Parameterising a generic model for the dynamic energy budget of Antarctic krill Euphausia superba

Abstract

Dynamic Energy Budget (DEB) theory is a generic and comprehensive framework for understanding bioenergetics over the entire life cycle of an organism. Here, we apply a simplified model derived from this theory (DEBkiss) to Antarctic krill Euphausia superba. The model was parameterised using growth curves, and conversion factors for body composition and length-weight relationships. Subsequently, the model was used to predict a series of life-history traits (as function of body size) that were not used for parameterisation: instantaneous growth rates, ingestion and respiration rates, weight loss on starvation, and the number of eggs produced at spawning. Within the DEB framework, these traits are not intrinsic properties of the organism, but tightly coupled model outputs that depend on body size, life stage, and environmental conditions. Overall, the model predictions are consistent with the patterns in the (rather uncertain) observations, lending credence to the model assumptions underlying the DEBkiss model. More work is needed to fully elucidate the bioenergetics of the E. superba life cycle, but this analysis demonstrates how a dynamic budgeting framework can ensure consistency among the different life-history traits. Thereby, such models help in the interpretation of experimental results and the comparison of species, but can also form the basis for predicting population dynamics and the impacts of stressors.