| Slender tuna | |
|---|---|
 | |
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Scombriformes |
| Family: | Scombridae |
| Subfamily: | Scombrinae |
| Tribe: | Thunnini |
| Genus: | Allothunnus |
| Species: | A. fallai |
| Binomial name | |
| Allothunnus fallai Serventy, 1948 | |
| Synonyms[2] | |
Gasterochisma fallai(Serventy, 1948) | |
Theslender tuna,Allothunnus fallai, is a species oftuna, the only species in the genusAllothunnus, found around the world in the southern oceans between latitudes20° and50° South, although there are two records of probablevagrants, one inLos Angeles Harbour and the other from the North Pacific subarcticgyre.[1] It has a more elongated body than other species of tuna with which it issymaptric such as thealbacore 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 seconddorsal andanal fins resembling a small albacore, but the slender tuna lacks the long sweeping pectoral fins characteristic of albacores.[3] Thepectoral fins andpelvic fins are purple on their distal portions and black near their bases.[4] Its length is up to 1 metre (3.3 ft)[2] and it can weigh up to 12 kilograms (26 lb).[3] It occasionally forms schools and its main prey iskrill but it is also known to prey onsquid and smaller fishes,[2] such asjack mackerel.[5] It is a species of minor commercial importance, taken mainly asbycatch by fisheries for other tuna species.[1] It has rather oily flesh, paler than that of other tuna, but the flesh is palatable when cooked,[2] although it is suitable forcanning.[4] 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 ofomega-3 polyunsaturated fatty acids in the flesh of this species caused theCSIRO to declare that the slender tuna was Australia's healthiest seafood dish.[5]
