Sitting Dockside Podcast: Fish Habitat Part 3 of 3
1st Apr 2022
Sitting Dockside Podcast - Episode 001- Fish Habitat
Brought to you by Private Water Natural Resources Association.
If you missed Part 1, read it here. If you missed Part 2, read it here.
Matt Rayl: I want to hit on that but finish what you're going to say and then we'll jump to that.
Dr. Brian Graeb: Well, and we'll– there's a... that's probably the topic for another talk, but we did – we had four years of constant radiotagging. And we targeted larger fish and the cool part was we had some fish that were tagged before we fixed habitat and their tags stayed after– effective post habitat treatment, you know, improving habitat so we got to see a change in behavior of those fish beforehand and after...
Matt Rayl: And just to let everybody understand what radiotag is, basically they take like a little wand like that was on top of your house when you had to move it to get your TV stations they were– they actually walk out every day or very frequently and see where this bass is and they have a tag that's just basically communicating with that and they could say, "OK, it was a drive to the lake, that right there is where the fish." And that fish will move and they can track that particular fish with a transpondence to where it goes throughout the lake.
Dr. Brian Graeb: Yeah, yup. Yeah, we do– we actually do open cavity surgery on the fish to implant it inside the visceral cavity by the stomach and it's pretty wild. Pretty wild.
Matt Rayl: Anyway, you followed this fish before habitat, right?
Dr. Brian Graeb: Yeah, yup. Several fish before and after and it was neat that some of the fish were really large movers and some were short movers. This fish you know, red shirted picture, this fish, I've actually caught her three times, tagged her before. Her home range, she lives in about an acre and a half of water in a 100-acre lake, in the corner of a dam next to just the most perfect little piece of cut grass clump. You can imagine near tons of it, she just got the great home. And she doesn't move, she– and she was six pounds, I think when we first put a radiotag in her, we caught her again, in this picture, she was just about nine pounds. And we caught her the next year and she was way over 10 pounds.
Matt Rayl: OK.
Dr. Brian Graeb: She just figured out how to make a good living, but her life is in a really tiny chunk of the lake. And we have other fish that routinely would move the entire length of the lake. The lake is about a mile long, you know, they'd zigzag across, and they would move a mile down and a mile back, plus zigzags in a 24-hour period. So, just some crazy movements, and we summarized all those data and looked at some of the behaviors.
But basically, after we put habitat and the big movers kept moving a lot, but now instead of just randomly going around their home range, they would swim – they would swim from structure to structure to structure. So if they had three fish cities in their home range, they would spend a lot of their time going either on those or moving between those three structures. So it really changed how they use their home range. But yeah, fascinating stuff.
Matt Rayl: All right. Well, and then they would just basically go into that fish habitat station, and then– or city is what you used to call it, and then trying to forge a little bit and then move across it. Were they actually not moving as much when they those... or they– when you add it all together, they were still going the same distance?
Dr. Brian Graeb: The bass that we'd have tagged before and after, we used the same, they moved about the same amount, use the same amount of area, they're under the core home range, but they changed how they moved within that range.
Matt Rayl: Yeah.
Dr. Brian Graeb: We really expected the home ranges to go down with better habitat.
Matt Rayl: Yeah.
Dr. Brian Graeb: They didn't– we got an increase in growth, but it wasn't because they moved less. Just because they ate more.
Matt Rayl: Well...
Dr. Brian Graeb: Oh.
Matt Rayl: No, that's all right, I get it, I cut you off. But uh, I want to conclude with the, if you go back to the first image with a Grand Lake with the bathymetrics. Just as now we understand what you put now, what the fish are, this is where you put the fish cities. Right?
Dr. Brian Graeb: Right.
Matt Rayl: And some of those red dots are bigger than others or, there's two fish cities there?
Dr. Brian Graeb: A couple of them, we doubled up fish cities just to see what the size of the habitat would have on it. And those, the dots are actually precise GPS traces, the outline of them right along the edge. And we figured I think for impact purposes that you can extend that line about five meters beyond all these lines, but yeah.
