What Trout Hear and Smell, with Jason Randall
Podcast Transcript:
Tom: Hi, and welcome to the "Orvis Fly Fishing" podcast. This is your host, Tom Rosenbauer, and my guest this week is Jason Randall. Now, Jason and I did a podcast a couple of months ago about trout vision, and that one was so popular that we decided to do one on trout [00:00:30.019] sense of smell and their sense of hearing and their sense of vibrations, I guess you would call it. Jason is someone who has studied a lot of the scientific literature. He's a lifelong fly angler and educator and really knows his stuff as far as the senses of trout are concerned. So, he's always authoritative and always fun. And I get a lot of questions about, you know, how much can trout hear, can trout smell, or should I put scent on my [00:01:00.039] flies and so on. So, we're going to talk about all those topics and I think you'll enjoy it. I know I enjoyed talking to him. Now, before we do the fly box, if you want to go fishing with me, how about going to Patagonian Chile?
I have a trip at Magic Waters Lodge, February 8th through 15th, 2025, still time to sign up for this one. There's still a few spaces left, [00:01:30.200] I believe. And as I speak anyway there's a few spaces left. And this is perhaps my favorite place in the world to go fishing. The diversity of fishing there is everything from spring creeks down in the Pompas, to little tiny mountain streams up in the rainforest, to bigger rivers that you can float in a raft, to lakes where you can have giant brown trout [00:02:00.140] chasing dragonflies. It's just an amazing trip. And I love the people there. I love the guides and love the country. And my wife's going along with me. My wife, Robyn, is going with me. And she doesn't even fish. And she just loves it. She loves going bird watching and hiking and looking at glaciers and things like that. So, if you are planning on a trip and you have a non-fishing spouse, this is one of the best trips I think you can make where both [00:02:30.020] of you will be happy. So, anyway, hope you can join me there. If you're interested, it's listed there on the Orvis website under Chile, or you can call Orvis Travel and tell me you're interested in hearing more details.
And now the Fly Box. So, the Fly Box is where you ask questions or pass a tip along. And I try to help you answer your questions. And, you know, I think this is what makes this podcast is you, your questions, and [00:03:00.219] your interactions. And I want to thank everyone for the great questions. It really gives some variety to the podcast. And I'm happy to answer any question I can. So, keep them coming, either an email or a voice file, both of which you can attach to your email. And you can send me an email at
Well, Evan, I'm actually not sure because I didn't realize keel hooks were made that small. They were quite popular. They were [00:04:30.021] developed by a guy named Dick Probst in Michigan, who developed them for bass bugs mainly, bass streamers so that you could slide them through weeds without the chance of getting hung up. And they work pretty well there. As far as the small sizes are concerned, the only dry fly pattern I know that could be tied on there is an old Gary LaFontaine pattern called the Dancing [00:05:00.158] Caddis, which could be tied on a keel hook. It was kind of an upside-down caddis fly where the hook rides up and that would allow it to really skitter across the water without the hook digging into the surface film, which made, you know, skating or skidding a caddis easier. That fly and, you know, yeah, you could tie standard nymphs on them, stone fly nymphs. I think most people these days, if they want something that's going to be more realistic, have gone to a jig [00:05:30.120] hook, but you could certainly use a keel hook and just wrap some non-toxic wire in the front half of it to get the effect of a jig hook on a nymph without having to use a slotted bead or anything. So, you could try that, but I'm not sure why they made them that small. I don't think I'd ever use them.
Kai: Hi, Tom. Hi, my name is Kai and I'm 12 years old. I live in Nampa, Idaho, which is close to Boise, [00:06:00.680] and I have a question. So, I went fly fishing recently and spin-fished a little bit, but while I was fly fishing, I noticed that there's a lot of bugs in the water, but I didn't see any fish rise and eat the bugs. There were mainly caddis flies. I saw a tricoptera too and mayflies and maybe a beetle here and there. And the thing I was thinking about, were the fish overwhelmed on how many bugs there were, or on how [00:06:30.040] many fishermen that were constantly casting into the water? Thanks for answering my question. Thank you for all you do. Bye.
Tom: So, Kai, first of all, you know, if you fish enough, you're going to see that. There are times when trout just don't respond to an insect hatch and we don't always know why. We have our theories, but we don't always know why. But sometimes the water can have quite a few flies on it with no fish rising. And so there's a number of possibilities. One [00:07:00.079] is that there's no fish there. That's probably not the case. Another thing is that as you said, perhaps all those anglers in the water had spooked all the fish, so they were reluctant to rise to those insects. But you should always double-check to make sure that the flies that you see in the air are also on the water. Caddis in particular can be very tricky because they [00:07:30.019] form migration flights and they'll fly for miles and never hit the water. They live out of the water for about a month. And when they're doing these migration flights, they generally don't hit the water. They're just going upstream and then they're going to stop and go back to the bushes and migrate again the next night and they keep migrating upstream.
So, if they were truly on the water and not just in the air, [00:08:00.540] then, you know, who knows why the fish weren't taking them. I doubt if the fish were overwhelmed. I don't think they ever get overwhelmed by a hatch or too many bugs on the water. Usually, when there's a lot of bugs on the water, they're going to be feeding on them because there's abundant food available. So, I don't think they were overwhelmed. They sometimes get sated, you know, if it's a big mayfly and [00:08:30.180] the fish have been eating it for hours. They sometimes will get full and they will not feed as eagerly as they did at the beginning of the hatch. But I don't think they would ever get overwhelmed by a hatch. So, I don't think that was the case. Here's an email from Kevin from Bozeman. "I was fishing in the Gallatin River and two of the rainbows I landed had very large orangish-red markings, pictures enclosed. I've never seen rainbows like this in the river. What would [00:09:00.080] cause this? Possibly something they were eating? My second question is about fishing with my son who tends to fish streamers while I fish nymphs when the fish aren't rising. Is it better to let him fish the holes first or should I fish them first? Not sure which method spooks the fish less."
So, regarding your first question, Kevin, color in trout is not a very good indication of anything at all. [00:09:30.139] You know, a whole bunch of wild trout in the same pool can have widely different coloration patterns. And some of it's probably genetics, some of it's probably diet. You know, if they eat a lot of crustaceans like scuds or sow bugs or crayfish, they do tend to have brighter colors. So, it could be diet or genetics. I don't know which. I did notice that one of the fish in your picture had a little [00:10:00.220] bit of an orangish marking on the lower jaw, which indicates that it was a hybrid rainbow cutthroat. The other one I couldn't see. But I don't really know and I don't think even a biologist would be able to tell you why those fish had such bright orange-red markings on their sides. Pretty fish though.
Regarding your second question. In general, I think that [00:10:30.120] streamers disturb the water more because you're actively casting over a lot of current lanes and you're stripping it through the water. And sometimes it excites the fish and gets them to chase the fly and then they chase it. And while they're chasing it, they see you and then they spook. I've seen this happen. So, I would say it's probably best to fish in a hole with a nymph first. You're going to be a little bit more subtle and a little bit more selective as [00:11:00.320] to where you throw your fly. And in general, those fish you're going to chase a streamer are kind of a small part of the population that are going to be more ambush feeders than drift feeders. And you're going to pull those fish out with the streamer and you want to cover the whole pool. But I would say, if I were fishing with someone else and we were both going to fish in the same pool, I would say the nymph angler should go first and then the streamer angler.
Here's an email from Chris, [00:11:30.039] from North Carolina. "I have a question on a topic I've never heard anyone ask about. Where do you park when you see an attractive section of not posted stream? My go-to places other than obvious pullouts are the wide places in front of state bridges and occasionally a rural cemetery. Do other readers have suggestions? I'd also like to echo your suggestion of alternate waters and fish. Here in the Piedmont of North Carolina, I have been fishing [00:12:00.259] in small streams less than 15 feet across since the start of the pandemic and have never seen another angler of any sort on many of them. I've caught lots of bluegill, crappie, shiners, and occasional bass. There are many relaxing, pretty spots not far from population centers."
