Nile tilapia Oreochromis niloticus were produced in an experimental, on‐farm grow‐out cycle in which economic and production efficiencies were partially examined. Milled feeds were provided either daily (control) or on alternate days (experimental) at a given percentage of body weight, ranging from 20% initially to 2% at the end of the experiment. Growth, survival, feed conversion efficiency, cost, yield, and income were considered under the two strategies. Although the cost of feeds was cut in half by the experimental feeding treatment, feeding on alternate days did not reduce Nile tilapia growth or production performance variables, and yields were not significantly different. A trend favoring larger fish among the controls was not significant, and profit margins were higher for the alternate‐day feeding strategy than for the control strategy. Although feed conversion ratios varied considerably among the nine participating farms, the improved efficiency in the experimental groups was consistently observed and was statistically significant. It is possible that the improved performance attained by alternate‐day feeding is a result of reduced feed waste, either through more complete consumption of or improved nutrient absorption from available feeds.

This experiment assessed the effect of breeder’s behavioral stress response [i.e., eye color pattern (ECP)] during isolation on O. niloticus seed production. ECP change was marked by fractional color changes of the iris and sclera, which was transformed into scores ranging from 0 (no darkening) to 8 (total darkening). After isolation, breeders were divided into two social groups: proactive breeders (PB) were those with a mean ECP score of <2, and reactive breeders (RB) with a mean ECP score of >6. Two breeding cycles were done in six (1 m x 2 m x 1 m) net enclosures. Mean spawning rates (SR) in PB during the two cycles were 38.89±14.70% and 33.33±8.87% while 3.33±9.62% and 22.22±2.48% in the RB group. Total seed productions (TSP) in PB were 1,906.22±733.72 and 1,681.19±1,070.48 fry, and those in RB were 996.35±218.11 and 461.39±151.37 fry. There were no significant differences between the two groups on SR and TSP in both cycles. On seed production per female that spawned, however, significantly (P<0.05) higher means (796.33±77.68 and 726.33±124.08 fry) were observed in the PB compared to those in RB (522.73±54.68 and 335.83±44.98 fry). These results demonstrated that seed production in O. niloticus could be increased by selecting proactive breeders through the evaluation of their ECP during isolation.