Tuna belong to the family Scombridae. They are large, oceanic fish and are seasonally migratory, some making trans-oceanic journeys. Southern bluefin are found in temperate and cold seas of the southern hemisphere, but migrate to the tropics to spawn. They are a very large species, growing to 245cm in length and 260kg in weight, with a maximum age of 40 years. Southern bluefin mature between 8 -11 years of age (about 155cm in length). Young fish migrate seasonally between the south coast of Australia and the Indian Ocean. The only known spawning ground is in an area south-east of Java, Indonesia.