Just when you thought there wasn’t enough to worry about, along come bottom trawlers. While the fishing technique of dragging a heavy net along the bottom of the seabed is     nothing new – indeed, there was a British commission inquiry into the practice as far back as 1866 – the sheer size of modern super trawlers maximises their destructiveness. Centuries-old sea coral forests are bulldozed by the thirty-tonne nets, non-targeted fish and turtles become indiscriminately tangled in the web, and the disturbed sediment releases more carbon than the entire aviation industry each year.