Size structure of zooplankton ingested by four commercially important bivalves

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 Area noae. Ingested zooplankton ranged in maximum linear dimension from 60.1 to 1398.5 mu m. 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.Original Abstract: Iako neki skoljkasi imaju sposobnost hranjenja zooplanktonom, taj aspekt ekologije skoljkasa jos uvijek je relativno slabo istrazen. Svrha ovog istrazivanja bila je pridonijeti poznavanju velicinske strukture zooplanktonskog plijena kod cetiri gospodarski znacajne vrste skoljkasa koje zive na istom podrucju. Istrazivanje je provedeno od svibnja 2009. do travnja 2010. u Malostonskom zaljevu -- najvaznijem podrucju za uzgoj skoljkasa u istocnom dijelu Jadranskog mora. Analizirana je velicina zooplanktona konzumiranog od strane uzgajanih vrsta dagnje Mytilus galloprovincialis i kamenice. Ostrea edulis te vrsta koje na tom podrucju zive u prirodnim populacijama dlakave dagnje Modiolus barbatus i kunjke Area noae. Velicma konzumiranog zooplanktona kretala se u rasponu od 60,1 do 1398,5 mu m. Velicinski raspon zooplanktona pronadenih u zelucima vrsta M. galloprovincialis i O. edulis suspendiranim u vodenom stupcu bio je veci od zooplanktona pronadenog u zelucima vrsta M. barbatus i A. noae. Statisticki znacajna razlika u velicini konzumiranog zooplanktona pronadena je izmedu vrste O. edulis i tri ostale vrste.