EFFECT OF FEEDING STRATEGY AND CARBON DIOXIDE-CARBONATE SYSTEM DYNAMICS IN THE REPRODUCTIVE CONDITIONING OF THE KUMAMOTO OYSTER (Crassostrea sikamea) MAINTAINED IN A RECIRCULATING AQUACULTURE SYSTEM

Manuel Segovia*, Juan Benavides, Carmen G. Paniagua-Chávez
Centro de Investigación Científica y de Educación Superior de Ensenada, B.C.
Carretera Ensenada-Tijuana No. 1839 zona Playitas, Ensenada B.C. México 22860
msegovia@cicese.mx

Recirculating aquaculture systems (RAS) are widely used in the reproductive conditioning of different aquatic organisms including mollusks because water quality, including the carbon dioxide-carbonate system dynamics, can be handled in these systems. Therefore, the objective of this work was to evaluate the effect of feeding strategy and CO2-carbonate system on the reproductive conditioning of the Kumamoto oyster, Crassostrea sikamea.

Two 10-week experiments were performed to study the effect of feeding strategy: continuous (C) and discontinuous (D) and carbon dioxide-carbonate system dynamics: RAS with calcium reactor (WCR) and without calcium reactor (WOCR).  The first experiment was performed at 180C and the second was completed in a temperature gradient from 18 to 24oC. All experiments were carried out by triplicate.

Physical-chemical parameters (temperature (oC), pH, total ammonia nitrogen (TAN), N-NO2, N-NO3, alkalinity, CO2, CO3-2,    HCO3-1) were registered daily. Condition index, gonad development and gonadosomatic condition index were used to determine reproductive conditioning.

Significant differences (P < 0.0001) in pH, alkalinity, TAN, N-NO2, N-NO3 CO2, CO3-2, HCO3-1 were detected (Figure 1).  Feeding strategy and carbon dioxide-carbonate system dynamics have an effect on the reproductive conditioning of Kumamoto oyster (Figure 2).