Dissolved Oxygen

[nofearengineer]

I've been doing a bit of reading lately on water chemistry and its effect on fish. A couple of lackluster trips to lakes, where I couldn't find the fish reliably sparked my brain into action. How much effect is the level of dissolved oxygen having?

I read that largemouth bass prefer approximately 9 ppm (parts per million) of dissolved oxygen. They can survive anywhere from 3 ppm to 13 ppm, but 5-9 is optimal. (In the winter, when their metabolism is really low due to the cold, they can tolerate as low as 1 ppm, but that's a special case.) The bass, being cold-blooded, has a metabolism that depends on the water temperature. So if the water is hot, the bass will be hungry. However, if there isn't enough oxygen in the water to metabolize (digest, layman's term) food, the bass won't eat, regardless of how high its metabolism gets. They'll either waste away from starvation or have a stomach full of rotting food, unless they can find some water with more oxygen in it.

Well, since Mark (Woody) and I are going to hit Lake Monroe this weekend, I checked Indiana's DNR website for water quality information for the lake. Turns out, they post the water temperature, height, and the dissolved oxygen at various depths of the lake. For instance, this week's numbers show the dissolved oxygen dropping to 3.1 ppm at 20 ft. So I guess I will put away my super-deep-diving crankbaits, and go for a shallower approach. Hopefully, this will save me a lot of wasted time.

However, I imagine they take their oxygen readings out in the middle of the lake. I would think in cuts where small creeks flow in, the mixing of the water might push some more oxygenated water deeper. So if the topwater or shallow-water bite isn't happening in hot weather, like we're accustomed to, I think deeper ledges near secondary points might still be good fishing spots for a deepcrank, jig, C-rig, or slow-rolled spinnerbait.

I've been trying the last couple of days to find a reasonably priced oxygen sensor online with a 30' cable or so, so I could take my own readings and record them, but no luck as of yet. If anyone here knows of any such thing, please let me know.

I'd appreciate any thoughts or comments on my thoeries/ramblings.

[Kevin]

I think there is a fine line you have to draw between research science and reality when it comes to bass fishing... particularly when involving the metabolism of largemouth. While dissolved oxygen certainly can play a major role in the warmest months of the year, metabolism due to water temps and its effect on feeding volume/frequency, I think, is an entirely different subject.

Science claims that in colder temps, a largemouth has a lesser metabolism and in warmer temps, the largemouth has a greater metabolism. I wholeheartedly agree. However, what I disagree on, is that metabolism is in direct correlation with feeding volume/frequency.

Case in point... do you ever catch a FAT largemouth in the winter? You bet! Some of the fattest fish I catch are in wintertime temps. Ironically, some of the skinniest fish I catch in the year are during summer.

If there are a lot of fat bass being caught in the winter, what is it about their metabolism that is allowing them to be fat? We all agree a largemouth's metabolism is lesser in colder temps, so why are they feeding so heavily? Again, I think it's because metabolism and feeding volume are not in direct correlation.

I think we are all used to catching bass in the winter and having those fish fight lethargically like a wet sock. They rarely break the surface and will rarely crush your lures like they do in warmer temps. We as humans have varying metabolisms as well, but, do we that have higher metabolisms eat more and look fatter? Quite the opposite I think. Those that tend to have higher metabolism tend to be naturally leaner. I have days where my metabolism is high (lots of energy) and days where my metabolism is low (very tired), and just because I'm tired doesn't mean I eat less. I eat a lot no matter how I feel.

The difference is, with bass, they just eat smarter in the winter, and thus the reason for the more difficult fishing. Because of the lesser metabolism, they won't be moving a lot and will tend to hunker down on offshore structure. I also believe their feeding window is reduced, due to the shorter days.

I really don't put much thought into DO readings, mostly because your sonar will paint a much better picture as to the life at certain depths. One of the best things to do is to zig zag some points to quickly get a read as to depth baitfish are hanging in. If you don't see bait at a particular depth, good chances are you won't find bass there either.

I recently had the chance to fish with one of best anglers on the BASS tour and in one conversation we had, the topic of the many "science research" articles in magazines came up and I asked him what he thought about them. He made it very clear that "most of that stuff is garbage". I think he'd agree it's worth the read, but what he taught me is take it with a grain of salt, and what you learn with your rod and reel is what matters most.

