Mika Lappalainen | Friday, 25 April 2025
Hot topic on social media during past week, what fish can smell. There has been few discussion and posts about it. We all know that fish has amazing ability to scent. Salmon and trout can find their home-rivers with scent. That's mind blowing thought, you come from sea and there are several rivers close by... and they find right one.
Discussions were pretty much that when you wade your smell will spook the fish. I don't buy that like that. Yes when you start wading for sure there is different scent going on river. Yet mammals will do the same. Is it scent what will spook fish or something else?
Think about like this, you have river which is 20 meters wide and 1 meter deep and let's take stretch as 50 m long. Let's take quite slow flow like 10 m³/second. So we have 1000 m³ water, it will take 100 second with 10 m³ flow that water changes.
There was story about guide who was pissed off as some other fisherman came to fish above them, about 200 meters above. Guide went to tell them that they need to move as they are spooking fish with smell. When they didn't want to move, guide walked 1,5 km upstream and peed on river to ruin fishing from those guys. No, I call it bullshit. You would have 30 000m³ litres water where you mix your 0,5 litre urine. Yep sounds valid.
Yes fish has amazing ability to smell. Do they know which one is for danger and which one not. Yes they do, yet I don't think our wading and scent what is coming has any factor on that. Most likely our wading takes sand, mud etc from bottom and throws it to fish, that will certainly spook fish. It is easy think that they smelled us as you fucked up with your wading.
When I wade my only concern is not to get things loose, that will easily ruin fishing. At the same time in some places and with some fishes is great system to get some fish on your feet and start frustrating sight nymphing. Mud is always bad, sand not so much.
Back to the scent, there are some scent which will certainly kill your catching. Biggest one is stress scent what fish produce during fight and after release (depends how it goes). That's why you should remove your fish from spot as fast as possible and fight in different area. I have seen in many places how hooked fish spooks all the other fish and that spot is gone. If you are able to move fish side and then play, you are not spreading stress scent on that spot. Yes water flow will do same as I told earlier yet that scent will spook fish in spot and game over. Scent will get milder as it goes down.
I have tested this during ice fishing. If I have low water, less than two meters. I start to catch perch or whitefish and those are too small to take I will move them few meters and release from other hole. I have release fish from same hole as I caught, and sometimes bites stops right away after release. If I have been able to pull fish up straight without any play and it has been easy to unhook, then it has been possible that eating continues, but often it will have break. This is quite easy to observe in stillwater with ice cover as flow is minimal.
So my opinion is that fish doesn't get spooked from our scent. Fish can find right waters etc, yet they won't be able to say that what is for dangerous except those stress scents. I would say that how we wade has much more impact than how we smell.
Imagine people smoking and handling flies and lures and they still catch fishes. Some fish certainly smell scent from baits and that attracts them to come around, some scents are add to lures for attractive. Is that for fisherman or for fish.
As a guide I would never say that fish smelled us and we spooked them. I would rather say that we kicked some mud, walked over fish or went so that fish could see us. Those are biggest reason why fish are spooked, not our scent.
I know some of you will totally disagree with me. When you have good points and observations, I'm more than happy to hear those. Until that I stick to my knowledge.
Have a nice weekend and go fishing
Mika from Finland
Ps. We have two day ice fishing competition at our lake. It will be great and next week ice fishing will be awesome there.