Influence of activity in a heterogeneous environment on the dynamics of fish growth: an individual-based model of roacl |
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Authors: | F Hölker †§ B Breckling ‡ |
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Institution: | Leibniz-Institute of Freshwater Ecology and Inland Fisheries, D-12587 Berlin, Germany;Institute of Hydrobiology and Fishery Science, D-22767 Hamburg, Germany;Ecology Department UFT, University of Bremen, D-28334 Bremen, Germany |
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Abstract: | A spatio-temporal individual-based model (IBM), including bioenergetic principles, is used to investigate how energy costs coupled to activity represent a variable fraction in a heterogeneous environment and how this is related to another energetic criterion, the potential individual growth, under the conditions of a structured environment. With this approach, it is possible to connect simulated spatio-temporal activity patterns with the energetic needs required for these activities. By using simple foraging rules and a modified random walk model it is possible to reproduce spatial distributions and length frequency distributions. The simulated spatial distribution of roach Rutilus rutilus in Lake Belau, Germany, results in a mean weekly activity multiplier (standard metabolic rate + activity costs) (standard metabolic rate)−1] of 1–9 with deviations >100% during a simulated year. These deviations are of key importance to differences in the growth rate of individual simulated roach. |
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Keywords: | IBM spatiotemporal activity bioenergetics phenotypic variability Rutilus |
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