of days fishing fleets can stay at sea.

The European Commission has said its long-term aim is to allow severely depleted cod stocks to replenish by 30 percent in certain fishing areas.

For hake and sole, the Commission is calling for up to a 50-percent cut in catches. For North Sea cod, cuts from last year that reduced catches by 45 percent, would stay in place.

In Sweden, where there are nearly 2,000 full-time fishermen, the new quotas would have a significant effect, said Bertail Adolfsson, chairman of the Swedish Westcoast Fishermen's Organization.

"If this doesn't change, there will be no professional fishermen left," he said.

Environmentalists say that after years of overfishing, tough new controls are needed to prevent Europe's waters from suffering the same fate as those of eastern Canada, where once-rich cod fields were fished almost to extinction.