Fisheries Dynamics
Fisheries exemplify the challenges arising from the intricate dynamics and feedback loops between human behavior and the natural environment. Assessments of the status of a fishery rely on data on population variability over time and estimates of harvest rate and total catch. These data are used to understand the regulatory mechanisms underlying the relationship between fishing and population productivity. However, when fishing activity is illegal, unreported, and/or unregulated (IUU), traditional fisheries models can underestimate the vulnerability of fish stocks to collapse. There is a need, therefore, to develop general methods to incorporate information about human decisions regarding when and how much to fish, and rule compliance into population assessments. We developed novel approachs to model population demography of fished populations, incorporating ecological estimates of natural mortality, population censuses, and catch data that can inform estimates of reported and unreported fishing mortality. We consider four alternative modelling parameterizations that reflect real-world scenarios in which the degree of unreported fishing and the relationship between reporting rate and fish abundance differs. We show that ignoring IUU fishing can severely bias estimates of vital rates and population dynamics. Using social knowledge to account for IUU in model formulations can improve their predictive accuracy. We then applied our models to real-world examples, including community based management of Arapaima spp. in South America, commercial Flounder fisheries in the North Atlantic, and Walleye recreational angling in the Midwest.
Publications and Talks
Brooks, G. C., E. A. Hultin, E. Martins, L. Castello, and H. K. Kindsvater. in prep. Integrating unreported harvest information into ecological fisheries models.
Castello, L., A. Abreu, E. S. Brondizio, G. C. Brooks, S. J. Campos, P. Cunha, A. Fleischmann, C. Franco, E. A. Hultin, D. Hymans, H. K. Kindsvater, E. Martins, and M. Sorice. 2024. An approach to assess the integrated social-ecological dynamics of freshwater fisheries. Workshop on the Ostrom Workshop, Bloomington, Indiana, USA.
Hultin, E. A., G. C. Brooks, H. K. Kindsvater, and L. Castello. 2024. Predicting fishery sustainability with integrated socio-ecological models. Workshop on the Ostrom Workshop, Bloomington, Indiana, USA.
Hultin E. A., H. K. Kindsvater, G. C. Brooks, and L. Castello. 2024. Predicting population dynamics of Arapaima spp. from social and ecological variables. World Fisheries Conference, Seattle, WA, USA.
Hultin, E. A., G. C. Brooks, H. K. Kindsvater, and L. Castello. 2024. Identifying drivers of Arapaima population dynamics in a floodplain ecosystem. Southern Division American Fisheries Society Meeting, Chattanooga, TN, USA.