Two new projects funded by the Australian Government Fisheries Habitat Restoration Program (FHRP) will give Wet Tropics fish populations a boost – and provide the Wet Tropics Report Card with some new fish-focused indicators of waterway health.
The Wet Tropics has the highest diversity of freshwater fish in Australia with over 80 species now recorded. It is estimated that as many as 50% of them need to move between freshwater and estuarine environments for spawning and larval development but their movement can be hampered by man-made structures. Major dams, barrages and weirs are the obvious barriers to fish movement, but even relatively small structures such as culverts, bunds and road crossings can have a major impact on the overall health of fish populations.
Without free movement to spawn and recruit, fish populations can be dramatically reduced. Restoring access of predatory fish such as barramundi, mangrove jack and jungle perch to freshwater environments can improve ecological balance and help control pest fish such as tilapia. Creating passage for smaller species is critical to maintain the diversity that keeps our tropical systems healthy and vibrant.
The first of the two FHRP projects will identify all of the man-made barriers to fish movement within the Daintree, Mossman and lower Barron systems from the river mouths to the escarpment. They will be prioritised on their impacts to the health of fish communities and then in terms of the cost and technical feasibility of remedying the problem. Identifying and prioritising fish barriers will improve the regional report card with additional robust data. This project will complement a similar project funded by the Queensland Government for the Murray and Tully systems.
The second FHRP project will upgrade road culverts within mangrove habitat near the Cairns Airport. Since the culverts were installed connectivity between high quality wetland and freshwater habitats has been cut off. Whilst not contributing directly to data for the report card, this project will improve local fish recruitment and the diversity of fish upstream, complementing the Trinity Inlet Net Free Zone and reducing the need for artificial stocking of local systems with hatchery barramundi.
Wet Tropics Waterways partnered with Catchment Solutions and OzFish Unlimited to secure the funding for the projects, which will be managed by Terrain NRM with ongoing involvement from Wet Tropics Waterways, Catchment Solutions and OzFish.
Greg Vinall, Manager of Wet Tropics Waterways, said healthy fish populations and healthy waterways are interdependent.
“These days most of us are aware that we can’t have healthy fish populations without healthy waterways. But it’s also true that you can’t have healthy waterways without healthy fish. Removing key barriers to fish movement can help restore the ecological balance, diversity of fish and natural trophic interactions that are vital for a healthy waterway”.