OUTDOOR WORLD COLUMN BY DON MACLEAN
Stroll down the aisle of any tackle shop and you will likely find a wide assortment of artificial baits and scents for trout and other sport fish species.
These baits and scents are produced in a variety of forms, shapes and colours by a number of manufacturers with the two most popular being Berkeley’s Gulp and Power Bait. This product comes in a variety of shapes ranging from trout pellets to fool newly stocked trout to night crawlers and minnows. The orange, red and white bait paste has become a standard for fishing trout in Gairloch Lake during the winter season.
All these artificial products attempt to fool fish by offering a bait that both looks, and smells, like the natural. Some of these products are very lifelike and I know a lot of anglers who find them very effective. I fished the Bras d’ Or Lakes a few falls ago with several anglers who used orange power bait on tiny #12 treble hooks as the bait of choice for rainbow trout. All I caught was codfish, but that’s another story.
There is no question that smell plays a very important part in the life of fish such as trout. Since they live in a liquid environment where seeing is often difficult fish depend a great deal on smell to home in on potential sources of food. While fish lack an external nose, they have an elaborate sensory system which allows them to smell extremely well.
In fish such as trout this takes the form of two small openings above the mouth where water enters the nasal cavity. Inside this cavity is a large surface area of cells that can distinguish unique chemicals or pheromones that are produced both by the environment, food and other fish. Unlike land based mammals where the nose is used for both smelling, and breathing, in fish the nose is used only for smelling, there is no connection between the nose and mouth in fish. Fish use their gills for breathing.
Experiments on fish have shown that they are sensitive to very small amounts of certain chemicals and pheromones. The ability to smell is very important to fish for both finding food and in navigation. The smell of their home stream is believed to be what guides salmon to their native rivers and there is a critical period in the life of fish such as Atlantic salmon that they imprint on their home river. This process is believed to take place early in life when they get ready to leave freshwater and enter the ocean. If moved to another river before this process occurs, they will imprint on the new system and return there to spawn when they come back from the sea. Fish can also release chemicals which serve as alarm substances that can be smelled by other fish in the pool.
The sense of smell plays a major role in a trout’s life and knowing that can make you a better angler.
Don MacLean is an outdoor writer and biologist who lives in Pictou County.