A question I'm often asked about Sailfish is "what is the purpose of the huge dorsal fin or sail?" While free swimming or snorkelling at close quarters with these bold and curious Sailers (bold because they’re not shy to swim close to free-divers & display intimidating postures with their dorsal fins spread high & wide) I have observed that the fin plays an integral part in the awesome feeding behaviour of Sailfish. Sails, like dolphins & most other schooling pelagics, co-ope