King Threadfin

Habitat Distribution

• Native to northern Australia; range runs from the Ashburton River in Western Australia, across the Top End and Gulf of Carpentaria, down the Queensland coast to the Brisbane River in the south-east.
• Shallow, turbid coastal waters, tidal rivers, estuaries, and mangrove creeks — almost always over sand or mud substrate rather than hard bottom.
• Populations are strongly regional — unlike barramundi, which can move hundreds of kilometres along the coast, threadfin tend to stay in the catchment where they were born.
• Juveniles use shallow, low-salinity inshore nursery areas; larger fish move into deeper tidal reaches and the lower estuary.

Key Locations

• Gulf of Carpentaria — one of the most significant stocks in Australia, subject to ongoing commercial and recreational fishery assessment.
• Hervey Bay and the lower Brisbane River, Queensland — the southern edge of the range; these populations are particularly sensitive to pressure given the fish's regional fidelity.
• Tidal rivers and estuaries of the Northern Territory — the Daly, Roper, and other Top End systems hold good numbers in the right conditions.
• Kimberley and Pilbara coasts, Western Australia — from the Ashburton River north, with fish in the major tidal river systems of the Kimberley.

Specific Spots

• Sandbanks and mud flats at the edges of tidal flow — threadfin use their pectoral filaments to feel for prawns and small fish along the bottom, so any shallow flat adjacent to deeper water is worth working.
• Mangrove creek mouths on a run-out tide, where baitfish and prawns funnel out of the draining flat into the main channel.
• Deeper holes and channel edges in tidal rivers, especially where current pushes past a bend or a submerged snag — larger fish hold here and move up onto the flats to feed.
• In the Brisbane River, schools have been found in the deeper water around the port precinct; further north, the lower reaches of major river systems concentrate fish during cooler months.