By Alex Kirby BBC News Online environment correspondent

Conservation groups say wild Atlantic salmon now face threats throughout their life cycle.

They say the fish have declined by two-thirds in the past 30 years, and are increasingly susceptible to impacts from industry.

The conservationists say the rapid growth of salmon farming is one of the main threats to the wild fish.

But the industry says what is happening to the wild stocks is not its fault.

Salmon farmers around the North Atlantic produced 4,783 tonnes in 1980, and 658,735 tonnes in 2000.

Bill Taylor, president of the Atlantic Salmon Federation (ASF), said: "Research shows that farmed fish negatively affect wild Atlantic salmon.

"Escaped farmed fish interbreed with the wild salmon, which weakens the wild gene pools, and compete for food and habitat.

Spread disease

"Confinement of fish in sea cages contributes to the spread of disease and parasites."

Tom Grasso is US director of the marine conservation program of WWF, the global environment campaign.

Campaigners say farmed fish are a problem

He said: "With wild Atlantic salmon stocks fading fast in countries like Germany, France, Spain, and disappearing completely in some rivers on the other side of the Atlantic, it's time to act to prevent further declines."

The North Atlantic Salmon Conservation Organisation (Nasco), set up to oversee wild salmon stocks, starts a meeting in the Faroe Islands on 2 June.

But the conservationists say it has made only "limited progress towards saving the species".

Bill Taylor said: "Voluntary self-regulation of the salmon aquaculture industry simply isn't enough. Plus, it is leaving responsible operators at a disadvantage.

"Nasco governments must create a level playing field by implementing legislation that makes environmentally sustainable aquaculture mandatory across the industry."

ASF, WWF and their allies, including Greenpeace International, say other steps are necessary as well.

They want "fish-farming free zones" to protect wild salmon rivers and bays.

They are also calling for the closure of commercial wild salmon fisheries on their migratory feeding grounds in the Faroes and West Greenland.

Accepting the principle

Chris Poupard speaks for the non-governmental organisations accredited to Nasco.

He told BBC News Online: "It's very hard to generalise about salmon farmers, because the standards of regulation vary considerably.

"They're quite high in Norway, though many people break them. But in Scotland there's virtually no regulation at all.

"We're not opposed to salmon farming, but the problem is that most of the regulation is voluntary."

Salmon farming has increased hugely

Tom Grasso told BBC News Online: "Most of the farming is unsustainable for the survival of the wild salmon - and for the industry itself."

A spokesman for Scottish Quality Salmon told BBC News Online: "Our members are committed to improving the quality and sustainability of salmon farming in Scotland.

"This commitment includes working wholeheartedly with wild fisheries groups as well as the government.

No connection

"Our industry is one of the most tightly regulated food industries in Europe, scrutinised by 10 different statutory bodies and subject to more than 60 pieces of legislation.

"We operate to a standard over and above the regulatory framework.

"Stocks of sea trout have been declining on the west coast of Scotland since records began in 1952 - long before salmon farming became established.

"Wild Atlantic salmon are also declining on the east coast of Scotland and in south-west England, where there are no salmon farms.

"There are many factors involved - global warming, changes in salinity, mid-Atlantic fishery practices, predators, and much higher levels of background pollution."