This dataset contains the supplementary data and code accompanying the publication: Ward, D., Hill, N., Melbourne-Thomas, J., Welsford, D., Arangio, R., McNeill, M., Wotherspoon, S., Ziegler, P., Corney, S. (2025) Exploring mechanisms of change in a Southern Ocean fishery with a co-produced network model, ICES Journal of Marine Science. The study aimed to elucidate likely responses of the system to change, and mechanisms by which environmental, ecological or fishery behavioural changes could affect catch rates and toothfish stocks in the Heard and McDonald Islands (HIMI) fishing area. In the study, we co-developed a set of 128 qualitative network models of the Heard and McDonald Islands (HIMI) Patagonian toothfish fishery–stock–ecosystem interactions system with knowledge holders from industry and science. These different model versions capture different possible configurations of interactions for which the sign of the effects (positive or negative) are unknown. For each model versions, we simulated 10,000 quantitative instances of the qualitative model. We analysed these model outputs to understand 1) mean qualitative responses of system components (nodes) in 8 test scenarios (press increases in environmental, fishery, or ecosystem nodes); 2) how ‘unknown’ effect signs affected qualitative responses of key nodes to change; and 3) relationships between responses and the strength of effects originating from nodes being perturbed. Please refer to Ward et al. (2025) for more detailed description of the methodology and findings, and the README file for description of data and code contained in this repository.

The demersal fish assemblages on the Kerguelen Plateau has changed through time. This study aimed to detect, quantify, and map these changes. This study uses existing data collected from the Random Stratified Trawl Survey (RSTS) program administered through the Australian Antarctic Divisions (AAD). Raw RSTS data between 2000 and 2016 was extracted from the AAD database. The RSTS data contains information on the abundance (catch per unit effort, CPUE) on fish. RSTS data were paired with environmental data to be modelled. Hierarchical models of species communities (HMSC) were used to make inferences and predictions in the changes of demersal fish distribution. This record contains all the environmental data, R code, and outputs from this project. Raw RSTS data needs to be requested from the AAD under the authorization of AFMA.

Climate change is already influencing the worlds oceans. The Kerguelen Plateau as been identified as a climate change hotspot. This study aimed to predict and map how climate change will impact the distribution of demersal fishes. This study uses the published modeled (see https://doi.org/10.25959/4GVK-RM21) to take in predicted oceanographic variables under various IPCC climate change predictions. The oceanographic variables are provided by the FESOM model. Hierarchical models of species communities (HMSC) were used to make predictions in the demersal fish distribution for the 2020s, 2030s, 2040s, and 2050s. Predictions were mapped to explore the regions of change. This record contains all the environmental data, R code, and outputs from this project. Raw RSTS data needs to be requested from the AAD under the authorization of AFMA.