Ingredient: Tuna
Category: Fish
Season: All:
Tuna are several species of ocean-dwelling fish in the family Scombridae, mostly in the genus Thunnus.
Tuna are fast swimmers, they have been clocked at 70 km/hour (43 mph)—and include several species that are warm-blooded. Unlike most fish species, which have white flesh, tuna have flesh that is pink to dark red.
The red colouring comes from tuna muscle tissue's greater quantities of myoglobin, an oxygen-binding molecule. Some of the larger tuna species, such as the blue fin tuna, can raise their blood temperature above that of the water through muscular activity. This ability enables them to live in cooler waters and to survive in a wider range of circumstances.
Some tuna species and fisheries have been over fished and some tuna fisheries are at risk of collapse.
Increasing quantities of high-grade tuna are entering the market from operations
that rear tuna in net pens and feed them a variety of bait fish. In Australia
the southern blue fin tuna, Thunnus maccoyii, is one of two species of blue fin tunas that are kept in tuna farms by former fishermen. Its close relative, the northern blue fin tuna, Thunnus thynnus, is being used to develop tuna farming industries in the Mediterranean, North America and Japan
Canned tuna was first produced in 1903, and quickly became popular. In the United States, only Albacore can legally be sold in canned form as "white meat tuna"; in other countries, Yellow fin is also acceptable as "white meat tuna."
Fishing vessels can exploit this association by searching for herds of dolphins. They encircle the herd with nets to catch the tuna beneath. The nets are prone to entangling dolphins, thus injuring or killing them. As a result of public outcry, methods have been made more "dolphin friendly", now generally involving lines rather than nets. |