Seasonal and spatial variability in growth of Mytilus edulis L in a brackish sound: comparisons of individual mussel growth and growth of size classes

Growth of Mytilus edulis L. in a brackish Danish sound was estimated from individually measured mussels and measurements of discrete size classes. In winter, individual mussels grew faster than size classes of mussels, and in summer, the inverse situation occurred. The effect of size-specific mortality of larger mussels in winter, and smaller mussels in summer on the population dynamics is discussed. Spatial variability in growth was analysed by comparing von Bertalanffy growth rates estimated for discrete size classes of mussels at different locations in the sound. Faster growth rates were measured in the western part of the sound characterised by a higher salinity and current speed. The observations were supported by results of cage experiments with individually marked mussels. (C) 1998 Elsevier Science B.V