Threadfins form an important component of barramundi fisheries and are likely to play a significant ecological role in northern inshore habitats. Despite their importance and the expansion of coastal fisheries, the status of the threadfin resource in most parts is unknown whereas in WA they are considered fully or over-exploited (Pember et al, 2005). This uncertainty arises from the limited understanding of threadfin biology, stock structure and a lack of available data on resource exploitation (Welch et al. 2002). The inshore net fisheries across northern Australia are currently managed separately and under vastly different management regimes. However, without knowledge of threadfin stock structure the appropriate spatial scales of management is not known. In August 2003, the Northern Australian Fisheries Management Forum (NAFM) signalled its intention to move from single jurisdiction-based fishery assessment and management towards a more integrated approach that reflected the management needs of species across their northern Australian range. Elucidation of threadfin stock structure is vital for their management at an appropriate ecosystem scale. Attending to these critical issues for threadfins will also provide a framework for addressing management of other inshore species that are fished in adjacent State and Territory waters. Consequently, this project addresses research priorities outlined by QFIRAC, the NT FRAB, Fisheries WA and Sunfish.

Industry has also expressed major concerns for the sustainability of the threadfin fisheries. These concerns are based on fishers’ personal experience’s, whereby large concentrations of king threadfins usually associated with inshore fishing grounds, especially in the south-east Gulf of Carpentaria, are now being encountered much less frequently, and their movement on and off the grounds is much more erratic than previous years (G. Ward, pers. comm.).