Fish biology and ecology

Abstract

The chapter summarizes current knowledge on fish biology in Lake Kinneret. Nineteen native fish species belonging to six families populate the lake. Three of these species are endemic to the lake and four other species are endemic to the Jordan Valley system. Eight alien species are found in the lake. Four of them are breeding in nature, three cannot breed but are regularly stocked, and one is a hitchhiker that cannot breed. Growth rate equations and weight-length relationships are presented for the dominant cyprinids (Mirogrex terraesanctae, Hypophthalmichthysmolitrix, Cyprinus carpio, Barbuslongiceps, Capoetadamascina, Carasobarbuscanis), cichlids (Oreochromisaureus, Sarotherodon galilaeus, Tilapiazillii, Tristramellasimonis), grey mullets (Lizaramada, Mugilcephalus), and catfish (Clariasgariepinus). The long-term changes in fish community composition in the lakewere associated with introduction and invasion of fishes; changes in fishing intensity; modifications of the littoral, and changes of the lake ecological regime. Temporal dynamics, spatial distribution, total abundance and biomass of fish in the lake were studied based on long-term hydroacoustic monitoring. The size structure and abundance of fish in the pelagic zone of the lakedisplay explicitseasonal changes associated with fish spawning migrations and winter-spring recruitment of the dominant bleak M. terraesanctae. Water level fluctuations beyond natural have modified the littoral habitats, which are of specific importance during different life stages of fish. Water level has an immense impact on fishreproduction, survival, recruitment, population dynamics, and eventually determines the catches of commercially important species.