So there are some work out of out of Texas looking at brush piles and the size, shape and configuration. And one of the interesting results they found on there is really no, no– it didn't really matter how big the structure was, if they went out and they saw one big, usually female bass on that structure, they wouldn't see any medium-sized bass, they'd probably see some small bass, but they wouldn't see any, you know, a little bit smaller, medium-sized. So that's, and we kind of looked at that too, we didn't quantify it very well but anecdotally observationally, you know, we saw on that giant complex structure, if we'd see one big fish, we would rarely see other big fish around them.
So some of this work if doing these in the future, now I would never put two fish cities together, I'd always spread them apart because you have then double your chances to get a big fish to sit on them if they're going to be, if they're going to expe– they're going to display that type of behavior. So we'd really taken that and just taken the same amount of habitat but just made it in smaller discrete chunks, something like that.
Matt Rayl: Yup. And then I'm going to get asked about the one in the middle there you have in a deeper range look, but I think it's probably out front of their dock there. Yeah, did that hole just have many fish, is it shallow? Or was depth important?
Dr. Brian Graeb: This one is actually, this is the– this is a little, it was almost an island, they've got cypress trees on top of here. This before it's really sharp break and sharp drop off. Narrow between these banks, the wind blows this direction. So I'm sure current moves there. This was already a really high, highly attractive spot for bass. Because we had two years of telemetry before we put habitat and so we knew the areas of high use and areas of low use. So one of the things we did, this area up here was pretty low use so we said well, what if we put habitat up there, will we get more fish to use it? And the answer is, yes. We routinely go up there now and find more fish. So that did help increase the use on some of those areas. But yeah, did I answer your question?
Matt Rayl: Yeah. What about depth? Did it matter?
Dr. Brian Graeb: No, not really. All the structures, I shouldn't say that we– all the structures covered from about 2, 3-feet deep on the shallowest part out to, ideally we'd get out to about 12 feet of water for those really tall structures. But in the upper end of the lake, there's no– above this line, there's nothing deeper than about 9, 10 feet. So, we'd go out as far as we could, but we, you know, our deepest spots might be only seven or eight feet. So we really didn't see, I guess I should, I should say, we really didn't design this to answer that question, because we tried to cover from shallow to deep at each site to standardize it.
Matt Rayl: I got you. Interesting. Well, any closing thoughts?
Dr. Brian Graeb: Well, I had one more example how to do these.
Matt Rayl: Oh, did you? OK.
Dr. Brian Graeb: So I thought I'd throw this up there for folks to follow.
Matt Rayl: Yeah.
Dr. Brian Graeb: So here's one and here's– we've taken this, this design, now, we put it all over the place. Here's a project we did last summer up in southern Kansas. And that's a gravel pit, it's a great, great place to work so we can see a lot of the stuff happening. This gravel pit was an absolute habitat desert. Like a lot of lakes nowadays, there was one sunken sailboat out in the middle of it that was about the only thing for structure. So we're starting with a blank slate.
So we, you know, the way we calculate this we go in with GIS and we trace the shoreline and you know, it's a 23-acre lake and there's 2,050 yards of shoreline so we say we want to impact 20% of that shoreline. So I know I need to make an effect on about 410 yards of it. So each of the kind of the newer cities we have impacts 30 to 40 yards, so you multiply that out and you know we know we need to 13 to 14 fish cities in this lake. And in this lake, we also started adding cedar trees. We're mixing natural and artificial and I think that's really important thing to do.
But I wanted to throw this up there because I think this is probably the place I know before I started working in it and what I see around the country, a lot of people have great intentions and great ideas of doing habitat and putting structures out. But I would argue that the vast majority of it are doing it on much too small of a scale. If you look at all the stars here are the locations of an individual fish city and each fish city in this case is I think 10 pieces of artificial habitat and several pieces of cedars all together. So we might have 25, 30 individual pieces of habitat all in one giant complex replicated 14 times across that lake. So that's the scale it takes to get enough habitat in there to make a bump on that population.
