Fisheries long term monitoring program : summary of barramundi (Lates calcarifer) survey results : 2000-06

Abstract

The Long Term Monitoring Program (LTMP) for barramundi began in 2000 with fishery-dependent and fishery-independent surveys, which focused on investigating biological aspects of this species including age and length frequency distributions, length-weight relationships and sex ratios. Measuring these parameters annually provides important information about the dynamics of exploited barramundi populations on the major fishing grounds over time, and helps detect changes in the biology of the species not discernible from commercial catch and effort logbook data or recreational angler diaries.

This report is a summary of the data collected by the LTMP over the first seven years of the barramundi program. The summary report presents information on a range of biological characteristics of the fishery.

Results obtained from the surveys show:
• The Gulf of Carpentaria barramundi fishery is harvesting a narrower range of fish sizes compared to the Queensland east coast fishery.
• The Gulf of Carpentaria and the Queensland east coast barramundi fishery is highly reliant on a restricted set of age classes.
• Trends in the gender structure data collected in the Gulf of Carpentaria are now evident. The results from the surveys demonstrate that the younger and smaller the barramundi, the more likely it is to be a male fish.
• The length–weight relationships and age structures presented in this report are important input data for barramundi stock assessments (Hall et al. 2006).
The information presented may be incorporated into assessments of the barramundi stock and contributes to the annual status reports for the inshore fin fish fisheries. The data also help assess the performance of fishery management planning initiatives. This ongoing monitoring and reporting will help ensure that Queensland's barramundi resources are managed on a sustainable basis for maximum community benefit into the future.