I Nyoman Yoga Parawangsa
The four lakes in Bali, known as "Catur Danu," hold significant cultural, historical, and ecological value. They are an inseparable part of the cultural life of the Balinese people. Functionally, these lakes play a crucial role, especially as natural water reserves. The lake ecosystems in Bali maintain the continuity of the hydrological cycle through the surrounding forest ecosystems, which are integral to the lives of the Balinese people.
The uniqueness of Bali's lake ecosystems, which are confined to the highlands, has driven the government to maintain and protect these ecosystems through Regional Regulation No. 2 of 2023 concerning the Bali Province Regional Spatial Planning Plan for 2023-2043. The main objective of this regulation is to create a beautiful, holy, and sustainable lake area while maintaining the lakes' function as reservoirs of stable and high-quality water.
Despite these regulations, Bali's lake ecosystems face ecological problems and anthropogenic pressures. Issues such as shallowing, pollution, eutrophication by macroalgae, uncontrolled tourism activities, excessive cultivation, and the introduction of foreign fish species threaten the lakes. The presence of non-native fish species can dominate fish communities, threatening the sustainability of native fish populations and negatively impacting the lake ecosystems.
To address these challenges, comprehensive data collection is needed, combining traditional methods with modern techniques such as molecular identification using DNA barcoding. This research will utilize environmental DNA (eDNA) metabarcoding analysis to highlight the importance of molecular data in rapidly assessing the biological richness of freshwater fish in Bali's lakes.
The expected outcome of this research is a comprehensive morphological and genetic species checklist for the fish diversity in the four lakes of Bali. This data will be instrumental for fisheries management within these lake ecosystems. It will support the maintenance of native fish species, address the potential introduction or dominance of foreign fish species, and enhance the development of native species for aquaculture and the freshwater ornamental fish trade. Furthermore, the availability of molecular data will expedite the assessment process using eDNA, facilitating more effective and efficient regular monitoring.
Another key achievement of this project is capacity building for stakeholders around each lake. These stakeholders include local governments, the Indonesian Nature Conservation Agency, and local communities. Currently, fish release activities in Bali's lakes are not monitored by stakeholders or the surrounding communities. Generally, institutions or agencies conducting these activities release fish without monitoring the species being introduced. This practice can lead to the introduction of non-native species into the lake.