Testing zooplankton secondary production models against Daphnia magna growth

Abstract

Modelling secondary production rates in the zooplankton is essential for population ecology studies, but assessing these rates is difficult and rarely done. Here, five secondary production models are tested by measuring Daphnia magna growth. To provide a range of growth rates, Daphnia were cultured under three different nutrition regimes (yeast, cornflour, and phytoplankton). Length and biomass were monitored daily in three simple time-course experiments to provide the growth rates, which ranged from 0.11 to 0.30 d–1 with secondary production rates of 350–643 µg dry mass d−1. Secondary production was predicted best by the freshwater crustacean-based model of Stockwell and Johannsson (1997). Marine copepod-based marine models were totally unsuitable.