Monitoring Strategy for Analyzing the Impacts of Coastal Finfish Aquaculture on Seafloor Sediments in Indonesia

This paper presents the development of a simple and generally applicable monitoring strategy for analyzing the environmental impacts of near shore finfish aquaculture in Indonesia. The proposed strategy has been tailored for remote aquaculture sites and primarily comprises sediment sampling, analysis of the chosen sediment indicators, and statistical analysis. The investigations were performed at a target aquaculture site in the northwest of Bali, Indonesia. On-site assessments were conducted for sediment quality underneath the largest fish farms accounting for 80% of the site´s production and at pristine reference locations. In this study, the effectiveness of several sediment indicators for monitoring benthic impacts was investigated. As total organic matter was found to be an effective indicator for the site in Indonesia which could be determined using a simple and inexpensive method, it was recommended for regular monitoring. The monitoring strategy was successfully integrated into a methodology under development at Germany to holistically estimate the carrying capacity of aquaculture sites. The effectiveness of the strategy in optimizing the relationship between the predicted carrying capacities of individual fish farms and the results of on-site assessments at the reference farms was demonstrated. From the analysis results, fish farms affecting the site in Bali were identified and recommendations made to ensure environmental sustainability. The proposed monitoring strategy has wide applicability and is currently being up scaled to several target aquaculture sites by the Indonesian government.