THE INVERTEBRATE ZOOBENTHOS OF LAKE TIBERIAS. II. QUANTITATIVE DATA (LEVEL BOTTOMS)

ABSTRACT

Lake Tiberias is a warm monomictic lake. Anaerobic conditions in the hypolimnion (below 15–25 m) appear shortly after stagnation sets in, and last 8–9 months out of 12. The lake bottom can be separated into four faunistic belts: littoral, sublittoral, epiprofundal and profundal. The epiprofundal (15–25 m) is least populated both qualitatively and quantitatively. The biomass in the sublittoral reaches a maximum 7.6 g/m² out of which 4.2 g are oligochaetes and 2.8 g nematods. In the profundal the maximum value found is 3.6 g/m² out of which 3.4 g are nematods and 0.2 oligochaetes. The biomass calculated as an average for the whole lake bottom (without molluscs) is 8.5 kg/ha.