After years of warnings against eating cod because of concerns over low stocks, experts in Norway claim there are now "too many fish in the sea".

Cod stocks in the Barents Sea from which Norway sources 91% of its cod are now at their highest levels since the Second World War, according to data from the Institute of Marine Research in Norway.

And some Norwegian cod fishermen claim that Barents Sea cod stocks are now so big that if more is not fished, there is a danger their feed source could prove inadequate and the older cod will start cannibalising the younger cod. "We don't want to be blamed if we have this kind of collapse," warned Webjørn Barstad, head of department at the Norwegian Fishing Vessel Owners Association, alluding to fishermen being blamed for previous stock collapses caused by over-fishing.

The Norwegian and Russian governments last week agreed a 16% increase in the 2011 Barents Sea cod quota, to 703,000 tonnes, but exporters claim that more cod could be fished and stocks would remain at sustainable levels. "We have scientists who are very conservative. They always tend to give lower quotas than you really could fish," added Per Magne Eggesbø, CEO of Vartdal Seafood, which supplies frozen-at-sea cod to the UK.

However, Greenpeace warned against complacency, adding that the industry needed to build precaution into the system.