Hendricksons. One of our favorites. The first of the Big Five . . . Hendricksons, Sulphurs, Isonychia, Brown Drakes, and Hex. The Hendricksons on the AuSable and Manistee watersheds offer the trout a large meal both in size and quantity just as warmer water temperatures have the trout’s metabolism kicking into gear. Sporadic hatching can begin when stream temperatures in the mid forties occur for a number of consecutive days or “degree days”. The huge emergences, however, occur when the water temperatures reach the low 50’s. These temperatures coincide with prime feeding temperatures for trout.
The Hendrickson family actually is comprised of three separate species (ephemerella subvaria, invaria, and rotunda) that show up as Spring begins to warm our rivers. Don’t worry about the Latin—the fish don’t speak it. What you need to know is that all three species thrive in our rivers and that the insects can vary from size 12 to 14 and from a creamy tan to a dark reddish brown depending on species and sex. Now I’m not saying you should turn the flies over to see if you should be fishing a male or female pattern, but I am telling you to have a variety of pattern options.
Hendrickson nymphs are crawler nymphs and as a result have a stocky thorax - think body builder with huge shoulders and skinny legs. The nymphs darken before hatching and can be imitated nicely with a pheasant tail nymph in a 12 or 14. Nymphs and emergers are vital for this hatch and should not be overlooked. There are a few emerger patterns that I would not go astream without. Another effective method is to fish the floating nymph just in or under the surface film. Fishing the Hendrickson emergence effectively is all about versatility and attention to detail. Well, I suppose that is true in all of fishing.
That being said, there has probably been no better fishing in my career than the fishing that I’ve experienced during the Hendrickson spinner falls of the AuSable. It’s a fickle game as spinner falls are dependant on our inconsistent, Michigan, Spring weather. The mating flights should, theoretically, take place on warm April and May evenings . . . theoretically. Factually, Hendrickson spinner falls in the AuSable valley can take place in the morning or even in mid-afternoon. Again, when chasing this hatch, the angler has to be prepared, alert, and versatile. As always, stop by the shop and we’ll do our best to get you the right spot and the right gear.
If you can’t make it into the shop on your way up North, visit our online store and prepare yourself with our Hendrickson 12 dry fly selection or our complete life cycle Hendrickson 18 selection. Fishing time is precious; don’t go on the water under gunned.
Sulfurs . . . the second of the big five
When we talk about Sulfurs we’re talking primarily about Ephemerella dorothea or more commonly known as the miniature eastern sulfur. These mayflies hatch from late May through July and will range from size 14 to 20, depending on sex. Although, another variable is the time of the hatch, usually the larger mayflies hatch first and will continue to decrease in size until they are finished.
As Nymphs they are poor swimmers and prefer bottoms of quiet pools and eddies. They have amber to medium brown bodies, have three fringed tails, and are 6 to 8 millimeters in length. As Emergers, they’ll congregate in slow water. Since, they are such poor swimmers they prefer to make their break for the surface in overcast skies and still have a terrible time breaking the surface film. The emergence of a days’ hatch will usually take place within one to two hours of an afternoon.
Once they become Duns, both males and females have creamy yellow bodies with shades of olive to orange, pale gray wings, and three tails. A large amount of these Duns will remain attached to the shuck and are extremely easy targets for feeding trout. One main difference that will become common through their remaining time is that females can and often times will be a full size larger than the males. As they take to the air they do their best to find the nearest cover of streamside vegetation. Within twenty hours they’ll swarm over riffles as Spinners and mate. The males are rusty with brownish gray wings and are six to seven millimeters in length or size 18-20. The females have creamy yellow bodies with hyaline wings and are seven to eight millimeters in length of size 18. After mating, the males fall and are consumed by the eagerly awaiting trout. The females will often return to their vegetative cover to rest while the eggs develop and soon return to the air above the water to lay their eggs. Most females cast their eggs from above the surface, but some will repeatedly dip into the film spreading the eggs. Following their life’s purpose they fall to the water as the males did.
Brown Drakes; #3 and Bigger…
As a member of the summer jumbo group the Ephemera simulans or the Brown Drake. This mayfly hatches from late May through mid-June, in sizes from 8-12, mostly dependent on date of emergence and not of sex.
Unlike sulfurs, the Nymphs of the Brown Drake are good swimmers, but still prefer slow moving water with areas of sand and gravel. These nymphs have well developed tusks and strong legs that allow them to dig protective U-shaped tunnels that conceal them from both predators and sun light. Their slender bodies conform to their tunnels and are tannish brown with dark brown markings; they have gray gills, and three heavily fringed tails.
The Nymphs make their break for the surface with ease, and once at the surface they spilt from the shuck and the Duns sit above the film and make several attempts of flight while their wings take shape. Once they are able they fly straight to the nearest vegetative cover and begin the molting process that is highly dependent upon temperature and can last anywhere from 24-48 hours after Emergence. Although, it best to remember that it is water temperature that gets this process started in the first place, usually around 50 degrees F. Their Emergence will normally last from 3 – 7 days, with the heaviest Emergence happening during the mid-late afternoon.
As Duns, they have slender brownish tan bodies with three tails that match the length of their bodies. Their wings, both forewing and hind wings are a molted mix of brown and tan. They are normally 17 -22 millimeters in length or a size 8. Once the molting process has taken place they will once again take to the sky above streams after sunset and gather to mate as Spinners. As usually, the males will fall to the water shortly after the mating sequence and are gorged upon by eagerly waiting trout. The females will fly back to their roosts and allow the eggs to fully develop before returning just above the waters surface to continue the cycle for yet another season. As Spinners, their body colors have faded from that of their vibrant Dun colors and are from 12 -18 millimeters or a size 8 in length. Feeding trout truly do prefer the slightly dulled colors of the Spinner over that of the Dun, which you’ll notice as light has left the sky and the once calm waters will be broken with that of feasting trout.