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| Do muskies actually consume more fish before ice up and that's why they are so fat( besides eggs in females). Or is it due to slower metabolism with lower water temps? |
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| in my unscientific opinion, a lot of the fat fall muskies we catch are fat all year long but live most of the season in places where they don't run into anglers or baits very often. i never bought the theory that skinny or normal girthed muskies suddenly start eating all the time in the fall and that's why they put on weight. lots of the fattest fish we catch in the fall are also some of the cleanest fish of the year. obviously they feed heavier in the fall but a fish putting on a bunch of weight in the span of 4-6 weeks with cooling water temps just doesn't make that much sense. |
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Location: Ashland WI | I had actually thought they fed more in the summer when their metabolism was faster. |
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| Do males put on girth as well? |
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Location: Ashland WI | Sudszee - 11/13/2017 4:09 PM
Do males put on girth as well?
I'll leave this one for todd..... |
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Location: Green Bay, WI | I think they probably feed whenever they can, but they clearly capitalize on the spawning behavior(s) of the prey species they feed on--like Shad, Ciscoes (Lake Herring) and Whitefish. If those fish are congregated to spawn, experience has shown us that the muskies aren't far away. So yes, I do think they tend to feed a lot in the fall as winter approaches because, well, they can.
That said, I think they gain more weight in the fall because they're eating high-calorie prey at a time when their own metabolism has slowed. Simply put, they're eating more than they're using so they gain weight. And that's not a bad thing given that they need to devote (caloric) energy into gamete production. But again, since they're poikilothermic and their body temperature is within a degree or so of the water they're swimming in, their metabolism can't help but slow.
So essentially they're sitting on the couch in a cold room, watching television, eating little smokies and potato chips and not working out. You'd get fat too!
TB |
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Location: Chisholm, MN | If they bite more in the fall, why are they so freaking hard to catch? |
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Location: Eastern Ontario | Give me Sept 12 months of the year and I'm a happy man. In Nov and Dec its a lot of of fruitless hours hoping we encounter a monster that has spent the summer out in Lake Ontario feeding on Lake Trout and other deep water forage. Or as I call it fishing for Unicorns |
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Location: Green Bay, WI | Kirby Budrow - 11/14/2017 3:51 PM
If they bite more in the fall, why are they so freaking hard to catch?
I didn't say they bit more in the fall, only that they *ate* more... |
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| Egg mass is a factor. Slow metabolism is a factor. Also much of their food is also fatter and full of eggs in the fall, so they're getting a lot more out of a meal. They have to eat more often in warmer temperatures, but they are likely exerting a lot more effort to eat food that's not as substantial. |
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Location: Grand Rapids, MI | Without going and digging up past articles,etc. (meaning I'm not going to cite a source other than memory). I believe that most of the super fish harvested in October, November, December have relatively empty stomachs and lots of eggs. That leads me to believe that any actual "fat" is accumulated in late August and September as water temps drop. It appears very little feeding is happening late in the year. |
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Location: oswego, il | Based on most of the late fall and winter fish that crap all over my boat, i think they either do eat alot or digestion slows down more than what they have ate making them like most musky fisherman full of #*#*.
Males put on girth during the spawn if you know what i mean. 
Edited by ToddM 11/16/2017 2:09 PM
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| Will Schultz - 11/16/2017 1:21 PM
Without going and digging up past articles,etc. (meaning I'm not going to cite a source other than memory). I believe that most of the super fish harvested in October, November, December have relatively empty stomachs and lots of eggs. That leads me to believe that any actual "fat" is accumulated in late August and September as water temps drop. It appears very little feeding is happening late in the year.
I don't necessarily disagree with you, Will. But catching a fish with little or nothing in its belly might just be an indication that those fish were hungry and attempting to feed when caught. |
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Location: Already Gone | esoxaddict - 11/16/2017 2:14 PM
Will Schultz - 11/16/2017 1:21 PM
Without going and digging up past articles,etc. (meaning I'm not going to cite a source other than memory). I believe that most of the super fish harvested in October, November, December have relatively empty stomachs and lots of eggs. That leads me to believe that any actual "fat" is accumulated in late August and September as water temps drop. It appears very little feeding is happening late in the year.
