"Cod are a third of the way back - haddock better, and saithe even better than that, " Dr Frank told me.

BBC: Nature's spring: Cod bounce back

Comparing the 1991 data with information gathered for the year 1800, prior to the age of steam and mechanisation in the fishing industry, showed up clear reductions in the numbers of cod, haddock, saithe, cetaceans and seabirds.

BBC: The model should aid future management of the North Sea