How Water Temperature Affects Saltwater Flats Fish, with Aaron Adams
Podcast Transcript:
Tom: Hi, and welcome to the "Orvis Fly Fishing" podcast. This is your host, Tom Rosenbauer. And my guest this week is Aaron Adams of Bonefish & Tarpon Trust. Aaron is my go-to guy whenever I have a question about the biology or the science of saltwater game fish. And this week, we're gonna explore how water temperature affects saltwater game fish. We do a lot of talking about how it affects trout fishing, and to a certain extent, bass fishing, but we've never done anything on saltwater game fish temperatures. So, for those of you salty characters out there, I hope you'll find this enjoyable and educational. I always enjoy talking to Aaron, and I think you'll enjoy listening to him.
And before we do the Fly Box, I just have an announcement. I still have three, or maybe two, spots left on my hosted trip to Swain's Cay in The Bahamas, May 11th through 17th, 2024. It's a wonderful place. It's one of the most attractive lodge... I haven't seen lots and lots of lodges in The Bahamas, but of the ones I've seen, it is definitely the nicest looking and most comfortable lodge that I've seen in The Bahamas. It's a great location. It's on the Middle Bite and Andros. And the fishing is awesome. Some of the best bonefishing in the world. The guides are world class. And there's a flat right in front of the lodge where you can go bonefishing on your own before or after your day of guided fishing. The fish are tough, but they're there. The fish in front of the lodge, anyways, are tough.
I don't do hosted trips to any place that I don't love. You know, I pick the places I go to for hosted trips because they're my favorites, and I think you'll enjoy them too. I go to places where I know that people that go along with me are gonna have a wonderful time. Anyway, if you're interested in one of those two remaining spots on the Swain's Cay trip, contact Orvis Travel and they will tell you more about it. There is also some information on the Orvis website about the trip. But Orvis Travel can fill you in on any other details. And I hope to see you there.
All right. Let's do the Fly Box. The Fly Box is where you ask me questions or you make a comment or you share a tip with other listeners. And if you have a question, I try to answer it. You can send your questions to me at
First question is an email from Tim. "I've been looking into signing up for a steelhead class at a local fly shop, and the thought occurred to me today that these classes are taught by guides. I've heard you say that guides can live and die by their tips. While you've addressed tipping etiquette for guided fishing experiences on multiple occasions, I'm not sure that I have heard you comment on whether it would be expected after a classroom experience. Our tips expected are normally given after classes. My instinct is that tips would be more normal after a private casting lesson, but not for something like a group steelhead class. Does the answer change when the class includes some on-river instruction?"
Well, Tim, that's an interesting question. I never thought of that before. I've taught many, many, many, manyclasses on fly tying, and reading the water, and all kinds of other things, and no one's ever offered me a tip. So, I would say that probably it's not necessary. You know, typically, a guide does these classes for one of two reasons, either they're being paid by the fly shop already to give the class, or more likely is they're doing it to help promote their business and build their brand build their identity in the business. So, you know, you wouldn't tip someone for doing a promotion or advertising. It is advertising. It's the way a lot of guides get the word out about their operation.
So, I think that they're gonna be compensated either way. So, I would say, no, I don't think you need to worry about tipping for a group class like that. Private lesson or private on-water instruction, yeah, that might be a good place to offer a tip, but I don't think you need to in a class.
Kirk: Hey, Tom, as a two-time scoutmaster Eagle Scout and fly-fishing merit badge counselor, I have an extra appreciation for what you do for our sport. So, thank you. I have a cabin up in the mountains close to the Provo River in Utah. And even though it can get overcrowded, it is my go-to river. With that said, my first question is that I have recently converted into a double-nymph rig with small tippet rings and the weights at the base to keep my flies freer from moss and debris. It takes about twice as long to set up this rig, but my hope is that I'm giving a more natural presentation and a more effective one. What are your thoughts about the effectiveness of this setup?
My second question is that I've always been taught that when nymphing tail water flies, that getting down to the bottom of the river is ideal. However, trying to distinguish between little rock or moss twitches bouncing along the bottom of the river versus an actual take seems to be a bit of a challenge. If I strike at all the strike indicator movements, I feel like I will not give the trout much of a chance hitting my nymph or possibly spooking it. On the other hand, if I don't hit at every little twitch, then I realize that I could be missing out on a possible good strike. Any advice on striking a happy medium on that would be appreciated.
Lastly, I was able to check something off on the old bucket list recently by catching some German brown trout in Germany. It is amazing how much we have in common with other countries when you wade a river there. We are blessed to have you as a resource, so thank you.
Tom: So, Kirk, you didn't say exactly where you're putting those weights and the tippet rings, but it sounds like you're putting a weight at each junction where the tippet ring connects to the main line of the tippet. And that's an interesting way of doing it. I hadn't ever thought of doing it that way. I think it might be effective, but I need to know exactly how you're setting that up. I would just experiment. There's lots of experimentation, I think, to be done still with nymph fishing. We learn new little tweaks on nymph fishing every year, every time you go out. And I think it's worth a try. Regarding your question about strikes. First of all, you don't really need to get your flies on the bottom for nymph fishing.
Trout don't often feed on the bottom. If you look at the way their eyes are set up, they're more set up for looking up. And most of their food comes from above them. So, yes, they might be lying close to the bottom. And if your fly is too far up in the water column, they may not see it, or they may not be interested in battling the current to get at it. You just wanna get the fly close to their zone so that it's not so much of an effort for them to grab whatever you have drifting in the current. So, I wouldn't worry about being on the bottom. And it sounds like you are fishing a little bit too deep, because if you're constantly ticking bottom constantly, constantly,, constantly, then you're probably gonna hang up more often. And yeah, it will be difficult to tell will you get a strike.
So, you should be ticking bottom every once in a while, but if you're ticking constantly, then you're probably fishing too deep. And, you know, the philosophy is...I mean, it's a real cliche in fly fishing, but hook sets are free. But if you're getting bumps all through your drift, then yeah, you don't know when to set the hook. With experience, you'll be able to determine the difference between a fly ticking bottom or your weight ticking bottom and a fish taking it. And, you know, a lot of it comes from experience. I don't know how to describe it. But when a fish takes the fly, it's usually a little longer hesitation than a little tick or a bump. If it's a little tick or a bump that immediately stops, you know, it's just a very brief thing, you wouldn't hook that fish anyways because it's probably already spit it out.
But often, you know, the fish can spit a fly out, but they don't always. And those are the ones that we usually hook. They can spit it out so fast that you may not even detect the strike. So, we have to go for the ones that are a little more aggressive and are really, really grabbing onto the fly. So, there is a little bit of difference between bottom... Sometimes you can tell, sometimes you can't, but there's a little bit of difference between bottom and a strike. And I think that'll just come with time. When fish takes, it's more of a pause than a twitch that you would get from the bottom, I guess is the best way I can describe it.
Okay. Let's go back to an email. This one's from Cody from Idaho. "My question is, when you're blue lining and don't wanna wear your wading boots, what kind of footwear do you typically wear? I'm looking for something I could hike in and also wet wade if I have to." Well, Cody, you know, wading boots these days are made pretty well. They have a lot of support. And although probably wouldn't wanna climb a mountain in wading boots, you know, you can do plenty of hiking. You probably want something with a rubber sole. And if the rocks are slippery, you're probably gonna wanna put studs in that rubber sole, depending on where you're fishing. But you don't wanna walk a long way in felt-sole wading boots.
I'll regularly hike a couple miles in regular wading boots, and I don't have any problem with it. Make sure that you also wear a neoprene sock with that wading boot, because if you don't, if you just put your bare feet inside a wading boot and you hike a long ways, you're gonna get blisters. And even wearing a pair of, you know, ordinary cotton or wool socks inside wading boots, they can wear out pretty quickly because there's a lot of abrasion that happens inside a wading boot. But if you have a good fit and you have a decent pair of wading boots with good support, then I would just hike in with your wading boots. The other option, obviously, is to take a little backpack with a lightweight pair of wading boots and put those in the backpack and you know, wear your hiking boots to the water and then put your wading boots on once you get there. But that depends on, you know, how comfortable your wading boots are and how far you're gonna walk.