I don't necessarily disagree with you, Will. But catching a fish with little or nothing in its belly might just be an indication that those fish were hungry and attempting to feed when caught.
Yes. I have to agree with Jeff. The ones that I am lucky to boat in mid to later November were feeding on spawning ciscoes. I know this, because I was puposely live bait fishing for them...with ciscoes. In popular spawning areas. Along with Bondy baits, imitating spawning/struggling ciscoes. Along with several other guys, doing the same. It's kind of a known tactic, and if you can stand the weather, it's semi-productive if done right.
I have to assume that they were hungry. What else would they be doing attacking my bait presentation.? |
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Location: Green Bay, WI | Will Schultz - 11/16/2017 1:21 PM
Without going and digging up past articles,etc. (meaning I'm not going to cite a source other than memory). I believe that most of the super fish harvested in October, November, December have relatively empty stomachs and lots of eggs. That leads me to believe that any actual "fat" is accumulated in late August and September as water temps drop. It appears very little feeding is happening late in the year.
Most of the big fish I've caught in Green Bay in October/November are crapping all over the place in the boat, lol. So that certainly means they've been feeding--hard to have fish poop on an empty stomach. That being said, if their metabolism is slower due to cooler water temperatures, it must not be *that* much slower if there's no food in their stomach. I've never seen anything in the literature that quantifies the degree to which their metabolism slows, but I would have to think that it doesn't slow all that much if 1) they're pooping all over the boat, with 2) an empty stomach.
So I think they are basically converting forage into biomass just as quickly in the fall as they are in the summer, for the most part. But in the warmer water of summer it takes more of those calories just to keep the lights on...and therefore they don't put on the weight during those months. |
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Location: Already Gone | tcbetka - 11/16/2017 6:16 PM
Will Schultz - 11/16/2017 1:21 PM
Without going and digging up past articles,etc. (meaning I'm not going to cite a source other than memory). I believe that most of the super fish harvested in October, November, December have relatively empty stomachs and lots of eggs. That leads me to believe that any actual "fat" is accumulated in late August and September as water temps drop. It appears very little feeding is happening late in the year.
Most of the big fish I've caught in Green Bay in October/November are crapping all over the place in the boat, lol. So that certainly means they've been feeding--hard to have fish poop on an empty stomach. That being said, if their metabolism is slower due to cooler water temperatures, it must not be *that* much slower if there's no food in their stomach. I've never seen anything in the literature that quantifies the degree to which their metabolism slows, but I would have to think that it doesn't slow all that much if 1 ) they're pooping all over the boat, with 2 ) an empty stomach.
So I think they are basically converting forage into biomass just as quickly in the fall as they are in the summer, for the most part. But in the warmer water of summer it takes more of those calories just to keep the lights on...and therefore they don't put on the weight during those months.
I like this explanation. it's an interesting discussion.
I also want to say that I enjoy your posts Tom...I for one, am glad to see you back on here again.
Thanks.
Mark |
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Location: Green Bay, WI | Mark Hoerich - 11/17/2017 8:43 AM
I like this explanation. it's an interesting discussion.
I also want to say that I enjoy your posts Tom...I for one, am glad to see you back on here again.
Thanks.
Mark
You're welcome Mark--and thanks for the comment! It's nice to be back on the board again, now that my "home remodeling & construction" season is finally coming to an end. There's only so much of that a guy can take, and I reached my limit well over a month ago...
