Slipping into the realm of subconscious.. old man (civvie) sits opposite engage. Tells us his great grand father used to be a trawler man in Victorian times working out of Scarborough. Back then he says huge runs of tuna would appear off the north east coast chasing the herring shoals and behind these tuna were.. Great white sharks. They were well known to the fishermen of the time and were frequent visitors to our shores. Towards the end of the thirties the herring disappeared due to over fishing and with that the tuna vanished as did the sharks..