The slender tuna, ''Allothunnus fallai'', is a species of tuna, the only species in the genus ''Allothunnus'', found around the world in the southern oceans between latitudes 20° and 50° South, although there are two records of probable vagrants, one in Los Angeles Harbour and the other from the North Pacific subarctic gyre. It has a more elongated body than other species of tuna with which it is symaptric such as the albacore The colour is blue-black on the back with silvery greyish-white sides, however some individuals have a coppery sheen soon after capture. It has a small second

dorsal Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage The fus ...

and

anal fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported o ...

s resembling a small albacore, but the slender tuna lacks the long sweeping pectoral fins characteristic of albacores. The

pectoral fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish aquatic locomotion, swim. Apart from the tail or caudal fin, fish fins have no direct connection with the vertebral column ...

s and

pelvic fin Pelvic fins or ventral fins are paired fins located on the ventral (belly) surface of fish, and are the lower of the only two sets of paired fins (the other being the laterally positioned pectoral fins). The pelvic fins are homologous to the hi ...

s are purple on their distal portions and black near their bases. Its length is up to and it can weigh up to . It occasionally forms schools and its main prey is

krill Krill ''(Euphausiids)'' (: krill) are small and exclusively marine crustaceans of the order (biology), order Euphausiacea, found in all of the world's oceans. The name "krill" comes from the Norwegian language, Norwegian word ', meaning "small ...

but it is also known to prey on

squid A squid (: squid) is a mollusc with an elongated soft body, large eyes, eight cephalopod limb, arms, and two tentacles in the orders Myopsida, Oegopsida, and Bathyteuthida (though many other molluscs within the broader Neocoleoidea are also ...

and smaller fishes, such as

jack mackerel Jack mackerels or saurels are marine ray-finned fish in the genus ''Trachurus'' of the family Carangidae. The name of the genus derives from the Greek (language), Greek words ''trachys'' ("rough") and ''oura'' ("tail"). Some species, such as ''T ...

. It is a species of minor commercial importance, taken mainly as

bycatch Bycatch (or by-catch), in the fishing industry, is a fish or other marine species that is caught unintentionally while fishing for specific species or sizes of wildlife. Bycatch is either the wrong species, the wrong sex, or is undersized or juve ...

by fisheries for other tuna species. It has rather oily flesh, paler than that of other tuna, but the flesh is palatable when cooked, although it is suitable for

canning Canning is a method of food preservation in which food is processed and sealed in an airtight container (jars like Mason jars, and steel and tin cans). Canning provides a shelf life that typically ranges from one to five years, although under ...

. The high oil content of the flesh is caused by the oily nature of its diet and varies over the tuna's life, fish which have just fed are high in oil but specimens caught at the end of their migrations will have relatively low oil content. The high concentration of omega-3 polyunsaturated fatty acids in the flesh of this species caused the

CSIRO The Commonwealth Scientific and Industrial Research Organisation (CSIRO) is an Australian Government agency that is responsible for scientific research and its commercial and industrial applications. CSIRO works with leading organisations arou ...

to declare that the slender tuna was Australia's healthiest seafood dish.

References

* Tony Ayling & Geoffrey Cox, ''Collins Guide to the Sea Fishes of New Zealand'', (William Collins Publishers Ltd, Auckland, New Zealand 1982)

External links

* * {{Taxonbar, from=Q18960418 Scombridae Fish described in 1948 Tuna