Project number:
2016-235
Project Status:
Completed
Budget expenditure:
$663,818.43
Principal Investigator:
Quinn P. Fitzgibbon
Organisation:
University of Tasmania (UTAS)
Project start/end date:
31 Oct 2016
-
31 Oct 2018
Contact:
FRDC
SPECIES
The export of southern rock lobsters from southern Australia to markets in Asia is one of Australia’s most valuable fisheries and currently accounts for approximately 3500-4000 tonnes with a gross revenue of approximately AUD200 million. The export industry is an important component of the market supply chain as it provides the link between fisheries and the international markets. The ability to maintain or hold lobsters for extended periods is imperative for the industry to capitalize on fluctuating market demand and gain maximum return for the fishery product. During the 2016 season, levels of pre-export mortality has been severe with losses in the hundreds of $1000’s reported by several exporting companies. Industry have been forced to change operating practices and on-sell lobsters soon after landing placing further strain on revenue. High levels of post-export mortality have also been described by purchasers which is damaging to the Australian Southern Rock Lobster brand. This damage has been reported to have already resulted in a significant drop in the international price for Australian lobsters which combined with losses due to mortality is placing significant strain on the viability of the Australian lobster export industry. It is feared that continual poor performance of exported live lobsters will trigger key Asian markets to place a moratorium on the Australian product that could jeopardize the entire fishing industry. Considering the severity and widespread nature of this event and in depth and concerted effort is warranted to determine the cause of the mortality and to develop strategies to minimize its impact in future fishery seasons.
1. Undertake an epidemiological investigation to describe the magnitude of the event and to identify potential environmental and management risk factor(s) associated with increased mortality
2. Examine the underlying physiological processes or mechanisms resulting in lobster mortality and potential links with marine biotoxins
3. Full review of the pathology from both the Tasmanian and South Australian mortality events during the 2016 season as well as further characterisation of any significant pathologies (e.g. antennule gland changes) observed in these investigations as well as further pathological investigations for the 2017 season.
Final report
ISBN:
978-1-925646-81-8
Authors:
Quinn P. Fitzgibbon
Charles Caraguel
Stephen B. Pyecroft
Caleb Gardner
Ryan Day
Kandarp Patel
Johanna J. Mahadevan
Final Report
•
2020-02-26
•
25.84 MB
2016-235-DLD.pdf
This report details the results of a multifaceted research program led by the Institute for Marine & Antarctic Studies, University of Tasmania in collaboration with the School of Animal and Veterinary Sciences, The University of Adelaide. The work was undertaken to better evaluate post-harvest mortality of Southern Rock lobster (SRL) and investigate tools and processes to improve lobster holding within the SRL processing and exporting industry sector. The research was conducted to investigate a recent apparent increase in post-harvest mortality of SRL across the entire SRL industry sector in Tasmania, South Australia and Victoria. The research program was comprised of dedicated investigations of the physiology and pathology of moribund lobsters and the epidemiology (or patterns and associated factors) of lobster mortality across the industry sector and within case facilities. Complimentary research was conducted to inform and educate industry on “best practices” for post-harvest maintenance of live SRL and to develop practical extension tools to determine quality and vitality of captive SRL stock.
Collectively, the physiological and pathological investigations did not support the systematic association of a detectable crustacean pathogen with lower post-harvest SRL survival. However, a field survey suggested a limited holding capability in some exporting facilities leading to sub-standard stock survival and impacting commercial processes. Anecdotal reports from industry suggest an increased sensitivity of lobsters in recent seasons and the project hypothesis is that the animals are experiencing reduced holding capacity and increased mortality rates post capture as a result higher physiological stress, reduced immune function and then overwhelming infections with secondary bacteria or loss of physiological maintenance leading to death. However, further investigations, particularly on the role of potential unknown viral pathogens, is required to completely rule-out an infectious aetiology.