Well, thank you Chris for that email. And regarding your suggestion, yeah, you know, warm water anglers, people who are targeting bass or crappie or panfish, [00:12:30.399] whatever, generally tend to fish from boats or they fish from shore. And, you know, not many of them will fish in a stream and cover a lot of water in the stream. So, those kind of warm water streams generally don't get fish much. And I'm glad you found yourself some places with solitude not too far from civilization. It's a great idea. Regarding your first question, I think you've picked the good [00:13:00.000] ones. You know, it's more important where don't you park. I mean, if it's a wide pullout, like a truck turnaround, or here in the North, a snowplow turnaround, generally those are good places to park. Near state bridges, if there's a wide enough area, it's a good place. Yeah, near cemeteries, rural cemeteries is a good place. The other thing is, the thing is you want to be careful where not to park. You know, [00:13:30.259] the obvious place not to park is in front of a farm road where a farmer might need to get his or her tractor into a field or a combine or some other machinery.
So you want to be careful if you do park near a gate to a field, that you park well away from the entrance to that, so they can get their farm machinery in. And I know that [00:14:00.360] states have various rules on how far from the traveled part of the road you need to be. And you probably should look that up in your state driver's manual. I'm not sure. But in general, you know, if it's outposted and there's a wide enough pulloff, I'll use it. And the other thing is sometimes particularly if you're in a farm country, you can often park in farmyards. Farmers are generally [00:14:30.304] pretty receptive to anglers, working farmers anyways. Some of the big industrial farms, not so much. But the working family farms, they're generally receptive and you want to stop at the farmhouse and maybe you can park in the barnyard or, you know, somewhere in one of their fields. It's often good to get permission from a local landowner. But other than that, I think you pick the right places. Let's do [00:15:00.120] another email. This one is from Todd in Dallas, Texas. "Early this morning before the heat set in, I decided to head out for some bass fishing here at Lake Texacoma in North Texas. On the way to my spot, I was listening to the Orvis podcast talking about catching carp in Central Park of New York City on the Fly. I had heard of carp fishing on the Fly, but honestly knew very little about it. It was a fascinating way to pass the time as I drove to the water, [00:15:30.879] but I was going to target bass today. So, I brought my 6-weight clear water rod, a box of clouser minnows, woolly buggers, and poppers.
The first five minutes out, I get a strike, but I immediately knew it wasn't a bass. It was big and fought differently. That's about the best I can describe it. I had to play this fish quite a bit using the 6-weight. Once it got close, I was able to determine that it was in fact a carp. I felt like I was slightly under a gun, but managed to finally get it in. It took the clouser. I kinda laughed [00:16:00.539] after getting the hook out and setting it free. It was literally less than 10 minutes after hearing you and your guests talk about how challenging carp on the fly can be. And here I am just a few minutes later catching my first without even trying, or even knowing what I'm doing for that matter. Beginner's luck, I guess. I fished for another hour or so in that area and even started site fishing several carp I saw cruising without any further success. Still, it was a thrill, and can now see why so many people are targeting this [00:16:30.120] fish. Looks like I'll be heading back down to that same spot again soon. I just thought it was a fun story to share. Thank you for the educational and entertaining content you provide. I truly look forward to every episode as they come out, which by the way, can you do a podcast about monster-sized brown trout before my trip to Arkansas this October? I figure if listening to this podcast worked for carp, it might just work for browns. Just throwing it out there."
Well, Todd, I'll have to think about [00:17:00.080] that. And you keep trying on those carp. They are challenging and a small clouser might be a good idea for carp. I would try some other things. If you don't have any specific carp flies, maybe try some... If you have any smaller boned fish flies, you might want to try those. I've caught lots of carp on boned fish flies like Crazy Charlie and Spawning Shrimp and things like that. So, generally smaller, [00:17:30.619] lightly weighted flies or even large trout nymphs will catch them. So, good luck, and I hope you get some carp on purpose.
Colin: Colin from Boston. I met you last week at the Test Cast event at Orvis-Wellesley and just wanted to thank you for a great presentation, an interactive discussion. And I did have one follow-up question, but I wanted to say the 12 Steps for Trout presentation was really [00:18:00.119] thorough, informative, and I appreciated your answer at the end about environmental conservation. I've got two kids. I want to see them out on rivers, being able to catch trout in the future. And some of the specifics you talked about, what we have the power to change, regulating pesticides, and protecting some of these rivers and fish for future generations. I think it's really important. I think environmental conservation is one of the few issues left that can really unite people across [00:18:30.140] the aisle, different political backgrounds. It can really unite us for public action. So, I want to thank you, Orvis, and the long, long list of conservation partners that you guys support. Keep fighting the good fight. I love what you're doing. So, my question came up during your discussion on stoneflies.
So, you mentioned that East Coast trout don't seem to hit topwater stoneflies the way they do out West. And I agree wholeheartedly. I mean, I've seen the pictures of the prolific [00:19:00.059] salmon fly hatches, my brother's out in Bozeman, Montana. And I've never seen a trout eat a live stonefly on the topwater. I've fished from North Carolina, Tennessee, up the Appalachian Mountains on the East Coast. And really, I haven't seen it, but I have caught a lot of trout on Chubby Chernobyls and stimulators. So, I was wondering, do you think they're taking those as stoneflies? I've seen them in the spring before, there's hoppers and crickets out. So, I just wanted to get your thoughts on that. [00:19:30.059] Thanks for everything you do.
Tom: Well, thank you, John, for that call and for your comments. Appreciate that. And it was great to meet you. I too have never seen a trout eat an adult stonefly on the water in the East. However, using a throat pump, I have occasionally found them in trouts's gullets. So, they do eat them, but I think it's rare. And I think [00:20:00.599] it's they eat them more like they would eat a moth or a grasshopper or a cricket, or other terrestrial, because, of course, they hatch out of the water. So, when they get onto the water, it's generally they get blown onto the water or when they're coming back to lay their eggs. But they do eat them. And, you know, just because a Chubby Chernobyl was tied, I guess, to imitate a stonefly, doesn't mean that fish think it's a stonefly. You know, we [00:20:30.929] tie an imitation of something and we think we're imitating one thing. The fish might think it's something else. And I think that in the case of the Chubby, it's just a buggy-looking thing that trout see as food. They probably don't think it's anything in particular. They're not going to look at a Chubby and say, "That looks like a stonefly. I don't eat stoneflies." They're going to look at it and see those rubber legs wiggling [00:21:00.180] and that foam body and say, "Hmm, that looks good. Looks like a bug. I think I'll eat it." They eat moths and they eat other fairly large insects, say on a regular basis. So, just keep fishing those Chubbies, and don't worry about the fact that fish aren't eating stoneflies. It's a great fly.
Here's an email from Ian in North Wales. "Thank you for your consistently great podcast. They inform, educate, and entertain in equal measure." A comment. [00:21:30.279] "I often fish in natural lakes and reservoirs in North Wales that have some native fish, but are also stocked with various trout species. So, I found the 24th June 2024 podcast with Chad Critchley interesting and useful. One thing Mr. Critchley didn't mention was how to deal with multiple hookups on a multi-fly rig. I recently witnessed a very young but highly accomplished competition angler practicing on my local lake and at two times he had two and sometimes [00:22:00.180] three fish simultaneously hooked on his four-fly rig. I guess that helps win competitions, but it didn't look like that much fun. I usually fish a single fly so I don't have this problem myself." A question. "I noted your enthusiasm for the pro trout lines and I'm likely to buy one soon. What criteria would make me choose the more expensive textured line over the smooth? And I have to say these lines would be much better value for me if they were double tapers." Another comment. [00:22:30.680] "One of your recent podcasts made a passing reference to UK carp angling. This is mainly a highly specialized form of bait fishing that seems to generate a degree of obsession, devotion, rarely seen in other forms of angling. There's not much fly fishing for carp done here, although I expect it will grow in popularity."
