Paul Roberts

Finally getting back to this. You know, life just happens. Back to the fun stuff... Was fun to see people’s responses. Lots of really astute responses; No surprise there. Hope it got you all thinking, especially those new to thinking about what’s gong on below in our bass waters. OK, let’s pry the lid up on this lake a bit and take a peek. These data represent 30 mature (2 to 5lb; avg 3.5lbs) largemouths that were followed by telemetry for 24hrs once a month for 4 years. Each fish was located 6 times per tracking day. That data was then pooled to create seasonal snap-shot images. The summer data are from single 24hr periods in June, July, and August, repeated over 4 summers. I guess we could call this “A Day on the Lake” from the bass’ perspective. As one might expect, distributions of fish were not random. In the following image I’m representing the tracking observations using a bass or pike icon on the locations frequented by each species. Each image represents a cluster (>10) of observations. These clusters show where activity was concentrated. From here we can speculate as to why. The drawn lines encircle multiple observations that appear to be related to the clusters, possibly hunting activity. I ignored locations with less than 4 observations (most were single observations sprinkled about the lake) since: it’s known that some individual fish travel more than others, and that our interest lies in seeing where fish were most apt to be concentrated during these 12 24hr periods over 4 summers. Again, these were mature quality bass averaging 18” and 3.5lbs ranging from 2 to 5.25 lbs, with two breaking 5lbs. There's a concentrations of bass on the north milfoil covered point (with the humps you can make out in the depth map now buried in milfoil). (everyone pointed that one out. It's the most obvious structure piece in this little lake). Bass use -likely feeding activity- continues up into the north end milfoil flat. Notice that there is some patchiness to the weed density there, with an irregular weed line and open patches (W side of flat) that would give bass a hunting advantage on bluegills. (A-Jay had called attention to this important aspect of fishing weedlines -important to both bass and anglers). There are also some irregularities in the weeds at the inside turn at the base of the point on the E side. The tip of the point, and the clean lip where it drops off into the main basin, has a collection of observations too. Some individuals in this cluster were actually out past the clean lip and almost certainly suspended; a classic resting location. E, there is a concentration near the boathouse that sits perched over a deep slot coming up out of the basin along the N end of the dam. There is also a point and ridge at the boathouse with a deeper pocket just north. This is an interesting area and some bass use it. (I believe senile1 called out this spot). The bass there may be crayfish hunters at times, and/or keeping bluegills at bay under the boathouse. I wondered if anyone feeds bluegills at the boathouse. The slot may also be a resting location. The main story for bass in this lake during summer however is not in the main basin at all, as neat as it looks, but in the shallower south channel, in particular its’ southern most end. (Toad Mode, Roger, and T9 had called this out). The milfoil beds in the N end had comparatively few observations and the researcher suspected that the milfoil beds were so dense that bass had difficulty hunting there, and there’s a lot of research that supports this idea. My experience with milfoil has been that bass love it. But patchy broken areas are easiest to fish and presumably make for more effective hunting there for bass. The researcher said that the telemetered bass generally avoided the dense milfoil areas. It’s possible that oxygen deficits overnight within the beds moved fish out, or made it unstable enough to be reliable summer habitat. Milfoil needs a lot of light and I’ve seen dark overcast summers kill it off enough that decaying milfoil could be an issue at times. The researcher suggested that the south channel held so many bass because of the presence of longleaf pondweed. He suggested that it was the complex form (the open understory) of the pondweed that made this area good for bass as they likely could more efficiently hunt bluegills there. The irregularities in the pondweed probably allowed space for a greater diversity of vegetation as well. This area may be where the majority of the bluegills live as well as good hunting grounds. There’s another potential factor here. The headwater inlet just happens to contain a spring. (Robert Riley suggested this possibility). The researcher felt that the spring didn’t influence the area the bass used but I would want to take a temperature profile to rule that out. He had reported only surface temperatures. The researcher also stated that summer surface temps never surpassed bass tolerance limits. This spring acts as the major thermal refuge for the lake’s pike population during summer. Pike selected temperature over depth and cover there, with the greatest concentrations found well up the inlet channel (outside the map). There were also pike in the main basin and they dominated the depths of the basin. Bass were excluded from the main basin either by presence of large pike, temperature (possibly even a thermocline), or both. (Several of you guys were onto this as soon as the word "pike" was mentioned). This is a great general observation: In small waters, the shorelines offer the vast majority of food shelves. In big waters, food shelves may be unattached to the shoreline, but they serve the same function as shoreline-attached shelving. Also, the fact that small waters tend to offer littoral prey species rather than pelagic prey keeps bass hovering tighter to those shallow shelves.

