The origin of the Kinneret fauna

Abstract

Tristram, in 1888, stated that the overwhelming majority of species in Lake Kinneret are of Palaearctic origin, but that there are, in each class, exceptions which can be accounted for only by the geological history of the Rift area. Annan-dale, in 1915, found that ‘the most remarkable point in the distribution of aquatic animals of the Jordan system is the fact that, whereas there is an unmistakable Ethiopian element among the fish, no such element can be detected with certainty among the invertebrates’. Annandale found an answer to this anomaly in the theories of the geographer Suess (1906). According to these theories, the Jordan Valley was covered, in the Pliocene by the ‘Jordan Lake’ which was drained at its southern end by an ‘Erythrean River’ which reached the Red Sea at the level of Aden. Upward tectonic movements and climatic changes cut off the Jordan system from the Erythrean Valley, which was then filled with the Red Sea waters. In a later stage, high salinities developed in the now closed system. As long as the Erythrean River connected the Jordan system to Africa, there was a constant colonization of the Jordan waters by African species which were trapped when the connection was cut off, and, with the further increase of salinities, most of the African species perished. The only animals which were able to survive were the fish from two families, Clariidae and Cichlidae.