A bioenergetic growth model for Western Baltic cod

Here we present a bioenergetic growth model for Western Baltic cod (WBC) in the Belt Sea (ICES SD22) developed for the statistical and programming environment R. The model predicts yearly growth of cod for the age classes two to four and can be run for the period from 1979 to 2018. The model incorporates environmental data obtained from the Baltic Sea Ice Ocean model and contemporary gained process knowledge on temperature related WBC spatio-temporal distribution and food intake.

The model can be used to track growth changes in WBC over time, but also to investigate the detrimental effects of warming on the growth of WBC as shown in Funk et al. (2023).

Hamburg University, Helmholtz-Center GEOMAR, Thünen Institute for Baltic Fisheries, balt_ADAPT
Model code


Abbildung 311-western cod

© Steffen Funk, UHH

Set-up of the individual-based bioenergetic growth model.

(a) Schematic representation of important model components and their influence on growth:
(1) temperature conditions (SST and TDiff, see material and methods)
(2) temperature at residence depth,
(3) food availability and related food intake,
(4) physiological processes and
(5) growth in length.

(b) Functional pathways (arrows) within the bioenergetic model:
rectangles denote temperature variables (SST and TDiff),
diamonds denote estimates derived from sub-models I–III;
grey ellipses indicate estimates based on published physiological functions;
hexagons display cod individual length and weight.
i—time step, j—size.

Figure was taken from Funk et al. 2023