Mayflies

A small upright sail on the water, and trout that stop chasing and start sipping. You do not need to name the species to fish it well; you need to match the size and the stage.

What you see

Upright wings on the surface, or fish sipping in a lane

Stages

Nymph under the stones, dun on the surface, spinner falling spent

When

Warm evenings on lakes; early season and autumn on the streams

Tie on

An Adams in 14 to 16, or a Klinkhåmer for the sippers

There is a moment on a still Snowy Mountains lake at the end of a warm day when the fish stop chasing and start sipping, and if you look closely at the water in front of the rise you will see why: small upright sails drifting on the film, a dozen, then a hundred, each one a mayfly that has just this minute climbed out of its own skin to sit on the surface and dry its wings. The trout know exactly what that means.

The mayfly looks more complicated than it is. You do not need the Latin. You need three things. There are three stages the fish eat: the nymph under the water, the dun on the surface, and the spinner that falls back spent in the evening. The dun is the one you can see and the one that makes a trout stop and watch. And size, profile, and whether the fish are taking on the top or just under it are the decisions that matter.

Where you will meet them in this guide is on still evenings on high lakes and on cold streams at the start of the season and again in autumn: the flat glides of the Eucumbene at Denison, the glassy tableland pools of the Numeralla, the weed edges of a clear lake like Thompsons Creek. A few duns in a consistent lane with fish tipping to them is a better sign than a cloud of insects with no rises.

The fishing is simple. A Parachute Adams in fourteen or sixteen, drifted without drag through the lane the fish is using, will do the rest on most Australian trout water. Carry a Klinkhåmer for the day the fish boil and never show a dun, because they are taking the emerger just under the film, and a Pheasant Tail for the day they never break the surface at all. On a lake, be in position before the rise starts, on the bank the breeze is pushing the insects toward, with the light behind you.

What they are

Mayflies are the insects whose dun sits on the surface with wings up like a sail. The nymph lives in the water, among the stones of a riffle or the weed and silt of a lake margin, for months or a year. The hatch is the change into the dun, on or just under the surface, and the dun’s short flight to the bankside grass. A day or two later it moults again into the spinner, the clear-winged adult that mates over the water and falls back onto it spent, wings flat, in the evening. Trout eat all three stages, and the nymph most of all. The one you can see, and the one that makes an angler stop and watch, is the dun.

You do not need a Latin name to fish it. Size, profile, colour in the broadest terms, and whether the fish are taking on the top or just under it, are the decisions that matter.

When and where

NSW DPIRD’s Snowy Mountains guide treats mayflies as part of the regular warm-weather evening hatches on the lakes, alongside midges and damsels, and as early-season dry-fly food on the alpine creeks. That is the picture this page is written from: still evenings on high lakes, and cold streams at the start of the season and again in autumn, not a national hatch calendar. The flatter glides of the Eucumbene at Denison, the glassy tableland pools of the Numeralla and the weed edges of a clear lake like Thompsons Creek are the kinds of water where you will see them.

A hatch can be sparse and still worth fishing. A few duns in a consistent lane, and fish tipping to them, is a better sign than a cloud of insects with no rises. On a lake the rise often compresses into an hour around dusk; on a stream a small hatch can come off in the middle of a cold morning and be gone before you have changed flies.

How to fish it

When fish are taking on the top, tie on a Parachute Adams in fourteen to sixteen and drift it without drag through the lane the fish are using. Cover a rise; do not spray the gaps. If they refuse, drop a size. If they keep boiling and you never see a dun, they are taking the emerger or the nymph just under the film, and a Klinkhåmer hanging its body through the surface is the fly, or a Pheasant Tail on a short dropper under the Adams as a dry-dropper. If nothing is showing and you know the nymphs are there, nymph the same water.

On a lake, be in position before the rise starts, on a bank the breeze is pushing the insects toward, with the light behind you. On a creek the same Adams works all morning as a searching dry, hatch or no hatch. Leave the spent spinners and the Latin names for the day the fish are refusing everything else; matching the stage and the size usually matters more than naming the species.