Matt Rayl: Right. Wow. Yeah, when you actually– so how many, I guess you have it here though, is on that one of those fish cities, it's... I mean take a guess how– is it 20 by 20, 30 by 30 in feet?
Dr. Brian Graeb: It's more in yards, so it's a– if we were looking at a buffer around the outside, it's each one of them is going to impact that 30 to 40 yards. So... and it has to do with how close or how far apart you place them. We like to put a little bit of space between each piece of the artificial then we might come in and cram a cedar tree down between them. But to start off, we spread it out, so if you measure the outside of that coverage area you'd probably impact about 40 yards of shoreline is how we look at it.
Matt Rayl: Wow. Yeah. I would say majority of people that are trying to do habitat are grossly undersized on the size that they're planning.
Dr. Brian Graeb: I've seen it. It's astound– when you when you put all this stuff together on the shoreline before you go throw it in the lake, it's astounding. It covers– it looks like it's amount of habitat, but then when you go out and actually drop it in the lake, it really doesn't cover that much. That much area.
Matt Rayl: Right. And then... but if I see this guy's dock here at the gravel pit, I mean, you didn't put anything out in front of it. So why didn't you choose to do that?
Dr. Brian Graeb: Well, we came back in later and we actually filled this cove up...
Matt Rayl: Oh.
Dr. Brian Graeb: ...with, I think we probably put about 15 pieces of artificial and 15, 20 cedar trees. Because this quickly– we did all this in the cold water. And then as soon as it start warming up, we realized this was probably really important spawning cove, it was shallow, it was getting– it was warming up a little bit quicker than the rest of the lake kind of protected back there. And so we absolutely filled that out with habitat. And this dock. They don't– it's kind of high off the water, they don't do much fishing off of it. So...
Matt Rayl: Oh.
Dr. Brian Graeb: ...we really didn't do much of anything. Yeah, the most angling that's going to happen on this lake will be out of a boat. So we didn't have to worry about the dock piece. But if there is a dock, the way I deal with it is I'll do the fish cities pretty much in the pit. I'll put one fish city right at the edge of casting distance away from the dock. But then I'll hang some individual pieces underneath the dock and do maybe a couple more on the outside. But you don't want to have zones where you know that it's open and know that it's full of habitat for novice anglers and teaching people. But yeah, we'll put more in around the dock. But it's usually kind of a separate thought process from the rest of the lake.
Matt Rayl: Right. Right. And that's where the difference between habitat and attractors are. So...
Dr. Brian Graeb: Yeah, yeah.
Matt Rayl: That's right. Good. So is this all we have? Right here?
Dr. Brian Graeb: This is it for that one. It sounds like we need to talk more about bass behavior on the next talk, but...
Matt Rayl: Yeah. This was good. But yeah, man, I appreciate you coming. And having cutting edge science with PWNRA is pretty awesome. I mean, we're really blessed to have professionals like you, because there's not many scholastics that really are focusing towards you know, private water resource and to have somebody with your talent, somebody that's actually excited to work along development of private water resources is awesome. So, I have to thank you with that. And I appreciate you being here and taking the time to explain all this cool stuff.
Dr. Brian Graeb: Thank you, Matt. Yeah, we're a dying breed, people that are actually working and interested in even just reservoirs in general. So I appreciate you having me on. This is great, and hopefully it helps the people out.
Matt Rayl: This podcast, Sitting Dockside is brought to you by Private Water Natural Resources Association.
Dr. Brian Graeb: I appreciate it, Matt. Thank you.
Matt Rayl: Nonprofit, built just to educate private pond and lake owners to water quality, and fisheries, and all of that good stuff. There's videos. There's places to read, and there's a community built right into that website. So, if you want to learn more, jump to pwnra.org and click, and by all means, make sure that this continues in the future in podcast, education, video. Become a member. If nothing else, there's tons of platforms, YouTube, Facebook, just hit like, send a comment. We appreciate everything you can do here at PWNRA.
If you missed Part 1, read it here. If you missed Part 2, read it here.
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