Multi-Level rule-based modelling of eastern Baltic Cod bioenergetics and species-habitat interactions
Despite extensive research in the past ICES scientist are currently not able to conclusively explain the ecological interrelationships which drive the current changes in the eastern Baltic cod stock. Equation-based macro-models do not deliver useful insights since they are not able to adequately depict the underlying physiological processes of cod. Therefore the aim of this project is the development of an agent-based multi-level model of the bioenergetics and behaviour of cod as well as of the hydrography of the Bornholm-Basin and the relevant aspects of its prey. Ultimately, the model developed in this project shall serve scientists from the fields of fishery biology and fish physiology as a simulation tool for academic research.
Established equation-based macro-models currently do not deliver reliable predictions on stock biomass and on the state of the stock. Hypotheses on possible mechanisms which may explain, e.g. the increased occurrence of “meager-cod” (food shortage, hypoxia effects) and the lack of larger cod (fisheries, increase of natural mortality) can currently not be tested. At the time when changes in the stock occurred (approximately since 2010) no relevant experiments where conducted. The environmental conditions at that time cannot be replicated and the cod of that time have since died or are no longer in the condition they were then.
Since biological samples of ecological systems cannot be collected retrospectively, ecological hypotheses which pertain to the past can only be investigated with the aid of computer models. Such models however have to adequately and flexibly represent the dynamics of complex ecological systems at different scales, and yet remain clearly readable at the same time. The modelling language ML-Rules (originally developed for the modelling of cell-biological systems) appears promising in meeting these high demands and thus shall be used as a basis for our research.
The model will be developed as a set of submodels which depict separate aspects of the ecological system. Here, among others, habitat and behaviour of cod as well as its prey and bioenergetics in the Baltic Sea environment will be addressed. Due to the rule-based approach, each submodel can be developed and validated individually and the complete model can subsequently be used in its entirety.
8.2016 - 12.2020
Project status: ongoing