ABOUT 150 Murray Darling rainbowfish were released into the Mildura Riverfront Endangered Fish Nursery on Sunday, World Environment Day.
Hardy Sunraysia locals braved the cold at Ornamental Lakes to learn about the river and fish migration.
Mid-Murray floodplains recovery reach co-ordinator Peter Rose said World Fish Migration Day, celebrated last month, was aimed at raising awareness about the need for open rivers for fish migration.
“All of our native fish need to move around to some degree,” he said.
“In (the Riverfront Endangered Fish Nursery) we have the purple spotted gudgeon, an endangered fish that is actually breeding here.
“They need to move around and be connected up to the floodplain and when the floods come along they will be able to move up and back into the river and disperse and find other habitats.”
Mr Rose said he was representing the Tri-state Murray NRM, which comprises national resource management agencies working together to bring back native fish that often need to migrate.
“Our native fish don’t really respect borders,” he said. “A lot of them need to move long distances. We need to work together across the three states at a scale that the fish need to work at as well.
“We have got some amazing freshwater fish. Golden perch is a really good example, they actually need to move long distances upstream to spawn sort of hundreds to thousands of kilometres.
“Golden perch have actually been tracked moving 2300km, which is one of the biggest freshwater fish migrations in the world.”
Mr Rose said that there were several barriers to fish movement, including irrigation, fans, road crossings and weirs.
New South Wales Fisheries manager Iain Ellis, who is also the co-ordinator for the lower Darling River fish recovery strategy, said Mildura Weir was affecting important fish migration.
“It turns out by looking at the chemistry in their bones that pretty much every golden perch that people catch in the Murray in this part of the world started life in the Darling River,” he said.
“Which is why connectivity and fish migration is so important and we use fish ladders to get fish past things like weirs.
“The (Mildura) one doesn’t work very well, it was designed as a quick fix. We tried to remediate that and essentially what that means is if we don’t help golden perch go through Mildura Weir, fishing upstream ultimately we are going to run out of fish.
“So that is why on Fish Migration Day my big pitch is get behind fish ladders, get behind fish connectivity.”
Mr Rose said Murray Darling rainbowfish were being released into the riverfront nursery as they were a threatened species.
“The fish actually migrate around as well, they often get caught in traps at fishways during fish monitoring,” he said.
“They are a bit of wetland specialist fish as well, they like aquatic plants and clear water and they are a really pretty fish.”
The event featured stalls and a barbecue lunch, and provided education to visitors about fish, the river and migration.
This year’s World Environment Day theme is Only One Earth.
The campaign calls for collective, transformative action on a global scale to celebrate, protect and restore the planet.
