Latin names: Thunnus obesus
Common Names: Tuna
Wild Caught - Australian and Imported
- Commonwealth Eastern Tuna and Billfish Fishery (553t 2012)
- Commonwealth Western Tuna and Billfish Fishery (167t 2012)
- Imported from Indian Ocean, Western & Central Pacific Ocean fisheries
Bigeye tuna is a highly migratory species of tuna that is targeted by fishing vessels managed by a number of different countries. Due to high demand for bigeye tuna, fishing pressure on the species is intense. Fishery reports that have assessed the stock status of the species at a regional level indicate that stocks in all areas where bigeye tuna are caught are depleted beyond sustainable levels. Bigeye tuna is now listed as 'Vulnerable' to extinction on the IUCN Red List.
Australian fisheries target bigeye tuna along the eastern and western coasts. The stocks targeted are the same stocks as those caught in other fisheries in the Pacific and Indian Oceans.
Bigeye tuna are caught using longlines in Australian waters. Threatened species caught on the longlines include shortfin mako sharks and green turtles. The available research indicates that the bycatch of sharks is not likely to be resulting in declines to the populations of these species based on stable catch records from the fishery (this measure is commonly used by fisheries scientists as a measure of whether the abundance of a species is declining). However, there is a need for better understanding of many shark species populations.
Management actions to reduce the impact of fishing on vulnerable marine wildlife in Australia include limits on the amount of sharks that can be kept for sale and modifications to fishing gear to allow larger sharks to break free. Turtles are often released alive.
Bigeye tuna caught in the Pacific and Indian Oceans is taken using longlines, gillnets and purse seines associated with Fish Aggregating Devices (FADs). FADs are artificial objects that float on the surface of the ocean, which exploit the natural tendency of fish and other marine wildlife to aggregate under floating objects. The bycatch of large numbers of sharks, including whale sharks, and turtles has been well documented in FAD associated fisheries. Longlining and gillnetting is also responsible for the capture of threatened sharks, turtles and seabirds.
The countries that manage the fisheries generally do not monitor the bycatch caught, and independent observer coverage is low to non-existent.