A drop in maritime traffic may be behind a surge in the number of sharks seen in British waters, according to an expert. There have been multiple sightings of both basking and porbeagle sharks in recent weeks with members of the public spotting them closer to the shore than usual. Some have ended up in marinas while others have been photographed and filmed in the sea just off the coast. David Sims, Professor of Marine Ecology, Ocean and Earth Science at the University of Southampton, believes the spike could be due to a drop in maritime voyages. Scroll down for video