The hexed life: Michigan's biggest trout bug
Hex emergers or spinners bring some of the biggest trout of the year up to the surface. (Morgan Sherburne/News-Review / June 27, 2012)
This collection of words — nymph, dun, spinner — describes the stages of life a hex bug goes through between its life as a wriggling nymph to the end of its short adult life.
"A mayfly starts out as larvae in the water. They're what's called a burrowing mayfly," said Kristin Thomas, aquatic ecologist with Michigan Trout Unlimited. "They live in the soft, usually silty sediments."
The larvae, says Thomas, uses their tusks to dig down into lake or stream sediment. In the cold of Northern Michigan, hex larvae stays in river and lake bottoms as long as three years.
At the right time, when the larvae has collected enough warmth in its body, it will start to swim up through the water column.
All along, the hex larvae have fed trout and other fish, some of them very large. And even as they drift up through the water, trout will grab them.
"Trout are opportunistic feeders. They like to hang out in flowing water and catch larval bugs as they are floating by, before they hatch," said Thomas.
Those larvae that make it to the surface of the water do so in the thousands, and they emerge as duns — wet, new, immature hex flies. Their wings are like cellophane, and, from tip to tail, hex can measure almost two inches.
Trout candy — and crack for dry fly anglers. The hex brings the biggest trout of the year to a river's surface, trout that usually are eating other trout.
Duns lift from the water's surface, settle in bushes and treetops alongside the river, and mature into adults. Then, they mate in clouds over the river, usually late, 10 p.m., after dark. On a quiet night, under a thick cloud of adult hexes, you can hear their wings scissoring. On a clear night with a good moon, the light gleams through their wings. They look like rising bubbles.
This is when you start listening for feeding trout, when hex are rising as duns. Most nights, you can't see the rising trout; you listen for them and cast where you think the trout are feeding. You can fish an entire evening's hatch to one fish, only to turn on your headlamp and find the river has become carpeted with dead hex flies.
After the hex have mated, they fall to the river, dead, as spinners. They live as adults for less than a day, usually. Anglers work the hex hatch hard, but trout work it harder.
"It would be similar to us going to an all-you-can-eat buffet where they feed you at your table," said Thomas. "You can eat and eat and eat and it just keeps coming."
By the end of a hex hatch, a fish can be stippled with fat.
After the hatch is over for the night, you can sometimes see the carnage. Broken bodies of mayflies — sections of wings and tail — float down the river. Perhaps they were eaten after they were already dead, able to deposit their eggs.
In any case, as you walk back to your car or put the boat back on the trailer, hundreds of thousands of eggs drift down to the sediment of the river, ready to start the process all over again, a June or two from now.
While hex have to die, trout don't — at least not at the hands of anglers. It's easy to fish out a stretch of river. Consider practicing catch-and-release for the majority of your trout, if not all. A trout released this year will only get bigger for next year.
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