Fish homes and highways.
Fish in the Wet Tropics need to migrate between habitats for different stages of their life cycle, but thousands of barriers are getting in the way and having a negative impact on diversity and fish stocks.
Recreational fishers from all around the world come to Hinchinbrook. Any project that enhances fisheries values and the diverse ecosystems that support them will benefit the community too.
It is estimated that up to 50 per cent of our region’s most iconic fish species, like barramundi and jungle perch, need to migrate within freshwater environments and between fresh and saltwater for spawning and larval development. Yet thousands of barriers caused by urban and agricultural development – things like weirs and causeways – are restricting fish movement and limiting the amount of habitat they can access for various stages of their development.
Several projects are looking at ways to remediate these barriers to improve the connectivity of fish habitats. The Fish Homes & Highways Project in the Murray and Lower Herbert catchments is being delivered by Terrain NRM, Hinchinbrook Shire Council and the Herbert River Catchment and Landcare Group. The project includes aquatic weed control, feral pig management and streambank stabilisation as well as engineering works at road crossings.
Rowan Shee, Project Manager at Terrain NRM, said 18 fish barriers will be improved with engineered solutions.
“Over the next year we’ll be constructing about eight rock ramp fishways to remove drop barriers. A weir will be removed and, in several locations, we’re replacing high velocity pipe crossings with bigger box culverts that allow slower flows so fish can swim through. Some causeways are also being replaced with streambed level crossings.”
“These changes will help open up more habitat. One barrier at Gedges Crossing will open up a network of 250 kms of connected waterways further upstream,” he said.
Engineered fishway solutions are expensive but sometimes the only option. Dr Geoff Collins, a scientist with OzFish Unlimited North QLD, has been monitoring constructed fishways in North Queensland.
“We’ve mainly been monitoring rock-ramp fishways, which are designed to simulate a natural riffle environment of a stream or river,” he says.
“We use custom-built traps that are placed across the fishway on the upstream side to capture and assess the range of fish species migrating through. We also collect information on fish communities upstream and downstream, assess water quality parameters and measure the velocity of water.”
Geoff says monitoring has revealed that fish species, across a range of life stages, are using the fishways to migrate.
“At a fishway in Palm Creek near Ingham we’ve recorded 16 fish species including barramundi, tarpon, spangled perch, rainbowfish, empire gudgeon, hardyhead, glassfish, bony bream and three species of eel-tailed catfish.”
Michael Nash, Natural Assets Manager at Hinchinbrook Shire Council welcomed the Australian Government’s investment in fish habitat connectivity.
“Recreational fishers from all around the world come to Hinchinbrook to explore the rivers, estuaries and reefs of the region. Any project that enhances fisheries values and the diverse ecosystems that that support them will ultimately benefit the community too,” he said.
Fish Homes and Highways is funded by the Australian Government’s Reef Trust.