Composition and Abundance of Zooplankton in a Natural Aquarium, Lake Balikligol (Sanliurfa, Turkey) and New Records

Balikligol Lake also known as the holy Halil-ur Rahman Lake is an important tourism centre in Turkey. Since its waters and fish are considered to be holy, the shallow lake has a dense fish population and can be considered a unique natural aquarium. In this natural aquarium, seasonal changes in the zooplankton community structure were evaluated in terms of species composition and abundance for the first time and a total of 34 taxa were identified, 29 of them belonging to Rotifera, 3 Cladocera and 2 Copepoda. Two of these rotifers Lecane thienemanni (Hauer, 1938) and Notommata glyfura Wulfert, 1 935 are new records for Turkey. In addition, L. thienemanni is new for Western Asia. The species richness was high in summer. Total abundance ranged from 941-23.312 ind. m(-3), exhibiting a major peak in early spring and a minor one in early autumn. In terms of density, Rotifera dominated with 63%, followed by Copepoda with 33% and Cladocera with 4%. Predation pressure from fish, high temperatures and low oxygen values had significant impacts on zooplankton composition and abundance, especially for the crustacean community.