WWW.WAS.ORG • WORLD AQUACULTURE • DECEMBER 2024 57 (CONTINUED ON PAGE 58) TABLE 4. Length gains of S. spilurus at two-week intervals during the study period. Time Treatment group T1 (0.75 PL/L) T2 (1.25 PL/L) T3 (1.75 PL/L) T4 (2.25 PL/L) Week 2 1.02±0.05a 0.87±0.02b 0.67±0.02c 0.60±0.03c Week 4 0.65±0.03a 0.51±0.05b 0.46±0.01b 0.37±0.02b Week 6 0.57±0.01a 0.48±0.03a 0.34±0.04b 0.26±0.01b Week 8 0.53±0.04a 0.41±0.04ab 0.35±0.04bc 0.23±0.03c Results are expressed as mean ± standard deviation of the mean. Means with the same letters indicate no significant difference between treatments. TABLE 5. Weight gains of S. spilurus at two-week intervals during the study period. Time Treatment group T1 (0.75 PL/L) T2 (1.25 PL/L) T3 (1.75 PL/L) T4 (2.25 PL/L) Week 2 0.042±0.001a 0.026±0.001b 0.020±0.001c 0.015±0.001d Week 4 0.094±0.003a 0.059±0.004b 0.041±0.005c 0.030±0.003c Week 6 0.138±0.011a 0.104±0.010ab 0.072±0.015bc 0.039±0.005c Week 8 0.188±0.018a 0.124±0.003b 0.084±0.008b 0.039±0.003c Results are expressed as mean ± standard deviation of the mean. Means with the same letters indicates no significant differences between treatments. TABLE 6. Survival of S. spilurus during the study period. Treatment group Stocking density Survival rate (%) T1 0.75 PL/L 99.56±0.225a T2 1.25 PL/L 99.47±0.216a T3 1.75 PL/L 98.30±0.394ab T4 2.25 PL/L 97.64±0.434b Results are expressed as mean ± standard deviation of the mean. Means with the same letters indicate no significant differences between treatments. Analysis System (SAS) and all comparisons were considered significant at (P<0.05). Results and Discussion At the beginning of the experiment, the mean weight and mean length in all treatments were not significantly different (P>0.05). However, final mean lengths and weights of all treatments were significantly different (P<0.05) (Table 1, Figures 13 and 14). The greatest lengths and weights were obtained in treatment one where the density was lowest. High stocking densities are often associated with stress, competition for food and living space, and more energy expenditure in antagonistic interactions. This LEFT: FIGURE 18. Length gains of S. spilurus fry at two-week intervals during the study period. Means with the same letters indicate no significant difference between treatments. RIGHT: FIGURE 19. Weight gains of S. spilurus fry at two-week intervals during the study period. Means with the same letters indicate no significant differences between treatments.
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