The cause for the apparent sensitivity remains unclear, which could be related with environmental stress, such as increasing water temperatures. The south east coast of Australia has been identified as an ocean warming hotspot. The impact of this environmental change on SRL physiology currently remains unclear and should form the basis of future research. The project is particularly concerned that environmental change may be impacting lobster moult cycles resulting in weak pre- and post-moult lobsters being landed during the fishing season. Currently there are no practical and accurate methods available for industry to identify pre- and post-moult lobsters. The project strongly recommends that improved tools for the assessment of lobster moult cycle and stress condition are developed and made available to industry stakeholders across the entire post-harvest chain of custody.
Investigation revealed considerable differences in industry live lobster management practices and apparent levels of mortality across the sector. These findings suggest a role of post-harvest practices for improving lobster performance in holding. Physiological and epidemiological investigation particularly highlight the potential for transport related emersion, stocking practices and sub-optimal physicochemical water quality (particularly low pH) to impact SRL mortality in holding. Mortality appears most severe during the warmer months during summer likely due to the heightened metabolic demands of lobsters associated with higher temperatures. The project strongly recommends that the Australian SRL industry focusses dedicated effort towards optimising post-harvest practices from wild capture to international export.
The project has taken significant steps towards facilitating improved industry practice through:
- Initial validation of improved lobster quality assessment tools, handheld lactate meter
- Assessment of water quality measurement tools
- Industry education on best practices through industry workshops
- The development of an SRL processors industry best practice guide
- Development and validation of new immune function assays for SRL
- Development of SRL haemolymph biochemical profiling capacity in Australia
- Development of an SRL health assessment procedure manual
In conclusion, the SRL industry is in a period of change and the industry must adapt to this change. The industry is changing in terms of its business model, political atmosphere and physical environment, all of which heighten the requirement for optimal post-harvest processes. The increased value of lobsters and reliance on live export has meant that even low levels of stock losses can have significant financial or SRL brand consequences. The political atmosphere is changing as consumer perceptions on the health and welfare of lobsters is increasingly becoming an important marketing issue. Finally, SRL exists in a global warming hot spot which appears to be placing new challenges for appropriate post-harvest processes. It is clear that the ultimate outcome for a lobster is dependent on the sum of its experiences through the entire post-harvest chain of custody. This project has focused on practices by the processing and holding industry sector. For optimum performance of SRL from capture to market, requires further research on other aspects of post-harvest processes, including the fishing industry and post export maintenance sectors.
Anecdotal evidence suggests the industry has accepted the need for improve industry practices and several companies have made efforts to improve operations. Feedback from industry suggests that levels of mortalities across the sector have reduced in recent seasons which may be because of these improved maintenance practices. Attached to this final report is an impact statement from one of Australia’s largest SRL processors and export companies which details how the company pro-actively acted on project findings/recommendations and implemented numerous changes to company practices. In the most recent 2018-19 season, this company has experienced a 50% reduction in mortality that may be attributed to these improved practices. A 50% reduction to mortality loss across the industry sector represents a FRDC return for investment of 3-fold in just a single year and 30-fold over a decade.
Recommendations
The project findings suggest a need for improved industry practices, particularly in the key areas of:
- Post capture transport, particularly on land dry transport procedures
- Post transport recovery and purging procedures
- Holding facility aquaculture systems
- Water quality monitoring and maintenance
- Live lobster handling procedures
- Data collection and stock traceability
- Stock quality assessments
Details regarding these recommendations are provided in this report and to industry within the “Best Practice” guide.
The project gathered feedback from industry members about industry concerns and future research priorities. The project identified 19 knowledge gaps or potential future research priorities regarding best post-harvest practice for live SRL. Written feedback on priority ranking of these research priorities were received from industry participants. Based on this feedback the top ranked future research priority for the post-harvest maintenance of live SRL was:
- The development of improved tools and validation of condition/vitality assessments and relationship to survivability during holding, including Brix, lactate meter, reflex responses
Further to the ranked priorities, another priority which was not ranked at the industry workshop but was brought up by industry participants as a high priority was:
- The assessment and refinement of on-vessel handling and maintenance processes to improve post capture lobster condition/vitality/survivability
The project supports these two research priorities as they extend best practice across the entire chain of post-harvest custody from capture to export and will result in tools that will inform fisherman and processors on the quality of the stock and suitability of maintenance practices. We consider the next most important research priority would be the development of improved transport technologies and procedure to limit emersion stress on lobsters.
