A research trial has led to the surprise discovery of a rare fish in the Perth Hills that was previously thought to be extinct north of Margaret River.
Three years ago, members of the Bibbul Ngarma Aboriginal Association (BNAA) took an eDNA sample as part of their BoorYul-Bah-Bilya project to assess the health of the Mandoon Bilya (Helena River).
The team expected to gain a lot of information through the experiment – eDNA detects species present in an area through DNA left behind in the environment – but they never thought they would come across Balston’s pygmy perch.
BNAA executive director and environmental scientist Francesca Flynn told Today it took time to confirm the eDNA sample was correct, but a recent investigation by the Department of Water and Environmental Management left no doubt the fish were alive – and thriving.
“We went out with (DWER) and did this fish survey, and we checked a lot of places along the river, and it was there, in the area we thought it was,” he said.
“It was amazing to find it. We were all so happy. I was crying. It was so special to think that the little fish survived, and it’s 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 great opportunity.”
“We just started as BoorYul-Bah-Bilya Rangers, so to be able to find this fish has been a great moment for us. Not many people get to see this fish, so it was amazing to be there and be part of the discovery,” he said.
“Hopefully, it will lead us to do more of this kind of work – to go into the Country, discover what’s still out there, and learn how we can better protect our rivers.”
Balston’s pygmy perch were known to inhabit much of the South West, but were long believed to be extinct from many rivers and wetlands north of Margaret River.
The small fish grow up to 6cm in size and live in thick reeds along the river.
The fish species were in the upper catchment area above Mundaring Weir and Flynn said he believed it was because of the area that the fish were able to survive after all these years.
“What it means is that the river, which we knew, is strong and strong and special,” he said.
“It really hasn’t been affected like other rivers. A lot of other rivers have had agriculture and mining and refining and all kinds of things, whereas this river has been left alone.”
This discovery is not the first for the BNAA team. In 2024, the group found a new population of qukka in the Perth Hills.
Famously associated with Wadjemup (Rottnest Island) the quokka population is also known to exist in the South West and South Main forests; however, the number has decreased over the years.
“This was another win for eDNA because we found another local extinct species that was thought to be extinct for a long time in this region,” Flynn said.
“We have an animal monitoring program to understand what kind of animals live in the river … and this animal was seen on the animal cameras.
“We were all happy, so we went out one day and collected poo from in front of the camera and we tested it for eDNA again … and it was qukka poo.”
Flynn said the quokkas live along the creek in the same areas where the pygmy perch was found.
“There’s more out there than you think,” he said.
“We’ve never seen someone running across the road or in the woods or anything, they’re so hidden, there’s no sign when you go out to check the cameras, except for their poo, but they’re out there.”
Flynn hopes the two discoveries can help bring better protection to the watershed and the Helena River as a whole.
“There are many things this means, but ultimately, we hope it will lead to better protection of this area, more recognition that this is a very special place that deserves your protection, and also more effort and resources dedicated to understanding this fish … and the quokkas,” he said.
