The externalities value of mangrove forest conversion into fishponds in the coastal area of wulan delta in demak regency

The high dynamic development in Wulan Delta coincides with the mangrove forest conversion into fishponds. The purpose of this research was to determine the externalities value of mangrove forest conversion into fishponds in Wulan Delta in Demak Regency. This research used a quantitative descriptive method. The data were collected through surveys using questionnaires and an interpretation of fishpond and mangrove forest use through Sentinel 2A on 2016 and 2018. The targets in this research were residents of Menco Hamlet and fishpond owners in Wulan Delta. The data were processed by calculating the economic value of the direct and indirect uses of mangrove forests as negative externalities, and fishpond production as positive externalities. The analysis was carried out in a descriptive-quantitative way by comparing the negative externalities value and the positive externalities value of mangrove forests conversion into fishponds. The results of this research show that the conversion of mangrove forests into fishponds indicates negative externalities. The negative externalities are indicated by fishpond productivity which is not able to surpass the mangrove forest use, even in terms of direct value only.