The investigation of seasonal variations of Mollusca fauna in Sariçay, Karamenderes, Kocabaş and Tuzla streams (Biga peninsula-Marmara; Turkey)

The present thesis was performed to determine the seasonal variations and distributions of mollusca fauna in the streams of Biga Peninsula, Sarıçay, Karamenderes, Kocabaş and Tuzla Streams, in relation with environmental variables and biotope structure. With this aim, sampling stations were selected, 3 for Sarıçay Stream and 4 for Karamenderes, Kocabaş and Tuzla Streams. In the field study, benthic samples had been taken as two replicates, quantitatively and also, water quality parameters such as temperature, salinity, dissolved oxygen, conductivity and pH measured in situ. In the laboratory, turbidity, total suspended solids, biochemical oxygen demand, chemical oxygen demand, nitrate and phosphate of water, pH, conductivity and grain size of sediment had been processed and analyzed.According to the taxonomic data, 6 gastropoda and 2 bivalvia in Kocabaş Stream, 17 gastropoda and 9 bivalves in Sarıçay Stream, 11 gastropoda and 4 bivalves in Karamenderes Stream, 14 gastropoda and 3 bivalves in Tuzla Stream had been determined in all stations throughout the study. Among gastropoda, Myosotella myosotis, Oxyloma elegans, Radix labiata, Gyraulus albus, Gyraulus piscinarum, Ancylus fluviatilis and bivalves, Unio pictorum, Abra ovata ve Mytilaster lineatus are the new records for the Biga Peninsula region.Water temperature, pH and habitat structure were detected as the most effective factors with respect to seasonal variations of the Mollusca species in the studied Streams. In addition, with the distributional point of view, Physa acuta, Radix labiata, Radix auricularia, Melanopsis buccinoidea, Pisidium casertanum, Dreissena polymorpha, Valvata macrostoma, Abra alba, Ventrosia ventrosa, Oxyloma elegans, Theodoxus sp. Valvata naticina species were found affected water temperature and pH by MDS analysis.Mytilaster lineatus ve Unio mancus eucirrus (Bivalvia) were found that affected from the sediment parameters, pH and conductivity, while Pisidium casertanum from the water quality parameters, temperature and pH had been described.