Project number: 2004-057
Project Status:
Budget expenditure: $233,684.00
Principal Investigator: Ian Potter
Organisation: Murdoch University
Project start/end date: 29 Jun 2004 - 1 Mar 2008


Successful management of a fishery for any species requires a thorough understanding of how that species will respond to different levels of exploitation. Such an understanding depends on managers possessing certain crucial biological data that have been acquired using an appropriate sampling regime, laboratory techniques and analysis of the results. The key biological data that are required for a species are as follows: (a) age and size compositions, growth curves and age and length at maturity for both sexes, (b) length and age at sex change in the case of hermaphroditic species, (c) location and duration of spawning, (d) fecundity and (e) estimates of mortality. These data enable scientists to assess the status of the stock(s) and thereby provide advice to managers, who are then in a strong position to formulate appropriate management strategies.

The following three species have been identified as “indicator” species for management purposes: western blue groper Achoerodus gouldii, queen snapper Nemadactylus valenciennesi and bar-tailed flathead Platycephalus endrachtensis (Fisheries Management Paper 153; Report of 2003 RFAC/RecFishWest research planning meeting). However, there are no reliable data on the crucial biological characteristics listed above for any of these species in Western Australian waters (e.g. FishBase). Managers thus require these data for management purposes.

Since the results of many of the age and growth studies of fish species in various regions are not of the standard required to produce reliable data for management purposes, there is a need to produce guidelines on the extent and quality that are required of such studies for management purposes.


1. Determine the size and age compositions, growth, reproduction and mortality of western blue groper Achoerodus gouldii, queen snapper Nemadactylus valenciennesi and the bar-tailed flathead Platycephalus endrachtensis.
2. Supply the above data to the Department of Fisheries, Western Australia, in a format that can readily be used for management purposes.
3. Use the results of the above studies to highlight the essential elements of age and growth studies that will produce data of the required quality for management.

Final report

ISBN: 978-0-86905-932-6
Author: Ian Potter

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