Here's an email from Scott. "Does nylon have a shelf life? If so, how often would you recommend replacing your old tippet? And what would you suggest to do with a tippet that's expired?" So, Scott, I almost didn't answer this one because I answer it over and over and over again. I'm obviously not getting through to people because I keep getting the question. So, if I keep getting a question, then I figure that the word just isn't getting out there. So, here's the deal. Monofilament will break down over time. UV light, ozone in the air can break down nylon. And it does have a shelf life. If it's been in a store and in sunlight, it's probably not gonna last very long.
If you keep it in your basement and keep it away from the sun and away from electric motors, which can produce some small amounts of ozone, you know, it probably last a couple years, but you never know. What I do is I don't worry too much about, say, 2X and heavier tippet because it's just thicker and less chance of it breaking down. But my finer tippets it's down to 7X, I generally replace them every year. You know, it's not that expensive. I usually use most of it up during a season anyways. So, I will pretty much replace all of my finer tippets every year. And again, I don't worry too much about the heavier sizes. Now, that's nylon. Fluorocarbon does not break down.
It's one of the problems with fluorocarbon and a reason you have to be really careful about tippet scraps, is because it doesn't break down. Now, even though nylon breaks down, we know now that it releases a lot of microplastics in the environment. So, we don't want that in the water either. But fluorocarbon doesn't break down. I have some fluorocarbon that's probably 15 years old that I still use because I know that it's still gonna be as good as it was the day I got it. It just doesn't degrade. And the best way to tell with your tippet material is to just pull some off the spool and try to break it and see how much force it takes to break it. If it snaps really quickly, you probably know about how strong a 4X or a 5X tippet should be.
If it breaks where it shouldn't, where, you know, you don't have to apply much pressure, then replace it. As far as what do you do with your tippet that's expired. Well, you know, you can put it in your trash and it's gonna go in the waste stream. I keep my old tippet around. I use it for practicing knots. You know. When I'm trying to learn a new knot, I'll keep a spool of it around. I use it for fly tying. You can use it for ribbing on nymphs and streamers. And, you know, you can hang pictures and stuff with it. So, you know, it's kind of handy around the house. You have to use special knots. Can't use the same knot to use in some twine, but I do keep it around and try to try to reuse it rather than put it in the waste stream.
Here is an email from Miller. "I've always fished bamboo rods that my dad made. And a slower casting motion is hardwired into my anatomy at this point. That being said, is a fiberglass rod a viable option for carp bass and, or bonefish? Or should I bite the bullet and get a fast-action graphite rod and learn to cast that?" Well, Miller, I think fiberglass rods are awesome, in particular, for bass and carp. You know, the slower action really works well, I think with bigger bass bugs and for carp. You know, fiberglass rods can be quite delicate. Plus, carp fight hard and fiberglass rods can withstand a lot of stress. They can really bend way down into the butt and protect the tippet. So, I think that, absolutely, a fiberglass rod would be great for carp bass.
Bonefish, yes to a certain degree. You know, a longer, say, a 9-foot for an 8-weight fiberglass rod is going to be quite heavy because fiberglass is just a thicker and heavier material when you make a bigger rod out of it. But certainly can be done. You know, a faster action graphite rod is going to give you a little bit better performance in the wind for bonefish. But people use fiberglass rods for bonefish as well. So, I would not necessarily feel that you need to get a fast-action graphite rod if you're moving into those other species. Here's an email from Justin. "The temps have just hit freezing, and I've found myself dreaming of warm days out on the carp waters. I've been listening to all of your old carp episodes in preparation for next year."
"It seems there is always something to learn as carp have a way of humbling a person. During your carp adventures in 2023, did you learn any new tricks or maybe discover a new essential piece of carp equipment, flies, line, net, etc.? Perhaps there is a carp catch that sticks out in your mind from this year." Well, Justin, I can't think of many carp catches that stuck out in my mind from last year because I had a terrible year fishing for carp. Where I, where I fish for carp, I fish some rivers and we had a lot of high water over the summer here. I mean, it was nice to have a good full rivers throughout the summer, but it made carp fishing difficult. The water was often too high or too dirty to carp fish. I did do some carp fishing on a large lake in Vermont, Lake Champlain, where there are numerous very large carp, and I didn't do very well.
I have a friend, Drew Price, who guides Annette Lake. And both of us scratch our heads on those carp. I think I learned something really important. It seems that the carp in these bigger lakes do a lot of their feeding in deeper water and then come into the shallows in the afternoon to kind of of warm up and digest because we see lots of cruising carp, but we don't see a lot of indications of feeding. We see them moving, we see them sitting still. You can catch those fish sometimes if you're lucky, but, you know, a cruising, moving carp is a difficult target. And you really need to catch carp consistently, you need to find them on a flat where you can see them, where they're actively eating. Either you see their mouth open, you see them tailing, you see them mudding, and we just didn't see that much of that this year.
So, one of the things that I'm bound to determine to do is try to find out where those carp do their feeding. Hopefully, it's not in deep water, because in that case, you know, carp fishing is all-site fishing. And if they're doing their feeding in deep water, I'm outta luck with a fly rod. But that's what I learned, that you really need to look for feeding carp, not just... Finding carp milling around in an area doesn't necessarily mean you're gonna be able to catch them. So, I guess that's what I learned this year. But thanks for asking. And hopefully, next year will be a more productive year.
Jonathan: Hi, Tom. I've got a suggestion and a question. I do a lot of saltwater fishing at the end of the season. I once got this suggestion myself to take all my backing off of my wheel and really rinse down the sort of hub of the spool. Salt can get trapped under there, even if you do rinse off your reels, which I do, and I know you don't. But I would recommend doing that because the salt can, if pressed up against that reel, will corrode even the fancy anodized aluminum. My question is about knots and leaders. I was in The Bahamas recently. I had a great trip, caught a bunch of fish. But also, over the course of the week, broke a couple off. I didn't get cut off, I broke them all off. And about half of them came back broken off at the knot to the fly, half of them were more clean cuts.
Now, first, this made sense to me. You hear about knots being a certain percentile strength of the leader, and the system has to fail somewhere, so why not there? But then another part of me thought if I had had maybe a couple more pounds of strength there, I could've horsed that fish outta the mangroves or what. I guess the other way of asking this question is, should knots ever break. Thanks, Tom.
Tom: Well, Jonathan, that's a great tip. And I should remind people all the time, do what I say and don't do what I do because I don't take very good care of my tackle because I like to abuse tackle, I like to put it through as much difficult...I like to put it through its paces and, you know, I work with the product development staff and I field test. So, I wanna be as tough on equipment as I can. And not washing reels is one thing that I shouldn't be doing, but I do it just to see how well they're gonna hold up. So, yes, absolutely, that is a great idea to take all the backing off your saltwater reels and wash them down thoroughly and get all that salt out of there.
And you're absolutely right, it can corrode the inner part of a spool. So, that's a really good tip for people. Regarding knots, you know, the knot is always the weakest link. There's no knot that's 100%, I've heard, except the Bimini twist, which is really not...it's a knot, but it's used to double line. It's not used to put on a fly, and it's quite difficult and quite bulky. So, no, there's no knot that's 100%. So, you typically, if you're gonna break something in your system, it's gonna be at a knot. It's usually either at the fly, the fly to tippet connection, or between your tippet and the next section up on your leader if you have, you know, a knot in your leader.
So, if you break your leader up from the fly, let's say you're using a Atlas tapered leader, and your only knot is your...two knots, one knot is your loop at the end of your fly line, which is almost never gonna break. And then your weaker knot is the knot that connects your fly to your tippet. It's usually gonna break there if you don't have any other knots in your leader. Now, if it breaks, say, a foot or two or three up from your fly, and you come back and your leader looks shorter and your tippet looks heavier, that's probably an indication that you got a wind knot when you were casting. You know, wind knots aren't really wind knots, they're casting knots. We all get them, especially when it's windy, but we all get them, it ties an overhand knot in your tippet or up on your leader.
