Understanding environmental and fisheries factors causing fluctuations in mud crab and blue swimmer crab fisheries in northern Australia to inform harvest strategies
Utilisation of boat ramp cameras to estimate recreational fishing catch and effort in key Victorian fisheries
There is no current information on total recreational fishing effort or landings for Victorian fisheries and therefore no continuous time series on these variables, as is the case in most jurisdictions. This represent a key knowledge gap, and hence risk, for fisheries sustainability in the state and has resulted in several fisheries (i.e. those with significant recreational catch) being assessed as ‘Undefined’ in the most recent SAFS round.
In addition to the above, the Victorian Government has brought out several bay and inlet fisheries over the last two decades, meaning recreational catch is the most significant harvest component for most species/stocks. This also means that there is no longer commercial logbook data being obtained on which to base assessment of these species/stocks. As such, having recreational catch and effort information will enable more sophisticated population dynamic stock assessment models to be used for assessment purposes. Victoria possesses such a model that is parameterised for the Western Victorian Snapper Stock (WVSS), complete with management strategy evaluation, that cannot be used to inform decision making at present because the landings from the largest fleet (i.e. boat based recreational fishers) are currently unknown.
Recreational catch and effort information will be used for ongoing stock assessment to inform management advice to inform the following immediate, direct priorities: 1) WVSS harvest strategy, 2) rebuilding of the Gippsland Lakes black bream stock, 3) Corner Inlet Management Plan, and 4) assessment of the eastern Victorian snapper stock.
Maintaining productivity and access to Estuary Cockle across sectors through improved science-based decision making
The lack of knowledge on fundamental fisheries biology, uncertainty in stock structure, population dynamics, and cross-sectoral harvest levels, means that current stock assessments are unequipped to reliably determine stock status or inform recommended biological catches (RBCs), and that management of the resource occurs within a high degree of uncertainty. These EXCEPTIONAL INCREASES IN HARVEST and UNCERTAINTY SURROUNDING SUITABLE RBCs create an URGENT NEED TO DEAL WITH THE SUBSTANTIAL KNOWLEDGE VACUUM FOR THIS RESOURCE. Without this improved knowledge, the reasonable assessment of the status of the resource, estimation of appropriate harvest levels, harvest strategy development, implementation of appropriate management, and informed decision making on how best to utilise the resource, will continue not to be possible. Furthermore, environmental variability and species-habitat-fishery interactions are likely to impact stock dynamics and biomass, which in turn affects the magnitude, profitability, and social outcomes derived from the resource. Thus, efficient exploitation and effective management of the resource within a harvest strategy framework cannot occur without: 1) spatial definition of likely management units (stock structure); 2) estimates of stock biomass within those units; 3) estimates of basal population parameters and some appreciation of the influence of environmental stochasticity on resource productivity; and, 4) an appreciation of resource access across sectors. There is likely potential for further development in this fishery, to satisfy growing markets for the species both locally and abroad, but this will never be realised until these information needs are met.