TB |
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| I catch them on Suckers in late OCT all the way to freeze up--usually mid Nov here in N.WI..... They sure like those 16-18" live suckers in the fall---- And many times they swallow them almost instantly-- So I know they are feeding...... And I fish the same lakes throughout the season----- I definitely catch Fatter and Heavier fish from say Mid-Sept to Ice up than any other time of the season...And My Biggest Fattest fish always come very late in the season......If someone thinks they don't feed heavily in the Fall then that person has never done much musky fishing THROUGHOUT a whole fishing season....I also agree that while they may slow down some as the temp falls.. I don't think its that much.....Many Still Fight Like Hell in the cold water |
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Location: Green Bay, WI | Throughout the animal kingdom there are examples of creatures feeding vigorously with the approach of winter, in order to increase their fat stores as a means of survival. Bears, squirrels, bats, hedgehogs, and (according to Google) any number of other creatures. Heck, even my two dogs want to eat more in the fall as winter approaches. Therefore it seems quite reasonable to assume that fish are doing the same. And it shouldn't take much to do, given (as mentioned above) decreasing water temperatures result in a slower metabolism by default.
My only other point was that if a musky is crapping all over your boat when caught, then they have food in their GI tract. So they must be feeding in order to put food into said GI tract, because there is no other way to get food into the lower GI tract. And if taxidermists are reporting empty stomachs in fish caught in the fall (and then submitted for taxidermy), then it's not too much of a stretch to infer that the fish's GI tract is working at a pretty good rate...even in the fall.
Colder water (decreased metabolism) plus schooled prey (less energy expended for a meal) equals fatter muskies, by my thinking. |
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| So, it sounds like stomach acid does its thing and metabolism slows at lower temps causing fat stores. Makes sense. I'm not convinced the eat more though. You would think they would be easier to catch and more would be caught. |
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Location: Green Bay, WI | Well I believe the thought is that, by focusing on schools of pre-spawn and spawning prey (Cisco, Whitefish, Shad, etc), their prey is simply more abundant--so they eat more calories, just for that reason alone. And from an evolutionary standpoint, this would seem to make sense. Life is about energy management, and the more energy an organism can conserve...the better it usually does in the long run. I'm not talking about humans who have something of an "artificial" energy management system, but rather more along the lines of hunters & gatherers.
All living organisms need energy to survive. That energy comes from the metabolism of glucose, fats and protein, for the most part. Certainly it involves oxygen to a large degree (for aerobic metabolism anyway), but in aerobic organisms the fuel for ATP (ie; energy) production is basically glucose. Proteins in the diet are broken down into amino acids which can then be used by the organism as building blocks for their own muscle mass, but energy to drive the organism is largely from adenosine triphosphate. Since this is the fuel that drives the bus so to speak, pretty much all biological processes require it to continue.
So the thing to realize is that it takes energy to make energy. When a musky has to chase down food, that takes energy. Muscles need ATP to make the fish move. Their brain needs ATP to keep the lights on and drive their activities. Their red blood cells require ATP to bind oxygen, and their heart certainly needs ATP to circulate that blood to all parts of their body. In other words--it takes energy to go get energy. There's no way around it. Period. We use the concept of "calories" to describe it, but it all comes down to the production of ATP in the cells that require it to power them.
So the take-home point is that if a musky has to chase down a single 5-6" shad and burns more calories doing so than it gains from ingesting that single shad...it's running on an energy deficit. That's not the way to maintain life. So it should come as no surprise that the fish have learned (through evolution for the most part) that when cisco and whitefish school to spawn in the fall, it takes less energy to get a meal than it does to chase them down one by one. I doubt the fish think it through like that, but it's the end result nonetheless. Why spend 100 calories getting 200 from a single shad, when you can spend 200 to get 2000 calories eating 10 shad from the same bait ball? That sort of thing. In the first case you only double your energy spent, but in the latter instance you recover ten-fold your investment.
Sorry for the long answer, but I needed a more lengthy response to explain why (physiologically) I think we see these fish doing what they seem to be doing in the fall.