And that reduces the knot strength of a piece of material, some say by 50%. I think it's probably more like 60. It's only gonna be 60 or 70% of the breaking strength of a non-knotted piece, but it's still gonna be a lot weaker. So, if it breaks in the middle, you probably had a wind knot in there somewhere, or a nick in your leader, maybe it touched on some coral or limestone or something like that. So, no, there is no knot that's not gonna be the weakest length. One suggestion that I have for bonefish is that you tie your fly to your tippet with trilene knot. Trilene knot is the same as a standard clinch knot, not an approved, just a standard clinch knot, but you go through the eye twice, go through it once, go through it again. So, you kind of form a double loop in front of the eye of the fly. And then you tie a standard clinch knot.
You can find that trilene knot on the internet. And I like to use that when I'm using heavier hooks. I think it works well. You know, a lot of people use loop knots for bonefish. I don't like them. They tend to catch on stuff. They tend to catch on coral and grass and stuff like that. I'd rather have a clean connection to my bonefish fly. So, I don't use a loop knot. But some people use a loop knot. I don't think that's as strong as trilene knot. I don't know for sure, but I don't think it is. The other thing to consider is try using a heavier leader for bonefish. You know, sometimes you can get away with...you know, the standard bonefish tippet is 12 pounds for most people, but a lot of people use 16. And sometimes you can even get away with 20 pound if your flies are a little bit bigger. So, you might want to also consider going to a heavier leader for your bonefish.
Here's an email from Nick. "I really enjoyed your recent podcast concerning fly fishing leaderature. I'm an English teacher, and I love the books that bring my passions, reading and fly fishing together. Your guest made a statement that brought Norman Mclean's language up to par with Shakespeare. I cannot agree more with a guest. Mclean's use of language is elegant, simple, and staggeringly beautiful. A river runs through it is primarily an endeavor for Mclean to understand his brother. As my mom was in hospice this past summer, I kept telling people what I needed was mountains and rising trout. I finally got what I needed in September. I thought of McLean's work a lot over the summer and in Colorado in September. McLean said the river was cut by the world's great flood and flows over rocks from the basement of time. Under the rocks are the words, and some of the words are theirs. Some of the words are my mom's.
Two questions. My sister recently harvested a moose in Northern Ontario. What flies can I tie with moose hair she saved for me? Number two. The wisdom of my grandfather was that fish rarely bit after a thunderstorm, and so you would wait at least a day before going out after a thunderstorm. I've often had really good fishing just before a thunderstorm, but little the 24 hours after a storm. Is my grandfather's wisdom accurate or just a correlation?
Tom: So, your first question's easy. Yeah, moose hair is great for flies. Number of ways you can use it. One is for tails on dry flies or nymphs, but makes a real nice, stiff, durable tail on a dry fly. There are a number of dry fly patterns that use moose hair, the dark moose hair for tails. It doesn't make a really good wing material. It's kind of stiff for a wing. But if you tie nymphs with it, there's a really great method where you'll find in those moose hairs, some of them will be black, dark brown, and some will be white. They're often white down toward the base. And if you tie in a white one and a black one, or two whites and two blacks or whatever together and wind them as a nymph body and then coat them with head cement or UV resin, you're gonna get a really nice segmented body on your nymphs.
So, those are the two places that I think moose hair are most effective. I got some moose hair from a woman in our rod shop, Irene, who shot a moose a number of years ago, and she gave me enough Maine moose hair last me the rest of my life, but it is, it is handy stuff. And I always have some around. Regarding thunderstorms, that's a really good one. I mean, I have noticed very good fishing also before a thunderstorm. It gets dark and insects will often hatch a little bit heavier, and the trout will lose some of their caution. And I think it's mainly because of the sudden lowering of the light as opposed to anything else. I mean, some people say it's the change in barometric pressure. I'm not so sure I agree with that. But it does change the light level.
I shouldn't say this, but I had really good fishing during thunderstorms. You know, if the lightning gets too close, I will get out of the water. I've been tempted to stay on the water probably too many times during thunderstorms because it can be really good. And I have found right after a thunderstorm when the water goes up a little bit, just that gentle or sometimes not-so-gentle rise of water can really stimulate fish to feed. So, you know, I found right after a thunderstorm can be pretty good. What happens, I believe, after a thunderstorm and usually the day after a thunderstorm is not so good. I think grandfather's really right on that.
It may be that the water has gone up and gotten too dirty. It may be that the fish have fed so aggressively that they're full after the water rises because they've really been eating a lot of minnows and crayfish and earthworms and things like that when the water goes up. But I think there's another reason, and that is that, you know, if it's a front coming through, if it's a squall line, you're gonna get a high pressure system after that. And what you get from a high pressure system is generally cooler air. Trout don't generally like a lowering in water temperature that happens quickly. You're also gonna get bright sunlight and you're gonna get wind, and those conditions are generally not so great for fishing.
So, you know, the day after the thunderstorm, if it was a front, then I think, yeah, it's gonna be pretty slow. If there wasn't a front, if it was just an afternoon thunderstorm, you know, from buildup of cumulus clouds, cumulus and cumulonimbus, and I hope I said that right, clouds, and then it clears up afterwards but it's still, you know, kind of warm and still, I think that doesn't affect things as much. But cold fronts definitely seem to put the fish off for who-knows-what reason.
Here's an email from Gary from Kansas. "Hi, Tom. I hope you're having a good holiday season. Recently, I was listening to your podcast and heard you read an email where the sender was commenting about getting attitude from guides on the river. He said when he encountered someone fishing, he would have a brief conversation with them and come up with an understanding of where we will go so everyone can have a good time on the river. I have several problems with this. I've been fishing for well over 30 years, fly fishing for 3. And I enjoy it because it helps me escape being around people. I would rather not be around others when fishing. And I definitely don't wanna have a conversation with anyone I run into when I'm out fishing.
If I do see someone fishing, a brief analysis tells me which way they're going, if they're staying in one spot and so on. I don't need to talk to them about strategy or position. I give them a wide berth, not waiting by in the water, and go somewhere else a good way outta sight of them. Problem solved. If I'm standing in a pool or I have a line in the water off the bank, I hate when someone walks up to me and asks me literally anything. I'm fishing. And I definitely don't wanna come to an understanding where I'm gonna fish. I was here first. If the only person I see looking both ways a half mile down the river is you, 10 feet from me, you need to move on. Sorry, not sorry.
I've had people walk up and cast in the same spot I was standing in, walk above me 30 feet and ask if it's cool if they fish in the spot I'm casting to, and have a guy ask if he could fish 30 feet below me and literally jump in with a big splash before I even responded. Not cool. I found if someone is mad at you or telling you off, they typically don't do it for no reason. Think a little before acting. We all wanna have fun, but most of us would also like to be left alone." Okay, Gary. Well, you know, Gary, I got to sympathize with you because most of the sentiments you have are ones that I have. I generally, unless I'm fishing with a buddy, don't want to talk to anybody on the river. So, I sympathize with what you're saying. And yeah, I don't typically have conversations with people unless I meet them in the parking lot or on a trail into a river. If we're both walking to the river at the same time, I might say, "Hey, you're going up or down?" But I hear what you're saying, and you wanna be left alone. I understand that because most of the time I wanna be left alone as well.
Here's an email from George from Germany. "Thanks for all you and Orvis do for the sport. I'm quite new to fly fishing and learn a lot from you. Even though success is still not so great. I have two questions. One, can I use my 4-weight line for nymphing and improve it by turning it around, putting the backing end to the leader side? My idea is having a kind of shooting line to put my 20-foot leader on and having the weight far back on the reel. Second, how does developing new fly fishing products and new techniques change the productivity of fly fishing in the last 100 years? Thanks, and have a great winter season.
So, George, your first question is pretty easy. Yeah, you can do that, but do you really need to... I mean, the back end of a 4-weight line is still slightly thicker than a standard Euro nymphing level line. And my suggestion would be, instead of reversing your fly line, why don't you just put on like a 30-foot leader, just add some extra to the butt section of your leader, and keep the fly line inside the guides when you're nymphing or euro nymphing. And then if you decide to do some dry-fly fishing or some, you know, dry dropper or streamer fishing or something, you can just take off that long leader and put on a standard leader, and you don't have to reverse your fly line.
