How do sailfish reproduce

Their fusiform body is long, compressed, and remarkably streamlined. Indo-Pacific sailfish are dark blue dorsally, with a mix of brown and light blue laterally, and a silver-white color on their ventral side.

This coloration is a form of obliterative countershading. This species is easily distinguished from other billfish by the approximately 20 stripes of light blue dots present along their lateral sides. Their head bears a long bill and jaws filled with file-like teeth. Their massive first dorsal fin is sail-like, with 42 to 49 rays, with a much smaller second dorsal fin, with 6 to 7 rays.

The pectoral fins are long, stiff, and falcate in shape, bearing 18 to 20 rays. Pelvic fins are thoracic in position and up to 10 cm in length. Scale size decreases with maturity and scales are nearly absent in adults. Members of this species are exceptional swimmers, with a minute drag coefficient range of 0. Nakamura, ; Sagong, et al. Mature eggs are translucent and roughly 0. The eggs contain a small globule of oil that provides nourishment for the developing embryo. Newly-spawned fertilized eggs average 1.

Although the larval growth rate is influenced by season, water conditions, and food availability, size of newly-hatched larvae generally averages 1. Juveniles grow at an exponential rate during the first year, with females tending to grow faster than males and reaching sexual maturity sooner. After the first year, growth rate decreases. Indo-Pacific sailfish are estimated to reach adulthood at the length of cm. Based on this size, it is inferred that individuals generally reach sexual maturity at the age of 3 to 4 years and continue to grow throughout their lifespan.

Cerdenares-Ladron de Guevara, et al. Indo-Pacific sailfish breed year round in the thermocline layer. Females extend their dorsal fin to attract potential mates. Males have been observed chasing females in a competitive manner, which ends with spawning for the winning male.

Nakamura, During the spawning season in the western Pacific Ocean, Indo-Pacific sailfish over cm in length migrate from the East China Sea and head southward towards Australia for spawning. Indo-Pacific sailfish spawn throughout the year in tropical and subtropical regions of the oceans, while their primary spawning season is during summer in higher latitudes. During this time, these fish can spawn multiple times. Female fecundity is estimated between 0. During mating, a male and female pair up and swim together and release both their eggs and sperm into the water column.

Jolley, ; Luthy, et al. As a broadcast spawning species, Indo-Pacific sailfish do not provide any investment for their offspring. Indo-Pacific sailfish have an estimated maximum lifespan of 13 to 15 years; however, the average age of catch and release specimens is 4 to 5 years. Prince, et al. Spending most of their time in the upper 10 m of the water column, Indo-Pacific sailfish occasionally dive down to depths up to m to find food.

They are opportunistic feeders and eat whenever possible. Indo-Pacific sailfish tagged with Pop-up Satellite Archival Tags have been monitored traveling over 3, km to spawn or find food.

Individuals swim in dense schools structured by size as juveniles and organize into small groups as adults. Occasionally, sailfish swim in a solitary manner.

Trophic overlap of prey between juveniles suggests that Indo-Pacific sailfish feed in groups according to their size. Arizmendi-Rodriguez, et al. While there is little specific information on communication between individuals, sailfish can "flash" their body colors via activity of their chromatophores, and utilize other visual signals like dorsal fin movements during breeding. Their large eyes are flush to their head and are sensitive to low light conditions.

A pair of nares are located in front of their eyes, Indo-Pacific sailfish use these nares to detect dissolved chemicals in the water column. Like other bony fish, this species has a lateral line used to sense movement and pressure changes in the environment and otoliths in their ear canals assist in detecting auditory stimuli.

Typical foods of Indo-Pacific sailfish are epipelagic fish such as mackerels , sardines , and anchovies , as well as cephalopods. Sailfish been observed at cruising speeds with their dorsal fins folded back halfway in pursuit of prey.

