Fitbits for fish movements along the Cudgegong River

While we can’t count their steps, native fish along the Cudgegong River are having their movements tracked thanks to cutting edge technology that works like a Fitbit for fish, enabling scientists to take a deeper dive into how environmental water flows effect their behaviour.

For the first time, the NSW Department of Climate Change, Energy, the Environment and Water (NSW DCCEEW) have tagged 56 large-bodied fish including but not limited to common carp, golden perch and rainbow trout with acoustic transmitters so they can follow them over time.

The wireless gadgets ping every time they swim past sensors on a network of seven listening stations that act like underwater ears recording fish moving in and out of Burrendong Dam, moving around the river upstream and downstream of Mudgee Weir and into places like Lawsons Creek.

It’s an innovative 21st century approach that will enable scientists to collect robust data every six months to help guide the timing and design of environmental flows from Windamere Dam.

It comes on top of a winter 2025 fish survey which covered 12 sites between Windamere and Burrendong Dams including the Putta Bucca wetlands, recording 705 fish across 12 species including species of conservation concern like silver perch, freshwater catfish, and Murray cod.

Five exotic species were found and a range of smaller-bodied natives like carp gudgeon, smelt and flathead gudgeon. No northern river blackfish were recorded.

Around 36 per cent of the individual fish recorded this year were one of the exotic species common carp, redfin, goldfish, rainbow trout and mosquito fish (gambusia).

The good news is these fish have been declining in numbers over the past three surveys. Encouragingly, the presence of young Murray cod and young freshwater catfish suggests successful breeding in recent years, which is a great result for fish and river health.

NSW DCCEEW is planning to deliver a spring environmental flow in the Cudgegong River this year, to benefit native fish and support the nesting season of the endangered freshwater catfish.

Quotes attributable to NSW DCCEEW Senior Wetlands and Rivers Conservation Officer Tim Hosking:

“We know some people love to track their day-to-day activities with fitness watches, now we’re using a similar idea to learn about fish movements in the Cudgegong River. This will let us get a clearer picture of how environmental flows effect the movement and behaviour of both native and exotic fish.

“Miniature transmitters are implanted into large-bodied fish and every time they pass an underwater sensor it records their presence, which gives us helpful information about movement in the river.

“Combining this information with regular fish surveys we are hoping to gain great information about native fish that will help shape conservation efforts in the future.”