So, you can do it if you want, but I think you're better off just using a longer leader and then you don't have to worry about it. Regarding how new fly fishing products and techniques have changed productivity. Boy, that's a big question, but I'll try to answer it in broad strokes. Well, first of all, the development of better and stronger fiberglass and graphite rods and also fly reels with disc drags has enabled us to do a lot more saltwater fly fishing and be a lot more successful in some of those bigger species because we can reach the fish, we can cast the bigger flies and we have a strong drag. You know, in the old days when they fished for tarpon, they used single-action click and pawl reels and bamboo rods. It wasn't very easy, almost impossible, to land a good sized tarpon with that kind of equipment.
So, in saltwater, it's been a dramatic change. And in nymph fishing, you know, nymph fishing has become so broadly available and popular due to things like strike indicators and Euro nymphing techniques. It used to be a dark art that you know, very few fly anglers knew how to do. The few that were good at it were really good at it, but they just watched their floating line or leader for strikes, and that was difficult to determine. Difficult to present the fly properly and difficult to determine when they had a strike. So, things like strike indicators and fishing dry droppers and Euro nymphing has really changed to the point where nymph fishing is probably the most popular and widely practiced part of fly fishing for trout there is.
Whereas, you know, in the 1930s, '40s, '50s, even into the '60s and '70s, most people would either fish a dry fly or they would swing a wet fly, and they didn't do much dead drifting of subsurface flies as we do now. And then of course, there's the whole streamer game, which, you know, in the old days, streamer fishing was done mostly for landlocked salmon and brook trout in Maine. And it was done by more or less the way you would swing a steelhead fly casting across and down and letting the fly swing. And of course, now we have all kinds of articulated flies that swim through the water, and we fish streamers dead drift. We fish them upstream, downstream across stream. We strip them, we swing them. We do all kinds of things with streamers. And we're fishing much bigger streamers than people did 100 years ago.
So, lots and lots and lots of things have changed. Flies are always changing, and always will. And of course, modern fly lines have made things a lot better. Fly lines used to be made of silk, and they rotted, and you had to oil them and store them a proper way or they'd rot, and leaders were made from silkworm gut, which was heavy and stiff. And again, it had to be soaked and it would break down after a while. Modern nylon and fluorocarbon leader and tippets have made things so much easier and more convenient. So, lots and lots and lots of innovations. But it's neat that we're still kind of doing stuff the same way that they did 100 years ago. We're still casting about the same way. We still have snake guides on our fly rods. The fly rods and reels don't look that much different than they did 100 years ago. The silhouette of the whole fly-fishing game isn't that much different, but when you get down into the details, there are a lot of improvements that have made things just more durable and more accessible to people.
Another email from Matt from Western Massachusetts. "In September, my girlfriend and I spent a week in Northern New Mexico and booked a trip with Orvis-endorsed outfitter, Land of Enchantment Guides. We had an unforgettable experience and were really impressed with the customer service demonstrated by Noah Parker and Cody McKeever in the shop, and especially by our guide, Jesse Lee. This great experience gave us a lot of confidence in using the Orvis-endorsed directory of outfitters and guides for future trips. My question is this, some of my favorite sections of river are those that flow into reservoirs, but I've noticed the fishing really slowed down in the winter, especially when compared to tailwaters. I was curious if the trout maybe seek the depth of the reservoirs versus the relatively shallow pools of the river. I'm curious to hear your thoughts or opinion on this. Lastly, it was excellent to meet you in August at our TU Annual Banquet, and we really enjoyed your talk. Thank you for all your contributions to fly fishing."
Well, thank you, Matt, and thanks for the kudos for Land of Enchantment. It's a great outfit. And I've had Noah on the podcast before and he's a great guest. Maybe I should get him on again. Regarding the rivers that flow into reservoirs, the fish, if they're browns or brookies in the fall and rainbows in the spring will move into those rivers to spawn. And also, the rivers are probably gonna offer pretty good food during the spring and summertime because they're producing the insect hatches. There's gonna be more insect hatches in a river than there will be in a lake. So, they're probably in there then. But once the cold water starts, those fish really are gonna be more comfortable dropping back down into the reservoirs.
I mean, there might be some fish that stay in the rivers, but the fish have to contend with things like anchor ice and slush in the river during the wintertime, and they're gonna wanna get away from that stuff. They're gonna want to get away from floating ice flows. And they can find warmer water also deep in a lake. So, they're probably gonna drop down for the security of a lake. I mean, even in even in a river that doesn't run into a lake, you're gonna find that the trout are gonna seek out the deeper, slower pools during the winter time. So, there's nothing deeper or slower than a great big reservoir. So, they're gonna be more comfortable and they don't really care that there isn't as much food in the reservoir because they're not gonna be feeding much because The water temperature's pretty cold. So, yeah, I think you're exactly right that the fish probably just aren't there.
Jake: Hey, Tom, this is Jake calling from Maryland. I have a question for you that's rooted in a challenging fishing experience that I had recently. I've been an avid fly angler for the past 25 years or so, and most of that experience has been on small streams in the Mid-Atlantic region, particularly around the Piedmont Plateau and the Blue Ridge Mountains. So, I'm most accustomed to fishing streams full of narrow runs and deep pools and riffles. Recently though, a buddy of mine and I went on a blasting cast trip up into North central PA to do some fly fishing and some upland hunting. We actually camped out on the bank of a very famous trout fishery up in that area. And so, we really went into this trip with some high hopes and big expectations. Now, the good news is that the hunting was excellent. But unfortunately, we didn't so much as see a fish over four or five days on the water.
The stream that we were fishing was really perplexing to me because the whole section of it where we were camped out was about the same width. It was maybe 30 or 40 yards wide, and it was pretty consistently 18 to 24 inches deep. The bottom of it was rocky, but there weren't really any larger boulders or other structures. So, I just wasn't seeing any of the distinct features I'm used to seeing on trout streams that let me know where I might expect to find the fish. And so, I get out on the stream, and I go through all my go-to flies, the ones that have been bringing me success for decades, but none of those worked. After that, I decided to switch up my strategy, and I tried fishing a streamer and trying to keep moving as much as possible to cover as much water as I could. But even with that, I did not have any success.
So, my question is, how would you approach a stream like that that had such muted features? Thanks a lot for everything, Tom. We're counting on you to make next year's annual Blast and Cast a more well-rounded success.
Tom: Oh, Jake, one of the things that we all need to understand is that trout aren't everywhere in a river, particularly in deep rivers, or particularly in big rivers. The trout just aren't everywhere because the habitat isn't right for them. And the way you describe that water, if it's 18 to 24 inches deep with no large structure and no deeper slots or pools, there may not be many fish there or none at all. You know, if I saw a river like that, particularly in the fall when things are kind of getting slow and fish are gonna be searching out deeper water and slower water, I wouldn't fish a stretch of river like that. I would go somewhere else and find a place with more structure and some deeper pools. I mean, even in the summertime, fish do need some access to deep water just for protection or really heavy cover.
They need to go somewhere when predators threaten, they need to go somewhere to get away from those predators. And it's either gonna be deeper water or some kind of structure. And that water sounds like it doesn't offer any protection at all. Now, if a long, long, long riffle with 18 to 24-inch deep water was adjacent to a deep pocket or a deep pool or had some structure in it, those fish might spread out to feed in that kind of water. But they're still gonna need cover somewhere close by, somewhere they can swim to relatively quickly. How would I approach that, particularly in the fall? I just wouldn't fish that water. I'd go somewhere else on that river and find a place where there was different kind of structure.
Again, fish aren't gonna be everywhere. Because it's a large river, the other thing that you might want to consider is that even though it's known as a trout stream and you didn't mention which one it was, but some large rivers get too warm during the summertime and they stock them in the spring and the fishing is good in April, May, June, maybe into July, but then the water gets too warm and the fish either die or they go up into colder tributaries or go up into the headwaters and find a place that's got more oxygen and colder water. So, that stream could not have had any fish in it even in late summer. And so, when you went in the fall, you saw what happened, there were no fish around. So, you know, consider that there may not be any fish in there and you just gotta go look somewhere else.
