This study was carried out to investigate the effect of different stocking densities on the growth performance of common carp (Cyprinus carpio) fingerlings reared in concrete ponds to produce the requested fingerlings prior to the next production season.
This experiment was concluded the following treatments: Treatment 1 = stocked by the rate of 25 fish/m3 Treatment 2 = stocked by the rate of 50 fish /m3 Treatment 3= stocked by the rate of 75 fish /m3.All treatments were in triplicate, and fed with 25% crud protein of prepared artificial pelleted feed and reared in 20 m3 of concrete ponds. The duration of the experiment was 20 weeks.
Results are summarized in the following:
- Final body weight was affected with stocking density, the analysis of variance revealed that groups an average final weight decreased significantly (p≤ 0.05) with each increase in the stocking density. The same trend was observed in the body weight gain per fish. Total weight/pond and total weight gain /pond were in opposite trend where it were significant increase (p≤ 0.05) with each increase in stocking density.
- Total body length and relative growth rate (RGR%) of reared fish was significantly (p<0.05) decreased with each increase in stocking density at the end of the experimental period.
- The values of specific growth rate(SGR%) which influenced after rearing period (20 week) with the stocking density by slightly decrease with each increase in the stocking density.
- Condition factor (K) of Cyprinus carpio , showed a slight decrease with each increase in three stocking densities applied after the rearing periods of 137 days.
- Feed conversion ratio (FCR) was indicated that for stocking density tested improved with each decrease of the stocking density.
- The highest survival rate(91%) was combined to the lowest stocking density 25 fish/m3, while the lowest value (73%) was under the highest stocking density of 75 fish m3.
- Daily weight gain(g/fish)significant decrease(p≤0.05)with each increase in stocking density
- Water quality parameters through the experimental duration was in favorable range for fish culture (water temperature, dissolved oxygen, ammonia, pH, total hardness and total alkalinity).
- All results indicated that the total production and other growth performance parameters were decreased significantly (p≤ 0.05) with the increasing stocking density.