The Indo-Pacific sailfish, Istiophorus platypterus, is a large oceanic fish native to the tropical and temperate Indian and Pacific Oceans, one of eleven species in the small marlin family Istiophoridae. Recent research has shown the Atlantic sailfish (Istiophorus albicans) and Indo-Pacific sailfish are subspecies of the same world-wide species, although they do not interbreed. Indo-Pacific sailfish have been recorded in size up to 3.4 meters long and weighing 100 kg; they live up to four years. One of the world’s fastest fish, these cheetahs of the ocean are able to sprint for short distances at 110 km/hour. They hunt their main food source, schooling fish (mackerel, sardines and the like), by chasing them down, then turn suddenly in front of the school to stun or kill them with their long bill and pick their prey out of the water column. Sometimes this hunting is done cooperatively in schools with other like-sized sailfish. Indo-Pacific sailfish are opportunistic feeders and have been reported to eat more unusual prey such as pufferfish and toadfish species, as well as invertebrates such as crustaceans and cephalopods. Their large, erectile dorsal fin helps sailfish to herd their prey and it is folded back during periods of fast swimming. Females also attract mates by extending her dorsal fin out of the water surface, and it is thought that the fin may also play a role in temperature regulation. Indo-Pacific sailfish regularly come in close to shore, reefs and islands. Sailfish are a popular sport fish. They are caught commercially, although their flesh is considered tough and not great eating, and also as by-catch in tuna longlines. Sailfish are abundant in their range and their populations are considered stable, although many agencies work to protect and to regulate fishing of this species (including The Billfish Foundation).
(a href="http://www.arkive.org/indo-pacific-sailfish/istiophorus-platypterus/video-00.html#text=All">ARKive; Collette et al 2006; FAO factsheet; McGrouther 2011; National Geographic animals/; Wikipedia 2011)