Annual losses of up to 10% of lobsters during live transport are not uncommon and have a major financial impact. The fishing industry, including processors and operators are seeking ways to avoid this mortality. As deep-water pale lobsters are more susceptible to this mortality, this project will examine their wild physiological condition in great detail and compare it to shallow-water red lobsters.
Mortality events occur mainly around the time of season openings in Mid November so this will the period targeted in this research. Price often falls sharply at this time because of the combined effect of increase in supply and damage to market reputation that occurs when impacted shipments are received. Managing the landing of poor quality lobsters has always been difficult because longer closed seasons would prevent landing of poor quality product but also harms businesses.
Ideally the problem of lobster mortality in shipment would be managed by keeping the fishery open for extended periods but only landing lobsters when their condition is acceptable. The fishery tends to do this on a crude level by discounting the price of pale lobster. However this is not ideal because it impacts the price of some catches of pale lobsters that are good condition, and also allows the shipment of some red lobsters of poor condition. Directly measuring condition is a step towards better management of this issue.
Final report
This project provides the first comprehensive quantitative assessment of the health, physiological and nutritional condition of brindle and red lobsters from four different fishing areas of Tasmania at the start of the 2015 fishing season. Lobsters size (carapace length), baseline concentrations of haemolymph haemocyanin and bicarbonate were shown to be useful predictors of vulnerability to transport.
This information may help improve the management of these lobsters especially if portable meters are used in the field or test kits are developed through future R&D. Recommendations to minimise mortality risk were also made which included ensuring lobsters have recovered from the ground transport stress in holding tanks for several days, minimising emersion duration and reducing temperature prior to packaging.
