Chlorophyceae is a class of plankton commonly discovered in aquaculture ponds in tropical aquatic regions. Therefore, this study aimed to analyze the abundance levels of Chlorophyceae in pen-culture ponds during the dry season using a dynamic modeling system. The method adopted was a causal ex-post facto design, and the observed parameters were water quality and plankton abundance. The results showed the presence of various plankton classes such as Chrysophyceae, Chyanophyceae, Chlorophyceae, Dynophyceae, and Oligotrichea, as well as the discovery of 17 plankton genera. Water quality parameters identified Total Dissolved Solids (TDS) concentrations, dissolved oxygen levels, temperature, pH levels, and salinity ranging from 3.06–7.37 mg·L-1, 4.39–6.30 mg·L-1, 26.21–31.17 °C, 7.7–8.1, and 10–25 ppt, respectively. The average plankton dominance index (D’) showed Chlorophyceae dominance at 4.55, followed by Chyanophyceae, Chrysophyceae, Dynophyceae, and Oligotrichea at 1.78, 0.08, 0.07, and 0.01, respectively, falling in the index category of 0.5 < D < 1. Furthermore, the average plankton abundance dominance level (pi) signified Chlorophyceae dominance at 7.11E-01, followed by Chyanophyceae, Chrysophyceae, Dynophyceae, and Oligotrichea at 4.68E-01, 1.30E-01, 8.05E-02, and 3.96–02, respectively. This implied that in pen-culture water, Chlorophyceae significantly dominated over other classes. Dynamic modeling results showed the abundance of Chlorophyceae in ponds A, C, and D to be relatively uniform (± 5.00E-02 cell/ ml) compared to pond B (± 0.10E-00 cell/ml). It was important to acknowledge that as Chlorophyceae dominance increased (0.10E-00–5.0E-02 cell/ml), the total plankton abundance in the water decreased contradictorily (0.01E00–100E-04 cell/ml) due to over-dominance. On the basis of the modeling description, Chlorophyceae sustained for 20 weeks during the culture period, with optimal growth observed from the 1st to the 5th week. In conclusion, this plankton class experienced dynamic fluctuations during the pen-culture cultivation period, and the life cycle stability was dependent on water quality and temperature.
