page_title: Southern bluefin tuna
section_title: Sardine fishery
hierarchical_section_title: Southern bluefin tuna / Negative impacts / Sardine fishery
caption_attribution_description: Great white shark (Carcharodon carcharias) off South Africa
context_page_description: The southern bluefin tuna is a tuna of the family Scombridae found in open southern Hemisphere waters of all the world's oceans mainly between 30°S and 50°S, to nearly 60°S. At up to 2.5 metres and weighing up to 260 kilograms, it is among the larger bony fishes.
  Southern bluefin tuna, like other pelagic tuna species, are part of a group of bony fishes that can maintain their body core temperature up to 10 °C above the ambient temperature. This advantage enables them to maintain high metabolic output for predation and migrating large distances. The southern bluefin tuna is an opportunistic feeder, preying on a wide variety of fish, crustaceans, cephalopods, salps, and other marine animals.
context_section_description: Australia's largest single species fishery (by volume) has been developed since 1991 to provide feedstock for the southern bluefin tuna farming industry. Catches in the fishery increased from 3,241 tonnes in 1994 to 42,475 tonnes in 2005. According to the South Australian Sardine Industry Association, 94% of its annual catch is utilized as feedstock for farmed SBT, with the remainder used for human consumption, recreational fishing bait and premium pet food. Fishing effort is largely concentrated in southern Spencer Gulf and Investigator Strait near Kangaroo Island in South Australian state waters. Some fishing also occurs off the Coffin Bay Peninsula in the Great Australian Bight.
  Reduced availability of baitfish species is known to impact seabird populations. In 2005, the potential impact of this fishery upon colonies of little penguins was considered a future research priority, due to the relative paucity of alternative prey species. As of 2014, no such studies have been undertaken.
  The fishery uses large purse seine nets up to 1 km in length to catch sardines. Bycatch mortalities of the fishery include the common dolphin (Delphinus delphis) which is a protected species under state and federal legislation. The species is protected federally under the Environment Protection Biodiversity & Conservation Act.
caption: Great white shark
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