Aggregation in ecosystem models and model stability

- Bering Sea ecosystem models with different methods of grouping components were compared.
- Simplification of large model allows a better qualitative study of the ecosystem.
- Food web aggregation enables the effect of model structure on system dynamics to be evaluated.
- Benthic fish aggregation has less effect on system behavior than pelagic fish aggregation.
- The model reduction and the aggregation of pelagic fish led to the stable system dynamics.

Using a multimodal approach to research ecosystems improves usage of available information on an object. This study presents several models of the Bering Sea ecosystem. The ecosystem is considered as a closed object, that is, the influence of the environment is not provided. We then add the links with the external medium in the models. The models differ in terms of the degree and method of grouping components. Our method is based on the differences in habitat and food source of groups, which allows us to determine the grouping of species with a greater effect on system dynamics. In particular, we determine whether benthic fish aggregation or pelagic fish aggregation can change the consumption structure of some groups of species, and consequently, the behavior of the entire model system.