If recent reports are to be believed, the North Sea cod's days are numbered. But should we believe these reports? What do the experts say about the numbers of fish that are left? The Daily Telegraph recently ran the headline: "Just 100 cod left in the North Sea", external. It sounded fishy. Trawlermen were furious. "It just makes my blood boil - 100 cod in the North Sea?" fumes Brian Buchan, who's