PARIS — Amid heated debates about ways to improve the management of Europe’s fishing fleet and the European Union’s Common Fisheries Policy, owners of fishing boats in northwest France have set up a new organization to help prevent overfishing and ensure themselves a sustainable livelihood.

The group, Les Pêcheurs de Bretagne, or Breton Fishermen, formed in November by a merger of two existing groups, represents a third of the French fishing industry: 800 boats and 3,000 crew members, with an annual catch of 100,000 tons of fish — mainly hake, pollack, monkfish and langoustine, or spiny lobsters — worth €283 million, or $374 million.

Despite decades of regulation, an ever-increasing appetite for fish and indiscriminate industrial-scale fishing techniques have brought many fish species to the brink of extinction. According to the environmental activist organization Greenpeace, 80 percent of fish stocks globally are overexploited or at the brink of being so.

The Breton organization, an umbrella group for the local Atlantic and Channel fishing fleets, collectively manages an important proportion of France’s fishing quotas. Its members include single-boat captains and industrial flotillas like Scapêche, the largest French fishing fleet, which is owned by the supermarket chain Intermarché.