Rookwood Weir Fish Community and Fish Lock Monitoring 2022-2027
Completed in late 2024, Rookwood Weir will supply central Queensland with 86,000 megalitres of water each year for agricultural, urban and industrial use. As part of the project’s approval conditions, a comprehensive monitoring program was established to assess how the weir influences fish communities and habitat use across the Fitzroy Basin. This program supports the Rookwood Weir Waterway Barrier Works Offset Delivery Plan, which aims to maintain fish population connectivity and conserve key species throughout the catchment.
The monitoring adopts a catchment‑wide approach and began with pre‑construction surveys that provided essential baseline data. Ongoing assessments now continue upstream and downstream of Rookwood Weir and the Fitzroy Barrage, as well as at the Rookwood Weir Fish Lock and Fitzroy Barrage Tidal Lock Fishway (see separate project). These surveys track changes in species composition and abundance over time and help determine whether the construction and operation of the weir are affecting local fish populations.
Rookwood Weir Fish Community Monitoring 2022-2027
Fish community sampling is progressing well, with initial findings revealing a noticeable shift in species composition, particularly within the weir pool (upstream of the weir). Higher concentrations of bony bream, mouth almighty, sleepy cod, and tilapia have been observed in the weir pool since construction, aligning with these species’ preference for lentic, low-flow environments. Continued sampling will expand the dataset, enabling confirmation of these patterns and evaluation of their significance throughout the wider catchment area.
Rookwood Weir Fish Lock Monitoring 2024-2027
The fish lock is being monitored using a suite of complementary methods: customised traps installed at both the entrance and exit of the lock sample fish moving through the structure, supported by video observation, electrofishing, and netting at sites upstream and downstream of the weir. In addition, fish have been tagged with passive integrated transponder (PIT) tags, enabling detection at readers installed at the fish lock. This PIT‑tagged population will gradually be supplemented with acoustic‑tagged individuals to provide more detailed information on fish approach patterns and behaviour around the structure.
Over 29 days of sampling in 2025, a total of 8,153 fish from 23 species were captured moving through the lock fishway. Clear patterns of movement were observed at different times of day and under varying flow conditions. Ongoing monitoring will refine our understanding of these patterns and enhance fish lock operations by pinpointing optimal settings.
