AQUATIC INVERTEBRATE DISTRIBUTION IN NAHAL TANNINIM, ISRAEL

ABSTRACT

The aquatic invertebrate assemblage of a Mediterranean coastal river, Nahal Tanninim, was investigated during 1978–1981. Five stations were periodically sampled (82 samples total) ranging from an upstream freshwater section with seasonal flow to the convergence of the river with the Mediterranean Sea. Fifty-nine taxa were collected; the most species-rich groups were malacostracan crustaceans, gastropods and oligochaetes. The species richness of malacostracan crustaceans was greater than in all other coastal rivers in Israel. The isopod Cyathura carinata is known in Israel only from N. Tanninim. Comparisons among stations by cluster analysis indicate a high similarity among downstream stations characterized by permanent flow and oligohaline conditions. The fauna of the freshwater section characterized by temporary, intermittent flow differed significantly from the other stations. Limited evidence exists for the presence of a transition zone between the oligohaline and freshwater sections of the river.