Not as much as I used to. For a number of years I fished 100 to 150 days a year, from 4 to 14hr days. Schooling, jobs, and family arrested that development. But I've become a better man for it. I don't smell quite so bad and can speak in full sentences. All I used to say was "Fish on. Good Day!" Hey Vanbassin, cool having a S African basser here!

OK…let’s “flesh” this out a bit more… add the next skin –cover. It’s pretty apparent that lake basin alone tells us only so much –the ballpark but nothing about the playing field or the players. I was originally planning to add higher ecological community info later, as a third “layer”, but got ahead of myself. I didn’t want this thread to feel like a quiz. Instead I meant it as an instructive way of introducing fishing lake intel in terms of layers of information. Those layers are: structure (basin topography), substrate and cover (“edge” or niche complexity), and finally the players (the food chain). What’s interesting about this satellite image is that you can see the riverine shape of this little reservoir nicely. There was no “river” here, just a “wash”. Obviously the image was shot on a nice cloudless day. Once again: -Water clarity (~6ft by Secchi when measured) -Mean summer surface temps (75-81F) -Substrate is rubble beneath, mostly covered in silt. The dam is faced with modest sized rip-rap. No boulders, beyond the dam face rip-rap. The surrounding land is plain (once short-grass prairie). -There is precious little wood –the remnants of smallish deadfalls near shore here and there. -Vegetation present is Eurasian milfoil (Myriophyllum sibiricum), coontail (Ceratophyllum demersum), longleaf pondweed (Potamogeton nodosus), and sandgrass/muskgrass (Chara sp). Echoing T9 above: Clarity is adequate for light-loving milfoil, so its weedline is at ~8ft –about milfoil’s max depth in the region. Coontail can reach a little bit deeper. Chara can grow as deep as 20ft. but grows no more than 3ft tall and thins out quickly at the tops. Longleaf, an emergent “cabbage”, can root no deeper than about 4ft or so. -Fish species: Largemouth bass, northern pike, bluegill, few yellow perch. OK. Where are the bass here in summer? What looks good and why?

Fish can learn to anticipate food. Any aquarium owner will tell you this. Lakes and ponds with fish feeders can amass large numbers of fish, and bass home ranges around feeding areas can become very small and persistent, lasting the entire year including winter. Lakes stocked with trout (or other fish) on a regular enough basis can get predator fish waiting in anticipation. Some California lakes are known for this. But... as DRH2O experienced, once a year may not pan out.

Roger, and Senile1, now that’s the spirit! Of course more info is needed. I guess my FIRST question was/is, “What can we say by just looking at the basin –sans cover?" I’m not just asking where would you fish, exactly. I’m asking where do the bass live? Where are the likely sanctuaries/homes/bedrooms? Where are the likely feeding grounds/kitchens? What’s most important to bass in summer? What factors might influence things? I’ve provided: -a basin map -water clarity (~6ft by Secchi) -mean surface temps (75-81F) -prey species (mainly bluegill, few yellow perch) -And I’ll add that there is a competing predator –northern pike. And I’ll provide some cover info: -Substrate is rubble beneath, mostly covered in silt. The dam is faced with modest sized rip-rap. -There is precious little wood –the remnants of smallish deadfalls near shore here and there. -Vegetation present is Eurasian milfoil (Myriophyllum sibiricum), coontail (Ceratophyllum demersum), longleaf pondweed (Potamogeton nodosus), and sandgrass/muskgrass (Chara sp).

Questions you guys asked: Prey species: Bluegills and yellow perch. Substrate: Will provide that with the “cover” image. Public fishery. No boats allowed. But for our fantasy purposes, we'll have run of it.

Suspended fish are easy to mark. Those close to bottom are not. You probably know this, but just an FYI for other readers.

