Feeding, growth, and fecundity of Capitella sp. I in relation to sediment organic concentration

In marine soft-bottom benthic habitats, the disappearance of opportunistic species as succession proceeds following an enrichment or disturbance event is thought to be due to the exhaustion of a food resource. To further investigate this hypothesis, feeding rate, growth rate, and reproductive output (measured as embryo number and size) of the opportunistic deposit-feeding polychaete Capitella sp. I were measured in sediments with different protein concentrations but the same protein source. Feeding rates progressively increased as protein concentration increased over the range of 0.2 to 4.7 mg g super(-1); thereafter, feeding rate was constant up to a sediment protein concentration of 8.1 mg g super(-1), the highest used in these experiments. This response is not consistent with the predictions of optimal foraging theory, as applied to deposit feeders. Growth rate showed a similar pattern, progressively increasing then reaching a plateau at similar to 23% d super(-1) in sediments with 4.6 to 4.7 mg protein g super(-1). Capitella sp. I showed decreased fecundity and longer generation times (embryo sizes were not significantly different) in sediments with lower protein concentrations and did not reproduce in sediments containing