03/13/08 – Yes indeed, one of my favorite things about mayflies is that trout love to eat them. Oh, I think they are pretty floating down stream with their wings standing up like sails. Their mating swarms are an incredible sight and always just out of my reach. Those things and more make them a critter worth watching but what endears them to me is that they are trout food and trout will risk much to feast on them.
Armed with only the knowledge that trout feed on mayflies one can go the the rivers and streams of Maine and catch an occasional trout on an Adams or other standard, generic mayfly imitation. But armed with a little more knowledge about mayflies one can catch even more trout.
Trout don’t speak or read Latin – neither do I. But learning the Latin name for the common hatches in my area has helped me gain “a little more knowledge” about the mayflies I commonly see. I should say learning to read the Latin name has helped me because I still can’t pronounce most of them. None the less knowing the scientific name of insects has helped me locate information on life cycles, habitat, preferred water temperatures and much more.
Perhaps the most valuable information for me has been learning where different mayflies choose to emerge. A good example of emergence style is the comparison of the Quill Gordon and the Hendrickson.
Generally, mayflies emerge in one of three ways. One is for the nymph to crawl out of the water, in a manner similar to stoneflies, and emerge on a rock or branch – think Leadwing Coachman (Isonychia Bicolor). Another method is for the nymph to float upwards emerging just below or in the surface film – think Hendrickson (Ephemerella Subvaria). And yet a third method is for the dun to emerge from the nymph stage underwater, along the bottom, and then rise to the top fully in the dun stage – think Quill Gordon (Epeorus Pleuralis)
The Hendrickson and Quill Gordon nymphs have much in common. They like riffles and pocket water, both hatch in the May, June timeframe (around here) and while the Quill Gordon may begin hatching with high 40’s for water temperatures both are normally hatching when the thermometer reads 52 degrees.
But that’s where the similarities end because the Quill Gordon is a tough, hard fighting, two-tailed clinger nymph that likes to gather in the slow pockets scattered amongst the riffles and fast water they call home before hatching. There the dun emerges and riding a gas bubble rises to the surface fully emerged – a full fledged dun. To me that means a wet fly like the Gold Ribbed Hares’ Ear swung into the eddies of pocket water should produce and pre-hatch that has been a good searching fly for me.
However, the Hendrickson nymph, a three-tailed Crawler, lives a softer life and seems to care more about comfort and seeking out comfort. Enough so that when hatchtime comes the Hendrickson nymph leaves the riffles it grew in and seeks softer flows. This might mean a migration to the edges of the stream or crawling/swimming to the tail out of a riffle where the flows calm. And once in this softer water they like to practice the hatching rise to the surface. In this water give me a Bead Head Flymph that I can raise off the bottom and then lower back down imitating the pre-hatch rise and drop of the natural.
So while all mayfly nymphs and adults are trout food they are not all available at the same time or in the same manner during emergence. Knowing subtle differences like the preference for fast pocket water emergence of the Quill Gordon vs. the seeking out of softer water by the Hendrickson can improve your catch rate.
Because while trout don’t read or speak Latin they do know where those mayflies live and hatch, if for no other reason than the simple fact that Mayflies are trout food.
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