Malcolm Tull

This project investigates recreational and commercial fisher motivations for using a fishery and the beliefs, attitudes and perceived benefits of aquaculture-based enhancement programs and other management options. It also determines the total economic value for recreational fishing for Blue Swimmer Crabs (Portunus armatus) and Black Bream (Acanthopagrus butcheri) in a range of estuaries in south-western Australia and investigates the benefits of release programs in contributing to the optimisation of biological, social and economic objectives for those fisheries. Finally, it provides training for the next generation of fisheries and social scientists and fishery economists and project members engaged in community engagement and education.

Work was focused on two iconic small-scale estuarine fisheries in south-western Australia, i.e. those for Blue Swimmer Crabs and Black Bream. A two-phase approach to elicit common recreational fisher beliefs using semi-structured interviews (phase 1) and then sample a broader pool of respondents using closed-question online surveys (phase 2). Analyses demonstrated that motivations for recreational fishing were markedly different for the two fisheries, even when operating in the same system. Aquaculture-based enhancement was universally supported by the recreational sector as a fishery management approach as they believed it would enhance stocks and catches, and, although it may cause negative impacts, they were considered unlikely. Commercial fishers were less supportive of this management intervention. Enhancement of stocks was estimated to increase the economic value of recreational fishing through increased visitation. Biological modelling highlights that stocking could provide substantial benefits to the biomass of the target stocks, particularly Black Bream, but the parameters of any future stocking the need to carefully considered to ensure maximum benefits and the mitigation of density-dependent effects on wild stocks. Advice on the numbers and size-at-release for Blue Swimmer Crabs in the Peel-Harvey and Black Bream in the Blackwood River Estuary are provided to optimise the biological, social and economic dimensions of these fisheries.

A model of recreational fisher choice is used to assess the likely reaction by fishers to tighter management rules. Put simply, within this model the fisher stays fishing until the net benefit from another hour fishing is balanced against the opportunity cost of the extra time, reflected by the value of doing non-fishing activities elsewhere. Overall the survey results and associated analysis show a high degree of conformity with the model suggesting fishers behave quite rationally in the choices they make about fishing in the presence of tighter management rules.