Rare fish believed to be extinct north of Margaret River found in Perth Hills
A research trial has led to the surprising discovery of a rare fish in the Perth Hills previously thought to be extinct north of the Margaret River.
Three years ago members of the Bibbul Ngarma Aboriginal Association (BNAA) carried out eDNA sampling as part of the BoorYul-Bah-Bilya program to assess the health of the Mandoon Bilya (Helena River).
The team expected to find a lot of information through testing – eDNA identifies species found in an area through DNA left in the environment – but they never thought they’d encounter Balston’s dwarf perch.
BNAA chief executive and environmental scientist Francesca Flynn said: WAtoday It took some time to verify that the eDNA sample was accurate, but a recent investigation with the Department of Water and Environmental Regulation left no doubt that the fish was alive and thriving.
“We went out together [DWER] and we did this fish survey and surveyed a lot of areas along the river and the fish was there in the area where we thought it was,” he said.
“It was amazing to find it. We were all really excited. I was crying. It was really special to think the little fish had survived and was there.”
The team found 13 fish during the 24-hour survey.
BNAA BoorYul-Bah-Bilya ranger Trei Winmar was one of the team members who helped find the pygmy perch and said it was “a really great opportunity.”
“We’re just starting out as BoorYul-Bah-Bilya Rangers, so it was great timing for us to have already found this fish. A lot of people don’t get to see this fish, so it was amazing to be there and be a part of the discovery,” he said.
“Hopefully this will lead to us doing more of this kind of work, going out into the Country, discovering what’s still out there and learning how we can better protect our rivers.”
Balston pygmy perch are understood to be native to much of the South West region, but were long believed to have disappeared from most rivers and wetlands north of Margaret River.
The small fish usually grow to about 6 cm in size and live in thick reeds along the edge of the river.
The fish species were located in the upper catchment above the Mundaring Weir, and Flynn said he believed it was because of the fish’s location that they were able to survive after all these years.
“What this means is that the river we already know is resilient, strong and special,” he said.
“It’s not really affected like other rivers. Most other rivers have been farmed, mined, cleared and all kinds of things have been done, whereas this river has been left alone.”
This discovery is not the first for the BNAA team. The group found a new quokka population in the Perth Hills in 2024.
Quokka populations associated with the famous Wadjemup (Rottnest Island) are also known to exist in the South West and Great South forests; but over the years the numbers have decreased.
“This was another win for eDNA because we found another locally extinct species that was thought to have long since disappeared from this area,” said Flynn.
“We have a fauna monitoring program to understand what kinds of animals live in the river… and this animal was captured on fauna cameras.
“We were all excited, so we went out one day and collected some poop from in front of the camera and had it tested again with eDNA… and it was quokka poop.”
Quokkas live in similar spots along the stream where pygmy bass are found, Flynn said.
“There’s more out there than you think,” he said.
“We’ve never seen anyone running along the road or in the bushes, they’re very well hidden, when you go out and check the cameras there’s absolutely no sign of them other than their poop, but they’re there.”
Flynn hopes the two discoveries can help provide better protection for the basin and the Helena River as a whole.
“This means many things, but ultimately we hope it will lead to better protection of this area, greater recognition that this is a very special place worth protecting, and also much more effort and resources devoted to understanding this fish and quokkas,” he said.
