Seasonal composition and population density of zooplankton in Lake Karaboğaz from the Kızılırmak Delta (Samsun, Turkey)

Zooplankton composition and abundance were investigated seasonally at 6 sites in Lake Karaboğaz in relation to some physicochemical conditions. A total of 63 taxa were identified, among them 51 species of rotifers, 8 cladocerans, and 4 copepods. Rotifera represented the predominant component (79% of the total community), followed by nauplii, cladocerans, and copepods (15%, 5%, and 1%, respectively). The average total zooplankton abundance ranged from 9603 to 22,968 ind/m^3. The maximum and the minimum densities were measured in June and August of 2009, respectively. Of the identified zooplankton, 39 taxa were species with a low frequency in the lake. Among the species with the highest frequency of encounter were Coronatella rectangula, Chydorus sphaericus, Colurella adriatica, Keratella quadrata, Lecane closterocerca, L. bulla, and Polyarthra vulgaris. Zooplankton diversity showed a positive correlation with temperature and chlorophyll a. However, a significant negative correlation was detected between diversity and salinity.