In short:
The fishway at Menindee has reopened for the final season of its three-year trial, with 50,000 fish expected to travel through it before late May.
uncertain
fish → reopen → May
The reopening coincides with concern as the lakes and river experience low levels, poor water quality and algal bloom alerts.
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lakes → coincide → levels
The Basin Plan Review Panel will review findings after consultation with water users, holders and communities along the river.
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Panel → review → river
A fish passageway allowing fish to travel upstream into the Menindee Lakes has reopened for the final season of its three-year trial, as low water levels and poor water quality raise concerns about another potential fish kill in the Darling-Baaka this summer.
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levels → allow → Baaka
The passageway, operated by Finnish company Fishheart, is expected to see up to 50,000 fish travel through between now and late May or early June.
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fish → operate → May
The technology was installed to help reduce the risk of mass fish kills, including the 2023 event that saw about 30 million fish die in the area.
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fish → instal → area
Fishheart co-founder Mika Sohlberg said the increasing number of fish using the passageway each year had come from a better understanding of the river.
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number → say → river
"The first season we got 7,000 fish, and then around 30,000 fish," he said.
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he → get → fish
Fishheart regularly consult with a local group of traditional owners, who are able to share advice on fish behaviour.
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who → consult → behaviour
"Obviously the local fish are new to us," Mr Sohlberg said.
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Sohlberg → say → us
"It's like going fishing in a new place.
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It → go → place
When you go the first time in a new place, you hardly ever get a fish.
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you → go → fish
When you go a second time, you might get one fish.
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you → go → fish
But when you've been there 20 times, you get a lot of fish.
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you → get → fish
Regular upgrades to the cameras, lighting and artificially intelligent technology has helped to improve the system's ability to identify fish.
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upgrades → help → fish
Poor conditions
The fishway has reopened as the Menindee Lakes sit at a combined capacity of 29 per cent, with low rainfall in the catchment and algal bloom alerts in effect in parts of the lakes.
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Lakes → reopen → lakes
Cameron Lay, director of Freshwater Fisheries and Threatened Species at the New South Wales Department of Primary Industries and Regional Development (DPIRD) Fisheries, said the fishway could help reduce the risk posed by fish becoming concentrated in the Menindee weir pool.
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fish → say → pool
"I'm certainly worried, however we're here on the banks of the Baaka and we've done a number of things in recent years to try and minimise that risk,"he said.
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we → do → years
"Fish now have the ability to leave the Menindee weir pool which has been the site of a lot of those significant fish kills.
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which → have → kills
Some of that has been because there's been an accumulation of fish and there hasn't been sufficient resources, food, oxygen et cetera, for them to survive.
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them → be → fish
"So some of these initiatives, if they can allow fish to move out of the Menindee weir pool and up into the lake system and to migrate further up the Darling, then hopefully we've got a better change that we won't see large scale fish kills like we've seen in the past."
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we → allow → past
Mr Lay said there was concern around blue-green algae, although oxygen levels in the water were generally fine.
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levels → say → water
Blue-green algae can occur naturally in small amounts, but can rapidly multiply when weather is warm, water is still or slow-flowing, and excess nutrients enter the water.
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nutrients → occur → water
In large amounts, blue-green algae can deoxygenate water, potentially leading to fish suffocation.
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algae → deoxygenate → suffocation
"Things can change very quickly when you get extended periods of 40-degree days," Mr Lay said.
"
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Lay → change → days
"With El Niño developing, we have had challenging circumstances in the past when we've had really hot, extended dry periods, and that might be as big a concern as the amount of water that's actually in the river at the moment.
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that → develop → moment
Beyond the fishway
It is yet to be confirmed whether the fishway will be extended after the trial's conclusion, but Mr Lay said the fish passage was only one part of the broader work needed to improve river health.
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passage → confirm → health
He said outcomes from the recent Basin Plan Review would begin being implemented after they are released in December.
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they → say → December
One of the common themes the review panel heard during their tour of the river was that investment should be spent more broadly.
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investment → hear → river
"There's been a lot of focus in sort of purchasing water and water recovery and that has been an essential step," Mr Lay said.
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Lay → be → water
"The river can't survive unless it's got sufficient flow so that was probably the obvious and first priority area to focus on.
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that → survive → flow
But it's not the only problem that our rivers are facing."
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rivers → face → that
Along with the fish passage, he said water temperature and quality as well as habitat were vital to maintaining a healthy river system.
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temperature → say → system
"We have to address all those separate things if we're going to see a significant response in native fish populations."
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we → have → populations
The Aporia