EDIT: I forgot to mention Sudszee, that I don't believe the rate of the enzymatic reaction(s) in the musky's GI tract decreases much as the water temperature drops. As with all enzymatic reactions that I know of, an increase of about 10 degrees Centigrade (10C) will virtually double the rate of the reaction catalyzed by those enzymes. Certainly different enzymes have different temperature-dependent coefficients, but we can use 10C as an example as it equates to an easy-to-remember 50F. So if it gets 10C cooler, then the rate of the reaction(s) will be roughly halved. But the thing is that 10C (50F) is a BIG drop in water temperature--so in all likelihood we're not talking about gastric enzyme-induced reactions that are actually halved in terms of rate. This is supported by the observations that we've already been talking about: The observations that 1) many fish crap all over the boat when they're feeding a lot, 2) many fish caught in the fall crap all over my boat (thanks PointerPride), and 3) taxidermists apparently often report that large fish caught in the fall are found to have an empty stomach.
So this tells me that while the fish's overall metabolism is likely diminished in the fall due to falling water temperatures, the rate of digestion likely isn't.
Edited by tcbetka 11/22/2017 5:22 PM
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| If I remember correctly the biological explanation lies with the shift in metabolism, slowing as the water cools. They don't eat more but move less. Maybe this explains the short fall feeding windows. |
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Location: Green Bay, WI | I'm really not sure how much of a drop they have in metabolism, to be honest. Like I mentioned above--the biological reactions in metabolism (Citrus Acid Cycle, for example) are all mediated by enzymatic activity. And when you consider that it likely takes an 8-10C (46-50F) degree drop to halve the activity of most of these enzymes, then how much a decrease in "metabolism" is there really?
If summer water temperatures are in the 70-80F range, for the sake of discussion, and then the water freezes at 32F, that's a difference of about 40-50F. But the water temperatures in the fall are typically in the 40-45 degree range when the Ciscoes are spawning--and almost 50F when Whitefish spawn. Therefore compared to the summer water temps when we consider the fish's metabolism to be highest, we're talking about a drop of about 30-40F. Thus it doesn't seem as though the fish's metabolic rate is slowed as much as we might think--and again, the fish are still crapping all over the place when you handle them...so certainly their gut metabolism seems to be working pretty well.
Edited by tcbetka 12/3/2017 12:20 PM
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| While it is known that temperatures effect enzymatic activity of many enzymes in a gaussian dependence, I agree that direct manipulation of enzymatic turnover due to temperature is unlikely. This metabolic shift does occur during acclimation to cold temperatures and causes major changes in phosphorylation state of many mitochondrial enzymes. This is specifically true in the liver, gills and brain. You can also imagine that the membrane composition would be altered to maintain the fluid mosaic needed for oxphox and even the citric acid cycle due to increased protein density seen in mitochondria in fish exposed to cold temperatures.
I haven't seen any data that argues against a change in eating habits in response to temperature acclimation as it is indicated in multiple studies (will come back and add citations can't remember off hand), where there is an increase in pentose phosphate pathway in response to an increased need for fatty acids, perhaps for gametogenesis.
I would suspect after more reading that there must be some truth tcbetka to a shift to increased consumption during acclimation to cold temperatures. After reading it seems likely that this increase "appetite" would then return to baseline after sustained cold temperatures.
This is an interesting subject and I will devote more time to reading papers about this. |
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Location: Grand Rapids, MI | esoxaddict - 11/16/2017 3:14 PM
Will Schultz - 11/16/2017 1:21 PM
Without going and digging up past articles,etc. (meaning I'm not going to cite a source other than memory). I believe that most of the super fish harvested in October, November, December have relatively empty stomachs and lots of eggs. That leads me to believe that any actual "fat" is accumulated in late August and September as water temps drop. It appears very little feeding is happening late in the year.
I don't necessarily disagree with you, Will. But catching a fish with little or nothing in its belly might just be an indication that those fish were hungry and attempting to feed when caught.
