Tuna sushi is a food item consisting of a thin slice of fresh raw tuna served with seasoned rice and seaweed, originating in Japan.
In Japan, a tuna maki roll is referred to as tekka maki. Its name is derived from the gambling casinos known as tekka-jo, where rolled sushi was served because it was easy to eat while gambling.
In order to be considered for sushi, tuna must meet kata or ideal form requirements pertaining to color, texture, fat content, and body shape.
There are nine recognized species of tuna, a marine fish which spends the majority of its life in the middle depths of open water. All tuna species are fished commercially, but albacore, bluefin, skipjack, and yellowfin are the most heavily fished. Here is a quick guide to the five most popular varieties of tuna:
Albacore
Albacore is white-fleshed tuna, best served as sashimi or very lightly seared, almost rare.
Bigeye
Bigeye tuna has some of the same properties as a bluefin tuna, but the fish don't grow as large, and they don't usually have quite the same level of fat content. Bigeye tuna makes great sashimi, and is considered the most versatile of all tuna, making it a good choice to order in a restaurant or bring home to cook for the family. This variety, along with yellowfin, is called ahi in the Hawaiian Islands.
Bluefin
Bluefin tuna commands the highest prices of any tuna in the world. It has a very high fat content, and since fat is where all tuna gets its flavor, the bluefin is very sought-after, especially in Japan. Specimens of the highest quality are used in sushi and sashimi.
Skipjack
The smallest of the tunas, this variety is commonly used for light canned tuna.
Yellowfin
Yellowfin tuna, also known as ahi in the Hawaiian Islands, is very highly prized by fishermen and cooks.
Research on the tuna’s migration, feeding and spawning practices was begun in the 6th century BC by Greek fishermen that prized their delicate flesh.
Fifty years ago, large Atlantic bluefin tuna might sell for a penny a pound for cat food, if it sold at all. Today, that same bluefin tuna can sell for up to US$100 per pound, mainly due to the popularity of sushi and sashimi around the world.
The largest bluefin tuna weighed 1,496 lb (679 kg) and was caught in Nova Scotia on October 26, 1979.
The popularity of sushi is expected to continue to grow in the 21st century. The challenge will be keeping up with the demand. Tuna is especially in danger of being over-fished. At the end of the 20th century, some American restaurants were refusing to serve tuna in an effort to end the depletion of the species.
According to the Millennium Edition of Guinness World Records, in January of 1992, a 715 lb (324 kg) bluefin tuna sold for US$83,500 in Tokyo, Japan. The tuna was reduced to 2,400 servings of sushi for wealthy diners at $75 per serving. The estimated takings from this one fish were $180,000.
