Common carp (Cyprinus carpio) Stocked in Cage Culture in Dukan Lake, Kurdistan Region, Northern Iraq: Effects of Stocking Density on Growth Performance, Survival Rate, and Somatic Index

Abstract

This study examined the effects of stocking density on the growth, survival, and overall health of common carp Cyprinus carpio in net cages at Lake Dukan, in the Iraqi Kurdistan Region. Common carp with an initial weight of 180 ± 5 g were used in nine experimental net cages (7 m × 7 m × 3 m, 147 m3) for the study. The three different common carp stocking densities (1000, 1250, and 1500 fish/cage, or 6, 8, and 10 fish/m3) were assessed using three replicates for each treatment. The trial was conducted for 120 days, and the fish were fed commercial floating feed. Fifty fish were taken out of their cages at random every two weeks in order to assess their weight gain and adjust their diet. Total and daily weight, feed conversion ratio, survival rate, and somatic index were measured at the trail's end. The final weight, weight gain, daily weight gain, and specific growth rate (1546 g, 1363.9 g, 11.37 g, and 1.8), respectively, were found to be highest at the lowest stocking density of 1000 fish/cage, and the lowest stocking density had the best feed conversion ratio (1.52). Additionally, the fish applied at 1000 fish/cage had the highest flesh weight index (75.03) and ‌recorded survival rate (96%). It was determined that the condition factor and organ somatic index of cultured fish were unaffected by stocking density. According to our results, stock fish at a density of 6 fish/m3 with an initial weight of 180 g are suitable for the cage culture of common carp in northern Iraqi lakes.

Keywords

• biological parameters
• cage farming
• fish
• weight gain