Photosynthesis, water respiration and growth performance of Litopenaeus vannamei in a super-intensive raceway culture with zero water exchange: Interaction of water quality variables

Gross and net photosynthesis, and water column respiration of a super-intensive Litopenaeus vannamei raceway culture with zero water exchange were measured over 21 weeks using the light and dark bottle method. Spearman correlation analysis was used to explore the relationship of these parameters with other water quality parameters (O2, temperature, pH, alkalinity, TAN, NO2, NO3, dissolved orthophosphate, turbidity, TSS and VSS) and of shrimp performance based on growth rate and feed conversion rate. Net photosynthesis generally had negative values, indicating that the system was predominantly heterotrophic. Gross photosynthesis was significantly related only with VSS, and water column respiration was related only with turbidity. Shrimp growth rate increased with higher temperature and dropped with higher pH. Nitrite had a strong inverse relationship with shrimp growth rate (R2 = 0.8044, p < 0.001) and a weak relationship with FCR (R2 = 0.3319, p = 0.0284). VSS has a significant inverse relationship with shrimp growth rate (R2 = 0.4989, p = 0.0102) and a direct relationship with FCR (R2 = 0.5356, p = 0.0162). Photosynthesis and the water column respiration did not seem to have a significant impact on shrimp productivity.