Method for Estimating Ecological Carrying Capacity of DataPoor Coastal Finfish Cage Aquaculture Sites in Southeast Asia at System-Scale

Abstract

This study presents the development of a simple and generally applicable method for estimating ecological carrying capacity (ECC) of coastal finfish cage aquaculture at the system-scale in Southeast Asia and potentially other data-poor island nations. The ECC method relies primarily on results of dynamic models for simulation of organic loading due to multiple fish farms. In this study, the ECC method was successfully integrated within a methodology under development at Kiel University to holistically evaluate site suitability, ecological carrying capacities at farm-level and system-scale, as well as siting. Results of the application of the methodology for a target aquaculture site in northwest Bali, Indonesia, are presented in this study. Analysis of these results identified traditional fish farms located outside suitable areas and large-scale commercial farm clusters operating beyond ecological carrying capacity. Nonetheless, it was found that production output of the site in Bali is far below ECC and that it could be increased considerably without harming the environment. Recommendations have been made for reallocating the mispositioned farms as well as for reducing fish production of the farm clusters while expanding overall fish production to the east. The ongoing operational early warning monitoring at the site in Bali is being supplemented with regular monitoring of sediment quality in the seafloor and water quality in the aquaculture area to promote sustainable development. The proposed methodology has wide applicability and can be easily adapted to other regions for investigating present conditions and planning new aquaculture sites in pristine regions. The methodology is currently being up scaled to several target sites selected by the Indonesian Government to expand the activity.