A fishway close to Ingham’s town centre is the newest addition in a project that’s helping more than 100 species of fish – including barramundi, mangrove jack and jungle perch – to breed up in Wet Tropics waterways.

Terrain NRM and Catchment Solutions recently completed the 250 metre fishway at Gedges Crossing which will help fish to move through a weir. The structure is one of five fishways that have recently been built and one of 18 projects removing barriers to fish in the Murray and Herbert river catchments between Tully and Ingham.

Terrain NRM’s Deb Bass said other solutions have included bed-level creek crossings to replace causeways, culvert modifications and the removal of several creek crossings.

“We’ve also been working on invasive weed and feral pig control in these areas, and revegetation in an area where fish passage works were completed.

“This newest fishway is a curved rock ramp that’s at the side of Gedges Crossing on Pump Station Road, and is designed for lower flow conditions when smaller fish can’t get over the weir.

“It’s opening up more than 50km of upstream habitat to many different fish species.

“Fishways slow the water and create resting pools. The idea is juvenile fish can move upstream a couple of metres, then take a rest, then move up further and rest and so on.”

Terrain NRM has partnered with Catchment Solutions and OzFish Unlimited on the Fish Homes and Highways project, which is funded by the Australian Government’s Reef Trust program.

All the fishways were constructed in the dry season and the last one was completed just weeks before Cyclone Jasper crossed the Far North Queensland coast, bringing flooding rain.

“We’d already seen hundreds of empire gudgeons and shrimp species using the fishway at Lagoon Creek, moving up with the tide,” Deb said.

“OzFish Unlimited will be monitoring the fishways over the next six months to see the number and type of native fish moving through them.”

The construction phase followed extensive surveying in the Herbert and Murray River catchments. More than 3500 potential fish barriers were identified, leading to short-listing and on-ground inspections of over 300 sites to prioritise work based on the landscape, landholder willingness, accessibility, cost and development approvals.

Many native fish need to move between estuarine and freshwater habitats at different times of year, for several reasons:

• Migrate to and from breeding and spawning grounds
• Find deep waterholes and wetlands for refuge in the dry season
• Access waterways after drought
• In response to changing water quality such as dissolved oxygen levels
• Find new areas for feeding
• Evade predators

Some iconic fish that spawn in marine habitat and migrate to freshwater are barramundi, mangrove jack, sea mullet, freshwater eels, jungle perch and tarpon.

Barriers are structures or conditions that prevent fish from moving between different habitats. This can mean there is less overall habitat available for fish to live in, which can lead to reduced fish populations. Barriers also impact fish diversity and disrupt life-cycles.

Invasive fish species like tilapia and gambusia can survive and reproduce in degraded and polluted waterways much more successfully than even our hardiest native fish species. Enhancing waterway connectivity and health by removing barriers to fish movement is one way we can support native fish.

CAUSEWAYS: Causeways and crossings can effectively turn into small dams in low flow conditions, and only reconnect when high rainfall and flow events occur.

Can a small fish navigate the Murray and Herbert rivers and tributaries? That’s the basis for a new project to remove barriers preventing juvenile fish – including barramundis and jungle perch – from moving upstream to nursery grounds.

More than 3500 potential fish barriers have been identified in the Murray and Lower Herbert basins and a field team is now inspecting hundreds of them to prioritise work at causeways, culverts and areas with weed and feral pig problems.

The new Fish Homes and Highways project is being delivered by Terrain NRM to address threats to nationally significant wetland areas and coastal ecosystems.

Terrain’s Deb Bass said constructed barriers like weirs, causeways, pipe and box culverts could stop freshwater fish species that spawn in estuaries from safely moving upstream to wetlands to mature into adults. Not being able to reach nurseries to mature impacted fish populations and diversity.

She said constructed barriers were just one of the challenges for fish.

“Aquatic weeds like hymenachne can build up, creating a physical choke as well as a chemical barrier where there’s simply not enough oxygen left for fish to move through safely. Add feral pigs to the mix, which tear up waterways and create physical barriers, and you have a serious problem.

“Impacted fish include iconic species like jungle perch, barramundi, mangrove jack and tarpon.”

Experts have used high resolution imagery and desktop analysis to identify the potential barriers in the Murray and Herbert catchments. Three hundred barriers, considered the top-priority ones, are now being physically investigated by a field team.

Ms Bass said other factors including stream movement, flow rate, distance from the coast, physical specifications of barriers, and ease of modification are then considered.

“This way we can find out what interventions will have the best bang for buck as well as the best ecological outcomes for fish,” she said.

Who doesn’t love talking about fish?! That’s Adam Royle’s take on life, so he’s pretty excited about new fish passageways that will help scores of native fish species move between freshwater and marine waterways in the Hinchinbrook area.

Adam and other members of the Hinchinbrook Local Marine Advisory Committee have been working alongside OzFish with species surveys along Palm Creek where a zig-zagging fish passageway was built at Ingham’s Victoria Mill Weir a year and a half ago. They’re also working on a new project that’ll hopefully lead to a fish passageway being constructed near the Tyto Wetlands in Ingham.

He says the first two Palm Creek fish surveys have returned great results.

“We’ve seen a good number of species, including freshwater prawns, eels and spangled perch. There is absolutely no doubt that fish are moving between the upper and lower parts of the weir, something they haven’t had the opportunity to do at this scale since the weir was constructed.’’

The zig-zagging fish passageway is a series of 26 ramps and ponds or pools that fish can work their way up to get past the weir.

“That’s important to a lot of species, including mangrove jack and barramundi, because they spawn in the marine environment, the juveniles move up the river systems to find freshwater nurseries, and then when they’re of age, they need to return to the marine environment to start the cycle all over again.

“Fish passage barriers are a real threat to fish numbers and diversity.”

Surveys also show where improvements, or “tweaks”, can be made to the design of a passageway.

“We’ve been helping to set-up and remove short-term fish traps, and do fish species counts. It’s been great for our members, with helpers ranging from retirees to teenagers including my daughter Hope who absolutely loves helping with the surveys.”

The Hinchinbrook Local Marine Advisory Committee (LMAC) has recently partnered with OzFish on a different project that will include fish surveys at Tyto Wetlands and in the Herbert River, and initial design work for a rock ramp fishway near Tyto Wetlands. It’s funded through the Great Barrier Reef Foundation.

“The Hinchinbrook LMAC identified an issue where overflow from the Herbert River and localised rain fills up a water way adjacent to the Tyto wetlands. Fish move up through the flooded waterway but hit a barrier before entering the wetlands and can’t go any further.