Modeling the impacts of climate change on oceanic processes and fisheries: Upwelling systems as natural laboratories for understanding climate change impacts on marine ecosystems and fisheries

Presentation 2: Upwelling systems as natural laboratories for understanding climate change impacts on marine ecosystems and fisheries
Eastern Boundary Upwelling Systems (EBUS) are highly productive and highly variable ocean systems. Forage fish in EBUS represent some of the world’s most important fisheries resources, while playing a key role in the food-web as prey for other fish, seabirds and marine mammals. Understanding how the climate-driven variations and shifts in temperature, planktonic productivity, and oxygen conditions affect ecosystem functioning, fisheries yield, and fishing-dependent communities in EBUS can therefore help us to better understand the resilience of marine fisheries systems to climate change. This presentation will discuss process-based ecological models for the California Current (CaCu) and the Northern Humboldt Current (Peruvian) systems, which link fish population and food-web dynamics fitted to observations, to climate forcing from regional ocean-biogeochemical models and fisheries impacts. An age-structured Model of Intermediate Complexity (MICE) for the CaCu explicitly represents environmental driving of processes such as recruitment, food avail-ability, migration, and reproduction, using an ensemble approach to quantify ecological uncertainty. A spatial food-web model (Ecosim-Ecospace) for the Peruvian upwelling system captures environment-driven dynamics in fisheries resources, trophic interactions and regionally detailed socio-economic scenarios. Using future projections under regionally downscaled Earth system models, we assess climate-driven shifts in fish productivity, food-web interactions, spatial distributions, and fisheries over the 21st century. The presented models support ecosystem-based fisheries governance and the co-development of adaptation strategies to sustain blue food production under global change.

Webinar Presenter: Stefan Koenigstein studies marine ecosystems and fisheries, combining concepts and methods from ecology, ecophysiology, and the climate and sustainability sciences to investigate how marine living resources are shaped by environmental and ecosystem conditions, and impacted by fisheries and other anthropogenic pressures. Dr. Koenigstein uses ecological models as integrative tools to better understand system responses, feedbacks and possible future trajectories, incorporating observational and experimental data, regional ocean and earth system model output, and stakeholder input. A primary focus of the modeling is on increasing incorporation of biological processes and advancing quantification of uncertainty. Dr. Koenigstein aims to improve the potential of models for extrapolation into the future under multiple global change drivers, and support the co-development of scientific advice for ecosystem-based governance and adaptation.

Since 2025, Dr. Koenigstein has led the newly established Working Group Ecosystems and Resource Sustainability at Leibniz Centre for Tropical Marine Research in Bremen, Germany. Previously, Dr. Koenigstein was a Project Scientist at University of California Santa Cruz and NOAA Southwest Fisheries Science Center, working on multi-species population dynamic models for forage fish species in the California Current. He has worked in interdisciplinary research projects in Peru, Portugal and Norway, linking marine ecology to fisheries, with an additional focus on incorporating local stakeholder input. He has also led the development of an educational table-top/role-playing game for high schools and environmental education groups, teaching an understanding of ocean systems and their users (www.ocean-limited.com).

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