The story of a scientist who helped solve a Cold War mystery involving flatulent fish and Soviet submarines. During the Cold War, foreign submarines infiltrated neutral Sweden's territorial waters. In response, the Swedish navy built up a secret database of tell-tale signs to detect the presence of lurking subs and conducted high profile submarine hunts. But the country's submarine scare continued even after the end of the Cold War. So in 1995, the Swedish government launched an investigation. Alex Last spoke to Swedish biologist, Dr Håkan Westerberg, who discovered that one of Sweden's key indicators for submarines, was not what it seemed.

Photo: Herring shoal (Science Photo Library)