All right. That is the Fly Box for this week. Let's go talk to Aaron Adams about water temperature and saltwater fish. Well, my guest today is my old friend, Aaron Adams, and fishing buddy. Aaron is the director of science and conservation for Bonefish Tarpon Trust. And Bonefish Tarpon Trust is one of the finest science-based fisheries organizations in the world. And I have great respect for them. They do lots and lots and lots of good work, both research and policy and advocating for the right moves in conservation. So, Aaron, you've been on the podcast before, but welcome back.
Aaron: Thanks. Good to be on again to talk to you again.
Tom: Yeah, we gotta go fishing again sometime. It's been a long time.
Aaron: Yeah, we do. I wanna go out on a flat boat with you again so I can pole and then yell at you when you're on the bow.
Tom: No. Well, you don't want me to pole. We know all about that. I think we've told that story before, so we won't tell that.
Aaron: Yeah. No need to beat that dead horse.
Tom: No, it is a dead horse. So, anyways. You know, I've done a lot of podcasts on water temperature and trout and bass to a certain degree, but never done a podcast on water temperature and saltwater fishing. And I don't think it's something that a lot of anglers think about when they're saltwater fishing, but the fish being cold-blooded, it affects everything they do. So, you wanna kind of start and talk about how it regulates them?
Aaron: Sure, yeah. As you said, fish are cold-blooded, or most fish are, the fish we fish for, bonefish, tarpon, permit, redfish, snook, even striped bass, bluefish, they're cold-blooded. And so, their physiological processes are gonna change depending on the temperature. So, every fish will have a kind of maximum and minimum temperature that they can tolerate. For example, if water temperature gets below, say, 49, 50 degrees, bonefish, tarpon will die. Their physiology, their cellular processes just slow down so much that everything just stops. But even before you get to that, that death temperature, the lethal temperature they're gonna start slowing down a lot. So, for example, if water temperature gets into the 50s, tarpon, snook, they're not gonna feed for the most part. They'll slow down a lot.
A lot of times you'll see them, like if you see a snook after a cold front in Florida, it might be floating up near the surface trying to get as much warmth from the sun as it can. And a lot of times you can actually kind of go right up to and poke the fish, it's not reacting. So, it's kind of gone into just basic survival mode. It's there still living, but it's not really gonna be active. And then you get the top end of the range and, you know, fish can just can get too hot for them. So, their physiology, the system just kind of breaks down, and at that point, they'll just die from a complete physiological breakdown. So, all fish have temperature ranges they can tolerate. And then within that, they have preferences where they do best.
And so, the tolerances are why we see, you know, regional differences and where and when fish occur. So, for example, you know, tarpon, people have been catching them in lower parts of Chesapeake Bay for many decades. And they'll be up there during summer, maybe early fall, but as soon as the first decent cold front comes and starts to drop the temperature, that's when they'll start migrating south again. And it's mostly temperature-limited. You'll see the same thing with striped bass when they show up, for example, say on Cape Cod in the spring, that's typically temperature-related, seasonal for sure. But, you know, cold spring, they'll show up later than a warm spring. So, the temperature is a huge factor for how the fish survive, how they act, where they can go in different types of seasons.
Tom: Do you carry do you carry a thermometer with you when you fish?
Aaron: I don't, but I keep track of satellite data, from satellite data, and there are a lot of monitoring stations all over the coast that you can get water temperature from.
Tom: And if you have flats boat, you probably have a water temperature gauge in the flats boat anyways, right?
Aaron: I don't. Some people do, but I don't. Just keeping track of the weather, as I said, keeping track of the different monitoring stations that are out there that'll have water temperatures. I'm not super concerned about the exact temperature, you know, whether it's say 74 versus 76 degrees. I think people have to also think about what the temperature has been prior. And that's true not just for the temperature, but a lot of things. So, let's say you're on a particular flat looking for bonefish, when you see those bonefish, they're not just there reacting to the conditions that you're experiencing and they're experiencing, they also are in many ways reflecting what's been going on that flat for hours or maybe even days.
So, their behavior, say before or after a cold front or before or after a hurricane is going to be different even if on a particular day you're fishing for them, the conditions seem to be the same.
Tom: So, what does it do, I mean, what would you advise people fishing before or after a cold front for flat species?
Aaron: So, the way fish will be able tolerate, say, a minimum or maximum temperature, a lot of that has to do with the temperature that they're acclimated to. So, let's say you have a bonefish that's acclimated to a temperature that's, say, you know, a little bit cool, 76, 77 degrees. If you get a strong cold front come through the Florida Keys, for example, Northern Bahamas, that drops the water temperature from say 76, 77 down to 70, that's a pretty good swing and the fish will probably react to it by going into deeper water which won't get as cool as the flats, but they'll be fine.
If on the other hand that fish was acclimated to a temperature of water temperature, say 83 or 84, and it suddenly dropped down to 70, that would probably kill a lot of fish just from the shock of that dramatic temperature change. So, it's the rate of change of temperature, the actual temperature range over that rate, and then the temperature that those fish were already acclimated to. And the same thing is true for warmer waters. If the fish are acclimated to say 83, 84 degrees and the water temperature goes up to 90, they'll be able to handle it. But if they've been in water that's, say, in the mid-70s and all of a sudden it's 90, that's probably gonna cost pretty severe physiological stress and even some mortalities.
Tom: So, they will try to get out of there first, they'll try to go to deeper water?
Aaron: Yeah, exactly. Their behavior is going to kind of be an accumulation of what they've been experiencing over, you know, days or even weeks, especially for migratory fish like tarpon or striped bass. I mean, that's one of the nice things about, you know, fishing with a guide is they're in tune to all those different changes. And so, they're watching how the fish are moving around, they're familiar with the weather patterns, and so they can kind of figure out whether the fish are deep or shallow. So, if we think about this seasonally, let's use redfish as an example. So, for example, when I lived in Charlotte Harbor, back when we got normal winters, the water temperature on the flats in Charlotte Harbor would drop down into the 50s.
Let's say in the morning on a low tide, the water temperature on the flats might be 52, 53. Now, there were redfish up on the flats at that time or on the edges but they weren't active, they weren't feeding, they were just kind of hanging out on the bottom. But as the sun came up and the waters warmed up, the water temperature would actually go up to say 56 to 58. And when it did that, the redfish would get active for about an hour and they'd start feeding. And so, that was kind of the magic hour to fish for them. And then after feeding for an hour or two, even though it was still warm, they kind of stopped feeding and went back into kind of hanging out mode.
And I think at that point, they were digesting. So, digestion rate is gonna slow with a lower temperature. So, for example, their digestion rate is gonna be slower at 56 degrees versus say, 66 or 70 degrees. And so, I think with that temperature change, with 53, it was a bit too cool for them to do much, got up to 56, 58, that change of five degrees or so got their system moving a bit. And so, they got hungry, went out to feed, and then they basically got full and needed time to digest what they'd eaten, and so they kind of shut down again. So, that kind of gives you an idea of a winter type of feeding with redfish as an example.
On the other end of the scale, when it gets pretty warm since fish are warm-blooded, that means the metabolism is higher when it's warmer.
Tom: You said they're warm-blooded, they're cold-blooded.
Aaron: I'm sorry, they're cold-blooded. Yeah.
Tom: I have to correct you all the time here, Aaron. You're supposed to be a scientist.
Aaron: No, but I play one on TV. That's a true statement.
Tom: Yeah.
Aaron: Yeah, it's cold-blooded. When the water's warmer, the metabolism increases. And so, bonefish, for example, in the flats or on the edges of the flats, you know, during the summer, they're gonna be feeding more because they have to, just trying to keep up with that metabolism, you know, not putting it into growth necessarily, but just trying to keep up with that metabolism. And so, the feeding rate in under warmer temperatures will be higher. So, I mean, I could use redfish as another example. A lot of times in summer, early fall, redfish will tail pretty aggressively in the late afternoons into the evenings for a couple of reasons. I think one is they're pretty hungry because the water tends to be pretty warm in the summer.
