Stocks of cod around Britain are showing the first signs of reversing a decline that has threatened to wipe out the fish as a viable species.

For the first time in eight years scientists calculating fish stocks have advised the Government that it is safe to catch cod in the North Sea, albeit in small quantities.

The advice was issued by the International Council for the Exploration of the Seas (Ices), the body that advises fisheries ministers on fish stocks. It found that the number of young fish had increased substantially in comparison with previous years and there were indications that survival rates for mature fish had improved slightly.

“Results from the North Sea Fishers’ Survey indicate that the abundance of cod has remained relatively stable in the south and has increased in the central to western areas,” Ices scientists reported in advice published yesterday.

Bertie Armstrong, of the Scottish Fishermen’s Federation, said: “This is excellent news, reflecting scientific proof of what the fishermen had been reporting for some time – that cod was recovering in the North Sea.”

Though Ices has previously urged cod catches to be cut to zero, governments have routinely ignored the demand to balance the needs of the fishing industry.

Ices scientists have called for cuts in quotas, but calculated that for 2008 it should be possible for 22,000 tonnes of cod to be removed from the North Sea – about half of current levels – without threatening the revival.

This would mean a “total allowable catch” of between 12,000 and 15,000 tonnes, once natural movements of fish populations and illegal fishing have been taken into account. Illegal catches amount to more than half of permitted levels.

Martin Pastoors, of Ices, said there were grounds for optimism about cod levels in British waters for the first time in a decade. “We think that in the current situation there is a possibility of harvesting some cod while still increasing the stock,” he said. “Surveys show that the number of young fish has increased. These young fish could contribute substantially to the recovery of the North Sea cod stock.

“There are also some indications of higher survival rates. That’s really important and what’s needed for these stocks. Cod can grow very quickly.”

The speed that cod can grow, up to one kilogram annually, contributes to hopes that the overall quantity of adult breeding stock in the North Sea can more than double by the end of 2009. Scientists cited the unexpectedly high levels of young born in 2005 and encouraging numbers of one-year-old fish found in the North Sea this year as causes for cautious optimism. Cod can start breeding at 3 years old and are at their peak for spawning at age 4 or 5. They can live to 15, but such an age is rare today.

A spokesman for the Department for Environment, Food and Rural Affairs, said: “The UK is committed to the conservation of threatened fish stocks, to help ensure a long-term, sustainable future for our fishing industry. The UK has played a key role in EU recovery plans for cod.

“This report is advice – the next stage is for us to talk to the fishing industry and others about its implications. In the past EU ministers have decided that the social and economic consequences of zero catches would be too great. The same outcome is likely this year. However, further measures are likely to be needed to protect cod – especially juveniles."

European fisheries ministers will meet in December to agree quota levels. While it is unlikely that they will reduce them by 50 per cent, as demanded by Ices, it is expected that they will be lower than for this year.

The North Sea contains the biggest stocks of cod in British waters. Small quantities are found in the Irish Sea and in the northeast Atlantic, where Ices has advised that levels are so low that there should be a complete ban on cod catches.

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