Duns & Spinners
With summer upon us, mayfly duns and spinners make up a good part of our fishing. At this time of year we often see duns hatching and spinners falling not only at the same time, but different species as well. For instance, in the evening we might have March Brown and sulphur spinners on the water and sulphur duns hatching at the same time. What's an angler to do? This week our head guide, Jim Kukorlo, helps unravel the mystery.
Duns and Spinners
A mayfly life cycle has four stages: egg, nymph, dun and spinner. But let's include the emerger which is the nymph rising to the surface to become the adult dun. The dun has upright wings and they look like little sailboats floating downstream. Wings of the dun are semi transparent with a smoky brown, gray, or yellow tinge. The dun will hatch on the water and will float downstream until the wings are dry which will enable them to fly off the water and into the trees to molt. The life span of a dun is about 12 to 24 hours which will vary with different species. The dun will sit in the trees or other vegetation until it molts into a spinner. Duns have no mouth and don't eat anything. Fly fishermen uses a dry fly to imitate the dun stage of a mayfly. Since the dun floats on top of the water you can actually see a trout eat the duns that are riding on the water surface.
For all of my matching-the-hatch mayflies I prefer comparaduns or thorax style duns, the later made famous in Vincent Marinaro’s book, A Modern Dry-Fly Code. Comparaduns have split tails and the position of the wing gives it a more life-like look than traditional Catskill patterns. Without hackle the body lies closer to the water and the micro fiber tails keeps the fly upright, although I find that the thorax style flies with the crisscross hackle float better in riffles and fast runs than a comparadun. I also prefer traditional catskill patterns for my attractor patterns and for the flies I use when fishing the dry-dropper method.
With so much focus on the duns during a hatch, it is important not to forget the emerger. If the trout are taking the emerger the ring of the rise will be different and sometimes overlooked. When the trout are taking emergers you will see the dorsal fin break the surface of the water. This is a great time to use a dry dropper. Attach an emerger pattern to an 18 inch piece of tippet in the bend of the dry fly hook. The dry fly will also be you indicator if the trout takes the emerger.
The length of time that a dun molts into a spinner will vary with different species, but on an average it is between 12 to 24 hours. Once a dun molts it takes on a new appearance. Tails are longer and the body is slim and usually darker in color and the wings are clear and transparent. The sole purpose for the spinner is to mate and for the females to lay eggs. If you look closely you will see the egg sack on the female Hendrickson in the photo.
The male and female spinners form in a swarm usually over water but in some cases over land. In some species this occurs in early afternoon or late evening. As they hover over the water they do a up- and-down dance. Once the spinners mate, the females will begin laying eggs by dipping several times into the water. When all the eggs have been released the female dies spent on the water with her wings stretched out flat. This is what fly fishermen calls a spinner fall.
That's the short version of a mayfly adult life cycle, enough information for a fly fisherman to identify a spinner from a dun and to know when a spinner fall is happening. You can google the life cycle of any mayfly for more in depth information on individual species.
Sometimes duns and spinners can be on the water at the same. When there are duns, you can see the trout eating the adult insects on the surface. When a trout is eating a spinner the rise can be deceiving. The spinner is dead and not moving so the trout simply sips the dead insect slowly into its mouth. These rises can be hard to detect especially in the late evenly hours. I always carry a pair of binoculars in my pack just for occasions like this.
Fishing a spinner fall can be difficult for several reasons. If you’re fishing in a flat quiet pool with not much current, presentation becomes critical. Use at least a 5x tippet or even 6 or 7x in some cases. I find the downstream slack-line presentation to work best in these conditions. On very selective trout I will fish a sunken spinner and have found this to be effective especially during the trico hatch.
Have you ever been on the water early on a summer morning and see rising fish but can't see anything on the water that they are taking? The morning after a good spinner fall can offer some really good fish taking left over spinners from the night before. One of my favorite flies to use in a situation like this is the rusty spinner. Be sure to tie it in several different hook sizes.
Spinners are easy to tie. I use micro fibers for the tails and thin strips of white poly for the wings. Be sure to split the micro fiber tails.
Switching from spring to summertime can mean fishing smaller flies, longer leaders and smaller tippet sizes. Late afternoon and late evening fishing can be very productive so be sure to stay until dark and be on the lookout for spinners showing in the air above you. Sometimes it's the last half hour of day light when the spinners hit the water and it can a very exciting 30 minutes of fly fishing. Be sure to carry a head lamp or flash light for late evening fishing and a wading staff can come in handy when wading in the dark.
If you live close enough to a trout stream you can eat an early dinner and still have time to get on the water for the evening spinner fall.
Click here to view comparaduns and other mayfly patterns in our store.
Getting Soft Hackled
While Jim talks to us about mayflies, there are often times when caddisflies will be mixed in with the mayflies or when the hatch is all about caddis. While mayflies and caddis are both aquatic insects, the caddis behave differently and the observant angler will know how to identify and imitate the sometimes subtle differences. Chester Allen talks to us about caddis soft hackles in this excellent story.
Back at the Office
Meanwhile back at the office we are busy with 2021 calendar submissions. One of the calendars we submit to is “Inspirations” and while working on Barry's submission and admiring the images we decided that we want to share the photos with you so we've put them in an album for all to enjoy. See them here.