Food composition of the fish community in Lake Agmon

Abstract

Lake Agmon was created in the Hula Valley in Israel, in the northern part of the dried-up Hula Lake site, in summer, 1994. Samples of fish at ten stations were taken by electroshocker once a month, from January to December, 1996. The fish species whose food composition in the gut was examined in this study were: Tilapia zillii, Gambusia affinis, Clarias gariepinus, Cyprinus carpio, Pseudophoxinus kervillei, Acanthobrama lissneri, Hemigrammocapoeta nana and Oreochromis aureus. Food components were determined qualitatively and quantitatively. Assessment of the organism biomass in the gut contents was based on available data of phytoplankton and zooplankton. The food of G. affinis changed during the year, consisting high level of algae in winter and spring, and insects and crustaceans in summer. In T. zillii, a high percentage of algae were found in winter, and a high percentage of plants in summer. The food of H. nana consisted mainly of phytoplankton, but included high plants during most months; P. kervillei ingested mainly insects and crustaceans, with a high percentage of Daphnia spp.; and the diet of C. gariepinus comprised fish and invertebrates species, which varied with the seasons. C. carpio ate mainly invertebrates; O. aureus are vegetarian, and A. lissneri fed on both animals and plants.