[nofearengineer]

Originally Posted by Kevin

Science claims that in colder temps, a largemouth has a lesser metabolism and in warmer temps, the largemouth has a greater metabolism. I wholeheartedly agree. However, what I disagree on, is that metabolism is in direct correlation with feeding volume/frequency.

Case in point... do you ever catch a FAT largemouth in the winter? You bet! Some of the fattest fish I catch are in wintertime temps. Ironically, some of the skinniest fish I catch in the year are during summer.

I'm not sure we're disagreeing here. Yes, the skinniest fish are in the summer, because they can not find enough food to satisfy their metabolism. You and me burn calories according to how much work we do, mostly by choice. Cold-blooded critters are slightly different. They tend to do as much work as the calories they burn...backwards, if you will. In essence, the amount of calories the bass expends are not as much a matter of choice for him as it is for us. When the water gets so hot he can't find enough food to exceed his calorie needs, he's got two options, move to find more food, or move to deeper, cooler water to slow his metabolism down. Unfortunately, deeper water usually means less dissolved oxygen, so he digests whatever food he has managed to catch, but at a slower rate. He's improved his situation, but not by a lot. If he can find cooler water without decreased oxygen levels, our little friend has achieved his biological mission. He will continue to make hunting raids in the [EDIT]shallows[/EDIT] where he feels like a superfish because of the warmth, and then go back to deeper water to rest and fatten up on the food in his belly.

Originally Posted by Kevin

If there are a lot of fat bass being caught in the winter, what is it about their metabolism that is allowing them to be fat? We all agree a largemouth's metabolism is lesser in colder temps, so why are they feeding so heavily? Again, I think it's because metabolism and feeding volume are not in direct correlation.

Again, I don't think we're really disagreeing...Winter bass are fat becaue they're not expending a lot of calories, not because they're eating more...they mostly wait until some sleepy shad drifts right in front of their mouth, then.....SLURP! You said it yourself...bass eat "smarter" in the Winter. It's because they can afford to.

Originally Posted by Kevin

I have days where my metabolism is high (lots of energy) and days where my metabolism is low (very tired), and just because I'm tired doesn't mean I eat less. I eat a lot no matter how I feel.

Right...and if you eat a lot when your metabolism is down, just like that Winter bass, you will pack on extra weight. I don't think people will think of you as fat and sassy though!! (well, maybe sassy, but that's a post for another forum hahah) Conversely, I personally know it's possible to get so much exercise, you lose weight no matter how much you eat. (take a look at Body For Life by Bill Phillips...incredible...worked great for me before I ruptured that pesky disc in my back ) Remember, I think the controlling factor in the bass' digestion is oxygen level, not temperature.

Originally Posted by Kevin

I really don't put much thought into DO readings, mostly because your sonar will paint a much better picture as to the life at certain depths. One of the best things to do is to zig zag some points to quickly get a read as to depth baitfish are hanging in. If you don't see bait at a particular depth, good chances are you won't find bass there either.

And there you have it! That's my main point. I'm not asking the oxygen sensor where I should fish...I'm asking it where I shouldn't exert a lot of effort! I also look for baitfish on my sonar, but that merely tells me where the baitfish are right there. I think the oxygen level stratification might be more consistent across an entire body of water though. But I do know it could be completely wrong from time to time, like any method.

Anyways, thanks for the great responses, Kevin. It makes me think things through even better, to see where my arguments have merit, and where they don't and need more work.

Everyone else, don't hesitate to pipe up, cheerlead, or tell me I'm full of crap either! It's all good, as long as I get to wet a line once a week.

[Kevin]

Originally Posted by nofearengineer

I'm not sure we're disagreeing here. Yes, the skinniest fish are in the summer, because they can not find enough food to satisfy their metabolism.

I don't know if I buy into that theory. It could be true, but the food source is as generous in the summer as it is at anytime in the year. If a bass isn't satisfying their basil metabolic rate in caloric intake, then that fish is shrinking, something has to burn to keep the fish functioning and alive. I guess the real question is, what amount of food is "enough". I think that's where the science of all this becomes iffy.

Originally Posted by nofearengineer

You and me burn calories according to how much work we do, mostly by choice. Cold-blooded critters are slightly different. They tend to do as much work as the calories they burn...backwards, if you will.

I'm not sure I buy into this either. It's probably very true for a lot of other cold-blooded animals, snakes, etc.. but there are too many disclaimers to this science.