Another reason is as the sun goes down, that water cools a little bit. And so, that can kind of gives them a little bit of respite, puts the water temperature back more into their preferred range, kind of top or above their preferred range. And so, that's kind of that best combination of it's warm and so their metabolism is higher, so they want to eat more to kind of keep up with that metabolism. But then you have things starting to cool down, it makes them a bit more comfortable. That's why, you know, when we fished those years ago for redfish tailing, in the summer, it was in those late afternoon, early evenings to take advantage of that type of situation.
But you'll see the same thing with bonefish kind of looking for that sweet spot of best water temperatures. And by best water temperatures I mean the ones that'll maximize the efficiency of their energy expenditures and being able to put some of that into growth, not just, you know, trying to feed themselves all the time. So, for bonefish, for example, I would say that preferred water temperature range, all things being equal is probably 72 to 82 degrees. I mean, again, that's gonna shift some as far as their maximum activity, you know, depending on what the overall temperatures have been, you know, what they're acclimated to.
So, at any particular time, you can use the tides, time of day, and amount of sunlight, and all that type of stuff to figure out the best times and places to target bonefish when they're kind of at their maximum.
Tom: How about redfish? What's their maximum preferred temperature? Or not maximum, but just their preferred range?
Aaron: Preferred?
Tom: Yeah.
Aaron: All things considered, again, probably 60 to upper 70s or 80. Again, as far as, you know, their maximum activity, that's gonna differ some in the winter versus the summer type of situation. But I'd say that if you had it 60 to say 75, that's kind of would be perfect. If it gets above 80, they're gonna start to get pretty stressed out. If it gets up into the 90s, they might be there, but not doing well at all. So, for redfish, I'd say 60 to 75 would kind of be the peak there.
Tom: How about tarpon?
Aaron: Similar to bonefish and also snook, kind of that low 70s to low 80s. But interestingly, you know, all these fish also have, you know, maximum temperatures that they can tolerate. And a lot of times they can tolerate those maximum temperatures and physiologically do well. But then they can be more susceptible to say, being caught because that's expending a lot of energy and they're not able to recover as well because it's so hot. So from an angling perspective or even a science perspective, I'd say with bonefish, if we wanna tag bonefish in The Bahamas or even in the Keys, we typically won't do that during the summer, you know, like July, August even into September because water's just too hot.
And again, it's not too hot for them to be on the flats and feeding whatnot, but it's too hot for them to be doing all that, and then also to have us catch them and then also to have us tag them.
Tom: So, is it like trout where it's a combination of excess stress, their metabolism is already in high gear and the water holds less oxygen?
Aaron: Yeah. All those things. Correct?
Tom: Okay.
Aaron: And tarpon the same way, if the water temperature gets above, say, 85, maybe 87, you know, when we were doing the tarpon tagging projects, we'd stop tagging because we noticed that they weren't recovering as well due to that extra stress under conditions that they were already stressed because it was so warm. So, they were still on the flats but they were kind of at their maximum that they tolerate. And so, us messing with them to catch them and tag them could put them over the edge.
Tom: So, for your personal fishing, not tagging or science or anything, when do you stop fishing on the flats? What water temperature do you say, I shouldn't be fishing anymore?
Aaron: Well, for bonefish and tarpon is typically when that daytime water temperature gets into the mid to maybe upper 80s, I will kind of shift my focus. So, let's say I'm gonna go over to The Bahamas to fish for bonefish, if it's, you know, hot summer, July, August, I'll try and plan the trip so I can fish for tailors in the morning and maybe in the evening. So, I'll set it up also based on tides, because, you know, during the summer, the deeper ocean water's gonna be cooler than what's on the flats. And so, the bonefish will often sit off the edges or in deeper water and they'll ride that cooler water up onto the flats to feed. And so, that coolest time is in the morning because you have the cooler ocean water coming up, but you've also had the water on the flats in darkness, you know, no sun on it for, you know, 10, 12 hours.
And so, that water's cooler also. But that kind of gives you that maximum, you know, that best kind of temperature range. And it's also great because the water's shallow and, you know, the fish are gonna be tailing. If there are times when it's too warm, even then, the fish just won't push up on the flats, or sometimes it'll take them some time. So, you might expect the fish to as soon as the tide turns to come in that the fish would immediately be up on the flats, but sometimes those flats are still warm enough, even though it's been nighttime that they'll wait for a few inches or more of that deeper ocean water to push up on the flats and cool things off.
And that just kind of takes some time on the water, watching things to see how the fish are behaving. It's also sometimes, you know, better to fish on the deeper edges rather than if the fish aren't coming up onto the flaps, you know, because even as they come up and that sun starts to come up, things can warm up relatively quickly. That warm-up is slower on a cloudy day, which obviously makes it harder to see the fish, but if you're looking for tailing fish or waking fish, you can still do pretty well. So, in the summers when it's warm like that, I'll try and fish early in the day and then later in the day go fish for something else on deeper water like permit or mutton snapper, that kind of stuff.
Tom: So, outgoing tide on a hot summer day is probably not the time you wanna be fishing?
Aaron: Correct. Correct. because that water's been up on the flats getting warmed all day. And again, even if the fish are there, you know, it might be too much for them. So, one thing to do is, say if I want a flat and it seems like things are getting warm and I catch a fish, if a fish starts to have kind of a longer recovery time, you know, say it's taking longer for it to kind of get its wits about it or starts to kind of lose equilibrium, it kind of rolls, and usually if you catch the bonefish quickly, get them to hang, get the hook out, they're usually pretty energetic and can take off. If you find that that's not the case then it may well be getting too warm. And so, you just kind of have to discipline yourself to take it easy.
And the length of the season for which we might have to consider that it's too hot is longer than it used to be because of climate change. So, it's kind of like, you know, trout, they're stuck in the stream, it's not like they can migrate north because of climate change. So, you know, that's why Western Rivers will just kind of shut down the fishing in certain times of year because of that same type of thing, kind of exceeding their abilities physiologically. So, that's just something we have to keep an eye on, is if you have to fish, you know, you catch a couple of fish and they're having a really hard time and the water's warm, just kind of switch gears, fish for something else.
In contrast, permit, I'm trying to think... I don't think I've had a permit act like it's too hawked. I mean, if it's too much, they'll just leave the flats. You won't see them. But if they're on the flats, they're so mobile. If they're on the flats, I've never experienced an issue personally where, you know, they've been kind of physiologically at their edge because they've been too warm.
Tom: With all of the thousands of permits you've caught, right?
Aaron: I mean, it's interesting because, you know, fishing forum and a lot of different habitat types and different distances, you know, from open water and whatnot, permit seemed to have a pretty wide tolerance range on temperature. I'm not aware of any studies on permit temperature tolerance, you know, what's their maximum, what's their minimum. So, it's tough to say, you know, what would put them off. But again, they're so mobile, if things are not to their liking, they just won't be on the flats, they'll be somewhere else.
Tom: Do you think it's...you know, sometimes you see permits on the flats and sometimes you don't. Do you think that's a water temperature issue or is it something else?
Aaron: Oh God, with permit, it's probably so many things.
Tom: They're gonna continue to be mysterious, right?
Aaron: Yeah. Geez. I mean, for example, if the wind direction and speed has been consistent for say, four or five days, the permit will probably be happy. If that wind changes direction say from Monday to Tuesday, there's a pretty good chance that Tuesday they won't be there.
Tom: On the flat. They'll be in deep water.
Aaron: Yeah, they'll be somewhere else. I think that being on the wind direction and change will indicate a barometric pressure change. And so, you know, it could be a front coming or a high-pressure building or whatever it might be. It just happened so many times in my experience that the wind direction changes and the permit completely change.
Tom: So, it's probably not temperature, it's probably pressure and wind.
