THE CSIRO has announced the first confirmed records of recreational catches of Pacific bluefin tuna (Thunnus orientalis) in Victorian waters.
According to the CSIRO breakthrough came after two large tuna caught off Bass Strait in July 2026 were genetically tested and confirmed as Pacific bluefin tuna, a species rarely recorded by Australian recreational fisheries.
The fish were caught just days apart by Victorian anglers fishing wide off Western Port Bay in 50-60m depth. One fish weighed approximately 165 kg and measured 2.12 m, while the second weighed 131.6 kg and measured 2.02 m. Initially, both fish were assumed to be southern bluefin tuna (Thunnus maccoyii), a species commonly targeted by recreational game fishers in Victoria and more commonly associated with Australian waters.
However, Tuna Champions Scientific Ambassador Jonah Yick and experienced fisher Dave Standing, along with a few other fishers noticed several unusual features on the fish that raised questions about their identity.
“The fact that these two fish were caught in close proximity, literally on Melbourne’s doorstep, within 10 kilometres of the shoreline, is an amazing catch and story,” Jonah said.
“The Pacific and southern bluefin tuna look very similar to the naked eye but there are subtle differences which can be used to distinguish between the two species, which includes anal and second dorsal fin length, markings on their skin, body shape, and average size.”
Pacific bluefin tuna have been known to be caught by long liners (or commercial fisherman) in Victorian waters but they are usually in very deep water, a long way from shore.
Recognising the potential significance of the catches, Dave quickly contacted the anglers involved in both catches and coordinated the collection of muscle samples for genetic testing. The samples were then sent to Jonah, who subsequently passed them on to Principal Research Scientist Dr Peter Grewe – the lead geneticist working on tuna genomics at CSIRO in Hobart.
Dr Grewe ran an initial DNA screen using a rapid tuna species identification test developed at the CSIRO labs. The results indicated both fish were Pacific bluefin tuna. This was an exciting and significant finding, as these captures represent the first genetically confirmed Pacific bluefin tuna caught by recreational fishers in Victoria.
“I’m extremely confident in these results following a secondary forensic grade sequencing analysis further confirming our initial quick species ID test,” Dr Grewe said.
In a remarkable development, months later anglers off Lakes Entrance, Victoria, began catching large numbers of tuna weighing between 130 and 217 kg. Preliminary assessments based on external features suggest these fish may also be Pacific bluefin tuna. Samples have been collected from some of these fish from local recreational fisher Simon Webster, and testing is now underway by CSIRO to determine their identity.
Pacific bluefin tuna are among the largest and most powerful tuna species in the world, capable of growing to almost three metres in length and approaching 450 kg in weight. They are also one of the world’s most valuable prized fish, especially in high-end restaurants in Japan. There have only been a handful of Pacific bluefin tuna caught by recreational anglers in Australia, and the species has never been confirmed by recreational fishers in Victoria until now.
