An end-to-end model framework for understanding and predicting changes in Antarctic marine ecosystems

East Antarctic food webs support a diverse array of predators such as penguins and whales feeding on mesozooplankton, krill, and fish. We introduce the structure and evaluation process of an end-to-end Atlantis ecosystem model for East Antarctica (East Antarctic Atlantis Model, EAAM), the first whole-of-ecosystem model within the Southern Ocean. The EAAM is intended as a simulation tool to support decision-making for marine ecosystem management. A wide range of information ranging from literature to satellite data were harnessed to parametrise EAAM physical, biogeochemical, and ecological variables and forcings. The calibrated model was run for one hundred years, of which half were treated as a “spin-up” period. We tested its performance across a suite of criteria spanning important spatial and temporal characteristics of the ecosystem. The EAAM captured seasonal and interannual patterns in primary production and mesozooplankton abundance reflected in the consumption and population dynamics of predators. Within prey groups, mesozooplankton dominated in terms of biomass and were prevalent in the diet of higher trophic levels. Krill biomass fluctuated on a timescale of 5–7 years, a pattern supported by empirical observations, and influenced the biomass of its predators. Going forwards, the EAAM should be a valuable tool for exploring human pressures and scenarios of climate change, an urgent priority given the rate of change already evident in Southern Ocean systems. Model uncertainties can also be effectively used to direct future observation and data collection efforts.