Submitted to: Journal of Applied Aquaculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/9/2014
Publication Date: 3/23/2015
Publication URL: http://handle.nal.usda.gov/10113/1235691
Citation: McEntire, M.E., Riche, M.A., Beck, B.H., Carter, D. 2015. Effect of contrasting agents on survival, performance, and condition of larval hybrid striped bass Morone chrysops x M. saxatilis in tanks. Journal of Applied Aquaculture. 27:1-28.
Interpretive Summary: Adding the right amount of clay (Kaolin) or algae to the water to create turbidity (cloudiness) improves fry survival and growth, because hybrid striped bass fry are cannibalistic. The turbid water prevents the fish from seeing each other and also makes their live feed (zooplankton) standout. By adding algae paste at 350 – 583 algae cells/mL to tank water results in the optimum survival. The use of kaolin clay worked about as well as the algae paste at less than one fortieth the costs. By looking at various ratios of fry length and how uniform the ratios are among fry within the tank, some conclusions could be made about the cannibalistic interactions that are occurring among fry in the tank. Therefore these ratios could be used to predict and reduce future losses that could be expected during grow-out of the fry, or to determine the frequency of grading (removal the largest fry from the tank) that is necessary to reduce cannibalism. Increasing turbidity appears to allow the fry grow more uniformly in length and size along with improving survival.
Technical Abstract: Contrasting agents, either algae or inert soil, cause turbidity, which is important in the tank culture of larval cannibalistic fish. Optimization of turbidity is critical to successful tank culture of new larval fish, which should include 100 mg/L of sub 5 um particle size in the assessed range. The optimum tested range of greenwater culture for hybrid striped bass using algae paste once daily was between 629 - 1127 mg/m^3 (350 - 583 cell/mL). Dispersed kaolin worked as well as greenwater culture. Using contrasting agents improved fish length, condition, tail length ratio (TLR), and uniformity of the fish at the time of weaning onto prepared diets. Increasing turbidity appears to negatively skew fish length and TLR. Tail length ratio shows promise as an early indicator of cannibalism. Increasing turbidity appears to decrease the size advantage of the largest fish in the tank, which allows the smallest fish to catch-up.