Gulf of Carpentaria King Threadfin (Polydactylus macrochir) - addressing the knowledge gaps to support assessment, management and sustainable harvest
The proposal addresses the key needs specified in FRDC investment opportunity on GoC KTF in an integrated manner, in consultation and collaboration with industry, by a team of people highly experienced in the science and logistical challenges of working in the GoC. The ‘Needs’ in the FRDC Call for R&D Investment Opportunities were (1) stock structure, including spatial and temporal connectivity between regions (i.e., movement and reproductive connectivity), (2) quantify life history information at regional scales relevant to stock assessment, and (3) factors influencing variation in the relationship between catch rate and population abundance.
The proposal addresses these knowledge gaps, which continue to bring uncertainty to the GoC KTF assessment and management. Further details are included in the Methods section.
It is critical that the inputs to the stock assessment, such as the spatial structure of the model, standardised catch rates, and life history parameters (e.g., temporal and spatial variation in growth rates, proportion mature-at-age, proportion mature-at-length) are representative of GoC stocks. Independent review of the latest KTF stock assessment (Campbell et al. 2024) concurs with this statement. Past research has included GoC samples of varying levels of spatial representativeness (Garrett et al. 1997; Welch et al. 2010; Newman et al. 2010; Moore et al. 2011; Moore et al. 2017) primarily due to due to logistical challenges. Despite the past research, there remains spatial and temporal uncertainty in how KTF populations function in this large tropical region, which has highly variable patterns in wet season rainfall and flood - the primary drivers of nutrient input to coastal GoC ecosystems.