Well, thank you Ian very much for those observations and although it doesn't look like much fun to you, I would think catching two or three [00:23:00.039] fish at once would be kind of exciting and interesting, so I wouldn't mind doing it. I don't know, I think I've only caught two fish at once, a couple of times in my life and they were small trout so it wasn't really that exciting. Regarding your question about the pro trout lines, in general, the textured lines, which are a little bit more expensive, are going to shoot better and they're going to float a little bit better because of the textured [00:23:30.160] finish. There's more surface area in the textured finish and the little tiny bumps act as a kind of ball-bearing on the fly rod guide, so they shoot a little bit better. You can shoot a little bit more aligned. You can get a little bit more distance. However, they do make a little bit of noise when they go through the guides and some people just don't like the sound or the feel of those lines. So, we also make them smooth and it's a more traditional feeling [00:24:00.000] line. I go back and forth between smooth and textured lines and I honestly don't see that much difference in performance. I think it's a personal preference but if you are looking for the absolute highest floating line and you want to get a little bit more distance and a little bit of noise doesn't bother you, you're better off going for the textured lines and spending a little bit of extra money.
Here's an email from Mark from Rhode Island. "Purple [00:24:30.079] fly patterns seem to be the norm out West but are they effective in the Northeast?" Well, Mark, in my observations trout are trout, bugs are bugs and we don't know why trout are attracted to purple flies but they are, they seem to be, anyways. Whether a purple fly is any better than a black fly or another darker-colored fly, I don't know. I'm not so sure that that's important but [00:25:00.700] they are popular, they do work and I have caught a lot of fish in the Northeast on a purple-bodied Adams and I've also caught many fish on a purple Copper John and other purple nymphs and purple streamers. So, they work in the Northeast just as they would work nearly anywhere in the world. Here's an email from RK from New Jersey. "It's sometime between April and October. You're on [00:25:30.019] a small eastern stream, you know the type where an 8-incher is a jaw dropper, a blue liner. You get one dry fly to pick. A, a beetle, B, ant, C, cricket, D, chubby, E, humpy. What's it going to be? Why? Is there something not on the list? What size? What weight and length rod? What length leader in a diameter tippet? How are you fishing it? Are you plopping it down to draw attention? Are you twitching it? Does this change if the stream changes locations if it's a meadow [00:26:00.500] instead of a mountain?"
All right RK, first of all, it's going to be pretty straightforward for me. It's going to be a 7-and-a-half foot 3-weight rod. It's going to be a 7-and-a-half foot 4X leader. It's going to be a Chubby Chernobyl in size 12 or 14. And the reason for the Chubby Chernobyl is that it's going to float all day with repeated applications of desiccant powder. [00:26:30.000] I can fish one fly all day long and it will continue to float because I want to be able to see it. I want to be able to make sure that my fly is in the right place because I'm most often hanging a nymph on it and none of those other patterns are going to hold a nymph up when I fish a dry dropper. A beetle, an ant, a cricket. A cricket might hold up a nymph but they're hard to see because they're black [00:27:00.180] unless you got a poster or a piece of red yarn on it or something. And humpy is a good small stream fly. But again, I can't hang a nymph very well on a humpy unless it's a little tiny nymph. So, by using the chubby, it'll float just about any nymph except the very heaviest ones. I can see it, it appeals to the fish and I can fish a dry dropper on it.
So, I will, you know, switch flies occasionally [00:27:30.160] but that's what I'm going to go with. And if I'm in a meadow stream and the water is smooth and the light is good, I might fish a beetle or a humpy. I don't fish ants that much unless I fish them behind a bigger fly because they're just so hard to see. I'll fish a sunken ant sometimes. But, yeah, generally, it's going to be a [00:28:00.140] beetle or a hopper in a meadow stream if I can see the fly. But if the river or the stream has got any kind of current at all and any kind of bubbles, I really want that higher floating fly so I can see exactly where the fly is. And if I got a nymph hanging on there, I can see my indicator. So, I hope that answers your question.
Here's an email from Drew. "I've really enjoyed some of your more recent guests and [00:28:30.039] topics. This continues to be the go-to podcast for me. I especially like, although my wallet doesn't, your product reviews and recommendations. I have a couple of questions. One, I have a comment and a couple of questions. Number one, this is a comment. A few podcasts ago, I believe it was Dan, was asking about the history of trout in the United States. I want to recommend looking back at a few issues of the "American Museum of Fly Fishing Journal," [00:29:00.160] The American Fly Fisher." Now, get ready people, if you're interested in the history of trout in the United States, you're going to have to take notes because there's some references here. "They had a three-part series on how rainbow trout came to Missouri and your state too. These can be found in the spring 2021 volume 47 number 2, summer 2021 [00:29:30.380] volume 47 number 3, that's part 2, and fall 2021 volume 47 number 4, part 3. I know this is pretty area-specific, but it is very interesting and includes many maps and pictures that help describe it. I really enjoyed this magazine and enjoyed the episode with Sarah Foster."
And by the way, if you're not a member of the American Museum of Fly Fishing and you're interested in that journal, it's a [00:30:00.440] terrific magazine on the history of not just American fly fishing, but fly fishing in general. It's a little bit more of a scholarly journal, but it's a lot of fun. And there's some fascinating articles in there. And if you become a member of the museum, you get that journal four times a year. And it's actually a physical magazine, not an online magazine, which I very much enjoy. "Question one, [00:30:30.799] is there a difference between building a dubbing loop and splitting the thread and dubbing that way? It seems that they are very similar in end product, but I was wondering if there are times when you would prefer one over the other. Question three, I have a 9-foot, 4-weight Recon and honestly is one of my favorite all-time rods. With the release of the new Helios, I was wondering if Recons or even clear-waters go through improvements or are they usually replaced by a new model?" So, regarding your first question, [00:31:00.180] you know, I don't do the split thread dubbing method that much. I can see where it's useful and I think it would be useful, particularly on smaller flies where you don't have to insert a lot of dubbing, but you have to be careful with that method. You have to have a pretty strong thread and I generally use a 12/0 thread, which is tough to split and is not as strong as some of the other threads. Splitting the thread, and when you're spinning that dubbing loop, you're [00:31:30.070] putting a fair amount of pressure on the thread and it can break the thread.
So, I typically just make a loop with my thread and dub that way, but I can see where splitting the thread is quicker and easier and I just urge you to try it. I don't know if there's any advantage on one over the other. As you said, they pretty much achieve the same thing. Regarding your question about Recon rods or Orvis rods in [00:32:00.250] general, Recons and clear waters, we don't make a new series every year on every rod series. Usually, it ends up being three, four, five years and the philosophy at Orvis is we're not going to come out with a new series just to come out with a new series. There has to be a performance advantage or a strength advantage or a durability advantage, [00:32:30.223] if we're going to change the rod. So, when a new series of Recons comes out, it'll be announced as a new generation of Recon. You can bet that there's been some improvements made on that. The Recons from year to year, if the model number hasn't changed, in other words, the Orvis item number, then it's going to be the same rod. But you'll know when it's a new series because they'll say [00:33:00.339] new clear water, new Recon, and so on. And you can pretty much bet that they're going to be a better rod than the previous generation because we learn more with every new generation of rods on how to make them better, lighter, stronger, and more accurate.