Aaron: Well, it's pressure, very much pressure, I think wind direction, I think temperature, moon phase, especially in spawning season, their general attitude at the time, whether or not they went to their therapy session the day before. Permits are tough to figure out. But the people who spend the time, especially, you know, in a particular location, they will develop a sixth sense to what those factors are. So, when I lived on St. Croix in the Virgin Islands, and I fished for permit almost every day. And my friends and I, we'd kind of figured out, you know, what made those permit in those locations tick. And it was tide and wind and water temperature and pressure system, all those things. And for that location, we just kind of had it figured out for the most, as much as you can with permits, that we would find them. That has nothing to do with whether or not they're gonna eat.
Tom: Hey, let's talk about striped bass and bluefish for a minute, move north a little bit, but I have a theory that I wanna run by you about striped bass on the flats. So, those people who've fished striped bass on the flats know that striped bass, particularly in the spring, but sometimes I'll summer along, will come into very shallow water in, you know, May, June, but sometimes through the summer. And they'll come into super, super, super shallow water in great numbers. There isn't a ton of food on these flats. You know, there's some crabs and shrimp, but what you see is hundreds, sometimes thousands of striped bass in very shallow water, just kind of moving, just kind of moving back and forth. not actively feeding. You hardly ever see them busting bait.
Every once in a while, you see them turn sideways and people say that's a striped bass eating a shrimp. I'm not so sure if that's true or not, but my theory is, and what really brought this home to me was this past spring we were fishing for striped bass on the flats, and it was very good. And, you know, you get like 1 out of every 50 stripers to eat a fly, you know, if you're lucky. Most of them just kind of pass it by and ignore it, and everybody worries about the fly pattern. But the few of the fish that we did caught spit up fairly good-sized herring.
Now, there's no herring on those flats, they're out in deeper water. So, my theory is that those fish are coming into that warmer, shallower water, especially when the water's cold offshore to digest, to move into warmer water to digest what they've been eating offshore. They come in during the day. Do you think I'm off base, or do you think that makes sense?
Aaron: Well, you're always off base, Tom.
Tom: Yeah, yeah. Okay.
Aaron: But no, I think that makes a lot of sense because when I fished Cape Cod a lot, you would see them on a sunny day, on the rising tide push in from some deeper edges, where on the dropping tide, they would've been feeding in the rips. So, yeah, I think that makes a lot of sense. There is stuff up there that, you know, sand deals will bury in the sand up there. Certain times of year you can get, depending on the year, year is different, but you can get a lot of juvenile flounder, you get depending, again, every year is different, decent number of green crabs, some of the shrimp as you said. So, I think it's a mix. What you describe is if the fish's just kind of milling around up there...
Tom: Well, not milling., they're moving, they're constantly moving, but, you know, they don't appear to be actively feeding. And I think every once in a while, you throw them a fly and it's like tarpon during the day, "Oh, there's a little snack. I think I'll eat that now even though I've, you know, been eaten all night."
Aaron: Right. And it's interesting you say that because, you know, in research of fish diet, piscivorous fish or fish that eat other fish, the percentage of times when you would check one and get an empty stomach is often around 50%, maybe higher. We found the same with snook. And so, they'll have periods of high feeding activity and then, you know, digestion and hanging out and then opportunistic. I mean that follows with your theory as well that they had their high feeding activity period, they were kind of taking a break and then some, you know, eating opportunistically or, you know, digestion had gone well and they're starting to get hungry again.
But I mean, it reminds me of one of my favorite Lefty things. We'd been out fishing a bunch of people at The Bahamas and the bonefish just weren't eating and everybody was complaining and Lefty said, "I don't know why people think fish are always hungry. I'm not always hungry." So, I think it's that same thing, just because you see them up there doesn't mean... And that goes back to what I said earlier, is what you're seeing in those fish, the behavior, where they are, when they're there, isn't just the conditions that you're experiencing, it's what they've been going through for the past, you know, hours, days, or even weeks.
So, for example, the south side of the Cape in the spring when the fish are first moving in big numbers, a lot of times, they'll be feeding pretty heavily on the squid out in open water. And some of the fish break off and they push up on some of those shoals and they're actively looking for stuff. They're postponed fish, so they're pretty hungry. They're following that preferred temperature, water's getting into the upper 50s, maybe even 60s. And so, things are really starting to cook. And so, they're pretty hungry. Later in the year, you know, they're in kind of localized pattern, and so they're probably getting to that kind of daily title-related type of thing, you know, based on, like you said, feeding on the herring in the ribs.
Tom: Do you know what the optimum preferred temperature range is for striped bass and bluefish? It's gotta be lower than the Florida species.
Aaron: Yeah. I would say for stripers it's the 50s into the 60s. And again, that's gonna vary in location and time of year. But, you know, another example of climate change is with those increasing temperatures, especially in the Gulf of Maine, there's, you know, pretty significant striped bass fishery way up in Nova Scotia. And that used to be not accessible to striped bass because it just really didn't get warm enough to make them in that preferred temperature range that would make it, not that they couldn't tolerate, it's that they needed... Fish like striped bass or tarpon migrate. A big reason for the migration is, you know, they put on the feed bag, they spawn.
Striped bass, they spawn in the spring. Takes a lot of energy to do that. And so, then they're kind of spreading out looking for food. And you get that summer into the fall where you have all those different bait fish and shrimp and crabs who are reproducing and just getting superabundant. But you have to be able to take advantage of that. And if it's too cold, you're not gonna be able to be efficient enough at putting on the weight before you head back. So, that's I think a good example of, you know, localized striped bass kind of moving farther north because they can. But then you also get striped bass that, you know, over winter and, you know, rivers in North Carolina. And so, they don't need temperatures quite as cold and they seem to be able to tolerate temperatures a little bit warmer.
And, you know, even you'll get juvenile striped bass or relatively, not juvenile but young striped bass over winter on the Cape these days. But if it gets cold enough, they'll still be there and they'll still be trying to eat. But physiologically, they're really stressed out. A lot of times they'll have, you know, fungus growing on them, that type of thing.
Tom: Because it's too cold for them?
Aaron: Yeah, it's so cold, you know, their physiology just slowed down so much that they're making it, but they're not super happy from a physiological standpoint.
Tom: Why do they get fungus when it's cold? Is that because their immune system is not working so well?
Aaron: Yeah, none of that stuff is working as well. And then, you know, the fungus, it's there. So, it's not having a problem with the temperature, they're acclimated to that. And you'll see that on the top end of a lot of species temperature range as well, they're just so physiologically stressed, they can get somewhat immunocompromised in that situation. So, then they'll start to have maybe some lesions and those types of things. So, you know, for us it's trying to find that magic temperature that works for them as well to kind of maximize getting hungry fish.
Tom: So, it's kind of a combination of warm enough to get their metabolism in high gear, but cool enough so that they're comfortable in it?
Aaron: Yeah. Right.
Tom: Because the metabolism keeps going up with temperature regardless, even if it's at close to the lethal range, their metabolism's gonna keep rising, right?
Aaron: Yeah. I mean, they can try and regulate to some extent, but they're not gonna be able to control it that much, one of disadvantages of being cold-blooded. And, you know, it's interesting just to contrast, dolphin, porpoise, at being warm-blooded, they take advantage when it gets super cold. And so, fish will slow down a lot, whether it's redfish or snook or bass, seatrout or whatnot. And the dolphin will just have a field day because, you know, they have no problems with cold water. They generate their own heat, but the fish that they're chasing are just super slow and not able to get away as well. So, that's, you know, a good example of a contrast between warm blood and cold blood.
Tom: Let's talk about a couple other fish. You mentioned seatrout. I was gonna ask you about spotted sea trout and then also barracuda, which are one of your and my favorite fish to catch on the flats. What's their temperature range?
Aaron: Barracuda and tropical species, it's pretty similar to bonefish and tarpon. They seem to be able to tolerate a bit cooler. I think they get it up on the flats, you know, say January, but especially February in part, just trying to warm up, you know, get in that shallow water and try and warm up with the sun heating things up a bit. I don't know what their lower lethal limit is. For example, where I'm in Central Florida, even in winter, there's a few locations where we can find juvenile barracuda, you know, through the summer. So, you must have a lower lethal temperature. That's pretty common for smaller younger fish to have a wider temperature tolerance than larger fish. It makes sense because larger fish to some extent, they can move to get outta the bad situation, where the smaller fish, you know, if they move out in the open water, they're much more likely to get eaten. So, they need to, you know, be able to tolerate water range of temperatures.