From the uw video I've seen, it's pretty apparent that bass are often active under the ice. And it's pretty obvious that they feed under the ice. Outside of the spawn, activity and feeding tend to be lock-step. In northern natural lakes bass use deep weed edges. But in ponds they've been known to cruise shallow weedlines looking for all the world like hunting bass anytime of year, only slowed down. Every lake is its own. Your fish could be up feeding -maybe bc the weeds are still alive up there and prey is still there. Or the bass could have been pushed out of the depths by oxygen deficits below. How far they can move vertically in how much time is an open question. My guess is that air bladder issues would be heightened in the winter. Is it possible that you are finding two separate groups of bass?.

Good start. Dwight, I put summer water temps in to offer a clue on latitude. Spawn occurs last week in Apr/1st week in May in a lake this size.

I was referring to under ice. But, yes, zooplankton can be more prevalent deeper, esp in lakes with lots of zooplankton predators.

Macrophytes (rooted veges) also can continue to live and produce oxygen in winter too -even through relatively clear ice. Biggest side of the equation is respiration from decomposition. Bass relation to the thermocline is most likely food related. Probably they are there with the shad, which have similar temp "preferences". The shad are almost assuredly there with the zooplankton. Bass "prefer" the temperature where the food is. But they grow best at just over 80F.

Talking of structure and related stuff... I have radio-telemetry data for this lake. Thought we'd reverse engineer the bass habitat in this lake together. Where would you expect to find the bass during summer in this lake? Assume that you are going to fish this lake for the first time and these images are part of your research. What's important in making such an appraisal? What questions might you ask yourself? Our lake is a 60acre water retention/irrigation reservoir that is not used for irrigation anymore. Water levels do not appreciably fluctuate; there is no annual drawdown. It is 17ft at the deepest point. Visibility is about 6ft (by Secchi disk). Mean 24hr surface temps are 75-81F during summer. This first image provides depth, sans cover, with depths in feet coded by color gradation. I'll then supply a satellite view that shows further detail (cover). Then I'll reveal the known bass locations. My FIRST question is: “What can we say by just looking at the basin –sans cover? Where do the bass live? Where are the likely sancuaries/homes/bedrooms? Where are the likely feeding grounds? What’s most important to bass in summer? What factors might influence this? Have fun with this folks.

You can't, practically speaking. Instruments are expensive and impractical. You can only recognize conditions that might result in oxygen depletion. You probably aren't going to have to worry about it much being in AR. The biggest culprit is excessive fertility, and associated decomposition. O2 depletion in winter usually occurs under ice which blocks sunlight (for photosynthesis) and doesn't allow circulation with air. You probably have little concerns there being in AR. In summer, it usually happens below a thermocline but can also occur in stagnant areas in shallower waters with highly turbid water that blocks enough light coupled with high temps and high fertility. I suppose it's quite possible that a highly fertile pond surrounded by forest that doesn't allow wind circulation could create oxygen depletion in the depths.

Agreed. Even in small waters, the warmest isn't always what you are looking for. It can help, however, once you find wintering locations in your water -which means stability in terms of oxygen, lack of current, food, and temperature -probably in order of importance. Having warming conditions can be a plus, after you've figured out where your bass are. A general trend, in lakes that freeze, is for the warmest water to be on bottom and fish may follow this general trend. But in many bass waters, oxygen depletes down there and bass either move or become inactive.

Several things at work in dock situations -why underlying structure and mixed or breaks in cover are so important in these situations: -Depth is a component of bass habitat in general. This may or not play a major role in every location but at bare minimum it plays a seasonal role. -Physical objects are attractive to bass. -Breaks in cover allow bass to capture cryptic and elusive prey effectively. I should add (and to my above post) that complexity/diversity of cover both attracts prey fish and provides edges/breaks bass can exploit.

Several things at work in heavy cover areas, vegetation in particular -why underlying structure and hard cover objects are so important in these situations: -Depth is a component of bass habitat in general. This may or not play a major role in every location but at bare minimum it plays a seasonal role. -Physical objects are attractive to bass. -Breaks in cover allow bass to capture cryptic and elusive prey effectively.

