By Scott Shalaway
TROUT FISHING can be simple or complicated. When I was a kid, I caught trout using worms and dough balls on a bare hook. As an adult, I’ve seen fly anglers with thousands of dollars of equipment hook plenty of trout, and I’ve watched both types of anglers go home empty-handed.
As is often the case with outdoor activities, it’s not the equipment that determines success. It’s knowledge. Successful anglers, young or old, know their fish.
Trout require clean, cold, or at least cool, water. Stocked trout like it about 57 degrees, slightly warmer than the optimal temperature for those raised in the wild. As a rule of thumb, rainbows prefer the warmer pools and Pennsylvania’s state fish, the brook trout, like it cooler.
Brookies are more tolerant of acidity than their immigrant cousins, but far more sensitive to water temperature. While browns and rainbows can survive in water that reaches 80 degrees, brook trout will die of thermal shock when the water temperature reaches 75.
Trout waters must also be rich in oxygen, and oxygen content is tied to temperature. As the water’s temperature increases, its ability to dissolve oxygen decreases. That means water loses oxygen as it warms; conversely cold water holds more oxygen.
Water temperature can be dramatically altered by human activities. Logging activity for timber sales, housing development and other commercial ventures destroy shade along trout streams and cause water temperature to rise, thus destroying those waters as trout habitat.
Water pollution from organic sources, such as septic and sewer systems, likewise causes oxygen depletion because of bacteria decomposing the excess organic matter. And in coal country, flowing waters produce sulfuric acid as they flow over rocks high in sulfur compounds, and acidification makes streams uninhabitable by trout.
Just as every successful trout angler recognizes the importance of water quality, they must also have at least a basic understanding of why trout eat what they do.
Trout are visual predators that opportunistically eat a wide variety of foods. Trout prey consists of three basic types: small aquatic invertebrates, terrestrial invertebrates that fall into streams and larger prey such as crayfish, fish and frogs.
Small aquatic invertebrates present themselves to trout as they drift in a stream’s current. This “invertebrate drift” peaks just before dawn and just after dark, perhaps an adaptation to avoid hungry fish. Because trout are visual predators, they feed most actively when food is most readily available, at dawn and dusk. Skilled, experienced anglers can tempt trout throughout the day, but fishing conditions are usually best when fish are naturally feeding.
At certain times of the year, certain insects are available at the surface in great numbers. During mayfly hatches, when adult mayflies emerge at the water’s surface, they provide a virtually unlimited food source. Unfortunately, from the trout’s perspective, such hatches generally last only a few days.
Throughout the summer flying ants, bees, wasps, flies and grasshoppers find their way onto the water’s surface and into the mouths of trout. As trout approach 10 inches long, they get big enough to eat crayfish, frogs and an occasional careless mouse or bird.
Fly fisherman, of course, are intimately familiar with the seasonal diet of trout. In fact, fly fishing is defined by the lures that mimic potential trout prey. Dry flies float on the surface and simulate mayflies, stoneflies, caddis flies, wasps, bees and anything else that might float on the water’s surface. Wet flies and nymphs simulate adult and larval aquatic invertebrates and sink below the water’s surface, and streamers suggest minnows.
Like a magician performing a sleight of hand illusion, a fly angler aspires to trick the trout into striking the artificial lure. And based on the growing popularity of fly fishing–14.7 million participants in 2005–such effects are worth their weight in gold. According to the American Fly-Fishing Trade Association, retail sales for fly fishing totaled $727.3 million in 2004.–Pittsburgh Post Gazette