If you were to poll anglers as to when they could find the most active schooling bass busting bait on the surface, late-fall would probably be a top poll result. Late-fall bass will ravage schools of shad on the surface in temps in the lower 50's, sometimes even upper 40's. The "textbook" says these bass are "feeding up for the winter", which is partially true, but my point is.. at 50 degrees, what affords them the energy to bust shad on the surface?

Originally Posted by nofearengineer

Unfortunately, deeper water usually means less dissolved oxygen, so he digests whatever food he has managed to catch, but at a slower rate. He's improved his situation, but not by a lot.

Deeper water only "sometimes" means less dissolved oxygen. In most lakes, early summer will provide more than ample dissolved oxygen in deep water. It is only in late summer usually when the lake's been bombarded with dog days of heat, that life becomes unsustainable in deep water, forcing those fish to move shallow. DO readings are most effective for at least letting you know the current level of stratification. Whether it's worth the time to look up, I'm not sure. Could be!

Originally Posted by nofearengineer

Again, I don't think we're really disagreeing...Winter bass are fat becaue they're not expending a lot of calories, not because they're eating more...they mostly wait until some sleepy shad drifts right in front of their mouth, then.....SLURP! You said it yourself...bass eat "smarter" in the Winter. It's because they can afford to.

Bass will swim quite a ways in winter to hit a lure. They just work vertically, waiting for bait to swim over top of them. We all have caught fish on suspending jerkbaits in 6-10 feet of water fished over 20 foot breaks. Those fish weren't suspended most likely. They swam up from the bottom to feed. I just think you have to be careful not to label a bass' behavior. I've seen 10+ lb. bass hit a surface swimbait in 40 feet of water in the dead of winter. The bass was on the bottom and had no bones about swimming to the surface to hit a lure.

Originally Posted by nofearengineer

Anyways, thanks for the great responses, Kevin. It makes me think things through even better, to see where my arguments have merit, and where they don't and need more work.

Like I said, awesome thread. I wish there was a true way to find out if we we're right or wrong, but I don't think the bass are going to tell us.

I think the important thing is to always keep an open mind. Throw out the rule book, because if there's one thing I learned, bass don't play by our rule book!

[nofearengineer]

Yeah...I figure I'll figure it all out about 5 minutes before I die.

[Kevin]

Originally Posted by nofearengineer

Yeah...I figure I'll figure it all out about 5 minutes before I die.

Hahaha... Ain't that the truth. If you get a DO sensor.. keep us up to date on how it works and what you discover with it. I think we'd all be interested in hearing your experiences with it.

[nofearengineer]

Oh for sure...you guys know how tight-lipped I am. lol

[nofearengineer]

Haha...I've been sitting here eating my dinner, thinking hard about what you said about fall bass busting on topwater, Kevin, and I finally came up with a good answer. In fact, it actually scares me, because it makes too much sense, I might be on to something here.

A phenomenon called "Fall Turnover" occurs in lakes. For other people reading this: as fall begins, the water is still heavily stratified from Summer. You've got the hot surface, with good dissolved oxygen, a middle layer, which is a bit cooler, with slightly lower oxygen, and a cooler bottom layer, which is almost completely devoid of oxygen (read: no fish at all).

Well, when the cold weather of Fall hits, it can cause the top layer of water to cool off very quickly. The top layer, can quickly sink. Considerable "currents" can form, and oddly enough, within a day or two, the lake will be a constant temperature from top to bottom. Now this is a temporary condition...it only lasts for a few days to a few weeks.

Here is what I'm getting at. For a short period, the bass doesn't have any alternatives to being in the warmest water in the lake. He can't slow his need for food down by going deeper. Now, it's a given he's not as hungry as during July, but he's still hungry, relatively speaking. He might as well chase the baitfish up top, since he has nothing to lose, and the dissolved oxygen is the best there. When the lake settles down for the winter and oxygen returns to the deep areas, the bass will slowly follow.

Once again, this is all theory, but I'd like to think it is logical. I'd be curious to find out if bass bust on the surface of lakes that don't turnover in the Fall; i.e shallow lakes.

[1/4 stick]

Very interesting thread! I just found this while doing a bit of research spured on by the discussion. Thought you might find it interesting.

http://antoine.frostburg.edu/chem/se...cting-DO.shtml

http://www.newton.dep.anl.gov/askasc...6/gen06478.htm

I ponder how the fact that oxygen solubility increases in cold water could affect things.

