Standard Talk (15 mins) Australian Society for Fish Biology Conference 2022

Evidence of fish community fragmentation in a tropical river upstream and downstream of a dam despite the presence of a fishway (#25)

Dwi Atminarso 1 2 , Lee Baumgartner 1 , Robyn Watts 1 3 , Meaghan Duncan 4 , Jennifer Bond 1 3
  1. Gulbali Institute For Agriculture, Water and Environment, Charles Sturt University, Albury, NSW, Australia
  2. Research Center for Conservation of Marine and Inland Water Resources, National Research and Innovation Agency of Indonesia, Cibinong, West Java, Indonesia
  3. School of Agricultural, Environmental and Veterinary Sciences, Charles Sturt University, Albury, NSW, Australia
  4. Department of Primary Industries, Narrandera Fisheries Centre, Narrandera, NSW, Australia

Rapid human population growth has increased demand for water supply, food security, electricity, and flood mitigation worldwide. To address these challenges, governments have invested heavily in the expansion of water infrastructure. However, there is substantial evidence that globally, this infrastructure impacts aquatic ecosystems and can have a significant impact on the persistence of migratory fish species. Despite being well understood globally, the impacts of dams on migratory fish have been given scant attention in Indonesia. Thus, considerations for fish are rarely included in river development planning frameworks. To document the impact of riverine barriers on Indonesian freshwater fish, we surveyed multiple sites, using three different gears (gillnets, castnets, and bait traps), upstream and downstream of Perjaya Weir in the Komering River. The study revealed 13 of 36 species were found only downstream of the weir and five of 36 species were found only above the weir. The local extirpation of many species from upstream areas suggests that the Perjaya Weir hinders fish migration. Despite containing a fishway, the results indicate that fish are not successfully recolonizing upstream reaches.