Though whale sharks are more associated with the town of Donsol, whale sharks can also be seen in Pilar Bay near San Antonio. Interaction with the whale sharks is regulated by the local department office. With the help of WWF, strict guidelines were developed to protect the sharks. These include limiting the number of swimmers per boat, no scuba divers and staying further than three meters away from the sharks. In practise this rule is almost never applied. As many as 14 boats at a time may 'mob' a shark, with up to 30 or 40 swimmers following the shark on the surface. In recent years the number of male sharks have out-numbered female sharks by 20:1. The females that are seen are generally large mature adults in the 7m ~ 9m range. Increasing numbers of sharks show propellor marks on their backs. Anecdotal evidence from local fishermen suggests that prop strikes are from fishing boats in the off-season, rather than from tourist boats in the main January–May tourist season.