Title : Biometrics and production performance of freshwater pelagic copepods based on the algae (Spirulina Platensis) and baker s yeast (Saccharomyces Cerevisiae) in a continuous production system
Abstract:
Small-scale stocking of freshwater fish by fish farmers in rural or peri-urban areas remains a major challenge due to feed availability. Indeed, the unavailability and high cost of fish larvae feed constitute a significant obstacle to the development of artisanal fish farming. Hence the importance of this study, initiated to contribute to improving the mass production of freshwater zooplankton for feeding fish larvae and fry. It was conducted at the Applied Ichthyology and Hydrobiology Research Unit (URICHTHYDA) of the University of Dschang, Cameroon. To this end, nine (9) aquariums supplied with borehole water were seeded with 40 copepodites in stages 4 and 5 per aquarium. The copepods were fed daily with rations based on spirulina (T1), baker's yeast (T2), and a 50% spirulina/50% yeast mixture (T3). Water physicochemical data were collected daily. One week after inoculation, copepods were sampled every two days to evaluate biometric and production parameters. Data analysis revealed that only water conductivity was significantly affected (p<0.05) by the type of feed, with the highest value (173.44 ± 44 µS/cm) in treatment T1 and the lowest in T2. The final size of the copepods varied according to the type of ration. Indeed, a significant difference (p<0.05) was observed in the length of the cephalothorax, the diameter at the base of the urosome and the total length of the copepodites. Regardless of the developmental stage, treatment T3 recorded the largest sizes: 12.91 ± 1.44 µm, 40.16 ± 0.76 µm, and 130.83 ± 3.97 µm for nauplii, copepodites, and adults, respectively. However, the highest density (158.94 ± 160.54 ind/l) of nauplii was obtained in treatment T3, while the highest density of copepodites and adults (42.94 ± 37.50 and 28.05 ± 34.01 ind/l) was obtained in treatment T1. The highest fresh biomass value (15.90 ± 17.04 µg) was obtained in treatment T1, and the lowest in T2 (7.17 ± 3.75 µg).
Keywords: Aquarium, spirulina, yeast, nauplii, copepods, zooplankton.
