The export of Southern Rock Lobster (SRL) from Southern Australia to international markets is one of Australia's most valuable fisheries. There are increasing trends in post-harvest mortality of SRL confirmed by the recent Fisheries Research and Development Corporation project (FRDC 2016-235). This is costing the industry millions due to stock losses, decreased consumer confidence in product quality and reputational damage to the SRL market brand. The causes of this increased post-harvest mortality are inconsistent across the industry sector with a range of factors implicated including environmental stressors, novel health conditions, and sub-optimal post-harvest practices. Results from (FRDC2016-235) indicate a need to optimise live lobster management processes across the entire post-harvest chain of custody in-order to minimize lobster mortality and enhance the economics of the SRL fishing and processing industry sectors.

The FRDC SRL live holding project (2016-235) conducted an analysis of the processing industry sector practices and provided guidance for best practices. These recommendations have been welcomed by the industry and further consultation has identified a critical need to extend this approach to the fishing component of the industry.

This project will address these key industry priorities and conduct an analysis of on-vessel live lobster handling and holding practices, quantify the impact of systems and practices on lobster quality and provide recommendations on improving on-vessel post-harvest practices. The current FRDC traceability project (FRDC 2016-177) is trialing a range of traceability technologies that this proposed new project will extend and enhance on-vessels to strengthen the capture, monitoring, and analysis of post-harvest data on lobster welfare, quality, and handling practices.

This project will also extend the development of practical and easy to use tools for the evaluation of lobster health including the handheld lactate meter and refractive index. Building evidenced-based approaches to measuring health and stress will provide all industry sectors with improved measurement of quality, animal welfare, and sustainability at all points in the supply chain.

Size selectivity is an important aspect of southern rock lobster stock assessment models and has been estimated for different fleets, pot types, and areas. Temporal changes in size selectivity can lead to biased model results and can bias parameter estimates, such as pre-recruit indices (PRIs). These biases can manifest as trends that are unrelated to changes in the population characteristic they are designed to monitor. Several mechanisms for changes to size selectivity have created particular concern due to their potential to influence management decisions.

Firstly, in some areas southern rock lobster stocks are increasing significantly and are expected to continue to do so. One way in which these elevated densities may affect selectivity is if large lobsters deter small lobsters from entering pots, thus lowering the estimated PRI (an index used in TACC setting in Victoria)

Secondly, increased price differential between lobster size classes coupled with high CPUE is creating substantial incentives for high grading, both through discards and through changing fishing practices targeting different sized lobsters.

Lastly, seasonal changes in size selectivity have been observed in South Australia and may occur elsewhere. These have not been quantified and may occur in other regions.

Understanding these changes in size selectivity and mitigating the impact on the ongoing stock assessment modelling and harvest strategies will ensure robust assessments and avoid future management bias.