Of all the considerations being cast about concerning this most unusual trout fishing season, this one generally has escaped notice.
It’s all about compression, that compacting of time between the departure of ice from our most productive reservoirs and the start of full-blown insect season.
Dramatically late ice-off from the rich reservoirs of South Park, North Park and parts in between leaves precious little time — perhaps no more than two weeks — to prepare for the first real stillwater hatch of the year, the large midges called chironomids.
A rise in water temperature to the low 40s signals a stirring of midge larvae from the lake bottom. At popular reservoirs such as Antero, Spinney Mountain, Lake John or the three Delaney Butte lakes, midge swarms appear by mid-May and intensify as the water warms. One of the latest ice-outs in recent memory and subsequent delay in water warming may slow the process.
Still, the time between the open water and the start of what many fly-fishermen consider the most productive period of the year, will be brief this year.
These are exciting times on Colorado’s prime reservoirs, in part from keen anticipation made sharper by an extended winter. As we noted at last Wednesday’s opening at Spinney, early anglers score well using shiny spoons and spinners.
Hungry trout that haven’t seen a hook in six months are fools for the flash. Hardware increasingly becomes a passing fancy as trout become wise to the fraud while transitioning to a sequence of insect hatches.
Which brings us first to the midge, a most prolific insect that may number 50,000 per square yard in the substrate of the most productive lakes. Phil Rowley, a noted Canadian fly tyer and author, found during 15 years of throat-pump samples that 50 percent of the stillwater diet consisted of midges. Another 20 percent was scuds, the other early season diet staple.
Even better news: The chironomids in the aforementioned lakes reach relatively large size, up to an inch long. The so-called “Bomber” midge pupae, rusty red with a white head, is typically tied on a long-shanked size-12 hook. Trout find this fly easily and seldom refuse it.
Anglers either use chironomids individually or as a trailer from another pattern, perhaps a scud during the early season or, later, a damsel-fly nymph. Typically, the midge hatch begins closer to shore, then shifts to deeper water as the season progresses.
In every case, at or near bottom is the place to be. In the course of transforming from larvae to pupae, chironomids gather in their millions just above the mud or, in the case of many Colorado waters, the fringe of carpet moss layered across the bottom.
Trout, no fools, find the greatest concentration while cruising like lawn mowers along the carpet. Savvy anglers deliver their offering a foot to 15 inches off bottom.
This can be achieved either with a floating line and very long leader, 15 or more feet, or the increasingly popular indicator method by which the fly is suspended at that precise location. As a rule of thumb, the indicator method works best at depths of 10 feet or less.
Since these bottom-hugging transitional insects don’t move much, most takes come when the fly is completely still. Bite frequency can be hyped by slightly twitching the line every minute or so. This catches the attention of cruising fish, which then turn to grab the fly when it’s still.
By the same turn, windy conditions often are the worst for this type of fishing, causing the fly to bob and lurch unnaturally. On the lakes of South Park and North Park, this often dictates that the best fishing occurs in early morning before breezes stir. In nearly every case, the best of the bite subsides past noon.
Perhaps the greatest mistake most anglers make comes while choosing location. Some pick areas marked by tall standing vegetation, which have little to do with insect production and serve only to tangle lines and lose fish.
Instead, choose the seemingly barren open areas. Closer inspection will reveal a carpet-like layer of vegetation where chironomids — along with the later-emerging damsels and mayflies — reside.
You’ll get more bites, with a better chance of bringing the trout to net.
