Greenback Flounder
Rhombosolea Tapirina
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Quick Facts
Distribution
- The Greenback Flounder is a flat, oval-shaped fish that can grow to about 45 cm long. Its greenish to greyish or brownish upper side gives it a muted, earthy look that helps it blend into the seafloor.
- In Australia, it lives along the southern coast, from Western Australia around to Queensland. It is also found in New Zealand, where it is commercially important.
- This is a fish of soft, silty seabeds. Adults settle on silty sand from estuaries out to about 100 m deep, while young fish sometimes venture into rivers.
- Look at the Greenback Flounder from above and its body has a distinctly diamond-like outline, wide and deep for its length. Its snout extends into a small fleshy point that juts out slightly in front of its mouth.
- One feature that sets it apart from many flatfish is the underside: the Greenback Flounder has no pelvic fins on its pale belly. This is unusual among Australian flounders.
- Darker spots and blotches sometimes appear across the upper side. This patchy colouring shifts to match the seafloor and can make the fish very hard to spot when it is lying still.
- Greenback Flounders are active at night. While the bottom of the estuary is quiet, they move across the seabed hunting small prey.
- Adults feed on animals living on or in the seabed, including worms and small crustaceans. Young fish eat tiny shrimp-like animals, small worms and similar small prey.
- Females spawn offshore and in the deeper parts of estuaries, from late winter through to spring. The Greenback Flounder is a serial spawner, meaning females release eggs in batches across the season rather than all at once.
- Juvenile Greenback Flounders spend time in estuaries, where food is plentiful and conditions suit their early growth. As they get older, they tend to move further out into coastal waters.
- Greenback Flounders are caught commercially and recreationally in south-eastern Australia, with smaller catches also taken in Queensland and Western Australia. They are targeted with bottom-set gill nets and seine nets, and are sometimes caught as a bycatch in trawl fishing.
- Research into juvenile Greenback Flounders has shown they can handle changes in water saltiness fairly well. This may be part of why they are able to move between estuaries and more open coastal waters.
Species Interaction
Greenback Flounder: A Southern Estuary Favourite for Anglers and Nets
- Recreational Fishing
- Commercial Harvest
- Seafood
- Research & Rare Encounters
- Conservation
Greenback Flounder are caught by both recreational anglers and commercial fishers across southern Australia, from the South Australian lakes and Coorong to Corner Inlet and Tasmania. In Tasmania, recreational landings have in recent years matched or exceeded the commercial catch, reflecting genuine popularity with estuary and coastal fishers. Commercial catches have declined markedly since peak landings of over 30 tonnes in the mid-1990s, and management measures including mesh net closures in sensitive areas now apply in some key habitats. Researchers have also tracked the species using movement studies to better understand its estuary habits and support fishery management.
Scientific Classification
- Kingdom: Animalia
- Phylum: Chordata
- Class: Teleostei
- Order: Pleuronectiformes
- Family: Pleuronectidae
- Genus: Rhombosolea
- Species: Rhombosolea tapirina
Conservation Status
The Greenback Flounder is listed as Endangered under Australia’s Environment Protection and Biodiversity Conservation Act 1999. It inhabits estuaries, coastal lakes and shallow marine waters in south-eastern Australia, where declining water quality and altered freshwater flows have placed significant pressure on populations.
Interaction Highlights
Commercial
Tasmanian commercial landings have fallen sharply since 1990s peaks above 30 tonnes.
Conservation
Net closures and freshwater flow management aim to protect key estuary populations.
Research
Movement tracking studies in the Murray estuary reveal complex migration patterns.
How to catch
Greenback Flounder
Catch Difficulty: Moderate
Tackle: Running sinker rig, Paternoster rig, Soft plastic lure
Bait: Worms, Prawns, Fresh cut fish bait, Soft plastics
Technique: Fish bait on the bottom, Fish bait near reef or structure
Popularity: Occasionally targeted
Recreational Viewing
- Snorkeling & Scuba
Finding: Difficult
Temperament: Shy
Location: Sandflats, Seagrass Beds
Danger: None
