Thursday, April 24, 2014
By Ken Allen
A large pool on the Kennebec River between Solon and North Anson produces magnificent Light Cahill hatches each June, a large, cream mayfly tied on a size 12 or 14 hook. I lean toward the size 14 choice.
During this hatch my plan for success smacks of simplicity:
1. The pool mostly holds brown trout. When they surface to sip dead-drift mayflies, I sneak within close casting distance, taking care to avoid making tiny wavelets that spread across the surface and spook trout.
2. During hatches where insects float at exactly the same speed as the current, my plan entails dropping the fly above the rise ring, so the fly drifts back over the brown's lie without drag -- no matter how slight. If the insect's speed differs even minutely from the flow, it turns ultra-wary fish off cold.
Subtle drag can be difficult to ascertain unless the caster looks at a simple indicator such as a bit of foam, surface debris such as a leaf or blade of grass or anything beside the imitation fly. The fly and the free-floating item must be moving at exactly the same speed.
Drag begins when shifts in the surface film pull on the leader or line and "drag" the fly unnaturally across the surface. To beat this problem, veteran fly rodders change casting angles by moving a step or two left or right or maybe tie on a longer tippet and cast so it lands loosely on the surface. The latter allows the fly to float with the current until the leader straightens out and begins pulling on the fly.
A feature of the pool makes the fish spooky. The surface has shifting vagaries in the current that create myriad drags, and to complicate matters, the pool averages about six feet deep. Trout often lie near bottom and must rise up 51/2 feet to take the fly, a long ascension that gives them ample time to eyeball the prize. If anything is wrong, these fish have time to spot it.
I have named it "Light Cahill Pool," and every brown and occasional brookie that sips my fly there fills me with pride. It's a tough pool, one of those places that fills our heads with images for winter daydreams.
When I say Light Cahills, I'm talking about more than one species and even genera in Maine. About the time the bulk of the June Light Cahills have hatched, another fun mayfly starts hatching in earnest.
This next mayfly has a few colloquial names, and popular ones include "Leadwing" or "White-gloved Howdy," because the bug has lead-colored wings, and two white front legs and four dark brown back ones. Serious Maine fly rodders may call it "Isony," a short version of the Latin name "Isonychia bicolor." Bicolor refers to the two leg colors.
This swimming nymphs in the Isonychia genus have a fascinating emergence routine. Before shucking the larval case, larvae swim to objects sticking above the water -- the dry tops of river rocks, shore rocks, tree trunks lying into the water or the sides of bridge abutments.
In these spots away from the maws of hungry fish, they crawl on top before bursting from the nymphal case to become duns. Because of that, fish don't always rise to the duns, but rather they concentrate on nymphs, moving in the current. This rule has exceptions for sure.
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