Implications of environmental change and mortality estimates for sustaining fish populations in south coast estuaries

Managers, scientists and fishers now have an understanding of the implications of the age and size compositions, growth and total mortality of Black Bream and Estuary Cobbler and the current status of the stocks of those species in south coast estuaries. In particular, our fisheries-independent data has shown that the abundance of Estuary Cobbler in Wilson Inlet, which contributes by far the most of any estuary, to the commercial catches of this species, has declined markedly over the last 20 years. The outcomes of this project will assist in the development of plans aimed at sustaining the commercial and/or recreational fisheries for Black Bream and Estuary Cobbler and maintaining the environments of estuaries on the south coast of Western Australia. Such management plans can now be based on sound fisheries-independent data on the biology and contemporary status of those two species and knowledge of their relationships with the environment. Furthermore, managers can now be confident that the closure of certain areas within estuaries is an effective tool to protect the stocks of Estuary Cobbler in those estuaries. In addition, the implications of hypersalinity for the stocks of Black Bream within estuaries are now well understood by fishery managers and local communities. A wide understanding by fishers and members of local communities of the significance and benefits of the study has been created through their strong engagement with the research team during the course of the study. In addition, through their involvement in the study, two honours and a PhD student have been trained in contemporary techniques in fisheries science and population and community ecology.