Unlocking the Secrets of the Stonefly

Unlocking the Secrets of the Stonefly

Unlocking the Secrets of the Stonefly

by May 2, 2017

Early in June, on the Madison River just upstream a few hundred yards from Black’s Ford Access, the rainbows had been feeding ravenously on small elk hair caddis flies making for a wonderful day of fishing. Just then something landed on the back of my neck. I reached up and grabbed the culprit, not knowing what to expect. It was a huge black salmon fly. Let the fun begin
This is the insect of fly fishing dreams, at least the dreams that include catching monster trout during a salmonfly hatch that occurs on some western rivers and drives many fly anglers nuts.

Stoneflies are called by many names: little dark stoneflies, spring flies, willow flies, salmonflies, golden stones, little yellow stones, little green stoneflies, snowflies, sallies, needle flies, forest flies, and even roach flies. In the eastern part of the U.S. we hear mostly of little black stoneflies, little brown stoneflies and early stoneflies. In the Midwest, the East and the West, we often hear of golden stones and they are quite popular. In western states, the mystique survives around the huge black stonefly that’s most often called the salmonfly.

Stonefly adults are most important when laying eggs after mating-especially the larger species. Some drop eggs from just above the water, others skitter along the surface, while some land on the water, creating activity that stimulates savage strikes from hungry trout. They often fall, spent, after depositing eggs, and gather in eddies and slack water in large numbers, prompting trout to rise and slurp in a mouthful. This activity is great to look for on summer mornings.

Juvenile stoneflies are great crawlers – they have double claws on the end of their outer leg sections that help them to grab and move over rocks in fast water. Some have flattened bodies, making clinging much easier. Stoneflies are poor swimmers, and when they slip into the drift by accident or to travel downstream on purpose, they become easy targets for trout. Just before emerging, the nymph activity increases, creating great opportunities for catching distracted fish just before the hatch. At no other time do trout feed as voraciously on aquatic bugs as during the stonefly hatch. Huge trout, no longer strict insect eaters, have become opportunistic predators of smaller fish, but they cannot ignore the presence of the largest aquatic insect in the stream.

Stoneflies typically hatch just about the time trout come out of a long, difficult winter. During runoff conditions, murky water makes finding food more difficult, so trout take advantage of the stoneflies that happen by. Older, more experienced trout actively seek out the yummy stoneflies. During this frenzy for the stonefly, often these hungry trout will hang out in places you wouldn’t expect, even exposing themselves to predators. Water along the shorelines is cleaner during the muddy run off, and that happens to be the pathway out of the stream for stoneflies looking to crawl out onto the shore. Often trout will hold in water just barely deep enough to cover them, waiting for the next emerging surge.

The larger stoneflies in the West sometimes live as long as three years in the water before they emerge, and due tostoneflies1 this long nymphal cycle, stoneflies are always present in the stream, in varying sizes.

The life cycle of most stoneflies is simple: One to four years as nymphs and a few weeks as adults. Interestingly enough, some species don’t eat after they emerge, so they don’t have mouth parts as adults.

For food, stonefly nymphs prefer aquatic vegetation, benthic algae, and some species will feed on aquatic insects and arthropods, such as scuds and non-biting midges.

Stoneflies are considered by many to be an important indicator of the health of a stream, as they cannot survive in polluted water- so, if you see a stonefly, then the water quality is most likely very good, meaning there is going to be a lot of food in the water for fish. Other aquatic life-forms, trout food as well, also live best in better quality water.
stoneflies2You’ll find stoneflies in rivers or streams, and sometimes in cold water lakes with rocky shoals. They like well-oxygenated water and the nymphal stages are often found under rocks and branches. As they emerge from the stream, you’ll often see stoneflies climbing along rocks or branches on the edges of the water, and you may notice them in the trees near the stream or on vegetation. Often, when you see stoneflies in this form, it’s merely the husks they’ve shed as they’ve crawled out becoming adults.

Fly Fishing the Stonefly

Stoneflies are clumsy flyers – often crashing into the water, getting too soggy to fly. It’s a great time for a trout meal. Big trout often hang out under willows in shallow water, waiting for some love-blinded stonefly to fall in nearby or get blown off-course. Stoneflies in water struggle frantically, creating activity on the water surface, so giving your dry fly some action will increase the chance of a strike. Presentations don’t need to be delicate- a splashing entrance is a dinner bell for big trout. Stoneflies are always an excellent pattern for fish when there is no obvious feeding activity. Using a two-fly rig, you can use a stonefly with a dropper of some other likely aquatic insect to searching for feeding trout.

stoneflies3When stoneflies get loose in the current, they tumble along until they grab onto something for cover. You can imitate this action with a dead drift presentation close to the bottom. Sometimes placing some weight 18 to 24 inches above the top fly will allow you to bounce flies along the bottom, in the feeding zone.

You don’t need long leaders when fishing the stonefly, partly due to murky water, and partly because when trout seize on stoneflies, they want nothing else, and see nothing else. Keep your hooks sharp, and use strong leaders, in the 2X-4X range when fishing with stoneflies, because the likelihood of catching a monster is better than usual.

If you would like to learn more about fly fishing with stoneflies be sure to check out this podcast:

Salmonfly Hatch on the Madison.

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