Charlie: Hey, Tom. This is Charlie, coming at you from the high country of Western North Carolina. Thanks so much for putting on such a great podcast. I find the information that you and your guests present to be really valuable [00:33:30.259] as I continue to grow in the sport and get to chase this passion. I know you just did a deep dive on sunglasses, but it's left me with a question that I was hoping you might be able to help me with. As the days are getting longer, I'm finding myself with more opportunities to fish in the evening. A lot of the times with another angler in a boat in close quarters, so protecting my eyes is paramount. Inevitably, I find myself [00:34:00.339] casting to the bitter end of the daylight, but at that point, my sunglasses are more of a hindrance than a help, but I worry that taking them off leaves me susceptible to a stray hook. The two options I've considered thus far are a pair of safety glasses from the hardware store, or maybe a pair of the driving glasses with those yellow lenses. Anything you would recommend for [00:34:30.320] those situations where you're launching the boat pre-dawn or getting to the takeout as the lightning bugs are coming out? Thanks again for everything you do and stay with it.
Tom: So, Charlie, you are absolutely right that sunglasses are a hindrance in evening fishing, and I see people all the time with their sunglasses still on when it's just about dark. And that just cuts down your resolution, and you're not going to be able to see [00:35:00.059] things as well because you're blocking a lot of light and there isn't much light left. So, I think you're absolutely right that you should take off your sunglasses in the evening. However, as you so wisely state, that you need some kind of safety glasses, particularly if you're in a boat with somebody else and you never know where their casts are going to go. So, I think your two options are spot on. Either safety glasses [00:35:30.159] or the driving glasses with the yellow lens will enhance the contrast a little bit in low light. Again, they do cut down your resolution slightly. You can probably also get a pair of what's called Plano or clear glasses to wear in the evening. Maybe another idea would be to go for an eye examination and maybe you need just a [00:36:00.059] little bit of help on your distance vision.
You can get a pair of prescription glasses, which is what I do, and then wear your prescription glasses in the evening instead. Safety glasses aren't going to have that good optics. General safety glasses are pretty lousy optically. The driving glasses with the yellow lens is probably a better idea, and I would get as light a yellow lens as you can so that you don't lose resolution. Okay, [00:36:30.039] that is the Fly Box for this week. Let's go talk to Jason Randall about two more of the trout senses. My guest today is Jason Randall and Jason and I recently did a podcast on trout vision. And I wanted to do all the trout senses, and Jason said, "No, we can't do them all at one podcast there's so much on vision," but I wanted to do one on trout hearing and trout smell. [00:37:00.420] What can they hear? What can they smell? And does it matter to us? So, Jason, welcome back to the podcast.
Jason: Thanks, Tom. It's great to be back here with you.
Tom: It's always a pleasure having you on, and as I said before, your books are so valuable a reference for me when I'm doing my own writing. I crib a lot of Jason Randall because you've really done a lot of work with currents and trout senses, [00:37:30.300] and it's great stuff. You know the biology. You've studied the background. You've studied the studies, so it's great to have you back on the podcast.
Jason: Well, thanks, Tom. I appreciate it. I enjoy talking with you, especially when we get to talk about trout vision.
Tom: Yeah. So, let's talk about their other senses. Should we do smell first and get that one out of the way?
Jason: [00:38:00.039] Well, we can. You know, let's start with hearing.
Tom: Okay. All right.
Jason: Because hearing is such a vital importance to their well-being from prey capture to predator avoidance. You can think of their sense of hearing and their sense of smell too, really. It's kind of their long-range senses where their sense of sight might be somewhat limited [00:38:30.199] for distance because of clarity or water staining. Beyond a certain point, vision gets a little less accurate. Sound and smell can be transmitted for great distances. So, we can think of them, those two senses, really, as kind of their long-range senses.
Tom: Yeah. All right. So, let's talk about hearing and vibrations, both, right?
Jason: Well, the basis of hearing, of course, is [00:39:00.194] sound. And, you know, sound is created by some kind of a mechanical disturbance, and it's transmitted as mechanical waves then to our receptors or our hearing apparatus, and that then transmitted to our brain, and we perceive it as sound. So, if you look at the transmission of sound, it requires some kind of medium, whether it's air [00:39:30.139] or water, that's compressible and that can transmit these waves then of pressure changes that we register in our ear as sound. There's a great difference between air and water, and so five times more dense is water than air. And so, the transmission of sound and water is far different than it is in air, and then our ears, obviously, have [00:40:00.215] adapted to the way we perceive sound in the environment we live in. And then the trout's ear and their hearing receptor is very much attuned to the underwater world in which they live. And there's times, you know when you're standing in the river and you hear the sound of the rushing water, and you think, "How could they hear anything with all that background noise?" It'd be like hearing a whisper at a rock concert. How can [00:40:30.059] they hear anything? Look at their sense of hearing and their ability to hear. It's very much fine-tuned to the world they live in.
So, there's two ways that these mechanical waves are transmitted. One is by pressure, meaning that there is some kind of a compressibility to the medium [00:41:00.159] in which it's transmitted, air or water, and air is a lot more compressible. And so the second component or the second way that sound waves are transmitted, these mechanical waves, are through essentially particle collisions where particle motion, it's like dominoes where air or water molecules are agitated and the agitation is spread from [00:41:30.139] particle to particle, and air would be through the molecules of oxygen and nitrogen. And in water, it would be, you know, hydrogen and oxygen that is really propagating that mechanical wave. So, because air is so much more compressed, the nature of transmission of sound and air is more through pressure waves. The particles of air are so far apart because it is a very less dense medium that there [00:42:00.000] isn't that much particle-to-particle transmission in the sound. It's more in pressure waves. In water though, that's far more dense and the molecules are so much closer together just because of the density of the water. There's a lot more particle-to-particle collision, collision of one molecule into the next that were created by the disturbance in the water that created the sound, and we see a lot more particle-to-particle transmission, and that's called [00:42:30.110] particle motion.
So, in water, the hearing apparatus for trout, their ear, if you will, is really fine-tuned to this type of particle motion, and their hearing really is centered around an otolith, which is almost like a crystal from the old crystalline radios that we used to have that are sensitive to vibration. So, you can think of that component of sound in [00:43:00.079] water as more like vibration, where the transmission of sound in air is more along the lines of pressure waves and oscillations and pressures that we perceive. So, you go to your concert, and the musical instruments and the speakers are playing the music, they're creating mechanical disturbances in the environment that are variable in amplitude and frequency and pitch, and all of these [00:43:30.131] complex waves that are then transmitted through the air. Those pressure changes and oscillating pressure waves, and then our eardrum is very fine-tuned to pick up sensitivities and changes in pressure, and then we filter that out then in our brain, and then we hear Mozart's Concerto. Maybe in our case, it might be Led Zeppelin.
Tom: It might be. It could be...
Jason: Or maybe you're a grateful deadhead. I don't know [00:44:00.980] but that's what we're hearing. But if you took your cup of coffee and you set it on the speaker, take a look at the oscillations and the vibrations, the sense that are picked up in the fluid medium. You see a whole different set of mechanical waves just by putting your coffee cup on there. It's more like vibration. And so really, that's what is most perceived audibly for [00:44:30.179] trout as something that is heard. Now, in water, there is a wave component as well as the particle motion component. So, they do have a little bit of both. So, they are able to pick up waves. So, you can think of the wave as throwing a rock in a pond, and you see the waves that are transmitted as ripples across the surface. And trout can [00:45:00.480] detect those as well. But maybe not with the otolith in their inner ear. That's going to be something that's more perceived with the lateral line. Okay. So, the lateral line often gets kind of lumped in as a sense of hearing, but it's really not. It's more like, probably more analogous to a cat's whiskers that are picking up mechanical disturbances in the forms of these waves. These are going to [00:45:30.039] be low-frequency waves, and they can be amplified by the third component of the trout's "hearing apparatus," which is their air sac. And so that's like a resonating chamber that's alongside and kind of under their center of mass alongside the lateral line. So, that's kind of like a resonating chamber that facilitates these low-frequency sound waves.
