FISH ABUNDANCE AND DIVERSITY AS BIOINDICATOR OF WATER QUALITY IN SENGGURUH AND KARANGKATES RESERVOIR

Reservoirs serve as beneficial recreation areas for the surrounding community. Reservoirs are also habitats for various types of flora and fauna. Severalfamous reservoirs in East Java due to their fisheries potential are Sengguruh and Karangkates Reservoirs. This study aimed to determine the abundance and diversity of fish as bioindicators of water quality in Sengguruh and Karangkates Reservoirs. Fish and water quality parameters weresampled at three points in each reservoir, namely residential, tourism, and fisheries areas. All data were analyzed descriptively, while the correlations between fish abundance and diversity with water quality were determined using the Pearson’s correlation test. According to the results, three fishfamilies were found in Sengguruh Reservoir with a relative abundance of 26 - 55 ind/200 m and a diversity index ranging from 1.6510 to 1.7239. Meanwhile, in Karangkates Reservoir, four fishfamilies were found with a relative abundance of 41-43 ind/m and a diversity index of 1.7806 - 1.8787. The water quality parameters showed temperature of26-28.7℃, pH of 7.5-8.5, DO of 4.5-8.2 mg/L, CODof 20-28 mg/L, ammonia of 0.18-0.77 mg/L, and nitrate of 6.7 - 21 mg/L. Based on the diversity index value, both reservoirs are classified as lightly polluted, with abundance variables have no correlation with temperature, yet negative correlation is presented with DO, pH, and nitrate. In contrast, a positive correlation is shown with phosphate and ammonia.