The lower west coast demersal scalefish stocks in WA are exposed to a range of factors that vary spatially. The west coast bioregion stretches over 900 km of coastline along a latitudinal gradient (27° S to 34° S) including the capital city of WA, Perth. This multi-species fishery comprises species with variable distributions and abundances as well as exploitation levels. A three-year FRDC-funded research project examined regional variations in stock structure, age and growth and reproductive biology of the two key species; the endemic West Australian dhufish, Glaucosoma hebraicum and the nationally widespread snapper, Pagrus auratus.

Despite both species being large, long-lived demersal fish exposed to a similar environment, many aspects of their biology varied. The timing of the onset of reproduction in snapper varied regionally in relation to the water temperature gradient. In contrast to snapper, dhufish showed highly variable recruitment but few spatial patterns in biology as most of the regional variability in the biology of this species was due to the difference age classes. Lastly, results of isotope analyses of whole otoliths showed that adult dhufish are lifetime residents of their particular geographical location, whereas snapper sub-adults appear to be well mixed throughout the bioregion.