About Commercial Tuna Fishing

Tuna is a fast-swimming fish found in all of the world's oceans, except in polar regions. Some tuna species can grow to very large sizes, especially the bluefin tuna, which can reach weights of over half a ton. Tuna are fished commercially in many countries around the world. Tuna meat products range from canned light albacore tuna to raw sashimi bluefin. There are almost 50 tuna species, though only five are regularly caught by commercial fishermen.

  1. Species and Uses

    • Commercial tuna fishermen focus on five species: albacore, skipjack, bluefin, bigeye and yellowfin. Bigeye and yellowfin are most commonly used for tuna steaks. Albacore and skipjack are used primarily for canned tuna. Bluefin is a sought-after species for sushi and sashimi---a raw fish delicacy that's extremely popular in Japan. Skipjack make up almost two thirds of the overall tuna catch. Yellowfin account for 24 percent. Bluefin account for the smallest amount, according to a 2009 report by the International Seafood Sustainability Foundation (ISSF).

    Distribution

    • Almost 70 percent of tuna is caught in the Pacific Ocean, with 22 percent from the Indian Ocean and the rest from the Atlantic, according to the ISSF. In the United States, tuna tend to be found in southerly waters, with large fisheries around Hawaii. Tuna swim in the middle and upper layers of open ocean water, in depths of up to 1,600 feet, according to the Rhode Island Sea Grant. Tuna can migrate thousands of miles per year. Japan and the United States are the world's largest tuna consumers.

    Commercial Tuna Fishing Techniques

    • The purse-seine is an efficient form of rounding up and netting tuna. A round, floated net is drawn together around a tuna shoal---much like the strings of a purse. This method is controversial for the large volume of fish captured and the indiscriminate nature of the technique. It accounts for approximately 62 percent of all tuna caught, according to the ISSF. Other methods include long-lining and pole and line. The latter is considered the most sustainable way of fishing for tuna.

    Populations and Conservation

    • The amount of tuna produced worldwide peaked in 2004 at 4.45 million tons of fish per year. Some commercial species of tuna are facing intense pressure and possible population collapses, according to the website "New Scientist." Bluefin tuna is particularly at risk because of its high demand in Japan. However, skipjack tuna fishing is considered to be at a sustainable level.

    Bycatch

    • Commercial tuna fishing has been blamed for accidental bycatch of numerous species in the past---dolphins in particular. This led to the introduction of "dolphin-safe" labels in the 1990s for cans containing tuna that was harvested without trapping dolphins. Tuna fishing is also linked to the death of thousands of seabirds and turtles every year. Every five minutes an albatross is killed as a result of commercial tuna fishing, according to "Scientific American" magazine.