[Team9nine]

I've been trying the last couple of days to find a reasonably priced oxygen sensor online with a 30' cable or so, so I could take my own readings and record them, but no luck as of yet. If anyone here knows of any such thing, please let me know.

I'd appreciate any thoughts or comments on my thoeries/ramblings.

Depends on your defintion of "reasonably priced", but anything new that truly measures dissolved oxygen will run around $450+ to start and go up from there. If you find anything cheaper it is most likely a gimmick that just tries to corrolate temperature with D.O. content.

IDNR readings are taken down by the dam and would be pretty accurate for that end of the lake. Shallower readings would set up onthe slow side as the water there is more stained and shallower.

Lastly, I love investigating the "science" of bass fishing as much or more than anyone, but don't let it dictate or overrule your common sense. Bass are where you find them, and Kevin's comment on using a depthfinder to find the basic "deepest depth" you need to fish is spot on...

There are always exceptions, but that simple method will get you in the ballpark most every time.

-T9

[bamabassman]

wel ifn it were me.... itake an old crank telephone and hook it to the cable and............



oops, sorry wasn't meant to write that. lol.

[nofearengineer]

Team9, yes...I'm thinking $400-500 is what an entry-level lab-grade sensor and meter will cost. If I could scratch up a PIC board, I could make my own for around $150, but I don't really have the time to do the programming.

I really feel that when people refer to "common sense" as far as fishing goes, they really mean "fishing memories," which is just about as hit and miss as randomly selecting tackle from the box and giving it a whirl. Believe me, I'm all for the simple, in your face techniques. I've even advocated trolling to find bass, but I wouldn't hold my breath on it being a sweeping sensation, as the bass fishing industry makes more money on fish finders than trolling rods. "Find them with your hooks instead of your sonar" was a thought of mine.

All that being said, I think before a guy spends several hours and a hundred bucks in gas driving to a lake (like I do, unfortunately), he can make the most of what information is available to him even before he touches the water. I don't think that's over-analyzing...I just think it's a combination of eager anticipation and organization. I don't know about you, but I get my Hot Spots map out at least a few times before I go to a distant lake and mark spots that look interesting. To say "just wait til you get there, and see what the sonar says" seems short-sighted to me. I'm still checking my sonar, you better believe it, but what tackle I brought, and how my rods are rigged is going to depend on what my plan was.

[MississippiBoy]

Originally Posted by nofearengineer

......as randomly selecting tackle from the box and giving it a whirl........

You've just described my entire fishing process.

You saying there's a better way?

[1/4 stick]

Originally Posted by MississippiBoy

You've just described my entire fishing process.

You saying there's a better way?

There's been mention of a telephone before.

[CMorg]

This all sounds familiar...

http://www.bassfishin.com/bassfishin...ad.php?t=19010

[bonsaibp]

Originally Posted by Kevin

. Throw out the rule book, because if there's one thing I learned, bass don't play by our rule book!

Ain't that the truth.

[bassFishingWNY]

The turnover in the Great lakes, and finger lakes in NYS happen in the spring, and fall. I’m not too sure about water that’s not that deep? By that I mean 20-30 feet deep. But in NYS, that effects trout fishing. It sends the warm water down to the bottom, and the trout (brown) start heading for the creeks, spring for the rainbow.
But, this about bass fishing.
Kevin said he got fatter bass in the winter, could that be because the females are filling up with eggs? Or they eat better? I don’t understand all the scientific mumbo-jumbo, but bass hang in the weeds because they produce oxygen that bass need, gives them cover to hide in, and ambush food. If you read about bass, they don’t chase food in the summer, they lay in the weeds, and wait for the food to come to them. At night they go deeper, and in day light hot days, they go to the weeds to give them cover, and a place to ambush food. They don’t go deeper in hot days, no oxygen, no food. No weeds, they are under docks, any place were there is shade, and a place to hide.
Plants make oxygen, deep water don’t.

I know I’ll get slammed again, ask me if I care!!

[nofearengineer]

WNY,

Plants are actually responsible for taking more oxygen out of lakes than putting it in. This happens when they die and decompose, due to not being able to get enough light because of muddy water, quickly rising water levels, etc. Photosynthesis isn't really that big of a help, except in deepest Winter, when ice puts a thin cover on a lake, and the sunlight can still get through. However, fish don't need that much oxygen when it's super-cold anyway.

