They sure can.
Actually, a trout’s sense of smell is 1000 times more sensitive than a dog. The nostrils on trout are located just in front of their eyes which can detect tiny bits of chemicals in the water. So, if you’re thinking why isn’t this trout in that pool taking my wet fly? Well maybe, you shouldn’t have rubbed sunscreen all over your face and then tied your fly on.
Today you can find quite a few attractant concoctions in your local bait and tackle store. Some say that the scent of garlic, anise and even cheese are irresistible to trout. That maybe so but as a fly fishermen are you going to start rubbing cheese all over your woolly bugger? Probably not or maybe you will, who knows.
There have been many tests conducted on salmon migrating in a stream with different scents added to the water upstream of them. Researchers found that the scent of human skin, dogs, and even bears repelled the salmon backwards. Now this is very interesting considering that most fly fishermen add saliva to their knots before they cinch them down, what about a hot summer’s day? When you’re sweating a lot and wipe your brow and then tie your fly on, does this then repel the trout? I’m thinking not since we all still catch trout on a hot summer’s day.
Consider a steelhead holding in a deep pool compared to one that is holding in a seem or riffle. You’re fishing with your buddy who just happens to be a spin fisherman and he is using a roe bag compared to your egg pattern. You cast your egg pattern into the riffle and the steelhead only has a split second to take your pattern, so he hits it and you miss it, oh well. Then you cast into the pool and the steelhead refuses your egg pattern but then your buddy casts his roe bag in the pool and within a few seconds, wham! He has that steelhead on. Did the steelhead in the pool have a lot more time to smell your egg pattern compared to the smelly scented roe bag? I am sure that debate will go on and on.
Now before you start ordering some sort of attractant for your flies on Amazon, consider this, can a fly fishermen use scent on their flies? Will they lose their fly fishing card to the World Fly Fishing Club? I am sure they probably would but what the hell is the World Fly Fishing Club? No no, it doesn’t exist but if it did then I am sure quite a few fly fishermen would lose their membership considering some are using squirmy worms, beads, fly flotant and so on and so on.
Well bottom line is, yes trout can smell and yes depending on the scent your fly has and can repel or attract your tout and you need to figure out what scents those are. Maybe we just need to bath in a vat of hand sanitizer before we hit the stream.