The study of Carassius gibelio diet in Neor Lake of Ardabil province

Neor Lake in Ardabil Province was ecologically degraded recently and the invasive fish Prussian carp (Carassius gibelio) has been dominated. In 2017, the biological study of this species carried out in order to control of its population in the lake. Fish samples were caught by different equipment; Gill-net, Cast-net and purse seine. The average weight of fish was seasonally varied between 59.76±36.25, 54.72±42.85, 102.66±26.32 g while the average length of fish was ranged between 146.20±36.51, 133.40±38.20, 174.41±13.04 mm. The age of fishes was about 2 or 6 years. Intestine length was varied between 2.8±0.28, 2.88±0.34, 3.19±0.34 mm and the condition factor was calculated 1.67±0.28, 1.85±0.16, 1.90±0.15. Feeding intensity was calculated 250.34±136.91, 165.11±64.11, 163.45±86.99. The Prussian carp feed mostly on detritus. Six phytoplankton and four zooplankton phylum were identified in their guts which Bacillariophyta and Rotatoria were dominant respectively. From their gut contents were identified 44 phytoplankton genus and 10 zooplankton genus that Synedra and Rotaria were dominant respectively. The range of length and weight of C.gibelio showed the unfavorable environmental conditions for feeding and living of this fish in Neor Lake. The range of length and weight of carp showed the unfavorable environmental conditions for feeding and living of this fish in Lake Inver.