Man-induced Changes in the Freshwater Fish Fauna of Israel

Abstract

Changes in Israel's freshwater fish fauna during the past 50 years were caused by: (1) introduction or transfer of foreign and native species for culturing, development of fishery resources in Lake Tiberias and reservoirs, and ecological control; (2) land reclamations; and (3) utilization of water reserves for domestic, agricultural and industrial purposes. The exotic fishes that reproduce naturally in inland waters are Gambusia affinis, Cyprinus carpio, Sarotherodon niloticus and Basilichthys bonariensis. A population of Salmo gairdneri inhabits the upper reaches of the Jordan River, but it is doubtful if it reproduces. Non-naturally reproducing exotic species include: Hypophthalmichthys molitrix, Ctenopharyngodon idella and Aristichthys nobilis. These species are, however, artificially reared and propagated. The reclamation of Lake Hulah brought to near extinction Tristramella simonis intermedia. Pond culture and the construction of the national water carrier contributed to the spreading of several species into new areas; among them mugilids, Sarotherodon aureus and its hybrids with Sarotherodon niloticus. Due to wise management policy, the introduction of exotic fishes into Israeli waters proved to be economically advantageous without causing ecological disturbances.