Greg “Doc Lures” Vinall
ALF Podcast Host & Mad Scientist.
In a previous life Greg was an aquatic scientist and spent a lot of time analysing research data using spreadsheets. These days He’s less involved in the hard science, but still uses those skills to find the best fishing opportunities based on environmental factors.
Greg’s Theories On Scents & Attractants
- In order for fish to smell something, particles or molecules must be carried through water into the olfactory system via the nares (nostrils) on the fish’s snout. Chemicals such as oils that don’t dissolve or suspend in water are hard for fish to smell as they float to the water surface, without mixing and getting into the nares. If oils do get into the olfactory system they can smother the chemoreceptors that detect smells.
- Unlike humans, the fish olfactory system is not connected to the throat, so taste and smell are separate, although still closely related.
- Fish are thought to possess much greater variety of scent receptors, meaning they can smell more things than humans and may be more sensitive to smells than we are.
- Oil-based scents tend to stick to the lure more vigorously and when they do come off are less likely to be sensed by fish. Water based scents need constant reapplication as they don’t stay on the lure long. But being water soluble, they are easier for fish to smell and find.
- Many of the contaminants commonly thought to deter fish from biting, such as insect repellants, sunscreen and fuels are not water soluble and can even be formulated to stay stuck to a surface, so they may be less of a problem than we think.
- Smells that fish can definitely detect include sweat and ‘human’ smells (don’t pee over the side), soaps, especially scented soaps and protein based foodstuffs (eg cheese). Lures contaminated by these smells may deter a bite, although all are water soluble and would presumably wash off a lure within a few casts anyway.
- Fish that attack fast moving lures are probably attracted by visual, audio or vibration cues and probably don’t slow down long enough to pick up the scent. Fish not only detect scent, but have taste buds on their faces, so they may taste a lure that’s in close proximity if it has a water-based scent on it.
- Using the wrong scent may be worse than using no scent at all. Imagine being handed a piece of steak that smelled like fish. Because the your senses disagree on what the item is, you’d probably think twice before you ate it, if you ate it at all. We don’t want fish to think twice, so it’s important the smell matches the food item we’re imitating.
- Using too much scent can create sensory overload. Ben Diggles reportedly describes it as like putting too much chilli on your food. A little can attract, too much can repel.
- The jury remains divided on the value of scents and attractants. I feel the right scent could have a place in masking or at least diluting certain odours on lures, but I usually find they only make a difference when fishing with slowly worked lures that are in the fish’s face for a period of time. Most of the time I don’t think scents attract fish from a great distance or create a bite from shut down fish.