sailfish(20pts)

Sailfish

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This article is about the fish. For other meanings see Sunfish (dinghy) and USS Sailfish.



?Sailfishes


圖片參考：http://upload.wikimedia.org/wikipedia/en/thumb/5/50/Istiophorus_platypterus.jpg/200px-Istiophorus_platypterus.jpg

Indo-Pacific sailfish, Istiophorus platypterus

Scientific classification





Kingdom:
Animalia


Phylum:
Chordata


Class:
Actinopterygii


Order:
Perciformes


Family:
Istiophoridae


Genus:
Istiophorus
Lacépède, 1801


Species


Istiophorus albicans
Istiophorus platypterus

Sailfishes (genus Istiophorus) are fish living in all the oceans of the world. They are blue to gray in color and have a characteristic sail (dorsal fin) on top of them, often stretching the entire length of their back. The sailfish is a rapidly growing species, reaching 1.2 to 1.5 m in a single year. They can swim at speeds of up to 68 m/h making them the fastest fish in the ocean. They feed on the surface or at mid-depths on smaller pelagic fishes and squid. They don't grow to more than 10 feet and rarely weigh over 200 pounds. Sailfish usually keep their sails folded down to the side. When they feel threatened or excited, they raise their sail, which makes this slender fish appear much larger than it actually is.
A very interesting thing about sailfish (and also all other Billfish) is that they can eject their stomachs out of their mouths and then swallow them again without harm! In this way they can expell foreign objects they may have swallowed. It is not known whether the fish does this on purpose or as a result of something unordinary (such as being hooked by a fisherman). When hooked by fishermen and brought up quickly to the surface, the sudden expansion of the fish's gas-filled swim bladder pushes its internal organs out through the fish's mouth. This is usually fatal for the unfortunate fish but for some reason sailfish don't seem to be seriously bothered by their freaky version of "stomach-turning." Sailfish are also sometimes known as the fish that "walk on water." Sailfish have been seen to "run" along the surface of the water for over 200 feet using nothing but their wriggling tails to support themselves.



[edit] Species

Atlantic sailfish, Istiophorus albicans.
Indo-Pacific sailfish, Istiophorus platypterus.