Thousands of migrating fish are making their way through the Barwon River’s lower tidal barrage fishway. As part of the statewide VEFMAP program looking at the responses of aquatic systems in response to environmental flows, aquatic scientists from the Arthur Rylah Institute have been monitoring the numbers of fish moving through the fishway which was constructed by the CCMA in 2013.
Fishways are structures that allow fish to move past barriers such as weirs and regulators which would otherwise restrict their access to the rest of the river either up or downstream. These barriers are a major threat to migratory native fish across Australia, which need to complete part of their life cycle at sea or in estuaries.
CCMA organised for members of the Geelong Field Naturalists Club to come and see the Arthur Rylah staff in action and for them to learn a little more about the aquatic fauna of the local area, the majority of the species having never been seen by the group previously.
Sampling was done over nine weeks from October to December 2017. In total, just under 30,000 fish were recorded using the fishway. Two rare fish species were also recorded during sampling; Australian Grayling and Australian Mudfish. Both of these species are vulnerable to extinction and protected under state and federal environment legislation. It is encouraging to see that these species are still present in the Barwon River system and that they are using the fishway.
The objective of the monitoring is improve our understanding of native fish responses to environmental water releases to more efficiently utilise environmental water in the future.