Indo-Pacific sailfish breed year round in the layer of the ocean when the temperature begins to drop. Females extend their dorsal fin to attract mates. Males sometimes chase females to compete for the ability to spawn.
Nakamura, During the spawning season in the western Pacific Ocean, Indo-Pacific sailfish migrate from the East China Sea and head south towards Australia for spawning. Indo-Pacific sailfish spawn throughout the year in tropical and subtropical regions, while their primary spawning season is during summer in higher latitudes.
During this time, these fish can spawn multiple times. During mating, a male and female pair up and swim together and release both their eggs and sperm into the water. Jolley, ; Luthy, et al. Indo-Pacific sailfish are broadcast spawners, which means the female releases eggs and the male releases sperm in the water to reproduce. Fish with this style of reproduction do not offer any parental care to their young. Indo-Pacific sailfish may be able to survive up to 13 to 15 years.
However, when these fish are caught and released, their average age is 4 to 5 years. Prince, et al. Indo-Pacific sailfish spend most of their time in the upper 10 m of the water column and sometimes dive up to m to find food. These animals eat whenever possible. Indo-Pacific sailfish travel over 3, km to spawn or find food. Juveniles swim in dense schools and adults swim in small groups, they also occasionally swim alone. These fish likely feed in groups according to their size.
Arizmendi-Rodriguez, et al. While little is known about communication between individuals, sailfish can "flash" their body colors and other visual signals like dorsal fin movements during breeding. Their large eyes are flush to their head and are sensitive to low light. Indo-Pacific sailfish also have a pair of nares in front of their eyes, which they use to detect chemicals in the water.
Like other bony fish, this species has a lateral line used to sense movement and pressure changes and structures in their ear canals that help them hear. Indo-Pacific sailfish often eat fish such as mackerels , sardines , and anchovies , as well as cephalopods. While they follow prey, sailfish can be seen swimming quickly with their dorsal fins folded back halfway.
When sailfish attack a school of fish, they fold their fin back completely so they can move even quicker. When 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 will also feed on fish found lower in the ocean, similar to other billfish such as blue marlin , swordfish , and striped marlin.
The specific species they eat depends on the population sizes of their prey. Indo-Pacific sailfish that are hooked by longlines have been attacked by great white sharks and killer whales.
However, adult free-swimming sailfish are rarely attacked. Indo-Pacific sailfish are top predators that affect the population of their prey. These fish may also host several parasites. Nakamura, ; Speare, There are no known adverse effects of Indo-Pacific sailfish on humans. Weight: to pounds. Size relative to a 6-ft man:. This photo was submitted to Your Shot, our photo community on Instagram. Follow us on Instagram at natgeoyourshot or visit us at natgeo.
Share Tweet Email. Go Further. Animals Climate change is shrinking many Amazonian birds. Animals Wild Cities This wild African cat has adapted to life in a big city. Animals This frog mysteriously re-evolved a full set of teeth. Animals Wild Cities Wild parakeets have taken a liking to London. Animals Wild Cities Morocco has 3 million stray dogs.
Meet the people trying to help. Atlantic sailfish are smaller, typically around 6 feet long but topping out at 10 feet long and about pounds. Both subspecies of sailfish prey mostly on octopus, squid and bony fish. In the Atlantic, fish commonly eaten include tuna, mackerel, needlefish, jacks and halfbeaks; in the Pacific, jacks, anchovies, sardines, triggerfish and ribbonfish are dietary staples. Dolphinfish, also known as mahi-mahi, are a primary predator that feeds on sailfish.
Larger predatory fish and some seabirds also eat sailfish. Humans also fish for sailfish, but not often for food; their meat is tough and generally considered undesirable. However, because sailfish are so large and put up such a fight—often taking hours to land—recreational and trophy fishermen seek them out. Sailfish begin spawning in April, but most of this activity goes on during summer months.
Most spawning occurs close to land, the females swimming there slowly with their dorsal fins sticking up above the surface of the water, and one or more males following. Sailfish are popular in recreational fishing catch and release but have little value in the commercial fishing industry and cannot be fished commercially in the Atlantic Ocean.
Sailfish are also caught as bycatch by driftnets, harpoons and commercial, long-line tuna fisheries, where bycatch numbers are not accurately reported. Sailfish are considered the fastest fish in the sea, reaching top speeds of 70 miles per hour. The largest sailfish ever caught was Sailfish can live for 13 to 15 years. However, sailfish caught and released by sport fishermen have an average lifespan of only 4 to 5 years.
Sailfish spend their entire lives near the surface of the open ocean, but can dive up to 1, feet m to find food. Click here or below to download hands-on marine science activities for kids. FAO Species Catalogue. FAO: Family Istiophoridae.
0コメント