Growth and reproduction in bivalves; an energy budget approach

Cardoso, Joana Ferreira Marques Ferreira
Growth and reproduction in bivalves; an energy budget approach
PhD-thesis, Groningen Universiteit

Abstract

In estuarine areas, like the Wadden Sea, there are large differences in environmental conditions (i.e. temperature, salinity, food and currents), which influence growth, survival and reproduction of benthic animals. This thesis studied the effect of environmental conditions on growth and reproduction of five common bivalve species: the Baltic tellin Macoma balthica, the cockle Cerastoderma edule, the mussel Mytilus edulis, the soft-shell clam Mya arenaria and the recently introduced Pacific oyster Crassostrea gigas, which has been strongly increasing in numbers. During more than a year, field data for these species has been collected in different habitats (intertidal and subtidal of the Wadden Sea, and the North Sea coastal zone) and analysed using a general framework, the 'Dynamic Energy Budget (DEB)' model. By using this model, food conditions for the various species in the different habitats could be reconstructed.

All species presented a seasonal pattern in growth, with body condition increasing in spring and summer and decreasing in winter. Differences in growing period occurred between species and within species in different habitats. The timing of spawning and reproductive investment also differed between species and habitats. DEB model simulations suggested that food limitation occurred and that food conditions were insufficient for maximum growth. Besides, for the Baltic clam Macoma balthica, the current summer temperatures seem to be already too high for optimal growth. These results suggest that food competition must have occurred between species and that climate change may have serious consequences on bivalve productivity in the Wadden Sea.

Full text in pdf format


Go to DEB support page or the DEB info page