Aquatic Trout Food - Mayfly

Mayfly occur when water temperatures reach an suitable range, along with subtle changes in air pressure and UV light. It varies throughout the season, throughout locations and from year to year.

Mayfly live in the water all year round, and depending on the species, a number of years. They go through nymph stages, called instars, moulting, growing, awaiting their opportunity.

When conditions are right, Mayfly hatch into duns, and over a short time into spinner, and return to the water during the calmer periods to lay the eggs and complete the cycle. The life cycle of the mayfly is featured in more detail in one of our newsletter articles.

As a general rule, in the lowlands, mayfly activity will occur September, October and November and re-occur in March and April. In the highlands the mayfly activity will occur January, February and March.

Mayfly will hatch anything from just a few, to dozens, to hundreds, to thousands at a time over days, weeks and months, waning and peaking throughout the season and at various locations.

Trout will mooch around the weed, searching out and collecting mayfly nymphs.

As nymphs start to ascend the trout home in on this. As the nymphs start to emerge and hatch and more nymphs ascend the trout get more excited. When a good hatch occurs and hundreds of nymphs are ascending, some are hatching on the surface. If there is enough insects stranded in the surface, a number of fish can focus very heavily on both the ascending and emerging nymphs. When this occurs rolling rises and slashes are evident.

In dull, drizzly conditions with dozens to hundreds of mayfly sitting on the surface trying to dry out their wings, some fish will start to focus on the surface emergers and stragglers.

Fly fishing strategy

Arrive with comfortable timing to get some casting practice and suspend a nymph under an emerger, applying some slight movement to this team of flies. This will often bring results before the hatch occurs, and even if a hatch does not occur. Look out for surface activity which will become the target for fly presentation and as the hatch goes through its phases, more surface activity will come and go.

A very high percentage of the time when trout are showing near the surface, a good emerger, and if you like, a trailing nymph, will do a great job.

The essential ingredients of an emerger are where a basic nymph shape sits below the surface film, and a post of any bouyant material protrudes through the surface. CDC makes a good post to use in the light to calm conditions. Very little movement of the fly is needed here. An accurate presentaton a few feet ahead is adequate.

A deer hair post in rougher or windier conditions and more movement of the fly ahead of the fish, anything from twitches to pulls to find the mood of the fish and draw its attention, especially when there are high volumes of the natural.

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Fly fishing Tasmania - techniques for catching trout when mayfly are about.