WAMSI Node 4.4.2-3 - Spatially explicit assessment models for the west Coast demersal scalefish fishery

Updated: 2017-11-21

The capacity of management areas to sustain abundances of exploited species depends upon the dynamics of recruitment, and in particular the extent of dispersal between areas and the age classes contributing to dispersal. Like other marine fishes with pelagic larval stages (ca. the first 20-30 days), the dispersal of larval dhufish is likely to be profoundly influenced by oceanic currents. There is extensive evidence that the pole-ward flowing Leeuwin Current is responsible for the long-distance transport of marine fauna in the south-western Australian area (Hutchins & Pearce, 1994, Caputi et al., 1996, Beckley et al., 2009, Pearce & Hutchins, 2009). In addition, during the austral summer (December-February), when most spawning occurs in dhufish, wind driven currents drive flows along the west coast northwards and inshore of the Leeuwin current (the Capes Current; Pearce & Pattiaratchi, 1999, Feng et al., 2010), and these are believed to transport the larvae of marine fishes (Lenanton et al., 1996, Lenanton et al 2009b). The dhufish is characterised by inter-annual variation in recruitment (Lenanton et al., 2009), and it has been speculated that this may in part reflect variation in the strength of the prevailing currents. The aim of the study, in including alternate hydrodynamic conditions, was to explore the potential influence of a range of realistic larval dispersal scenarios on dhufish population dynamics.