Monday, December 9, 2013
By Ken Allen
Eight years ago on a Maine fly-fishing bulletin board, a young fly-fishing guide posted a comment that has stuck in my mind. He claimed that aquatic-insect hatches were so sporadic that he wondered why the events seemed important to people.
"Yee-haw," I thought and felt embarrassed for him.
Folks who have fly-fished for as long as I have often plan fishing days around emergence times -- say Hendricksons on May afternoons, light Cahills on June evenings, Hexes on late evenings in July or blue-winged olives at 10 a.m. to noon from mid-July through September.
You can add plenty of hatches to my short list, and surely, so could I if room permitted.
In short, fly rodders with experience just know when certain insects hatch. These events occur with enough predictability to give us rise rings to target at certain times of morning, day or evening, so often enough, proper planning ensures that we cast to rising trout day after day after day.
With all this fly-fishing certainty, though, times do pass when waters look deader than dead with zero surface activity. What do we do when no fish are rising to bugs floating on the surface?
I resort to an insect seining net. Veteran fly rodders place the net in a chute between two rocks that concentrate larvae in the funneled flow. Leaving this net for a minute or two -- or 10 -- often captures enough aquatic larvae to show us what's floating beneath the surface, where trout may be feeding like crazy out of our sight. My net turns around many of those days with no surface rises but ample underwater foraging.
It makes sense to match the most abundant insect in the net to an nymph imitation in size, color scheme and silhouette:
Size is easy because fly rodders merely hold an imitation next to a natural to see if it is the same length, similar width and thickness, etc.
Color scheme offers a trickier match because the tails, abdomen, thorax, wing case and legs may all be a different color, so we don't have an exact color scheme. In this situation, I first make sure to duplicate the shade of the abdomen and thorax, and then second the legs -- an easily arguable plan that works consistently enough for me.
The silhouette takes a little more scrutiny to make sure the submerged bug has a fat shape (like a clinger or crawler mayfly), long, thinner profile (like a swimming or burrowing mayfly), predominant wing case, easily discernible legs, etc.
In this third category, fly tiers back in the 1970s and into the 1980s took great pains to make sure if a natural nymph had a wide, flat shape, the natural should, too, and wide-bodied hooks became popular.
In fact, a manufacturer sent me a lifetime supply to field-test, and field-test I did, but the flat-bodied patterns produced poorly for me.
Old Joe Brooks of 1960s fame had a theory about nymphs drifting in the current that may explain the problem of flat-bodied hooks.
According to Brooks, a round-bodied nymph imitation with a collar or palmering worked best, and here's why: When this style of artificial fly rolled sideways during its drift downstream, it looked more natural because no matter which way the nymph tipped, the silhouette looked the same. When nymphs on flat-bodied hooks rolled sideways in the current, the fly looked unnatural because aquatic insects are more apt to stay upright. That philosophy worked for me, emphasized by my lack of success with flat-bodied hooks.
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