Thanks Dwight. I was aware of Finger Lakes' smallies chasing alewife above the thermocline, but always expected smelt to be too deep. I did once catch a pickeral off a downrigger 80ft down in one FL though. That was a surprise.

I assume you are after large bass. Does the lake have a strong popn of large bass? Are there fisheries surveys available to you?

Dwight, are the smallies on the spawning smelt in spring in general? Or just during die-offs? How about other times of year?

There are two families of crayfish, one being a burrower, the other living in "retreats" or "hides". Burrowers are more common in the south but there are N ones too. They overwinter in burrows, although I suspect in the N they may use lake bottoms. Retreaters live in rock, wood, vegetation and winter in the lake basin. There are usually crayfish in most waters. But, how abundant and important they are to bass is an open question. I look for signs of them -burrows in banks and freshly cleaned out retreats- in spring at around 55F. I’ve not done this in ponds or lakeshores, but crays being night active I’ve surveyed trout streams for crays at night with a powerful light and wow! There can be an amazing number of them unbeknownst to day anglers. Bass are primarily piscivorous -LM in particular- but crays are the next most common prey type.

Yes, there are lots of species of minnows. And they each have diff habits, so you can't generalize. If they all had the same habits in the same water ... there wouldn't be as many species. Don't try to guess what your bass are eating. Most bass won't ever see the vast majority of minnow species in NH. Creek chubs are rarely a main bass forage species in lakes, as they are mostly a stream species. There is the lake chub: http://www.wildlife.state.nh.us/Fishing/Fish_species/fish_conservation_profiles/lake_chub.php Maybe this is what you've seen? Bluegill, pumpkinseed, yellow perch, and golden shiners are the most likely species sharing largemouth habitat in your neck of the woods. Again, don't guess as to what your bass are eating. Contact your fisheries folks about your lake and the forage there. Find the website and email them. Most state fisheries folks are darn helpful, and in position to know stuff worth knowing. Then start researching habits and try to make observations on your waters. That said, you don't need to start knowing the forage base before you start casting. Keep fishing, and fill in the gaps as you go. Crestliner, smelt are a coldwater species and are known to live very deep -usually below the thermocline. They like water colder than most trout even. They are light sensitive so during the day they drop even deeper. Even deep smallies are unlikely to meet up with the shallowest smelt. Smelt are mighty fast too, and at temperatures when bass are sluggish. Even the smelt spawning run is less than likely the two would meet, since smelt spawn at night and hightail it lakeside before the sun comes up during a cold time of year. Maybe dying smelt during the spawn around spawning trib mouths might be the bet bet. Curious, have you found bass feeding on smelt? I've wondered myself on NYs Fingerlakes and Lake O.

What's the forage?

Shallow is where the food is produced; It's called the "photic zone". Deep is where the security and environmental stability lie. Matters less exactly where these are in relation to the land, just that they are close enough together that fish have ready access to both. And some clarity on the deep to shallow movements as I understand it: Such movements are most important in a seasonal context -which would make them "migrations" which answers the short term depth change issue. Buck did say that movements from the deep occurred "once or twice daily" so he wasn't (just) talking seasonally -which in terms of depth change is most likely erroneous. This does not preclude lateral movements however, from suspension to a shallow feeding shelf. And again, this "feeding shelf" could be attached to the shoreline (as in smaller waters, or steeper sided reservoirs), not attached to a shoreline (offshore), and it could also be not attached to anything at all, simply fish relating to schools of pelagic prey -something known to happen in some lakes, esp with smallmouth. I suspect however, that even those pelagic smallmouths "touch ground" every now and then on major structures. Probably even more so with pelagically focused largemouths -largemouth being different animals energetically.

North and south (and natural and res) share more than they don't. Aquatic food chains are based in two places the planet over: littoral (vegetation) and limnetic (open water). In many if not most waters bluegills make use of both. Focus on water body structure and fine tune with forage info as you acquire it.

My take on this question is that you don't have to deal with depths of 100ft for bass. On many ultra-deep lakes you can simply exclude a whole lot of water -horizontally speaking. Dealing with sheer square mileage... well the way I did it on L Ontario without electronics was to find smallie habitat -broken rock mostly- along (albeit somewhat distant) shorelines. With modern electronics...it's a whole new world.