The Assessment & Modification of Barriers to Fish Passage in the Namoi Catchment

The ability of native fish to move freely up and downstream within our rivers and wetlands is vital to their survival. Fish need to move in order to feed, find shelter and reproduce. Impeding fish passage through the construction of dams, weirs, floodgates and waterway crossings can negatively impact native fish by creating physical, hydrological or behavioural barriers that:

• interrupt spawning or seasonal migrations,
• restrict access to preferred habitat and available food resources,
• reduce genetic flow between populations,
• increase susceptibility to predation and disease through accumulations below barriers,
• fragment previously continuous communities, and
• disrupt downstream movement of adults and impede fish larval drift through
the creation of still water (lentic) environments

This project was undertaken to identify barriers to fish passage in the Namoi catchment and in doing so provide the former Catchment Management Authority (now Local Land Services) with information necessary to undertake targeted remediation works.