Drewes et al. (2025)
The aim of our IBM is to simulate the impact of changing extrinsic factors on the development of early life stages of the European smelt (Osmerus eperlanus). The provided code is the 1D – single individual – version used in the validation process that was published in Drewes et al. (2025).
The model covers three life stages, two under endogenous feeding conditions (egg and yolk-sac individuals) and the exogenous feeding larvae. Throughout the endogenous life stages, development solely depends on the provided water temperature. During the exogenous feeding, larval growth is defined via an energy conservation approach following the Wisconsin Energy Conservation model for early marine life stages (Kitchell et al. 1974). The calculation of successful prey encounters leading to the total amount of consumption is based on the ideas for sprat described in (Daewel et al. 2008). Overfeeding is prevented by the implementation of a maximum daily consumption that was calculated based on the individual size and extrinsic conditions. The individual’s mortality is described via a superindividual approach (Scheffer et al. 1995).
Extrinsic forcing for this version of the IBM can be described as constant values,
value ranges or using realistic observation or model based timeseries. The nominal values for intrinsic parameters are further provided. Values are given with respect to the finally tuned version that was published in Drewes et al. (2025).
Matlab code of this model is available as Zenodo repository:
https://doi.org/10.5281/zenodo.16421799
Drewes D, Schrum C, Pein J et al. Environmental controls on the development of early life stages of European smelt in the Elbe estuary. Ecol Modell 2025;510:111313. doi: doi.org/10.1016/j.ecolmodel.2025.111313
The calculation of successful prey encounters leading to the total amount of consumption is based on the ideas for sprat described in Daewel et al. (2008)
Daewel U, Peck MA, Kühn W et al. Coupling ecosystem and individual-based models to simulate the influence of environmental variability on potential growth and survival of larval sprat (Sprattus sprattus L.) in the North Sea. Fish Oceanogr 2008;17:333–51. doi: 10.1111/j.1365-2419.2008.00482.x
- In this version, the IBM cannot simulate lateral advection as only a 1D representation of the individual development over time based on the extrinsic forcing is calculated
- After reaching a length of 25 mm we decided to end our simulations – at this length larvae developed extensive swimming capacities and it is possible that our energy balance approach would need to be revised for such larger individuals