For the most part, however, motion, shape, noise, and water displacement are the primary stimuli that cause fish to strike a lure. Most game fish sense and are attracted to your lure long before smell or taste figure in the picture. Once fish do get close enough to your bait and commit to striking, taste and smell certainly have an important impact on their final decision. Walleye are in the middle of the pack regarding their sensitivity to smell and pike are at the tail end.
Masking Those Negative Smells “Bug spray (DEET), sunscreen (PABA), fragrances, and nicotine are substances that are repulsive to fish,” said Pure Fishing Research Director Dr. Keith Jones. “Some substances, like DEET, are highly repulsive. Studies done in labs demonstrate that fish and probably many species, can detect, and are repelled by DEET concentrations as low as 1 part per billion. Other substances, detergents for example, are also extremely repulsive, as well as quite lethal. Nicotine would be only mildly repulsive.”
One trait most fish attractants have is the ability to mask or neutralize scents deemed negative. The favorable molecules in your fish scent will adhere to the unwanted molecules that have been placed on your lures, equating to a positive smell, if the molecules are of the right size, or no smell, if they’re the wrong fit.
“Masking agents work in two ways. One way is to dampen offensive odors and tastes by mixing in positive substances. The positive agent confounds the chemosensory system, diluting the offensive nature of the repellent. In the other strategy, the masking agent actually limits physical contact with the offensive agent. Oil-based scents operate in this way. They overlay the molecules of a fish repellent with an impermeable barrier, thus preventing the repellent from dissolving into the water and reaching a bass’s chemoreceptors,” wrote Dr. Jones in his book, “Knowing Bass — The Scientific Approach to Catching More Fish.”
Scent Receptors A receptor cell is necessary to distinguish certain tastes or smells, thus sending a positive or negative message to the brain. Water-borne molecules come in all shapes and sizes. A receptor cell will only allow the correct size and type of scent molecule to make it into the cavity, thus sending a signal to the brain. If the wrong size or type of molecule is offered, then no signal will be sent.
“Fish chemoreceptors (essentially small pockets into which the stimulant molecules fit) can accommodate only small, water-soluble molecules in the size range of about 50- to 500 Daltons (a measure of molecular weight). Those molecules that are too large to fit into the chemoreceptive pockets are not able to stimulate either the fish’s olfactory (smell) or gustatory (taste) system. A good molecule will elicit a positive response, while a bad one will be deemed negative.
So, by covering unwanted and negative smells we leave on baits, fish scent can play a large part in getting fish to strike that may not otherwise do so.
Longer Hang-Time Fish scent, whether through taste, smell, or masking properties, will often entice a fish to hold on to your bait longer, allowing extra crucial seconds for you to set the hook. Some fish chomp down on a lure for upwards of 20 seconds, leaving anglers to conclude scent definitely does make a difference.
In the labs they frequently run bait ‘taste tests’ wherein a fish is offered a small piece of soft bait. Accurate counts are made of the number of times the fish rejects the bait (i.e. spits it out) vs. the number of times the bait is consumed. Fish like walleye and perch typically reject pieces of plain (non-flavored) soft baits within one to two seconds, and virtually never eat one. In contrast, pieces of Power Bait are consumed about 95 percent of the time where Gulp is consumed at a rate of 99.9 percent.
When To Use It When fish are in a negative or neutral mood, such as during cold-front conditions or in heavily pressured waters, scent can up your odds.
Cold-water conditions, such as those from fall through spring, also call for the use of scent. Fish can be finicky then, due to lowered metabolism rates, so taste and smell are often triggering factors.
Any vertical presentation, especially when working a bait slowly and methodically, deserves an extra helping or two of scent. Fish have a longer time to inspect baits, so giving them something that smells positive is always a good bet. The same goes when working heavy cover.
In the angling world, you still need skill, knowledge, and determination to catch fish. Using scents, no matter how good, can never take the place of experience on the water, but they can certainly help. Take a look at fish attractants the next time you troll the tackle aisle — you’ll be glad you did.