The tonno it is a marine fish of the family of the tunnidi and is l' only fish in hot blood. Diffused nell' Atlantic and in the Mediterranean, lives in branches and comes fished with various systems, between which more the classic is the tonnara. Of it they exist various species: that one of the Mediterranean, the tonno red, has the long till 3 m and heavy body till 600 kg, with tail to semimoon, advanced parts blue-nerastro and whitish inferior parts or silver gray. There are then other species of inferior diminesioni (tonnetti).

The used variety more for l' canning is the yellow fin, thus said for the characteristic yellow coloration on the tip of the fins. This alive variety in branches in tropical or subtropicali waters and the medium weight of the exemplary of this species is gone around around the 40 kilograms. Fusiform body, lengthened in the young people, more solid in the adults; rather small eye regarding the size of the body; wide tail fin to moon form, lobes many appuntiti; posteriorly on the advanced and inferior profile they are present 8 - 10 pinnule. The color of the back is blue-nerastro, the gray-silver flanks; the pinnule they are yellowish with black margin.

Pelagica and gregaria species, typically migratrice, the tonno is the fastest swimmer, vorace a predator of fish, cefalopodi and crustaceans and can exceed the weight of 700 kg. In the Mediterranean one close reproduces the Sardinia and the Sicily, from june to the half of July, gathering in branches (gregaria phase), carrying itself in more superficial and coastal waters, suspending the feeding. The tonno period enters in the Mediterranean from the equatorial Atlantic through the strait of Gibilterra (genetic migration) in which it comes mainly fished. It comes captured with tonnara fixed, palangaro of surface, pulls ahead, nets to circuizione (to tonnare flying). It lives in moderated zones and subtropicali where the temperature of the water does not come down under the 10°C.

Like conserve

If acquired of the tranci or threads, is advisable to wash them in order to eliminate the blood and to dry with absorbent paper from kitchen. They can then be placed in refrigerator where they are maintained for approximately 2 days, best if riposti between two wrapped plates or in paper from kitchen or furnace.

For being sure to acquire tonno fresh of quality, he is advisable to control that the polpa or very solid to the lisca, the alive color or and l' smell gradevole. The skin must turn out lucid. If pressing the polpa with a finger it remains l' print, is symptom that the fish is not fresh but it has been fished already from various time or has been scongelato