Tuna is Actinopterygiirope-Percifoemes-Scombridae-Thunnus and is a generic classification for one type of bony fish. Tunnus is “tuna”, in Latin. Today of Japanese does one species in the Thunnus Bluefin Tuna (Thunnus orientalis) only refers to “tuna” even though it is called.
The total length of about 60cm from 3m to very depending on the reach. Moreover, spindle-shaped body, the body elliptical cross-section almost scale is very small or almost without exception around the pectoral fin, and body for fast swimming. Also, can swim at about 90km per hour up to par with the underwater torpedo. It has not been scientifically proven, but it is considered to reduce water resistance and soft lining of the body surface. The maximum migration rate of about 100km. For example, the maximum species of Northern bluefin tuna was the total length of 4.5m, over 680kg weight.
The genus contains eight species of tuna. Thunnus orientalis, Thunnus thynnus, Thunnus maccoyii, Thunnus obesus, Thunnus alalunga, Thunnus albacores, Thunnus tonggol, Thunnus atlanticus.
Its range is in the Pacific, the Atlantic, the Indian Ocean, the Mediterranean, the Black sea. Like this, tuna is living in many seas. Its habitat is widely distributed in temperate tropical waters worldwide, inhabiting different depths depending on the type and distribution area.
Tunas must keep swimming or they will die. Ecology was the mouth and the sea opercular (gill cover) swimming and open, breathe in through the water here and to stop swimming and choking, if not stop even at rest. Predators are carnivorous fish of the middle surface crustacean, cephalopoda and prey. Marine food chain in whale, seal, marlin, sharks along with other higher consumer be. Relatively small populations and hence also biological concentration prone to accumulate contaminants by a variety of problems that occurred. Moreover, according to the species IUCN Red List endangered species is described.
In conclusion it is seen from summer to autumn in the Kochi Prefecture offing.