| ຂໍ້ສັງເກດ |
In adults, seasonal migrations are observed between the warm water western and northwestern Australian spawning grounds and cold water feeding grounds off Tasmania and New Zealand (at temperatures of 13° to 15°C). The migration pattern of these tuna is revealed by the capture of progressively larger fish along the migration route (Ref. 6390). Juveniles 6-8 cm long have been collected on the North West Shelf of Austrlia and larger juveniles (20-60 cm FL) have been caught on the continental shelf further south (22-34°S) (Ref. 30319).
Young fish are generally closely associated with coastal and continental shelf waters, although some immature fish, from 3 years of age, move away from the shelf to feed in the waters of the West Wind Drift (40-45°S) of the Southern Ocean (Ref. 30318). They are caught by longline as far away as South Africa (Ref. 6390). By maturity, most southern bluefin tuna lead an oceanic, pelagic existence (Ref. 6390).
Feed on fish and benthic invertebrates (Ref. 168). |