So, in a sense, [00:46:00.139] it's as much a sense of touch in detecting disturbances as it is a sense of hearing these other two ancillary organs. And so it's how trout can position themselves right on the edge of a current scene. Mechanical waves are not necessarily only created by a sound disturbance. They can be created by current as well. Current differentials, trout can pick up the slightest change [00:46:30.159] in current differential and put themselves right on that scene where they can kind of hideout to save energy and then get out of the current to grab food. It's also a great long-range predator avoidance system as well. If a large predator is on the move, he's creating a bow wave as he swims through in his tail. Movements and fin movements are creating disturbances that are transmitted as [00:47:00.599] waveform energy and it's picked up by that lateral line. So, I remember one time I was walking in one of our small driftless streams up here and it was kind of a slower-moving pond, another pond in a pool. And I was standing there and I took some pictures and I was doing some observations. I took one step forward. I really didn't think I made any sound, but I created a waveform disturbance that went all the way up [00:47:30.120] into the head of the pool even against the current, by the wave of my movement. And even though the trout didn't see me, they all took off because that wave is perceived by them through the lateral line essentially and it warned them that a large predator, which in that case was me, was on the move.
Tom: Do you think though, and this is my theory and I could be totally wrong, that those waves that we push when [00:48:00.159] wading or when a heron steps in the water or whatever are picked up by their visual field because the water starts to wiggle in a way that's not normal?
Jason: I think so. I think that's going to be true. And that's why a heron kind of just knives through the water. You see them kind of just knifing their legs into the water. Like, a professional diver off a diving board, they knife into the water to create a little disturbance [00:48:30.380] as possible. I think truly that's how these [inaudible 00:48:33.970] are so successful is because all these things do play a role.
Tom: So, let's talk about the noise that we create when we wade. Let's say we're not pushing a bow wake but we're rubbing our metal studs on a rock or we're tapping the tip of our wading staff. Maybe it's got a metal tip instead of a rubber tip. [00:49:00.179] Do trout hear that? How far away do they hear that? And does it matter? Does it bother them?
Jason: Yeah, all are true. I think they do hear it. They can hear it from a long distance. And their frequency set of their inner ear, if you will, their ear itself is really tuned to those frequencies. And it really does kind of filter out a lot of the background noise of the river stream itself. [00:49:30.119] And so they are really keyed into those types of sound generated within that frequency range. And then again, they use their air sac as a resonating chamber, if you will, and then the lateral line will pick up those alternate frequencies. Which again, are those really heard, or are those more felt? And that's why sometimes a lateral line is to be referred to as a remote sense of [00:50:00.309] feeling. But essentially, they are detecting frequencies outside of their audible range, just like we do. You go to that Led Zeppelin concert and you can hear the full range of the music within the human ear. But you can also feel in the pit of your stomach or the hollow of your chest, you can feel the impact of the sound that you can't necessarily hear. And that's true of trout too.
So, they kind of can hear in this range and they [00:50:30.079] can perceive in another range. And so how that works for anglers in the river, is it tends to filter out a lot of that background noise that we would find very distracting. And it really concentrates, I think, their attention on those sounds that would be an immediate threat to them. And so I think anything that's disturbing the environment, whether it's us is wading or [00:51:00.679] another predator on the move, I think they pick that up. And so I'm very conscious when I wade that. I'm trying to minimize the impact of those metal studs on the gravel. And that clump, clump, clump of the wading staff, I do think, and I've seen it happen and you have too, that the trout are alerted by those sounds. They're considered unnatural. They may identify it with us per se, but they know it's not supposed to be there. They know it's not [00:51:30.434] probably healthy for them.
Tom: Yeah, I've seen the opposite and so I may disagree.
Jason: There you are stirring the pot again.
Tom: I know I'm stirring the pot here, but I have stood behind trout that I could see and without pushing a bow wave, without disturbing the water, made it with a little current. And I've rubbed my studs [00:52:00.019] on the bottom and I have tapped my wading staff tip. And I don't see any change in their body language. I don't see any movement or spooking or any indication that they're disturbed. Now, as soon as I push a bow wave, boom, it's over. They're gone.
Jason: Yeah. And I think certainly the bow wave is probably more readily identified [00:52:30.099] as a threat. Whereas, they may not perceive some of these other sounds we generate as threatening. It's all going to be conditioning their environment and the development of their predator avoidance systems and stuff like that. So, I'm not sure. I'll have to look at that, the next time I'm out in the water [inaudible 00:52:55.556].
Tom: Yeah. It's something that I've never had an [00:53:00.699] ultimate decision on it but it's just my observation and could be in different rivers. It would matter.
Jason: Yeah, I think so. And I think different in conditions, it matters too. There's times where the trout are already anxious. I mean, clear blue sky days, midday, mid-afternoon circumstances, even a sparrow flying over the pool can kind of put them on alert. [00:53:30.400] I think that different circumstances could certainly have an impact as well.
Tom: All right. So, I should probably pay more attention to my metal studs and my wading staff tip.
Jason: I think we all should. Yeah.
Tom: Okay. All right.
Jason: Anything we can do to stack that a little bit in our favor. Trout are such gritty adversaries. They do demand our respect. I think anything we can do, and sometimes maybe we get a little esoteric [00:54:00.480] on some of it, but that's what makes these discussions interesting.
Tom: And how far away do you think in the water can a trout perceive the sounds that we make when we're wading?
Jason: That's a great question. And it's really dependent on that dual nature of sound transmission. The particle-to-particle movement aspect of sound transmission doesn't go very [00:54:30.045] far. And so those probably qualify as higher frequency sounds that we make with our metal studs in the gravel or our wading stick, because those would be more particle-to-particle transmission. They don't go that far. But the waveform of that type of disturbance can go 30, 40 feet [00:55:00.079] up into the head of the pool where I found the problem. And they can even go around corners. So, they can follow river bends because they're low frequency, they can actually kind of walk around slight bends in the river. And that's why you don't need a direct line of transmission. That's why you could be in one room and your wife or husband in the other, and you could talk in one direction, but they could hear you through a closed [00:55:30.019] door. It's because those pressure waves can be transmitted from pretty long distances and they don't need a direct line of communication.
Tom: But those pressure waves are almost always going to have a visual aspect, right? The...
Jason: They're going to, but not necessarily.
Tom: So...
Jason: You're thinking of ripples on the water where mechanical waves in sound don't have to create a visual effect to be transmitted. [00:56:00.739] But yes, definitely those ripples you see on the water are the lowest in frequency. You know, they're very perceivable visually, but not necessarily all of them would fall into that category.
Tom: So, splashy wading, they can hear that, not just...
Jason: They can feel it and hear it. Yeah.
Tom: Feel it and hear and see it if you're not in a riffle that's pushing the waves back toward you.
Jason: You could say that, for [00:56:30.199] sure. And it's just like the rock concert, you can hear it and you can feel the music. They can hear it audibly detectable in their frequency of hearing, but they can also feel it through just like the hollowness in your chest. They've got a hollow organ too, their air sac and that's going to resonate and be able to detect sounds that may be out of the audible range. You feel a mechanical wave then as [00:57:00.519] that pressure waves.
Tom: Now, kind of the opposite side of things, we can use these sounds to our advantage with certain flies, right?
