Project number: 2002-004
Project Status:
Completed
Budget expenditure: $214,217.00
Principal Investigator: Ian Potter
Organisation: Murdoch University
Project start/end date: 29 Jun 2002 - 30 Mar 2006
Contact:
FRDC

Need

The progressive rise in the number of recreational fishers in Western Australia is increasing the fishing pressure on the most sought-after recreational fish species in this State. The potential thus exists for these species to become exploited at levels that exceed those that are sustainable. The absence of biological data for mulloway, an icon recreational species, and silver trevally, the third most frequently-caught recreational fish species, has meant that the existing and proposed regulations, that were aimed at conserving and managing the stocks of these very important species, were not based on appropriate biological criteria. There is thus a strong need to develop a sound database for these species, which encompasses such crucial features as size and age compositions, growth, length and age at first maturity, fecundity and the location and time of spawning. Since the sand trevally, which is also fished recreationally, is morphologically so similar to silver trevally that it is very frequently confused with this species, and indeed is currently considered collectively with this species for management purposes, there is a need to understand the significance of those differences that are likely to exist between the habitats and biology of these two species.

The urgent need to acquire biological data on mulloway and silver trevally to underpin management plans has been highlighted by both RFAC and RecFishWest.

Objectives

1. To obtain the biological data that are required by managers to develop plans to conserve the stocks of mulloway and silver trevally in Western Australia. This will thus require determining the following characteristics of both of these species:
2. Size and age compositions, growth rates and the sizes and ages at which maturity is first reached.
3. Locations and periods of spawning, and whether they are multiple spawners.
4. Batch fecundity.
5. Estimates of mortality.
6. To elucidate the patterns of distribution of the silver and sand trevally, and thereby determine the ways in which they differ.

Final report

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