Charles Clover: The picture is that about a third of the world's wild fish stocks have collapsed - defined as being fished to below 10 per cent of their abundance in 1950 - and for the rest the trend is down with only one or two places in the world managing their fish sustainability. This has huge implications for food security in a world with more human beings in it and for the functioning of whole ecosystems.
MK: There is an amazing shot in the documentary of an enormous seabed trawler that smashes coral reefs and lower ocean level sea life to bits as it speeds along. So, the threat is not just to fish, but to the actual seabed, is that right?
CC: That is actually the first image in my book and shook me when I discovered about it: the image of a beam trawler smashing its way across the seabed. I transposed it to the plains of Africa and it became a shocking image. Towed gear does alter the habitat and kills animals on the bottom as well as catching fish and that image explains that. It was worked out that a beam trawler killed 16 pounds of marine creatures to produce one pound of marketable sole.