Bass hide in weeds for the protection it gives them, not any respiratory benefit.

As to Spring turnover, the effect is somewhat lesser than Fall. When the ice on the surface of lakes starts melting, yes, it makes for a cold layer on top, which then starts to trickle down to the bottom. However, the water can't move down until it melts at 32 degrees. The bottom of the lake is probably at 36-38 degress. This is a very small temperature differential to drive any sort of equalizing current. The reason it is more pronounced in the Fall is there is sometimes a 10-20 degree differential between the surface and the bottom.

Does this qualify as "slamming you?" I guess you'll be the judge of that.

[1/4 stick]

While I'm all for understanding and knowing the scientific data on bass, their habbits, and how water contitions, DO levels, PH levels...etc, affect the way they react. And I certainly can relate to nofearengineer's thoughts on getting the most out of what time you get on a lake. That's the reason I've all but given up on lake fishing and stuck to begging the local farmers and pond owners into letting me fish their ponds.

I still think nothing other than actual fishing experiance on each body of water will result in better fishing. You can read all the books, buy all the fish finders, and do all the tests you want. If you find three bodies of water with the exact same conditions, including DO and PH levels, the fish in each body of water will react different to what you throw at them.

[nofearengineer]

All I really want to do is record some levels in a journal each time I go fishing, and at some point in the future, try and make some sense of it. I'm sure most of the good pros have written some things down so they could analyze it later, to see if there was a pattern to it all. I'm not touting this as some "Hey! I figured it all out!" system of fishing. This is no magic pill.

[bassFishingWNY]

"Plants are actually responsible for taking more oxygen out of lakes than putting it in. This happens when they die and decompose, due to not being able to get enough light because of muddy water, quickly rising water levels".
Plants make oxygen, when the die, they make carbon. That is what you are made of, and all life on earth. It's the oil, gas, we need to live. I never heard that carbon took oxygen out. They stop making oxygen when they die.
OK, cigarettes kill, that's carbon dioxide, another story, fish don't smoke!
I think you are wrong!

[nofearengineer]

WNY,

Did you get your chemistry education from the Daily Kos or something?

Plant's don't "make" carbon. They use carbon from the CO2 in the air or water to build their tissues from. I know this, because I have run a home CO2 injection system in an aquarium to boost plant growth. It is rather complicated, balancing dissolved CO2 with pH and carbonate hardness, so I won't go into more detail than that; no need to get into the minutiae.

When plants die, they don't "release carbon", so much as their organic tissues begin to break down. In layman's terms, their carbon basically starts back on the road to recombining with the oxygen the plant separated it from while it was living. The bottom of many lakes is covered with thick layers of rotting leaves, fish waste, and other detritus. Any available oxygen here quickly gets snatched up by the decaying material, so there is almost nothing left for the fish to breathe.

In addition, lakes with too many plants can have night-time fish die-offs, because plants actually take in some oxygen during the night, and if there is no wind to stir the surface, oxygen levels can drop really, really fast. This is mostly a problem with less complex plants, such as filamentitious alge. I'm sure you've seen small ponds before that were absolutely clogged with algae mats, and mysteriously no bass over 6" in length. That's what's going on there.

Anyways, I think it's great you voice your opinion. That's what I'm doing, posting my opinion. However, if I post something of a scientific nature, most times you'd be well served to at least entertain the possibility I'm right. Debate is great too. I may not be as good of a bass fisherman as many guys on here, but I know water chemistry backwards and forwards.

[1/4 stick]

Originally Posted by nofearengineer

All I really want to do is record some levels in a journal each time I go fishing, and at some point in the future, try and make some sense of it. I'm sure most of the good pros have written some things down so they could analyze it later, to see if there was a pattern to it all. I'm not touting this as some "Hey! I figured it all out!" system of fishing. This is no magic pill.

hehehe.. I understand, and nothing wrong with it at all. I just wanted to point out that the only critter that maybe harder to figure out their habits scientificly would be women. And we all know where trying to do that gets us. lol

Seriously, if you do it, I for one would be interested in the results. Unless you've already said to yourself, "Screw em, I aint gonna tell those wise-___s anything."

[nofearengineer]

I'll make a deal with you.

If I figure bass out, I'll tell you the secret.

If I figure women out, I'm keeping that one to myself for a while.

[1/4 stick]

In all honesty.... I'd rather have the bass secret. I'm sure it will cost less for the gear and peripherals.