Fish composition of Layang river estuary, Klabat Bay, Bangka Island, Indonesia

Estuary is a mixing area of freshwater and salty water coming from the sea. Fluctuation of tide and the ebb of sea water create a unique characteristic of this water body ecosystem. The ichthyofauna also has a behavior adaptation to the fluctuation of environmental in this system. Estuary is productive ecosystem and plays important role for marine fish species. The study was aimed to elucidate the fish composition and environmental condition of Layang estuary as an input for developing conservation of fish resource in this area. Fish sample was collected using a monofilament gill net belong to fisherman. Fish species information was also obtained through focus group discussion. Information about life cycle category, distribution, habitat and trophic group were collected from secondary source. There are 26 fish species dominated by marine migrant that some have a part of their life cycle dependent on estuarine system. From the functional biodiversity point of view, the fishes are benthopelagic and benthic species belong to benthicvorous group indicates the importance of Layang river estuary to support life cycle of marine migrants species. Spatially, there was a different salinity between upstream and down stream monitoring sites. Temporally salinity of the month representing the rainy season are also different from the dry season. Turbidity increased during observation especially in the rainy season while DO showed under continues degradation.