Project number: 2017-048
Project Status:
Budget expenditure: $739,957.00
Principal Investigator: Tony J. Courtney
Organisation: Department of Agriculture and Fisheries EcoScience Precinct
Project start/end date: 31 Aug 2017 - 30 Dec 2019


There is a strong need to improve the Queensland scallop stock assessment. This will be achieved by undertaking a fishery-independent survey of the stock and by deriving improved mortality rate estimates (F and M) used in the quantitative stock modelling.

There is a strong need to better understand the relationship between abundance of 0+ and 1+ year old scallops and benthic habitat type. Classifying the scallop fishing grounds into habitat categories which receive varying levels of fishing effort will improve the precision of fishing mortality (F) estimates, as well as provide some understanding of possible impacts on the stock from the Gladstone Harbour dredge spoil ground. This will be achieved by obtaining measures of bottom hardness and sediment composition, and relating them to scallop abundance.

As most of the scallop fishery is located in waters of the GBRMP, which is a World Heritage Area, there is an obligation to ensure that biodiversity and ecosystem services within the Park are maintained. The project will address these needs by improving stock assessment advice on the scallop fishery.

Finally, there is a need to maintain the Wildlife Trade Operation approval which is required to export saucer scallops internationally. The project will help address the terms and conditions pertaining to sustainability of fishing the stock required by the Commonwealth Department of Environment and Energy to secure this approval.


1. Design and carry out a comprehensive fishery-independent survey of the 0+ and 1+ age classes in the Queensland saucer scallop fishery
2. Undertake exploratory analyses on the relationship between saucer scallop abundance and bottom substrate
3. Derive one or more tagging-based estimates of the saucer scallop's natural mortality rate (M)

Final report

ISBN: 978-0-7345-0467-8
Authors: A. Courtney J. Daniell S. French G. Leigh W.-H. Yang M. Campbell M. McLennan K. Baker T. Sweetland E. Woof R. Robinson I. Mizukami and E. Mulroy
Final Report • 2021-03-01 • 23.19 MB


This research was undertaken on the Queensland saucer scallop (Ylistrum balloti) fishery in southeast Queensland, which is an important component of the Queensland East Coast Otter Trawl Fishery (QECOTF). The research was undertaken by a collaborative team from the Queensland Department of Agriculture and Fisheries, James Cook University (JCU) and the Centre for Applications in Natural Resource Mathematics (CARM), University of Queensland and focused on 1) an annual fisheryindependent trawl survey of scallop abundance, 2) relationships between scallop abundance and physical properties of the seafloor, and 3) deriving an updated estimate of the scallop’s natural mortality rate. The scallop fishery used to be one of the state’s most valuable commercially fished stocks with the annual catch peak at just under 2000 t (adductor muscle meat-weight) in 1993 valued at about $30 million, but in recent years the stock has declined and is currently considered to be overfished. Results from the study are used to improve monitoring, stock assessment and management advice for the fishery.

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