FEEDING-HABITS OF LARVAL MIROGREX-TERRAESANCTAE (STEINITZ, 1952) IN LAKE KINNERET (ISRAEL) .2. EXPERIMENTAL-STUDY

Interactions between the larvae of Mirogrex terraesanctae (Steinitz, 1952) in Lake Kinneret, Israel, and their zooplankton prey were studied experimentally. Prey species preference and size selectivities were measured. Larvae were hatched in the lab from eggs collected in the field, and fed different food items in various concentrations. The food items included lake zooplankton, algae, and commercial pellets. It was shown that small, first feeding larvae (7-8.5 mm SL) prefer small bodied zooplankters (< 180 mu). The effect of these food sources on larval growth was measured. It was found that larval Mirogrex grew at a higher rate when fed zooplankton prey sized from 63 mu-250 mu. Food items smaller than 63 mu, larger than 250 mu and Scenedesmus sp., produced less than optimal growth rates. The importance of Mirogrex feeding habits and their potential influence on the Kinneret ecosystem is considered.