The Japanese amberjack Seriola quinqueradiata, also called yellowtail, is a fast-swimming pelagic fish native to the northwest Pacific Ocean, from Japan to the Hawaiian islands. It grows to 1.5 meters long and up to 40Kg on a mostly piscivorous diet of small fish (such as anchovies and sardines) and squid. Japanese amberjack is very popular in Japan, used mostly raw as sashimi (where it is called hamachi if it comes from fish up to 3-5 Kg, and Buri if from fish larger than 5 kg). Wild Japanese amberjack stocks started to decline in the 1960s, and at this time commercial farming started to rapidly expand, especially in Japan, where it makes up 57% of farmed marine fish production. Japan produces between 140,000-160,000 tonnes/year, which in 2004 was worth almost $1.3 billion. Farms are populated by harvesting wild juveniles less than 1.5cm (called mojako) using fine-meshed nets; once they are big enough they are grown in pen nets submerged in the open ocean, harvest size depends on size of the pen. Japanese amberjack farming has been criticized as environmentally unsound, fish are grown in dense conditions causing pollution of rearing areas and promoting disease; farming requires 8 lbs of fish (often sardines) for 1 lb of Japanese amberjack (although often formulated pellets are now used as food); and the practice of removing larval fish from the environment to sustain the industry rather than rearing fish from eggs contributes to overall decline of wild stocks.
(Food and Agriculture Organization of the United Nations, Fisheries and Aquaculture Department; Trenor 2009; Wikipedia 2012)