Abstract
Chlamydomonas spp. and Chlorella spp. are plankton genera that can be used to determine the level of balance in the aquatic environment. The purpose of this study is to determine the abundance of plankton Chlamydomonas spp. and Chlorella spp. and its relation to the clinical performance of red tilapia in silvofishery ponds. The research method used is an ex post facto causal design with random sampling. The results showed that the water quality in the silvofishery ponds was very good, except for the nitrate parameters of 0.00-1.50 mg/L and salinity of 2-11 gr/L, which exceeded the quality standards. In the silvofishery ponds, 5 plankton classes were found, namely Chlorophyceae, Cyanophyceae, Chrysophyceae, Protozoa, and Dinophysis, consisting of 15 genera. The dominant class Chlorophyceae had an abundance of 2.88E+06 cells/ml. The class Chlorophyceae is dominated by Chlorella spp. (2.63E+06 cells/ml) and Chlamydomonas spp. (2.20E+05 cells/ml). The abundance of Chlamydomonas spp. in silvofishery ponds is closely related to phosphate solubility (0.988). Based on observations of clinical symptoms on the eyes, gills, and fins of fish, no disease infections or physical abnormalities were found in the fish cultured in silvofishery ponds. Fish tend to live well with a growth rate of 0.44 g/day. The aquatic ecosystem of the silvofishery pond, which is dominated by the plankton Chlorella spp. and Chlamydomonas spp., had a good effect on the performance and condition of the farmed fish. This study concludes that the abundance of Chlamydomonas spp. and Chlorella spp. was very dominant compared to other plankton genera. The presence of Chlamydomonas spp. and Chlorella spp. illustrates good and stable environmental conditions in silvofishery ponds, followed by no clinical signs of disease infection in the fish reared during the study period.