Sulphur Patterns

This is a brief rundown of typical sulphur patterns and when each should be employed.

The Ever Popular Bead Head Pheasant Tail is the most common sulphur nymph pattern.

When a closer match to a sulphur nymph is necessary, a Split Case nymph is a good choice:

When sulphurs are emerging, a CDC wing emerger pattern is a good bet:

Another pattern that is good to use if the trout are taking emergers is a biot bodied sparkle dun. The hairwing allows for good flotation especially in slow moving waters, and is reasonably visible from a distance.

Sometimes the trout target the duns, and when this is the case a CDC comparadun is a very good choice. The CDC wing is easily visible and floats very well. Treating the wings with a floatant allows the wing to stay above water, but the body floats flush with surface.

Finally, the last stage of importance during a sulphur hatch is the spinner fall. Only once have I fished a spinner fall, and I was completely unprepared. Now, I have developed this spinner pattern. The body color is actually tan since the spinners of E. Invaria and E. Dorothea commonly turn a tan color before falling spent on the surface. I do not have a picture of this pattern, but there are pleny of them floating around on the internet.

Sulphurs are a key food source for trout in the late spring in the Tennessee Valley. Understanding the differences between the two species of sulphurs present on East Tennessee tailwaters, and the flies that best imitate each phase of the emergence will be a good start in finding success during this very common late spring event.

Understanding Sulphurs

Since I spend the majority of my time fishing on East Tennessee tailwaters, the primary summer hatch I experience are sulphurs. In order to have greater success when fishing sulphur hatches I feel that a deeper understanding of the insect is necessary. So for my own benefit I did some research.

Sulphur hatches are common on the South Holston tailwater from late April thru October and on the Clinch tailwater in May and June. Two species of mayfly are typically lumped together as sulphurs, Ephemerella Dorothea and Ephemerella Invaria.

Ephemerella Dorothea typically hatch when the water is between 60 and 65 degrees and are around a size 16 to 18. Nymphs are commonly found in slower currents and pools, and can ocassionally be found in shallow riffles and are best imitated using pheasant tail and split case nymphs. They emerge in slow pools and tend to congregate in eddies. Emergence takes place just below the surface film and can be imitated using various CDC wing emerging patterns. After emerging from the nymphal shuck the dries drift for an extended period waiting for their large wings to dry. Dries are best imitated with deer hair or CDC wing comparaduns. Adding a bright red head to your fly can help to imitate the big red eyes found on this species. Sometimes the trout can become selective and feed only on the females that have a little green egg-sac on the rear. To date I have only fished one spinner fall, and was not very successful in matching the pattern. The photos at right are of specimens caught on the Clinch River.

Ephemerella Invaria typically hatch when the water is between 52 and 60 degrees and are usually found in slight faster flowing water than their Dorothea cousins. Invaria is also slightly larger than Dorothea at a size 14 to 16 and lack the bright red eyes. Fly patterns for both are similar with exception to the red head on the duns. The spinner is a darker color than the dun and patterns should be chosen accordingly.

Color variation is another issue. The specimens I have found on the South Holston and Clinch vary slightly in the depth of yellow color. South Holston duns appear to be more of a creamy yellow color and Clinch river duns are more of a mix between orange and yellow.

Information for this piece has been compiled from the following websites:

http://www.troutnut.com/

http://www.flyfishingsmokymountains.com/hatchme.html

Next up: Common Sulphur Patterns

Tight Lines and God Bless