Water quality, fertility, fish culture carrying capacity of Riam Kanan Reservoir, South Kalimantan Province

Abstract

Fish cultivation in Riam Kanan Resevoir has well developed based on the floating fish cage production development in the last few years. However, this development, if not controlled, will exceed the reservoir carrying capacity and can result problems in relation with degradation of water quality and its trophic status. This study was aimed at analyzing the water quality condition, the trophic status, and the fish cage culture carrying capacity in Riam Kanan reservoir. This study was carried out for 5 months, from May to September 2019. It applied field survey method to gather the water quality data. Water sample sites were pusposely selected as many as 7 stations, and water quality measurements were conducted 3 times at 2-month interval. There were 16 parameters measured, temperature, transparency, turbidity, TDS, TSS, pH, DO, TP, TN, NH3-N, free NH3, BOD, COD, NO3, NO2, and chlorophyll-a. Results revealed that water quality of Riam Kanan Reservoir was categorized as moderately polluted with mesotrophic fertility status. The capacity of total phosphorus load was 137.3 ton yr-1. Riam Kanan Reservoir has recently an excessive load of TP as much as 89.3 ton yr-1 that is equivalent to excessive fish production of 5,030 ton yr-1. The recommended fish culture production is 3,925 ton yr-1 or equivalent to 1,869 plots of floating fish cage.