Once they approach their prey, they turn their bill quickly and hit the prey, stunning or killing it. Indo-Pacific sailfish either hunt alone or in small groups. Aside from hunting schools of small fish, Indo-Pacific sailfish are also opportunistic feeders, occasionally preying on neritic and benthic prey, a behavior similar to other billfish such as blue marlin , swordfish , and striped marlin.

The particular species eaten by Indo-Pacific sailfish depend on the spatio-temporal distribution of their prey populations.

Remnants of cephalopod and fish mandibles found in their stomachs suggest the rapid digestion of soft muscles. Indo-Pacific sailfish hooked by longlines have been attacked by great white sharks and killer whales. However, predation of free-swimming sailfish is very rare. Indo-Pacific sailfish are apex predators that affect the population of their epipelagic prey in the open ocean ecosystem.

Furthermore, these fish serve as hosts for symbionts, as their stomach can be infected by the parasitic copepods Plannella instructa and the flatworms Callitetrarhynchus gracilis and Floriceps minacanthus. Nakamura, ; Speare, Indo-Pacific sailfish are frequently taken as bycatch by commercial tuna longliners in the Indian Ocean. They are also caught by gillnets, trolling, and harpooning by artisanal fishers.

In , an estimated 28, metric tons of Indo-Pacific sailfish were caught within the Indian Ocean. These fish may also host several parasites. Nakamura, ; Speare, There are no known adverse effects of Indo-Pacific sailfish on humans. Indo-Pacific sailfish are frequently caught by the nets of commercial tuna fishers, they are also caught by gillnets, trolling, and harpooning.

In , an estimated 28, metric tons of Indo-Pacific sailfish were caught within the Indian Ocean. These fish are generally considered a prized sport fish, and their meat is often used for sashimi and sushi in Japan. Although they are not threatened or endangered, Indo-Pacific sailfish are considered a 'data-poor fishery' by the Indian Ocean Tuna Commission due to the increased fishing pressure, with an average yearly catch between to estimated at 26, metric tons.

Indian Ocean Tuna Commission. Seychelles: IOTC. Arizmendi-Rodriguez, D. Abitia-Cardenas, F. Galvan-Magana, I. Food habits of sailfish Istiophorus platypterus off Mazatlan, Sinaloa, Mexico. Cerdenares-Ladron de Guevara, G.

Morales-Bojorquez, R. Age and growth of the sailfish Istiophorus platypterus Istiophoridae in the Gulf of Tehuantepec, Mexico. Marine Biology Research , 7: Chiang, W. Sun, S. Age and growth of sailfish Istiophorus platypterus in waters off eastern Taiwan. Yeh, W. Su, D. Liu, W. Ehrhardt, N. Hoolihan, J.

Horizontal and vertical movements of sailfish Istiophorus platypterus in the Arabian Gulf, determined by ultrasonic and pop-up satellite tagging. Marine Biology , Determining summer residence status and vertical habitat use of sailfish Istiophorus platypterus in the Arabian Gulf.

Idrisi, N. Capo, S. Luthy, J. Behavior, oxygen consumption and survival of stressed juvenile sailfish Istiophorus platypterus in captivity.

Jolley, J. On the biology of Florida east coast Atlantic sailfish, Istiophorus platypterus. Luthy, S. Serafy, R. Cowen, K. Denit, S. Age and growth of larval Atlantic sailfish, Istiophorus platypterus.

Marine and Freshwater Research , Mourato, B. Hazin, P. Travassos, C. Arfelli, A. Amorim, F. Environmental and spatial effects on the size and distribution of sailfish in the Atlantic Ocean. Carvalho, F. Hazin, J. Pachecco, H. They are under no special status or protections. All rights reserved. Common Name: Sailfish. Scientific Name: Istiophorus. Type: Fish.

Diet: Carnivore. Group Name: School. Size: 5. Weight: to pounds. Size relative to a 6-ft man:. This photo was submitted to Your Shot, our photo community on Instagram.

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