Flabby whalefish Flabby whalefish Flabby whalefish (Cetomimidae sp.) : Animalia : Chordata : Actinopterygii : Cetomimiformes : Cetomimidae Genera Many; see text Flabby whalefish are small, deep-sea cetomimiform fish of the family Cetomimidae. They are among the most deep-living fish known, with some species recorded at depths in excess of 3.5 kilometres. Within the family are nine genera and 20 species. Thought to have a circumglobal distribution throughout the Southern Hemisphere, flabby whalefish are the most diverse family of whalefishes. The largest species, Gyrinomimus grahami, reaches a length of some 40 centimetres. They are distinguished from other whalefishes by their loose, scaleless skin and lack of photophores. Living at extreme, lightless depths, flabby whalefish have evolved an exceptionally well-developed lateral line system: as the eyes are either very small or vestigial, this system of sensory pores (running the length of the body) help the whalefish to accurately perceive its surroundings by detecting vibrations. Named after their whale-like bodies (from the Greek ketos meaning "whale" or "sea monster" and mimos meaning "imitative"), whalefish have large mouths with the dorsal and anal fins set far back of the head. All fins lack spines, and the pelvic fins are absent. The fish also lack swim bladders. Flabby whalefish are a red to orange-brown colour in life; the fins and jaws are brightly coloured. This is explained by the fact that longer electromagnetic wavelengths (such as red and orange) do not penetrate into the whalefish's realm: animals which have evolved at this depth cannot see longer wavelengths, rendering the whalefish effectively black. Their stomaches are highly distensible, allowing the whalefish to pursue prey otherwise too large to swallow; an important adaptation in the abyss where food is scarce. Little is known regarding the life history of flabby whalefish. They are known to feed primarily on small crustaceans such as decapods, copepods and euphausiids. All males captured have been much smaller than females at a maximum of c. 3.5 centimetres. This suggests a strong sexual dimorphism similar to anglerfish: resources are at a premium in the deep ocean, making it sensible to limit size in males. As the male's only purpose is to supply sperm, only the female need grow large in order to reproduce effectively. Like many deep-sea fishes, flabby whalefish are thought to undergo nightly vertical migrations: they feed within the upper 700 metres of the water column by starlight and retreat back to the abyssal depths by daybreak. Judging by the latest studies, the younger whalefish seem to frequent shallower water than adults. See also: List of fish common names, list of fish families Family Cetomimidae Genus Cetichthys Genus Cetomimus Genus Cetostoma Genus Danacetichthys Genus Ditropichthys Genus Gyrinomimus Genus Notocetichthys Genus Procetichthys Genus Rhamphocetichthys External links FishBase entry on Cetomimidae Classification, diversity and biology of whalefishes and relatives FAVORITE ARTICLES: History of the World    History of the United States    History of Europe    Ancient History    History    Military History    World War I    Bombing of Dresden    California    US Constitution    Frank Sinatra    Boston    Marbury v. Madison This article is licensed under the GNU Free Documentation License at http://www.gnu.org/copyleft/fdl.html You may copy and modify it as long as the entire work (including additions) remains under this license. You must provide a link to http://www.gnu.org/copyleft/fdl.html To view or edit this article at Wikipedia go to http://www.wikipedia.org/wiki/Flabby_whalefish