The Tyenna is the river Hobart anglers fish after work in summer, and it punches above its size. From the forests above Maydena it runs fifty-three kilometres through Mt Field National Park and the small towns of the Tyenna valley to the Derwent, a big, fast freestone stream of boulder runs, bedrock and scattered timber, and Inland Fisheries Service says it provides excellent fishing for all methods with large populations of small to medium browns and rainbows and a few trophy fish taken each season. It is managed as a wild fishery dominated by browns, but it has a reputation as a rainbow river too, which is rare in Tasmania. Heavy rain in the south-west catchment lifts and colours it fast, and it clears fast; the Newbury gauge has watched it since 1964 and its record, drawn on this page, shows a river that runs five times higher in August than in February. Much of it is overgrown, so wading is how you reach the water, and the bed is big slippery boulders that IFS warns about in as many words. Summer and autumn, with the water low, are the best of it: upstream nymphing when nothing is rising, caddis on still evenings, hoppers along the open banks, and from November to the close the fish take dries. A kilometre and a half inside the national park is artificial lures and fly only, with a park pass on the dash.
Water and habitat
Fifty-three kilometres of mainstem falling from eight hundred and fifty metres to fifty, and the fall of the river drawn on this page shows a mountain river that stays steep most of the way down. The Newbury gauge sits about thirty kilometres down, reading flow and height. The bank survey from space describes a forested river: half the corridor dense timber, a third open woodland, a tenth cleared for farming along the valley floor, which is why so much of the river is overgrown and why the shade keeps it cool.
Big boulder runs, bedrock, scattered timber, pockets and pools. IFS calls it a large, fast-water stream, and the bed is very slippery. Bank fishing is possible at Westerway, inside Mt Field National Park and at Maydena; elsewhere the river is heavily overgrown and better waded.
Fish and forage
Brown trout dominate a river IFS manages as a wild trout fishery, and rainbow trout give the Tyenna its second reputation. Large populations of small to medium fish of both, and a number of trophy fish taken each season. Nothing is stocked.
Caddis hatch on still days and in the evenings, mayfly trickle through the day, and in summer the grasshoppers fall on the water along the open banks. IFS says good hatches can occur on warm afternoons.
When to fish it
Read the river's year on this page. The Newbury record puts the high water from June to September, five times the summer median in August, and a long low run from December to March. Heavy rain in the south-west catchment lifts and colours the river fast at any time, and it clears quickly; the Conditions card on this page tells you which state it is in today. Summer and autumn are the best times, IFS says, particularly for wading when the levels are low. From November to the season's close the fish take dries. The season runs from the first Saturday in August to the start of May.
How to fish it
Wade. A four or five weight, studded soles, a staff, and a leader you can roll under the overhang. When nothing is rising, upstream nymphing is the method IFS names: a tungsten Pheasant Tail or a Hare's Ear led through the boulder runs on a tight line, or a dry-dropper with a Stimulator over the nymph where the pockets are short. When fish rise, an Elk Hair Caddis on the still evenings and a parachute Adams for the mayfly through the day, a hopper along the open banks in summer. Early in the season or after rain, when the river carries colour, fish the nymph deep and the slower water.
Access and safety
About twenty kilometres north-west of New Norfolk via the B62 and B61, with most access points between the townships of Westerway and Maydena. Bank fishing at Westerway, in Mt Field National Park and at Maydena. Foot access along the rest has been provided by public and private landowners and is a privilege, not a right: where access is not signed you must ask, or you are trespassing. Leave gates as you find them, stay off fences, do not stray into paddocks. Inside the national park, fees apply and a park pass must be displayed on vehicles and boats.
The bed is the hazard. Large boulder runs, very slippery, in a fast river that rises quickly after rain in the south-west. IFS asks for extreme caution from wading anglers, and means it.
Regulations
Inland Fisheries Service states one set of rules for the Tyenna: a minimum size, a small daily bag, all methods permitted, and a season from the first Saturday in August to the start of May. Inside Mt Field National Park, about a kilometre and a half of river, bait is not permitted and the water is artificial lures and flies only. An inland angling licence is required, and a park pass inside the park.
Take the numbers and the dates from the current Tasmanian Inland Fishing Code and the IFS A to Z page for the river before you fish. They move, and this page does not carry them.