Fly fishers comfortable finding trout on moving water are often at a loss when it comes to stillwaters. At first glance lakes are flat and featureless. Figuring out where trout might be hiding seems daunting if not impossible. Believe it or not, lakes like rivers, are easy to read. As when fishing moving waters I use three main criteria to locate stillwater trout; comfort, protection and food.
Let’s look at two of the comfort factors I use to determine trout location, water temperature and barometric pressure. Comfort is perhaps the most important factor, for if a trout’s basic needs aren’t met it likely won’t feed. Water temperature is a critical comfort element. Trout are cold blooded and as such their metabolism is governed by the surrounding water temperature. A thermometer should accompany you whenever you are on the water. I attach a string to my thermometer so I can determine temperatures not only at the surface but down deep.
Get to know the temperature range of each species and use a thermometer to locate areas where they might be hanging out. Within their preferred temperature ranges trout and char have the required dissolved oxygen content to forage and digest their food quickly. Feeding fish are catchable fish!
|Species Preferred||Temperature Range|
As water temperature increases its ability to hold oxygen decreases. Trout become lethargic and reluctant to feed. In extreme cases waters become anoxic and blended with other factors such as algae die off create a condition known as summer kill. Trout caught in high temperature conditions have a difficult time recovering as there is not enough dissolved oxygen within the water to counter the lactic acid built up during the fight. In these conditions trout are best left alone.
Understanding the effect of water temperature helps guide your retrieve speeds. When temperatures are outside the preferred temperature range a slow pace is often required for success, particularly during cool conditions such as early spring and late fall. When fishing within the preferred temperature range use active retrieves appropriate to the natural pace of the food sources available.
Water temperature also has a critical effect on the trout’s food sources. When temperatures reach 50F the first serious hatches of the season begin. Chironomids emerge first followed by mayflies, damsels, caddis and dragon flies. No matter the lake this is the annual hatch progression.
During the daylight hours plants absorb energy from the sun through photosynthesis taking in carbon dioxide and giving off oxygen. This factor makes hanging around weed beds a worthwhile endeavor. Weed beds, are also the stillwater larder providing prime habitat for the myriad of food sources stillwater trout have to choose from and provide protective cover. I consider weed beds a prime lie as they contain all three elements I use to locate stillwater trout-comfort, protection and food.
Varying barometric pressure also affects trout behavior. A fluctuating barometer has a marked effect on trout behavior. As a cold front approaches trout often feed aggressively, but as the front passes and the temperature and barometric pressure drops conditions are typically tough. Brisk winds and blue skies often follow the passage of a cold front.
A trout’s swim bladder provides balance and stability. Many believe that the varying or rapidly dropping pressure negatively affects the swim bladder, putting trout off the bite. In many instances trout retreat to deep water until atmospheric conditions stabilize and trout once again strap on the feed bag. Consider moving off the shoals to the edges of drop offs to catch fish. Attractor techniques or hanging patterns in a near static manner is often the only way to coax fish in dour conditions.
Understanding the effect of water temperature and atmospheric pressure helps determine if trout will be deep or shallow and if they are feeding actively. Use this knowledge to choose the appropriate presentation technique and retrieve speed. Your success fly fishing stillwaters should increase.