Effects of cyclic feeding on compensatory growth of hybrid striped bass (Morone chrysops×M. saxitilis) foodfish and water quality in production ponds

An18-week study was conducted in12, 0.1ha ponds to evaluate the impacts of cyclic feeding regimes on hybrid striped bass (HSB) food¢sh production and pond water quality. Approximately 840 HSB [mean weight (std.); 91.08 g (8.18)] were stocked into each pond (8400 ¢sh ha ; 3360 ¢shacre ) and fed according to one of three feeding regimes. The three feeding regimes included a control (fed twice daily to apparent satiation), and cycles of 3 weeks feed deprivation followed by 3 or 6 weeks of feeding to apparent satiation (3/3 and 3/6 respectively). Compensatory growth (CG) was observed in both cyclic feeding treatments; however, the response was insuf¢cient for the ¢sh to completely regain lost weight. Final mean weight of control ¢sh (477.9 g) exceeded (Po0.05) that of ¢sh receiving the two cyclic treatments: 3/6 (404.7 g) and 3/3 (353.8 g). Speci¢c growth rate (SGR) of ¢sh in the 3/3 treatment increased during all three refeeding periods, and was signi¢cantly greater than controls during weeks 9^12 and weeks 15^18, which represent the refeeding phase of the second and third feeding cycles. Speci¢c growth rate for ¢sh in the 3/6 treatment was signi¢cantly higher than controls only during the ¢rst 3 weeks of the ¢rst feeding cycle. Hepatosomatic index and condition factor were highly responsive measures that closely followed the metabolic state of ¢sh on the feeding cycle. Of the water quality variables measured, total phosphorus was 32% lower in ponds receiving cyclic feeding versus control ponds. Soluble reactive phosphorus was 41% and 24% lower in ponds o¡ered the 3/3 and 3/6 cyclic feeding treatments, respectively, although, signi¢cant di¡erences (Po0.10) were only observed between control and 3/3 treatment ponds. Overall, CG was observed in HSB food¢sh grown in ponds, although 3 weeks of feed deprivation was excessive and did not allow for complete growth compensation.Weight loss during feed deprivation was in£uenced by pond water temperatures. Early season feed deprivation did not cause as muchweight loss as during the second cycle later in the season. Further studies on shorter deprivation periods applied during moderate to low water temperatures are needed to identify feeding regimes that minimize weight loss and result in a complete CG response.