1-Department of Fisheries, Faculty of Animal Sciences and Fisheries, Sari Agricultural Sciences and Natural Resources University, Sari, Iran , a.esmaeili@sanru.ac.ir 2- Department of Fisheries and Aquatic Sciences, Food Research Institute and Agricultural Sciences, University of Florida, Florida, USA
Abstract: (53 Views)
Introduction:Water hardness is one of the important factors of water quality parameters in the sexual maturation of broodstock, artificial propagation, and rearing of ornamental catfish in hatchery conditions. Materials and methods: In this study, the effects of water hardness were conducted on growth, survival, and nutritional indices of golden spotted catfish (Pterygoplichthys joselimaianus) from the larval to fingerlings stage for seven weeks. Ten-day-old larvae (n= 240; initial weight and length of 0.19 mg and 11.9 mm, respectively) were randomly distributed in four hardness levels (each treatment in three replicates) including 50, 150, 350, and 650 mg/L of calcium carbonate in 12 tanks with a useful water capacity of 90 L and stocking density of 20 fish per tank. Results and Discussion:The results showed that the growth indices had significant differences between treatments (p<0.05). Final body weight and length of the fish increased from 50 to 150 mg/L, but decreased greatly at 350 and 650 mg/L (p<0.05). Food conversion ratio and average daily growth rate showed no differences (p>0.05) between 350 and 650 mg/L levels; but both levels revealed significant differences compared to the lower levels (p<0.05). Significant trend was observed in the percentage of body weight gain and specific weight growth rate in fish reared at 150 mg/L compared to other levels (p<0.05); so that these values greatly decreased with increasing of hardness up to 650 mg/L. A relatively similar trend was observed in the percentage of body length increment and specific growth rate of length in fish reared at 150 mg/L compared to other levels (p<0.05). Highest (90%) and lowest (60%) survival rates were recorded in fish at 150 and 650 mg/L, respectively (p<0.05). Although all hardness levels, a survival percentage > 60% was possible to rearing the catfish larvae up to the fingerling stage; but lower levels (50-150 mg/L with survival percentage > 80%) are preferable. Conclusion: According to the findings of the present study, the hardness of 150 mg/L was suggested due to the higher final body weight and length, improvement of the food conversion ratio, increased in the growth rate of specific weight and length, along with the highest survival percentage for rearing of golden spotted catfish from the larval up to fingerling stage.
Esmaeili Fereidouni1 A, Namaei Kohal1 M, Hill J. Effects of water hardness on the growth, survival, and nutritional indices of golden spotted catfish (Pterygoplichthys joselimaianus). JAD 2025; 19 (3) :100-115 URL: http://aqudev.liau.ac.ir/article-1-837-en.html