UPDATED ASSESSMENT OF FISH DIVERSITY IN JADA BAHRIN RIVER, BANGKA ISLAND, INDONESIA

Abstract

Freshwater fish communities on small tropical islands are important components of regional biodiversity, particularly where rivers provide habitat for species with restricted geographic distributions. Jada Bahrin River on Bangka Island is known to support a diverse assemblage of freshwater fishes, but periodic reassessment is needed to document its current composition. This study aimed to provide an updated inventory of freshwater fishes inhabiting Jada Bahrin River and to identify species of native and conservation relevance. Fish observations and collections were conducted in the river system, followed by taxonomic identification based on available morphological characteristics. The current survey recorded 23 unique fish taxa representing a diverse assemblage of freshwater fishes. The recorded community included Parosphromenus deissneri, Betta chloropharynx, B. edithae, B. schalleri, Rasbora bankanensis, R. einthoveni, R. cephalotaenia, Trichopodus trichopterus, Nandus nebulosus, Luciocephalus pulcher, Belontia hasselti, Pristolepis fasciata, Anabas testudineus, Channa lucius, C. striata, Ompok sp., Kryptopterus sp., Silurichthys sp., Hemirhamphodon pogonognathus, Barbodes sellifer, B. lateristriga, Osteochilus spilurus, and O. vittatus. The occurrence of P. deissneri and several Betta species highlights the importance of Jada Bahrin as habitat for freshwater fishes with notable conservation and biogeographic significance. The presence of taxa identified only to genus level also indicates the need for further taxonomic verification, potentially through molecular approaches. Comparison with earlier records suggests that continued field surveys are important for capturing temporal and spatial variation in the local fish assemblage. The findings provide an updated baseline for freshwater fish diversity in Jada Bahrin River and support the need for continued biodiversity monitoring and habitat conservation on Bangka Island.