FISH populations in the Mackay–Whitsunday region are set to thrive following the completion of Queensland’s largest rock fishway, constructed on Jolimont Creek, north of Mackay.
Measuring over 100 metres in length, the fishway was designed to allow fish safe passage past a three-metre-high concrete weir – a significant barrier to fish migration that had been in place for more than 30 years.
The fish connectivity project was initiated by Mackay Regional Council, with on-ground
works funded through the Australian Government’s Reef Guardian Councils program. The
fishway was designed and constructed by Catchment Solutions, in partnership with Seaforth
Civil.
Matt Moore, Fisheries Ecologist at Catchment Solutions, explained that approximately half of the region’s 50 freshwater fish species migrate between the sea and inland freshwater systems as part of their life cycle.
“Fish migration between marine and freshwater habitats is a key requirement for many important recreational, commercial and Indigenous fishery species and is essential to maintain sustainable fish populations,” said Moore.
He highlighted several iconic species likely to benefit, including barramundi, mangrove jack,
jungle perch, tarpon, and long-finned eel, along with smaller prey species such as the colourful empire gudgeon.
The fishway functions like a series of underwater stairs, allowing fish to use short bursts of energy to navigate faster-flowing sections before resting in calm pools along the way.
“Our native fish are weak swimmers and poor leapers, so it’s critical we provide conditions like low-velocity zones and deep resting pools to support their upstream journey,” Moore said.
He also noted that the migration is particularly important for juvenile fish, such as young barramundi, which are just 50–100 mm in length when they travel upstream into freshwater
wetlands.
“Wetlands offer stable water levels and abundant food resources, helping juvenile fish grow
quickly and boosting their chances of survival when they return to saltwater to breed.”
Initial monitoring has confirmed the fishway’s success. In just five days, 15 freshwater species were recorded using the passage, with over 800 fish per day ascending the structure. Sizes ranged from just 16 mm to 750 mm.
Importantly, the monitoring also validated the effectiveness of Catchment Solutions’ innovative nursery slot design. The nursery slot creates a shallow film of water with a reduced velocity boundary layer, enabling even the smallest juvenile fish to safely navigate the fishway.
“It was fantastic to capture footage of tiny juvenile fish using the nursery slot – this size class
is often missing from fishway studies on large structures,” Moore added.
Local sugar cane farmer and landholder Rob Ellwood expressed optimism about the project’s impact on recreational fishing in the nearby St Helens to Cape Hillsborough Net Free Fishing Zone.
“Jolimont Creek flows into Murray Creek and into the Net Free Zone, so hopefully the
fishway will increase local barramundi populations,” Ellwood said.
Mayor Greg Williamson welcomed the fishway’s early success.
“In the Mackay region, we love our waterways and reef. Recreational fishing is one of the most popular ways our community connects with these environments,” Mayor Williamson said.
“It also has long-term benefits for tourism in the region as our region is well-known for its
outstanding fishing,” he said.
“The new fishway will enhance these opportunities even more by helping to boost local fish
stocks in the Seaforth and St Helens areas.
“We encourage locals, tourists and visitors alike to enjoy the incredible outdoor lifestyle and
fishing experiences our region offers.”
Jolimont fishway is the latest waterway restoration project completed by Catchment Solutions, following similar projects on the Herbert River in Ingham and Scrubby Creek in Logan City.
For more information visit www.catchmentsolutions.com.au.
