Energy Dynamics of Two Benthic Crustaceans in Relation to Diet

Abstract

Energy dynamics were studied in Asellus racovitzai (Crustacea: Isopoda) and Gammarus fasciatus (Crustacea: Amphipoda) fed various selected algal species (Cyanophyta — Oscillatoria sp., Anabaena flos-aquae, Anacystis nidulans, Microcystis aeruginosa; Chorophyta — Chlorella ellipsoidea, Scenedesmus dimorphus, Ankistrodesmus falcatus) and lake sediments. Calculations of growth, production, assimilation, and growth efficiency were made from measurements of weight change, respiration rate, and caloric content of experimental animals. Although growth rate, production, and growth efficiency were often highest in animals fed green algae, differences were not attributable solely to green vs. blue-green taxonomic groups. The relationship between assimilation rate and growth efficiency was examined, and the possible consequences of lower values of assimilation were discussed in terms of delayed development to maturity and reproduction.