King threadfin stock assessment—Queensland Gulf of Carpentaria

2024 stock assessment

In 2024, Fisheries Queensland completed a stock assessment on king threadfin in the Gulf of Carpentaria using the most current biological data, and commercial and recreational catch data to:

• determine the sustainability of fish stocks
• inform management decisions
• inform the development of a harvest strategy.

In this assessment, 8 scenarios were run covering a range of modelling assumptions. Results indicated that the number of adult king threadfin (spawning biomass) was between 13% and 44% of unfished levels in the Gulf of Carpentaria at the start of 2023. The model estimated that at the start of 2023 there was 29% chance that the current biomass was below the limit reference point of B20 (20% of the unfished biomass in 1956).

Access the Stock assessment of king threadfin (Polydactylus macrochir) in the Gulf of Carpentaria, Queensland, Australia, with data to December 2022 report, as well as the independent review and the response to that review.

Previous reports:

• 2020 Stock assessment report, review and response to the review.

How was the stock assessment conducted?

The 2024 assessment was guided with from a project team that incorporated a wide range skill sets from managers, scientists, monitoring and data specialists from the Department of Agriculture and Fisheries and 3 industry representatives. The stock assessment project team operated under a terms of reference (PDF, 153.9KB) to ensure a transparent and evidence-based approach.

The assessment used model called Stock Synthesis, one of the most widely used and tested stock assessment models in the world and is currently used by CSIRO and other Australian fisheries jurisdictions.

As best practice, Fisheries Queensland contracted an independent external review of the king threadfin stock assessment. The reviewers, Dr Simon Hoyle and Alistair Dunn supported the conclusions of the stock assessment results and agreed that the assessment has been competently constructed and is suitable given the available data.

Biomass estimates and key management actions

Probability distribution of stock assessment estimated biomass for the beginning of 2023

Estimated retained catch from 1955 to 2022

Acknowledgements

We thank the project team for contributing their time and knowledge and engaging constructively over the course of a 16-month project.

We acknowledge the significant time commitment and deep operational and technical expertise of our industry representatives. The project has benefited greatly from their input. Future assessments should continue to engage with industry members to further enhance assessments and build collaboration between industry and government.