The upper Mersey, above Pine Hut Plain and Lees Paddocks, is serpentine, myrtle-shaded water with trailing weed and partly submerged logs. It holds small browns and rainbows, and you often have to wade to reach them.

Below that, FlyLife describes access from Liena down to Latrobe, just above the estuary, with the named areas Merseylea, Kimberly, Weegena and Railton. On the freshwater reaches between Latrobe and Kimberley, overhanging willows throw shade, and trout hunt baitfish in it. In our experience that shade and the riffle edges are where to look first.

Clarke Falls isolates the stretch below Junction Lake from lake spawners, and Fergusson Falls marks the point above which only rainbows are described.

FlyLife’s writers describe a really good wild population of brown trout and rainbow trout, with browns in the 2 to 3 lb class in good seasons. Stocking records also list brown trout released in several seasons, which the stocking chart shows. Above Fergusson Falls the river is described as rainbow-only. Sea trout and native grayling are named as runs, and we would not plan a trip around either.

The forage is where the fishing is. Because the Mersey runs direct to the sea, whitebait feeders can be a feature of the lower river in spring, and each high tide during the run is described as bringing fresh schools, with the biggest tides bringing the most. In the mornings before Christmas, trout sip caenid duns in the slower currents, then take black spinners in the afternoon. After April rain, a downstream run of jollytails (common galaxias) can turn trout aggressive on the riffles and pools.

Spring is the whitebait season, starting in the lower river in the last weeks of August and reaching further up as the weeks pass. From spring to Christmas, plan on mornings for caenid duns and afternoons for black spinners. Autumn belongs to the jollytail run, which usually needs a good April rain to set it off.

Catch rates have been mixed: Inland Fisheries Service postal-survey data recorded a sharp decline in 2024/25 after around 25 years as one of the state’s best-performing rivers. The stocking and survey charts show more. We would choose your day carefully and lower your expectations.

Match the moment. For whitebait feeders and the jollytail run, a black or olive streamer in sizes 12 to 14 is a good bet; FlyLife’s flies table also lists an F-Fly in the same sizes for browns and rainbows. Around the Woolly Bugger pattern, keep it dark and let it swing through the shade of overhanging willows.

For the caenid mornings, look for rings in the slow water at the edge of the current, not in the riffles, and fish a small mayfly imitation there. Switch to a black spinner in the afternoon.

On the upper river, work slowly upstream and wade to the pockets you cannot reach from the bank.

Treat any access point as a location, not a statement of permission, and respect any fence or sign you find on the ground. FlyLife describes Inland Fisheries Service angler-access points and step-overs along the river.

As on any bush river, tell someone where you are going and when you expect to be back, carry water and a first-aid kit, and never wade a crossing you are unsure of. If you go into the upper river, plan the way out before the light goes.

No water-specific rule was found for the Mersey River. Before you fish, read the current Tasmanian Government Inland Fisheries Service fishing guide, check its closed-waters list, and take any season, bag and size limits and licence requirements from it.