Project number: 2014-218
Project Status:
Budget expenditure: $122,405.00
Principal Investigator: John L. Mayze
Organisation: Department of Agriculture and Fisheries EcoScience Precinct
Project start/end date: 11 Jun 2014 - 24 May 2016


Variability’s and inconsistencies in the application of the thumb pressure grading technique and regional and seasonal anomalies have led to some discontent with the Australian Industry Live Mud Crab Grading Scheme (AILMCGS).
The AILMCGS provides a range of physical attributes, along with a subjective assessment of shell-hardness to provide consistency in live mud crab grading on a national scale. Consistent grading gives buyers and consumers a product that defines price paid. Concerns have been raised that incorrect application of the scheme can be used to manipulate price at various stages of the supply chain.
Due to variables of lifecycle, seasonality, regionality, habitat, individual grader and grading techniques, it can never be a 100% guarantee of meat content associated with the given grade.
It is implicit to the scheme to apply pressure in a precise and readily reproducible way to minimise variations and damage to and loss of product. There has long been a widespread call from industry, including from members that are both satisfied and disgruntled with the current scheme, to have an objective method to determine crab quality. This relies on clear and precise testing protocols. The realities of the operation of this industry are that the use of hand testing is the ‘tool’ of choice and practicality at this stage.
Developing a science-supported assessment technique will standardise grading and allow for any seasonal and/or regional anomalies to be addressed. Ultimately, there is a need for a cost effective, practical on-board objective tool to provide assured grading standards.


1. attain a defined and precise assessment method of shell hardness using the current Australian Industry Live Mud Crab Grading Scheme (AILMCGS) across whole of industry
2. identify objective technologies and/or develop methodologies to support grading assessment within the AILMCGS
3. substantiate seasonal and/or regional grading anomalies within the AILMCGS and explore strategies to address them
4. increase profitability across industry through equity of grading practices and reduced product down grades and wastage

Final report

ISBN: 978 0 7345 0454 8
Author: John Mayze

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