A little ‘fish sense’ will improve your odds on opening day
It’s finally here. The morning of April 12 has dawned and the 8 a.m. start to the 2003 trout season is mere moments away. You’ve studied the Pennsylvania Fish and Boat Commission’s stocking schedules, scouted the stream and picked that perfect spot you know is home to that elusive trophy. You pop open your tackle box. Hmm, what looks good? For too many anglers, that’s all they take into consideration – the way a fly, lure or even a piece of bait looks. Like most animals, however, trout and other fish rely on a combination of senses when looking for food. Sight, sound, smell and taste all play a part in getting a fish attracted to what’s on the end of your line. Knowing how those senses work can help you understand just what might tempt a few more strikes. For the sake of this article, we’ll call anything on the end of your line a “lure,” be it a fly, bait or an artificial lure like a spinner. Let’s walk through from the time of your cast to the fish actually mouthing the lure.
HEARING AND SOUND: The sound of your lure hitting and then moving through the water is actually the first thing likely to alert a trout – or any fish. The movement of sound waves through the water are integral to a fish’s sense of hearing and to its overall survival.
Fish count on two different organs working together to locate and sense sounds. On both sides of most fish is a line of pores called the lateral line. The pores are the opening of tiny tubes that go through the scales into the body and end near a large nerve which travels to the brain. At the end of each tube are tiny hairs that vibrate when sound waves pass over them. The moving hairs stimulate the lateral line nerve. Because the tubes point in different directions, fish can accurately locate the area from which a vibration emanates.
Fish also have an inner ear, similar to humans. The inner ear aids in balance and hearing. The part of the inner ear involved in sound interpretation is called the otolith, or ear bone. Hair movement in the fluid-filled sack surrounding the otolith is what stimulates the attached nerves. Sound waves move through a fish’s body, almost as if it were not there, and reach the otholiths making them move.
When a baitfish or a lure or fly imitating food moves through the water, it gives off vibrations, which a fish can detect yards away. These vibrations can be heard and felt. When a lure is far way, the fish feels the vibrations with its lateral lines and pinpoints the location. As the fish gets closer to your lure, the sound of its rattling are also picked up by the earbone.
The fish then starts to rely on other senses like smell, sight and taste to determine if your lure is really food.
SMELL: As well as hearing your lure, trout and other fish can smell it from a distance. Fish have a very sensitive sense of smell. How sensitive? They can detect concentrations of chemicals as low as one part per trillion. That’s the equivalent of one ounce of chocolate syrup in a million railroad cars full of milk. Salmon can detect smells from the waters where they were bore from hundreds of miles away. Stands to reason then that a trout can smell that tasty nightcrawler from a few yards. Conversely, the same thing goes for the smell of bug spray from your hands on fishing line you have touched.
The sense of smell, or olfactory sense, is located in a fish’s nostrils, which are actually called nares. There are two pairs of nares on both sides of the snout. For humans, smells are detected by sensing chemicals dissolved in air. Fish detect these chemicals in water. As water flows through the nares, the dissolved materials trigger the olfactory organ which in turn transmit signals to the brain.
SIGHT: Once the gap between fish and lure narrows even more, the sense of sight plays a bigger role. Fish eyes work much the same way human eyes do, similar to a camera. There are some differences through. Fish don’t have eyelids or tear ducts, and they don’t have an iris that adjusts to different amounts of light.
Fish eyes are sensitive to movement. They have plenty of special cells called rods that alert them to movement and contrast and each eye can detect these on their own. Because fish have eyes on the sides of their heads, they are able to see nearly all around themselves. But like our own eyes, the two eyes must work together to enable the fish to seem in three dimensions, allowing the fish to determine distance from an object. And because the eyes are on opposite sides of their head, fish only have a narrow area of this “binocular vision” – directly in front and above their snouts.
This makes fish relatively nearsighted – while they can make out movement and images at a distance, they can’t see them clearly or judge the distance or depth. That’s why trout often swim right next to your bait or lure, close enough to eat it before turning away.
Scientists believe that freshwater fish can see color. The lure manufacturers sure do! Most researchers think that fish have three sets of cells called cones in the eye that allow for color perception. They think that two sets of cones are sensitive to color while the third picks up ultraviolet light, which we can’t detect with our naked eyes.
TASTE: Let’s assume that after feeling, hearing, smelling and seeing your lure, the trout is still interested. It decides to give your offering a taste. Better act fast before the fish spits it out. Again like humans, fish have taste buds. We have about 10,000 on our tongues. But fish have even more and they are found on the lips and mouth. Some fish – like catfish – even have taste buds on their skin and barbels. They have more taste buds on their skin than we have on our mouths and since the water is carrying dissolved materials to them, they don’t even need to touch something to taste it. Some kind of catfish can taste things from 15 feet away.
Knowing how fish rely on these senses can help anglers. When determining a lure’s ‘action’ don’t just consider how it looks, but how it might sound as well. Cast dark colored lures at night because the lure’s outline will contrast against the sky. When fish can’t see well, use live bait, or add some artificial scent to lures or flies.