Determination of Trophic Status and Floating Net Cages Carrying Capacity in Jatigede Reservoir

Abstract

Aquaculture activities with floating net cages are essential to increase fishery production. The existence of the fish cages in the Jatigede Reservoir is illegal because it is against local government regulations. However, the people affected by the dam's construction still maintain it for their economic reasons. Therefore, it is necessary to do a research to overcome these problems by determining the carrying capacity of aquaculture and evaluating the trophic status of the waters. However, the people affected by the dam construction still maintain it for their economic reasons. Determination of the carrying capacity of fish farming in the Jatigede Reservoir was conducted using the Beveridge method by calculating the remaining phosphorus still available in the Jatigede Reservoir and evaluating the trophic state index based on three indicators: transparency, total phosphorus, and chlorophyll-a. The sampling was carried out by purposive sampling method. The calculation results show that the condition of the Jatigede Reservoir is eutrophic to hiperthropic with a trophic state index (TSI) value of 66-71. The carrying capacity of the reservoir is 7,140.25 tons of fish/year. The development of cage aquaculture that exceeds the aquaculture carrying capacity  in Jatigede Reservoir. Reducing cage aquaculture fish production following its carrying capacity is important to preserve the environment and control eutrophication.