The wise fly-fisher never underestimates his or her prey. You may have your eye on a prize catch, but do you realize it probably has you in its eye as well? Not to mention its nose and ears?

It's hard to imagine that trout can really hear or smell you from its underwater environment, but these senses are actually very sharp. Brett Fogle writes:

When fly fishing for trout, do your best to avoid any artificial smells that are completely foreign to a trout stream. Avoiding these smells, though, of often easier said than done, as the sources of these smells can come from many sources. Fly line cleaners, fly floatants, epoxies and glue can all contribute alien smells to a trout stream. Other things such as aftershave, deodorant and even the smell of your clothing can all tip off a trout that an angler is near...

...Trout have an acute sense of hearing that is well worth understanding. Trout have two sound receptors. The first one runs along the length of the fish's body. This receptor picks up frequency vibrations - such as the banging of rocks or oars against a boat. A second receptor, located inside the trout's ear, is used to detect the movement of aquatic insects which the trout eats. This receptor is extremely acute, allowing the trout to hear sound frequencies well outside the human hearing range. This hearing receptor of the trout is what allows the fish to find food even in very murky water.

Learn how to avoid being caught out with Fogle's article: "Three Main Trout Senses."