Jason: Well, sure. That's a good point too. You know, the splat that a hopper makes on the water, that creates a visible wave. It creates a pressure wave that is detected, but not necessarily [00:57:30.260] visible. And it can also create that particle displacement aspect of sound too. And again, we have to keep in mind that these are their long-range senses. And so they could hear that hopper hit the water from a much further distance than they could see it. And so they could be attracted to the general area by the sound because they have the ability to triangulate sound [00:58:00.519] the same way we do. Their ears are on either side of their head, and they've got the lateral line on either side of their head, and then on this other side of their body, and then they've got this air sac ventrilate around their belly. So, this allows them, just like us, to pinpoint kind of the direction of the sound, and then they can go right to it. And then once they're in range, then they are a visual predator. They make their decisions on prey and eating visually, but their [00:58:30.139] sense of hearing could certainly focus their attention and draw them to that area. It's like, you know, I don't know if you prey in one fish, you know, and here comes a larger fish swooping in to take advantage of the easy meal. And he probably didn't see that happening, but he heard it.
Tom: Yeah. Well, one of the most effective ways of fishing a terrestrial, if you can see a fish, is to drop it behind them with a sound, and [00:59:00.139] you get a reaction strike. They wheel around and eat it without getting a good look at it. And that's a deadly...
Jason: Interesting. Yeah, that's a good point.
Tom: Yeah, you know, with a beetle or a hopper, it's often a deadly technique to throw it on their tail. Sometimes it scares them but...
Jason: Well, you know, there's always that. But, yeah, that works. But, yeah, and again, you know, it just gets their attention and gets them looking in that direction. And [00:59:30.059] sometimes they eat without looking. That's a good thing.
Tom: So, how about fishing in dirty water at night or even in kind of swirly water with a fly like a muddler with a deer hair head that creates vibrations, or at least that's the theory, right? That, a fly with a palmered hackle or a deer hair head or whatever creates vibrations that they can feel and they can track it down. [01:00:00.659] Just like...
Jason: Yeah, I think that's really an effective way of not only fishing flies but designing them as well, don't you think?
Tom: I think so, yeah. I mean, it's the theory, anyways. Seems to work.
Jason: For sure. And I think a trout or a fish can detect and discriminate between a bow wave and swimming activity from a potential meal from that of a predator, which is a potential threat. And so I think [01:00:30.135] that, you know, they really do key in on, "Okay, this is something to eat. I'm going to come here and take a closer look." Or this is a predator making a much larger disturbance with the tail movements and fin movements and that bow wake, and then they run. And I think sometimes, maybe this is a thought and maybe just building on that a little bit, but well you see giant, giant streamers, you know, and it kind of selects us maybe just for these larger fish, [01:01:00.436] you know,targeting larger fish, but maybe it's actually scaring away, you know, maybe some of the smaller fish and they're perceiving it as a threat and only the larger fish that are attracted to it as a meal. That's kind of an interesting thought.
Tom: How far away do you think they can sense those vibrations, you know, of a D&D or a muddler minnow or, you know, something with a big broad head made of deer hair, hackle [01:01:30.340] hair or whatever?
Jason: I think it depends on the current, you know, and how effective. And I don't know that we always know the answer to some of those questions, but they're interesting to conjecture about. But I do think that especially the pressure wave component of sound can be transmitted to great distances, but there's also attenuation involved, you know, over the longer distances. So, I [01:02:00.019] do think of the factor, how far exactly could they make that determination? I don't know.
Tom: Yeah, I don't either. I wish I knew.
Jason: But we'll keep trying though and go play with it.
Tom: Yeah. We'll keep learning, right? We're always learning.
Jason: Yeah, that's it, the learning sport, man. You know, it's a sport for people that want to keep learning.
Tom: Yeah. So, it's pretty obvious to anyone that's fished for [01:02:30.300] a long time that trout don't hear us talking above the water or yelling.
Jason: They don't, no. Contrary to what my dad told me when I was 6 years old and I was in the boat with him, and he said, "You can't talk." I think he didn't want to listen to the endless babble of a 5 or 6-year-old kid.
Tom: So, like...
Jason: Like, no, you're right. Because of the sharpness of the interface and the differences in sound transmissibility between air and water, the [01:03:00.840] pressure waves that we primarily use in sound when we're speaking or making noise above the water, does not translate into mechanical waves under the water. With the exception that if you're standing in an aluminum bottom boat and you've got that 6-year-old boy that's tap dancing and jumping around, that is a whole different thing. That those [01:03:30.313] disturbances are directly in the medium of the water and that does have a big factor.
Tom: Yeah. I know I've fished with redfish guides before who don't like loud talking in a boat because they feel that you can create some resonance with the hull of the boat and the redfish can sense it.
Jason: Well, I wouldn't dispute that possibility that our bodies could [01:04:00.320] transmit through our feet into the floor. That's becoming a little bit esoteric. But here's another example. If you take that transistor radio or that boom box or that speaker and you put it on the seat of the boat and you're playing Led Zeppelin, I think that's a whole different thing. We know that once we create [01:04:30.119] the sound waves with talking that's in the air that doesn't transmit into the water, they're probably thinking that the resonance that it creates in our chest, that would set up vibrations that would be transmitted through our feet, through the hull of the boat into the water. Maybe a little, I won't say far-fetched, but certainly esoteric and maybe something I wouldn't necessarily be concerned about. But [01:05:00.093] maybe they should just put some carpet on the bottom of the boat.
Tom: Boy, transistor radio, Led Zeppelin. Half the people who listen to this podcast don't even know what a transistor radio is probably. You're dating us, Jason.
Jason: That's just terrible. I know it, right? Well, that's what we grew up with, all right? And your dad telling you to shut up and sit down and quit dancing in the bottom of the boat.
Tom: I think Dad just wanted to drink his beer and didn't want [01:05:30.139] to be disturbed by the kid.
Jason: Yeah. I think that's true.
Tom: All right. So, that's sound and hearing. Let's talk about smell.
Jason: Yeah. Okay. I know we kind of hit that topic pretty well. There's a lot of physics in sound and hearing, and it's hard sometimes to really get a handle on it. But the sense of smell is a little bit more akin to ours. [01:06:00.500] They've got chemoreceptors and they have them concentrated in the olfactory organ, but they also have them on their lips and gill plates and externally as well. Some fish are really heavily skewed in that direction that are used to feeding in really turbid water like a catfish. They've actually got [01:06:30.079] gustatory receptors on their barbels...
Tom: Or eyes.
Jason: ...just because they have them all over their face in order to do prey identification in a really limited visual environment. Trout have that as well. Their sense of smell, their sense of taste like ours are pretty well linked, very, very sensitive. But I don't know. You always use the example of these salmonid fish that migrate [01:07:00.079] from way off in the Pacific Ocean and come up into their stream of origin, what we call a natal stream. How do they do that? Essentially, it's almost, from a strictly olfactory sense. It's almost impossible that they could register 1 part in 20 billion. The dilution effect of their natal stream is probably too great. It really [01:07:30.019] prompted a lot of investigation into, "Okay, well, what truly is the mechanism of migration and some of these things?" We really have come down to the point that there is really some kind of a geolocator device that is in play as well.
They found magnetite particles in the skulls of some salmonid fish that probably are [01:08:00.780] doing almost like a geolocator, getting them in a target zone off of maybe they're sensing magnetic field variations and getting at least close enough for their sense of smell to kick in. Yeah, take a look at other species too. Look at the Arctic tern. Every year they migrate 20,000 miles back and forth between Arctic and sub-Arctic, Antarctica. [01:08:30.555] And some of the new research has shown that they're not only following food sources and kind of swinging through in areas during their migration, but they're also following like the mid-Atlantic ridge of subsurface structure really in the ocean. They're following these things. How could they follow them so closely? Well, they do feel that there is some kind of a magnetic effect or some kind of a detector that [01:09:00.060] we still haven't quite identified. I mean, to go 20,000 miles a year is over the lifetime of an Arctic tern. They live to be 20 or 30 years old. That's like back and forth to the moon twice or something like that. It's crazy the distances that they cover and they cover it so accurately and consistently that there is the theory that there's probably some other device that's being used.
