Istiophorus is a genus of sailfish contains two species, the Indo-Pacific sailfish (Istiophorus platypterus) and the Atlantic sailfish (Istiophorus albicans). Recent research has proposed that in fact these are in fact not separate species but instead are subspecies of Istiophorus platypterus with different geographical ranges that do not interbreed. There is continued debate about this. While the subspecies show little genetic differentiation, they are morphologically distinct in coloration and size (with Istiophorus platypterus notably larger than Istiophorus albicans). Known as the fastest of the fish, the Indo-Pacific and Atlantic sailfishes have been clocked at 110 km/hr. Carnivores, they often chase down their most common food source, schooling fish such as anchovies, sardines, and the like, at high speed and then herd them with their large sail-like fin and stun them with their long bill-like jaw in order to pick their prey out of the water column. Sometimes this hunting is done cooperatively in schools with other like-sized sailfish. 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. Although popular sports fish, Istiophorus are not commonly found on menus. Sailfins are abundant and their populations are considered stable.
(ARKive; http://www.arkive.org/atlantic-sailfish/istiophorus-albicans/; Collette et al. 2006; FAO factsheet; McGrouther 2011; National Geographic animals/; Wikipedia 15 December 2011; Wikipedia 20 January 2012; Wikipedia 23 October 2011)