Hydroacoustic survey of NSW impoundments

How do we count the fish
in all that water?

NSW has a number of impoundments that form important freshwater recreational fisheries.

But how do we know how these fisheries are performing?

Why Hydroacoustics?

Netting and electrofishing surveys can be expensive and time consuming when covering large areas such as lakes and dams.

However, with recent advances in hydroacoustics (or sonar) techniques fish numbers can be quickly estimated over large areas.

How does it work?

Our hydroacoustic surveys use specialist fish finders designed to be more accurate and powerful for scientific purposes.

With new technology/ data processing techniques, fish numbers/ sizes, swimming depth, direction of travel and fish species can be determined.

What are we doing in NSW?

Trials were conducted at Narrandera and Gaden fish hatcheries to examine signals produced by Murray cod, Golden perch and trout.

Scans have been completed in sections of Windamere, Burrendong, Eucumbene and Copeton Dams. A full scan has also been completed on Jindabyne Dam.

All work has been undertaken by Infofish in collaboration with NSW DPI scientists and field technicians.

What have we found?

Lots of fish!

Scroll through the next few pages for highlights or see the interactive maps in the explorables part of the website.

These are preliminary results, with further analysis and data summaries to follow.

Copeton Dam

Highlights:

● 380 acres of water sampled.
● Over 1,100 fish longer than 200mm detected.
● About 5% of fish over 600mm
(< 1% over 800mm).

Copeton Dam

Windamere Dam

Highlights:
  
● 275 acres of water sampled.
● Over 1,100 fish longer than 200mm detected.
● About 12% of fish over 500mm
(4% over 600mm).

Windamere Dam

Burrendong Dam

Highlights:

● 430 acres of water sampled.
● Over 2,464 fish longer than 200mm detected.
● About 10.5% of fish over 500mm
(1% over 700mm).

Burrendong Dam

Eucumbene Dam

Highlights:
● Coming shortly

Eucumbene Dam

Jindabyne Dam

Highlights:
  
● 5475 acres of water surveyed
(all of the lake).
● More than 16,000 fish over 200mm recorded.
● About 50% of the fish recorded over 200mm were > 400mm.

Jindabyne Dam

What’s next?

Further samples are planned for NSW impoundments in 2020/21, with dams to be sampled routinely every few years.

Although these surveys provide some interesting maps as initial results, they also form part of a longer term project that will allow us to better understand our fisheries and provide optimal management into the future