Tuna

From Freepedia

For other uses, see Tuna (disambiguation).

? Tuna
Image:Tuna.jpg
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Actinopterygii Order: Perciformes Family: Scombridae Genus: Thunnus South, 1845
Species
Thunnus alalunga Thunnus albacares Thunnus atlanticus Thunnus maccoyii Thunnus obesus Thunnus orientalis Thunnus thynnus Thunnus tonggol

Tuna are several species of ocean-dwelling fish in the family Scombridae, mostly in the genus Thunnus. Tuna are fast swimmers and include several species that are warm-blooded. Unlike most ocean fish species, which have white flesh, the flesh of tuna is pink. This is because the tuna's blood has a higher oxygen carrying ability than other fish species. Some of the larger tuna species such as the bluefin tuna can raise their blood temperature above the water temperature with muscular activity. This enables them to live in cooler waters and survive a wider range of circumstances.

Tuna is a popular seafood. Some varieties of tuna, such as the bluefin, are endangered due to overfishing, while others are parts of well maintained fisheries, such as the bigeye or yellowfin.

Mercury levels are often relatively high in tuna, due to their higher position in the food chain and the subsequent accumulation of heavy metals from their diet. As a result, in March 2004 the United States FDA issued guidelines recommending pregnant women, nursing mothers and children to limit their intake of tuna and other types of predatory fish [1].

It is difficult to keep tuna in a captive environment; Monterey Bay Aquarium is one of the few aquariums in the world that successfully keep tuna in display.

Types include:

• Bluefin tuna, which can grow to 1,500 lb (680 kg)
• Yellowfin tuna
• Albacore tuna
• Bigeye tuna
• Blackfin tuna

Tuna are a common target for big-game fishing, and are mostly caught on artificial lures.

Other species

Species of several other genera (all in Scombridae) are commonly named "tuna":

• Skipjack tuna Katsuwonus pelamis
• Slender tuna Allothunnus fallai
• Bullet tuna Auxis rochei rochei
• Frigate tuna Auxis thazard thazard
• Kawakawa (little tuna or mackerel tuna) Euthynnus affinis
• Little tunny (little tuna) Euthynnus alletteratus
• Butterfly kingfish (Butterfly tuna) Gasterochisma melampus
• Dogtooth tuna Gymnosarda unicolor

External links

• Monterey Bay Aquarium's Seafood Watch program
• Bluefin tuna nutrition information
• Table of relative mercury levels in fish and shellfish (FDA)