Testing the feasibility of stocking Sand Flathead, Snapper and Estuary Perch has demonstrated the benefits enhancement can have in supporting conservation and climate-driven opportunities for Tasmania’s recreational fisheries.
Tasmania’s recreational fishery is a cornerstone of community life, with one in four residents taking part each year. With a recent statewide survey finding more than 830,000 finfish retained and 1.2 million either released or discarded annually, recreational fishing delivers significant social and economic value. However, some key fish stocks are under pressure.
That’s why FRDC project 2023-163, led by the University of Tasmania’s Institute for Marine and Antarctic Studies (IMAS), is assessing the feasibility of using hatchery-reared fish to enhance stocks of three key species: Southern Sand Flathead (Platycephalus bassensis), Snapper (Chrysophrys auratus) and Estuary Perch (Percalates colonorum).
Southern Sand Flathead is Tasmania’s most popular recreational species accounting for approximately 50 per cent of all finfish retained by recreational fishers across the state. Sustained recreational fishing pressure over several decades has led the fishery to be classified as depleted in Tasmania as per the Status of Australian Fish Stocks Reports released in July 2024. As a result, recent management interventions have seen bag limits reduced (from 20 to two fish per day in some regions) and introduced new size limits.
While these management reforms should support natural recovery, rebuilding biomass could take many years. That’s why stock enhancement is emerging as a potential additional management tool, to complement traditional fisheries management strategies.
The D’Entrecasteaux Channel south of Hobart was chosen as an ideal area to assess the feasibility for stock enhancement for Southern Sand Flathead. This sheltered, popular waterway is a hotspot for recreational fishing, but decades of heavy fishing have left the stock depleted, with fewer large fish and a stunted population structure.
The project uses EnhanceFish, a modeling tool developed by the University of Florida, to assess different fish release scenarios. Results showed that releasing larger juvenile flathead (greater than nine cm) delivers the greatest survival gains and boosts biomass more effectively than smaller fish. Importantly, proactive stocking also offers a chance to reintroduce more physically robust and diverse flathead, potentially counteracting the long legacy of size-selective fishing.
“Southern Sand Flathead are at the heart of recreational fishing in Tasmania, and we want to maximise the value of these species to the community,” says project co-investigator Sean Tracey, who leads the fisheries and aquaculture centre within IMAS. Continue reading on the FRDC website.