DNA barcoding reveals larval fish diversity and distribution along the Cibareno River (West Java, Indonesia)

Context. There is a global problem with ongoing riverine infrastructure projects where, despite knowledge of potential environmental impacts, there is rapid development, often without appropriate environmental safeguards. This results in fragmentation of riverine fish communities, especially diadromous species. Understanding freshwater fish larval ecology is critical to provide insight into the likely impacts of these projects. Aims. To assess fish larval biodiversity on the basis of DNA barcoding, abundance and its distribution pattern in the Cibareno River. Methods. Fish larvae were collected at six locations in the Cibareno River. The larvae were identified by DNA barcoding. Key results. A notable disparity was seen in the distribution of larval abundance in different locations. The non-native species, Poecilia reticulata, was the most abundant larval species, with an intraspecific diversity of 0.003 (99.7% similarity). The upstream area exhibited a lower level of larval species diversity than did the downstream area. Conclusions. Genetic identification can reliably identify fish larvae and determine their spatial riverside distribution in the Cibareno River. The conservation of connectivity maintains fish community integrity and diversity between upstream and downstream locations in the weir building plan. Implications. This discovery emphasises the relevance of larval identification in fish biodiversity assessment and sustainable fisheries resource monitoring.