2 results
Industry
PROJECT NUMBER • 2002-239
PROJECT STATUS:
COMPLETED

Rock Lobster Post Harvest Subprogram: the effect of on-board cold water stunning on the survival and growth of caught and returned western rock lobsters (Panulirus cygnus)

The relative recapture rates of returned stunned and unstunned lobsters have been quantified. Apparently conflicting results were obtained from two different areas of the fishery, but the results were deemed inconclusive due to low numbers of recaptures from water surrounding the Southern Group of...
ORGANISATION:
Geraldton Fishermen's Co-operative Ltd
TAGS
Tagging
Sustainability
Post Harvest
Fisheries Management
Bycatch

Rock Lobster Post Harvest Subprogram: quantifying and controlling hyper- and hyposaline-induced post-harvest leg autotomy in the western rock lobster

Project number: 2001-255
Project Status:
Completed
Budget expenditure: $47,626.00
Principal Investigator: Glen A. Davidson
Organisation: Geraldton Fishermen's Co-operative Ltd
Project start/end date: 29 Jun 2002 - 16 Jan 2005
Contact:
FRDC
TAGS
Resource Access And Allocation
Post Harvest
Invasive Species
Fisheries Management
Disease
SPECIES
Western Rock Lobster

Need

Post-harvest leg loss has been identified by many major stakeholders as a major and costly problem for the western rock lobster industry. FRDC project 2000/251 has developed a method for reliably inducing autotomy through the application of hypersaline seawater. Preliminary investigations show that concentrated seawater capable of inducing this phenomenon may be widespread throughout the industry, and lobsters may come into contact with this water regularly and throughout the handling chain. Further investigations into the extent and nature of this problem and development of solutions are beyond the scope and resources of FRDC project 2000/251. International literature searches reveal that there are no published accounts of similar phenomena in other crustacea.

Objectives

1. Survey salinity concentrations of surface films on individual lobsters and on relevant contact surfaces on boats and within factories
2. Describe the relationship between autotomy and exposure to seawater of various salinities for lobsters of various sizes and moult stages
3. Quantify leg loss during industry standard freshwater “drowning” procedures
4. Investigate the relationship between daily environmental conditions and levels of post-harvest leg loss
5. Field-test practical solutions for hyper/hyposaline-induced autotomy and make recommendations to industry

Final report

ISBN: 0-9757298-1-0
Author: Dr. Glen W. Davidson and Wayne W. Hosking
Final Report • 2005-06-01 • 656.99 KB
2001-255-DLD.pdf

Summary

The previously undescribed phenomenon of hypersaline-induced autotomy in western rock lobsters has been fully characterised. The extent of occurrence of hypersaline films throughout the post-harvest chain has been examined and found to be significant. Environmental factors contributing to the phenomenon have been investigated.

Appreciable leg loss has been shown to occur during industry standard freshwater “drowning”.

Washing of contact surfaces and cold-stunning have been shown to be effective methods for preventing hypersaline-induced autotomy and leg loss during drowning, with the potential to save the industry six figure sums each year by reducing loss of catch weight and downgrading of damaged lobsters.

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