Age, growth, sex ratio and feeding of Knipowitschia caucasica (Berg, 1916) (Actinopterygii, Gobiidae) in non-native species of Eğirdir Lake (Turkey)

Abstract

The population structure of Knipowitschia caucasica (Caucasian dwarf goby) in Lake Eğirdir (Turkey) was studied, using 400 fish monthly in 2008. Males made up 45.75% (183), females 50.50% (202) and juveniles 3.75% (15) of the population. The length-weight relationship and Von Bertalanffy growth equation were estimated as W=0.0141*L2.769 (r=0.7464), W=0.0116*L2.941 (r=0.8266) and W=0.0129*L2.8494 (r=0.8039) for females, males and combined sexes, respectively. This species can be mainly fed with Ochrophyta, Gammarus pulex and Ostracoda organisms. There is a food competition among Atherina boyeri, Aphanius anatoliae and K. caucasica that live mainly in coastal areas and share the same environment. The species has become one of the dominant fish of lake along with Carassius gibelio (non-native), A. anatoliae (native) vs A. boyeri (non-native).