[01:09:30.380] And we kind of come up with some of these ideas of magnetic theories, magnetic resonance, magnetic variations, whatever it might be. And it's the same as conjectured for some of the migratory fish. Then they get close enough where they can really smell them. And they're smelling is not really, are they smelling the chemical content and the actual water [01:10:00.300] type of their natal stream or is it something else? And now the current thinking is that they're actually smelling their kin, their conspecifics. That's a biological term that means their relatives. Other fish that they're related to, that are all coming in and out of that birth stream, that natal stream, if you will. They're smelling the fecal material and fecal recognition or bile acids [01:10:30.159] or some of these things that say, "Hey, these are my relatives, this is home." So, even though they're maybe not brothers and sisters to those fish because they're in different generations, they could be, or they're aunts, uncles, nephews, and nieces, but they have this kin recognition that, "Okay, this is our familial home, the home of our relatives and I'm going to go up this stream."
Tom: Interesting.
Jason: Yeah, it's pretty [01:11:00.047] cool stuff but...
Tom: Yeah, it is.
Jason: ...it's not perfect either. So, I mean, maybe it's 95%. That means 5% maybe go up the wrong stream and that's kind of a great design anyway because that helps with genetic diversity and avoiding creating purely isolated genetic pools.
Tom: Right. Yeah, there have to be some strays and certain things. I think Pacific salmon will stray a lot [01:11:30.301] more than say steelhead will.
Jason: You're right. Yeah, I think that's true.
Tom: Okay, so can trout smell our flies? Can they taste them? Should I be putting power bait on my streamers?
Jason: Okay, I have to confess. I was doing some research on this book and, yeah, it's a little embarrassing. You might...
Tom: No, I've done it too. Go ahead.
Jason: [01:12:00.260] Confession. We want absolution. So, I went over to the page store and I bought a bunch of mud minnows and I brought them home on my wife's cutting board which I found out did not endure me in her eyes. But I skinned all these little mud minnows with a scalpel and I thought if I could make it smell like a bait [01:12:30.199] fish, you know, or some kind of a meal. So, I created a slurry...
Tom: Go on.
Jason: ...and I took it with my fishing buddies down the river. And so they're in the front of the boat dipping their streamers in the water and I'm in the back of the boat dipping my streamers into the slurry and then throwing them out in the water and I did this until they caught me. [inaudible 01:12:54.479]. Oh man, you're a bait fisher but now...
Tom: That's why I always fish in the [01:13:00.180] stern.
Jason: Yeah, I know. But honestly, in the couple of days that I did it, it looked like a bit of difference. So, I don't know. Again, trout are visual predators. They make their determination visually. That's how they decide what to eat and they're curious. I mean, they know they make mistakes too or we would never catch them. But I don't think they're really relying as much on their sense [01:13:30.420] of smell as a prey determinant. Now, again, we talked about a sense of hearing, a sense of smell as being their long-range determinants, their stress hormones, and all kinds of stuff that they release that are somewhat attractive and will bring trout or sharks. It's like your bonefish. You catch your bonefish and all of a sudden, the shark shows up. That could be partly sound disturbance, that could be partly the stress [01:14:00.140] hormones that are being released by the struggling fish. So, yeah, they use them to get in the vicinity. And so I think the sense of hearing and the sense of smell certainly are long-range senses that get their attention but they don't make their decisions based on it. And I think that was born out in my slurry dipping experiment with my streamers on the white mirror. I didn't catch any more fish than anybody else. Otherwise, I would have had that patented to the [inaudible 01:14:29.491].
Tom: [01:14:30.927] And the thing about in a current is that the fly is moving so quickly through the current that they probably don't have any kind of chance to zero in on a smell.
Jason: Probably not. And you do have to remember that's true. That the current is unidirectional typically and it's moving downstream, and so they're not going to smell anything below them in that type of a situation. It's like hunting a good bird by a dog. They've got to get in the scent [01:15:00.220] of the bird before they can detect it.
Tom: Right. Probably, would you think that if you were bait fishing on the bottom where your bait wasn't moving that sense of smell might play a part?
Jason: Sure. I think that all the old corn balls that we used to do for catfish and stuff like that and the bait balls, those things, yeah. Again, in that kind of environment, those types of fish definitely [01:15:30.260] do make more of their prey decisions based on smell or taste with their receptors. I think in that environment, they've developed that part of their feeding strategy. But for trout and most other game fish, I don't think it's really that important as far as that goes. Close-range prey decision-making is not done based on those senses. It's visually.
Tom: Yeah. How about when they reject [01:16:00.340] our nymph or our streamer, when they spit it out, is that a taste reaction, or is that a tactile reaction, do you think?
Jason: Both, I would think. Both. I think it's instantly recognizable as fraud. Our trickery has been discovered and usually, it leads to, hopefully, a quick hook set on our part, but sometimes a broken heart on our part too. But, yeah, I do think, trout [01:16:30.279] are curious in all fish. We've done stomach pump analysis and you find cigarette butts in there and safety pins and weird stuff. And so I think it's like sometimes like an infant where everything goes in the mouth to be evaluated. And they do eject in a lot of stuff based on the artificial characteristic of that material, whether it's our fly or a cigarette. But I think it's pretty immediately recognizable as [01:17:00.359] fraud and expelled.
Tom: So, if we dipped our nymphs in mayfly slurry, do you think they would hold on to it a little longer?
Jason: Oh, good, now my wife has something else to look forward [inaudible 01:17:14.475], on the table. I'm going to be full of the bugs.
Tom: You haven't tried that. You haven't tried a mayfly slurry yet?
Jason: Yeah, you're trying to improve my marriage, which you're trying to do. Yeah, [01:17:30.500] but you know what? Again, power bait in past fishing, they too worked out. And so I don't know. I don't think it hurts anything if somebody wants to try that. I'll be very curious as to the results. But honestly, we know that trout and again, trout and bass are different too. You're looking at a classic ambush [01:18:00.159] hunter, as opposed to more of a chaser overtaker. So, their mechanisms for prey capture have evolved somewhat and developed somewhat differently. I don't know. The power bait stuff does for bass though, right? It works for catfish, the bait balls, and stuff like that. So, there is certainly that to be considered. But in all the literature I've looked at in [01:18:30.880] my own experience, I have found that it hasn't been a huge enough factor to make me want to scatter insects on the kitchen table.
Tom: Yeah, okay. Fair enough. We'll save your marriage.
Jason: Yeah, I appreciate that, 34 years and counting.
Tom: How about when a hatch starts? Do you think that trout can smell the emergence of the insects? Do you think that's...
Jason: You bet...
Tom: ...part of [01:19:00.140] it?
Jason: ...so can you. Yeah. I mean, the best example of that to me was fishing the hex hatch in Michigan. You're just sitting there. It's dark. You can't see anything. It's the middle of the night. You're up there fishing and all of a sudden, you get this, kind of this whiff of this odor that smells like a cricket box at the bait store. And you look up and you put your flashlight up and the sky is [01:19:30.000] just a thoroughfare of hex mayflies heading upstream to egg-lay and drop. And you can smell it and so can the trout. So, definitely, I do think there is a component of that, that wets their appetite and gets them kind of like Pavlov's dog as they start drooling. And it gets them alert to the meal at hand. But again, all [01:20:00.060] of that scent in the water, it's going to be picked up by their sense of smell, going to get them excited, going to get them ready to eat, salivating even if trout can salivate, which they probably cannot. But then their sense of sight takes over and then they capture their meals based on visual cues.
Tom: Okay. I got a product now.
Jason: We're going into business.
Tom: Yeah, you take...
Jason: I appreciate that branding.
Tom: ...that mayfly slurry [01:20:30.239] and you go upstream of where you're going to fish and you hang it in a cloth bag in the water and then you run downstream away from the water so you don't spook the fish. And you fish...
Jason: You won't disturb them.
Tom: ...a dry fly and the fish are going to be ready to rise, right? Because they smell the mayflies.
