During January and February 2025 the Inland Fisheries Service (IFS) surveyed a selection of the state’s rivers (across 16 sites) using backpack electro-fishing equipment. The aim was to assess the state of river trout populations after an 18-month period of abnormally high cormorant numbers in Tasmania.  The surveys involved electro-fishing a 100-metre section of each river or creek for three consecutive runs.

The results last year indicated that riverine trout populations were significantly impacted. The impact was greatest in the north-west, followed by the north-east, with less impact observed in the southern rivers. 

In response the IFS stocked 370,000 brown trout fry in some of the streams surveyed in the north-west and north-east, including tributaries of major rivers, like the Mersey River, during September and October 2025.

In February 2026, 12 of the river sites surveyed in 2025 were re-surveyed by IFS staff.

Pleasingly there was an improvement in trout numbers at most of the sites, despite the lower water levels this year at some of the locations. The attached chart shows that all sites except Seven Time, Redwater and Sassafras creeks had some level of improvement. A few sites had juvenile trout that may have originated from the 2025 fry stockings.

Numerous native species were also encountered during the survey, including river blackfish, galaxias, eels, lamprey and giant freshwater crayfish.

A detailed report on these surveys is currently being prepared.  The IFS will continue to monitor the recovery of trout populations over the coming seasons to help inform future management strategies.