Tom: So, when you have a severe winter, severe cold front in Florida where you live and you lose a bunch of snook in particular and tarpon, I think, is it usually the smaller fish? Can't the bigger fish just move to find warmer water?
Aaron: It depends. Again, a lot of it is the rate of change. For example, in 2010, we had a very severe cold front sweep through Florida, and, you know, the fish kill was tremendous from huge numbers of snook, tarpon in the estuaries, all the way out to the reef itself. So, there's a lot of, it depends. Overall from the 2010 freeze, it seemed that more snook, a larger portion of the snook population on the Gulf coast, say Tampa, Charlotte Harbor died then on the East coast in Indian River Lagoon. And that may be in large part because either the Gulf of Mexico shelf is wide and shallow and estuaries are shallow, so when cold came in suddenly like that, there was really nowhere for fish to go.
Indian River Lagoon has deeper access like the Intracoastal Waterway, which is close, you know, to any of the shallows. And then there's also the inlets, you know, out into the Atlantic Ocean, which is always gonna be warmer that time of year. So, a lot of it, it depends. But when that one came through in 2010, a lot of big fish got stuck up in the backcountry, which makes sense. In a normal year, you'll get a lot of big snook and some big tarpon up into the backcountry. And they'll find holes, deeper holes in the backcountry. Some of them might have freshwater springs. Ad if they have freshwater springs, that water temperature's gonna be relatively consistent, probably low 70s.
So, that's a good temperature refuge form during that. But when you have something as severe as a 2010 event, that didn't help. So, those kind of deeper dark bottom places that would stay warm under normal conditions just kind of became death traps for them.
Tom: And they didn't have time to get into really deep water?
Aaron: Right. By the time they could figure it out, their metabolism was slowed down so much that there just wasn't... That was terminal for them.
Tom: Okay. How about spotted seatrout? They have similar temperature regimes?
Aaron: They're similar to redfish. So, they can tolerate the cooler temperatures pretty well. They will get stressed when it gets hot. That kind of matches their geographic range. On the East Coast, Virginia part of the Chesapeake Bay, we have had trout and redfish for many years and they're starting to see them farther north and up into the bay now. And then of course, throughout the Gulf of Mexico. But then they'll also be down into, you know, South Florida Bay. Not so much anymore, but I've heard reports of trout on in the grass beds on the Gulf Coast of the Yucatan Peninsula, you know, what you think of as pretty far south. So, they have a pretty wide temperature range.
And the interesting thing too is that they're primarily summer spawners. And the joke is that if the water's warm enough, they'll be breeding like rabbits. So, it'll be interesting to see if their spawning season becomes extended, you know, as water temperatures get warmer, they don't get as cold in the winter. But yeah, for the trout, if it gets too warm, they just go deep. They won't be on the flat so much, or if they are, it'll be kind of early or late in the day, but they'll hang out on the deeper edges where it's cooler.
Tom: And I got one final question for you, kind of maybe a fun science discussion. You said at the beginning, most fish are cold-blooded. Do you wanna elaborate on that?
Aaron: Sure. Some fish are able to regulate temperature, bluefin tuna for example. They basically... Let's see what I remember, it's been a long time since I thought about bluefin tuna. Basically, muscle action can basically create the ability to regulate temperature, semi-warm blooded. We'll probably have someone who knows a lot more about tuna in your comment section and say, "Oh, that's total BS."
Tom: No, I've heard that too. I've heard that too that they're functionally warm-blooded.
Aaron: Yeah. So, there's a number of species of fish that have evolved a different system of being warm-blooded than you mammals, say, for example. And so, they can regulate, which may explain that pretty incredible migration capabilities of bluefin tuna.
Tom: Yeah. They seem to be able to live wherever they damn well please.
Aaron: Yeah, for sure. And then, you know, other species too will also use, you know, solar radiation to warm up. So, for example, you know, billfish diving deep, sailfish especially, you know, a lot of times you'll see them up sunning on the surface. And I think a lot of times, get a bit warmer after having gone to those depths.
Tom: Yeah. It's interesting. You see that in sometimes bluefish in Cape Cod Bay when they first come in, there'll be just hundreds of them finning on the surface. And usually, when you find a bunch of bluefish and you throw a popper in there, you're gonna get an eat. But I've had times where I threw and threw and threw and threw and those bluefish had no interest in eating, which is very unusual for a bluefish.
Aaron: Right. And they're usually large fish. They're big breeders that are pushing in. And you'll see them sometimes kind of daisy chaining on the flats trying to warm up, and late afternoon squid patterns are pretty effective on those fish.
Tom: Yeah. Well, next time I see it, I'll try that.
Aaron: Yeah. You and everybody else is listening to your podcast.
Tom: Well, thanks for the tip, buddy.
Aaron: Yeah. I think in my experience on those flat Stevie chain pink squid patterns.
Tom: Okay. I'll make sure I carry some.
Aaron: But you still have to find the right place, get yourself in the right position, be able to make the right pass.
Tom: Oh, really?
Aaron: Yeah. So, I don't worry too much about telling people which fly to use.
Tom: Yeah, that's the least of our worries in saltwater fishing, which fly. You gotta find them first.
Aaron: Find them, get in the right position, present the fly correctly, don't blow the cast, all those things.
Tom: Yeah. Don't trout strike. And don't let Tom pole the boat.
Aaron: No. You'll just go in circles.
Tom: Yeah, I'm good at that. All right, Aaron. Well, that's been fun and it's been educational, and I wanna thank you for educating us some on temperature and saltwater fish.
Aaron: Yeah, my pleasure. It's been fun to talk about it. I mean, for me, you know what, it's automatic for me now.
Tom: Right. It is for you, you're a scientist, but I don't think most people think that much about water temperature in saltwater fish. Some people do, but I don't think they do as much as they do in trout fishing.
Aaron: No. And they also don't think about as much about, you know, matching the hatch for saltwater as they do for... You know, for trout fishing, the first thing people do, they go to a fly shop, what are they eating? Or what hatches on or they turn over rocks to see what nymphs are going... Whereas in saltwater, that doesn't happen as much, but if you can figure out... You know, and temperature's also gonna affect what the fish are eating or season as well, because temperature and the season affect all their prey also. So, kind of matching all those. I mean, we haven't really talked about this since my book came out.
Tom: Your book, speaking of which...
Aaron: How long ago was that?
Tom: I don't know, but let's tell people the name of your book.
Aaron: Oh, it's "Orvis Guide to Fly Fishing for Coastal Game Fish."
Tom: Yeah. And it talks a lot about the different species and types of bait that those fish eat.
Aaron: Yeah. And there's a lot of stuff in there too about water temperature and matching water temperature with tides, dropping tide, rising tide, all that kind of stuff. So, it's all in there.
Tom: All right. And it's a great book. It's a great book.
Aaron: I taught you everything you know, that's for sure.
Tom: That's for sure, you taught me everything I know. Yeah, absolutely. Absolutely. How come you didn't teach me how to pole a boat?
Aaron: I was laughing too hard.
Tom: All right, Aaron. Well, I wanna thank you. Again, we've been talking to Aaron Adams who is the, what is your title again?
Aaron: Director of science and conservation.
Tom: Director of science and conservation for Bonefish & Tarpon Trust. And by the way, Bonefish & Tarpon Trust is a great organization. If you care about learning more about the habits and the migratory patterns of saltwater game fish, particularly tropical saltwater game fish, and you wanna give back to the resource, that's a good place to spend your money. Okay. Thank you, Aaron. I hope to talk to you soon.
Aaron: Yeah, my pleasure, man. That was fun.
Tom: Okay. Bye.
Aaron: Bye. Have fun.
Tom: Okay. Thanks. Bye-bye.
Man: Thanks for listening to the "Orvis Fly Fishing" podcast, with Tom Rosenbauer. You can be a part of the show. Have a question or a comment? Send it to us at