Yellowtail Kingfish (Seriola lalandi) is a member of the Carangidae family, otherwise known as Amberjacks or YTK. They are indigenous to Australia, ranging around the southern half of the continent, as well as the north and south Pacific oceans. Commercial aquaculture production was pioneered by fish farmers in Spencer Gulf, South Australia, but new operations have recently started (2016) in the mid-west region of Western Australia and near Port Stevens on the central coast of NSW.
Production begins with spawning of broodstock sourced from the wild or selected from cultured stocks. Fertilised eggs are collected from the spawning tanks and following a short incubation period of approximately 2 days the larvae hatch and are held in larval rearing tanks where they are fed an enriched diet of live zooplankton and artemia. After 21 days, the juvenile fish are transferred to nursery tanks and weaned onto a manufactured pellet. At between 60 and 100 days, fingerlings are transferred from the hatchery into sea cages at sizes ranging from 25 grams to 50 grams.
Fish can be harvested from as small as 800 grams, but the major market is for fish of over 4 kg. YTK have a rapid growth rate and depending upon location, can reach this size in less than 16 months.
To achieve this growth rate, fish are fed daily on a high quality pelletised diet to meet their nutritional requirements. Environmental conditions in the sea-cages are carefully monitored by farm technical staff and divers, and the health of marine and benthic environments regularly assessed to ensure farming operations are sustainable. Sites are fallowed and rotated in a similar way as land-based farmers rotate paddocks.
Australian Yellowtail Kingfish production is expected to exceed 2,000 tonnes in the near future. The product is sold for premium grade sashimi, and also to high-end ‘white tablecloth’ restaurants both in Australia, Asia and Europe, and demands high prices.