Monitoring and assessment
Four projects will improve the monitoring and assessment of Snapper stocks (research theme 3) and will contribute to the 2025 Snapper Stock Assessment – see Snapper management. This will include:
- the collection of biological samples of Snapper from throughout South Australia which will be used in multiple projects of the Snapper Science Program
- fishery-independent estimates of biomass
- improved estimates of recreational catches.
Biological sampling program
Project ongoing
The biological sampling program involves collaboration between industry and researchers to collect snapper samples from all South Australian waters. This information is used to monitor the characteristics of Snapper populations and provides samples (for example: otoliths and tissue) that are used in multiple projects of the Snapper Science Program.
Since 2000, a weekly market sampling program has been undertaken by SARDI researchers to provide biological data for Snapper caught by commercial Marine Scalefish Fishery (MSF) fishers in South Australia. The catches are primarily accessed through the SAFCOL fish market in Adelaide and augmented with targeted trips to regional areas. This was the primary source of biological data for Snapper and included information about length, weight, age, sex, and reproductive condition.
The closure of the Spencer Gulf / West Coast and Gulf St Vincent stocks since November 2019 prevented the collection of biological information from fishery catches. To overcome this, a targeted sampling program was implemented to collect representative samples and continue the annual time series of biological data. This involved contracting commercial MSF fishers to collect samples of Snapper from these regions, who operated under a Ministerial Exemption with a SARDI observer present. The fish sampled were processed at local fish processing facilities, and the fillets donated to FoodBank, Australia's largest food relief organisation, who distributed them to meet community needs.
The biological sampling program began in January 2020 and will continue throughout the fishery closure.
Fishery-independent estimate of biomass
Project in development
A fishery-independent estimate of biomass has become an essential component of stock assessment for Snapper in South Australia. Over the past decade, the spawning biomass of Snapper in Spencer Gulf and Gulf St Vincent has been estimated using the daily egg production method (DEPM).
This project will provide a fishery-independent estimate of biomass in summer 2024–25 that will be incorporated into the 2025 Snapper Stock Assessment. The method to be used will be informed by the results of projects on estimates of biomass.
Recreational catch reporting tool
Project in development
An understanding of catches taken by each sector is required to effectively monitor and assess Snapper population trends. As such, there is a need to generate estimates of catch and effort for the recreational sector that can be incorporated and used to inform decision making for the next fishery stock assessment. This data is also required to monitor recreational catch against the allocated shares prescribed under the Management Plan for the South Australian Commercial Marine Scalefish Fishery.
The project aims to improve the quality and reliability of data for the recreational sector and promote standardisation in reporting practices. The project will build on the outcomes of 'Developing a smart-phone application to record recreational catches' (FRDC project 2020-056) to further develop and improve the current SA Fishing app and progress recreational reporting.
Stock assessment report
Project commences September 2024
The next Snapper stock assessment in South Australia will be delivered in November 2025. This will involve a fully integrated assessment that represents a culmination of current approaches and incorporates learnings from the Snapper Science Program. The assessment will apply a weight-of-evidence approach to evaluate stock status using multiple datasets, including:
- fishery statistics from the South East region
- regional length and age structures
- fishery-independent estimates of biomass
- recent trends in juvenile Snapper recruitment
- outputs from stock assessment model
- stock status assigned following the National Fishery Status Reporting Framework.
The current fishery closures for the Spencer Gulf / West Coast and Gulf St Vincent stocks will be reviewed following the delivery of the Stock Assessment Report.
