Size structure of zooplankton ingested by four commercially important bivalves

Abstract

           Some bivalve molluscs are capable of zooplankton ingestion; however that aspect of their ecology is still relatively poorly studied. The objective of this investigation was to contribute to the understanding of size structure of zooplankters ingested by four commercially important bivalve species co-occurring in the same area. The study was performed in Mali Ston Bay – the most important bivalve aquaculture area in the eastern Adriatic Sea – from May 2009 to April 2010. We analyzed sizes of zooplankton ingested by cultured blue mussel Mytilus galloprovincialis and European flat oyster Ostrea edulis, and naturally-occurring bearded mussel Modiolus barbatus and Noah’s Ark shell Arca noae. Ingested zooplankton ranged in maximum linear dimension from 60.1 to 1398.5 μm. Zooplankton found in stomach contents of M. galloprovincialis and O. edulis suspended in the water column showed a wider size range than zooplankton found in stomachs of bottom living M. barbatus and A. noae. Sizes of ingested zooplankton significantly differed between O. edulis and the other three species.