Jason: Yeah, we're going to get rich. But what if somebody...
Tom: We are.
Jason: ...already invented that again?
Tom: Really?
Jason: Because you go out to some of these places and you [01:21:00.060] see these guys with a... I went into a bait store one time. There's a can of Del Monte corn. And I got there and some guys dumping wads of Del Monte corn and then drifting downstream in his boat and he's just catching fish after fish after fish on probably on corn. But I think, definitely, there's going to be something there.
Tom: Yeah, I remember stepping into a boat [01:21:30.420] on the White River in Arkansas and seeing the bottom of the boat littered with kernels of corn.
Jason: I know. Just don't get caught. Do that from the stern of the boat while your buddy's up front. But, you know what? If you're in the stern of the boat, anything that you're putting in the water, he's probably benefiting from because he's below it. So, he's catching all the fish and you're still not. Like, what?
Tom: All right. [01:22:00.020] So, we got a product. Corn, no, that's too pedestrian. We want to have a mayfly slurry.
Jason: Oh, man, we want something that people will pay money for. Otherwise, they could go get their own can of corn. But do you think Orvis would go for that or they would take back their product?
Tom: I don't know. And then I worry about the decimation of the mayfly population. Where are you going to get all those mayflies to make the slurry?
Jason: But you probably know a guy though, [01:22:30.121] right?
Tom: Yeah. Put my kid to work.
Jason: There you go.
Tom: Well, anyway, anything else on smell that anglers should know about, other than they probably should experiment and see if it works?
Jason: Yeah, I think so. Keep an open mind and anything that we can do to even stack the deck a little bit. I talk a [01:23:00.159] lot about how I have a program that I'd like to discuss, that talks about how to get to that upper 10% angler category. And my lefty once told me, he said that 90% of the fish are caught by only 10% of the anglers, which means 10% of the anglers are doing 90% of the catching. Do you want to be in that 10%, right? So, I put a program like that together and I just came up with the conclusion that trying [01:23:30.319] to get into that upper 10% isn't just 1 or 2 major things you could do. It's the sum total of hundreds of little things that you do that ends up maybe catching a few more fish at the end of the day. And that's what makes it so fun. I mean, it's fun because you and I, as outdoor educators, we get a chance to really dive into these things and share these things with a sport that's always so eager. We all want to keep learning and growing and that makes it [01:24:00.020] fun.
Tom: Yeah. And you've certainly contributed to that education over the years.
Jason: Well, thank you. I appreciate that, Tom. It's fun. I mean, we both have been in that part of our sport for a long time and it's humbling and it's just a real privilege to be able to do that. And you get to work with so many different people too, the other people that share those passions, that share their knowledge. And that part of it is truly humbling because you [01:24:30.000] realize that all these people that are with clubs and organizations that are engaging anglers and sharing their knowledge and giving of their time and energy and resources to help further our sport to continue the interest in our sport that will keep it alive into the future generations. It's just most people they do human work and oftentimes it doesn't get noticed. All these volunteers, whether it's project healing waters or whether it's TU clubs or other organizations, [01:25:00.500] I mean, they have a tremendous impact in our sport. And you do too. We get a chance to really engage with those types of opportunities a lot. And here in the driftless area, we've got driftless women on the field, that really create a great educational and safe environment for women. I just finished up with a five-day streamside program on the water teaching [01:25:30.055] program with Alter Fly Fishing Ministries.
It's kind of an educational retreat, if you will, focuses not only on becoming better anglers but becoming better people. And, you know, just these organizations, you don't find these in other sports. And we were working with Fly Fishers at the Crossing, another great, great program, a fellowship of anglers that really, I don't know, they're just so focused on, you know, getting people into our sport and engaging [01:26:00.039] them on becoming better people. And, you know, give a shout out to, you know, some of those guys that are doing it, Eric and Steve at Alter. And John and Kenny and Jim, you know, with these other groups, these guys work so hard. And, boy, I'll tell you what, it makes us really appreciate, you know, the sport that we have. And we're so blessed.
Tom: We are. We definitely are. We're very lucky. All right, Jason. Well, [01:26:30.199] that is a good note to end on. As always, it's been fascinating talking to you, and I'm sure my listeners have enjoyed this discussion.
Jason: We didn't put them to sleep. We kept enough mechanical waves going through the airways that we kept them going. It's like they've had an electric cup of coffee.
Tom: I hope so.
Jason: Hey, what's up next for you? I think you're going out to Colorado, right?
Tom: Yeah. In fact, when this drops, as people listening to this, I [01:27:00.220] will probably be in Colorado. I've got 10 presentations in a row at Orvis stores and dealers, and I'm really looking forward to it because I'm going to get to fish in between in the morning, probably chase some carp and some trout and some white bass and who knows what else, but it's always fun. Colorado is such a Mecca for fly anglers. It's going to be fun. And you're going out there too.
Jason: Yeah, I'll be out there. [01:27:30.159] I've got an underwater program out there in Sportsman's Paradise, west of Woodland Park, and I'll be fishing with Ed and Landon and maybe Pat out there, just hanging out and enjoying that part of our sport too, which is always so special. But just remember, those carp you're going to be catching there, they're going to be triggered by their sense of smell and taste. So, that might be a good time for that can of corn.
Tom: [01:28:00.300] I just go buy some power bait, right? I'm going to experiment with that on the carp, definitely.
Jason: Okay. Well, it's great talking with you, Tom, and thanks again for the opportunity to share this and have this discussion together.
Tom: All right, Jason. And where can people reach you if they want to follow your website or your blog or Instagram?
Jason: Yeah. That's good to share because you know what? We've referenced quite a few things today, and I will go back on my Instagram [01:28:30.140] and I'll post some of these things that could be useful illustrations to kind of complement our discussion here. I actually got that video that shows once in that pool and the disturbance it created. I'll post some of that stuff on my Instagram site and that would be @Jason Randall Fly Fishing on Instagram or you can just get me @Jason Randall on Facebook would work as well. [01:29:00.393] But typically I tend to be a little bit more attentive to Instagram and I'll post a lot of educational material on there. And certainly, people can message me or anything. Please, no making fun of me on Instagram, but you can certainly add comments to these things.
Tom: I like it when they make fun of me on Instagram. I enjoy that.
Jason: That's even better, right? Talking smack, that's the best part of our sport anyway, right?
Tom: Yeah. And you know what? People can buy your books too.
Jason: Yeah, [01:29:30.039] they could.
Tom: People can buy your books.
Jason: The one that I'm focused on is "Trout Sense" and that really dives into the sense of vision that we talked about before and the senses we talked about today. And then there's two other books that are considered the Fly Fisher's Guide trilogy, which were "Moving Water, A Fly Fisher's Guide to Currents" and then "Feeding Time, A Fly Fisher's Guide to [01:30:00.399] What, When and Where Trout Eat and then Trout Sense," which is "A Fly Fisher's Guide to What Trouts See, Hear and Smell." So, certainly, those are available. The newest book is called "Nymph Masters" and that's "Fly Fishing Secrets from Expert Anglers." And that was fun because you get to fish with some really great fishermen and steal their secrets and publish them as your own.
Tom: I don't think I have a copy of "Nymph Masters." I'm going to have to get a copy of that. I do have a [01:30:30.159] copy...
Jason: Actually, that's...
Tom: ...of the other three.
Jason: It was a fun book because there's so much of that camaraderie in our sport and they did share so freely and I gave them credit for their participation in that book. So, I didn't really plagiarize as much as I would say, but it was certainly fun.
Tom: Okay. All right, Jason. Well, thank you again, and hope to see you soon. Thanks for listening to the "Orvis Fly Fishing" podcast with Tom Rosenbauer. You can be [01:31:00.060] a part of the show. Have a question or a comment? Send it to us at