The original post was asking why they're so fat. I was attempting to explain that it's eggs and not fat or a belly full of fish that is making them heavy. |
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| I've never seen a fish pictured in late fall that doesn't appear to be larger (fatter) than let's say, summer. All of them can't be females pictured. |
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Location: Grand Rapids, MI | This relates to pond fish (koi) but should still be applicable because cold blooded is cold blooded
In warmer water (60-85 degrees) the metabolism of the fish is high and they can be fed 2-4 times per day. At this time you should be feeding a food with a high protein level such as Pond Care Summer Staple Food. If the water rises to 90 degrees or above you should stop feeding. In spring and fall when your water temperatures fall to 50-60 degrees, you should reduce feeding to once every 1-2 days and feed a low protein food such as Pond Care Spring and Autumn food. When the temperatures drop to below 50 degrees stop feeding the fish. On warm days the fish may become active and "beg" for food. Don't be fooled. Stay strong and do not feed. If the fish do need a little food, they will find enough growing in the pond. The algae that coats the pond liner is all they need. These cold temperatures slow the metabolism of your fish and food will not be properly digested. It can take 3-4 days for the fish to digest the food. It's not worth the fish's life to give it food.
http://www.watergarden.org/Pond-Info/Fish-Care-Feeding
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Location: Grand Rapids, MI | Sudszee - 12/7/2017 1:10 PM
I've never seen a fish pictured in late fall that doesn't appear to be larger (fatter) than let's say, summer. All of them can't be females pictured.
They're all going to be heavier if they only need to eat once every three days versus three times each day but the really fat appearing fish will all be females. Generally speaking most over 42" are females (though exceptions exist in certain locations/strains). |
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Location: Green Bay, WI | bbeaupre - 12/6/2017 4:12 PM
SNIP...
I haven't seen any data that argues against a change in eating habits in response to temperature acclimation as it is indicated in multiple studies (will come back and add citations can't remember off hand), where there is an increase in pentose phosphate pathway in response to an increased need for fatty acids, perhaps for gametogenesis.
I'm not sure that I follow what you're saying in that paragraph. Are you saying that *are* changes in eating habits when the water temperature changes and the fish acclimate accordingly?
I would suspect after more reading that there must be some truth tcbetka to a shift to increased consumption during acclimation to cold temperatures. After reading it seems likely that this increase "appetite" would then return to baseline after sustained cold temperatures.
This is an interesting subject and I will devote more time to reading papers about this.
I think there is as well. I think muskies, like most other predators, are likely opportunists to some degree. And over eons of time, they've just gotten conditioned to taking advantage of what nature gives them. So if there is a substantial tulibee spawn going into the winter, then the fish will take advantage of that.
Isn't it interesting how nature works--muskies (and other spring-spawning predatory fish) need to take in calories in the fall for gamete development, and nature obliges by giving them prey that schools when spawning. Awesome stuff!
TB |
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| tcbetka - 12/7/2017 6:17 PM
bbeaupre - 12/6/2017 4:12 PM
SNIP...
I haven't seen any data that argues against a change in eating habits in response to temperature acclimation as it is indicated in multiple studies (will come back and add citations can't remember off hand), where there is an increase in pentose phosphate pathway in response to an increased need for fatty acids, perhaps for gametogenesis.
I'm not sure that I follow what you're saying in that paragraph. Are you saying that *are* changes in eating habits when the water temperature changes and the fish acclimate accordingly?
I haven't seen any studies that say definitively that eating habits do NOT change. There are multiple that suggest they do during the acclimation stage, but do not suggest mechanism.
There are multiple studies that confirm significant metabolic changes that occur during during acclimation to lower temperatures. It seems that it is still largely unknown how this impacts homeostasis of the fish, but my hypothesis is that this change may funnel more resources into pathways (largely hepatic ) that lead to storage (fat ) perhaps by blunting the TCA cycle or directly preventing conversion of Glyc-3-P to pyruvate. Another possibility would be to force acetyl coA toward the lipid pathway away from TCA cycle and conversion to citrate.
It seems that this could be done directly at the enzyme targets of both pathways or indirectly by blunting the TCA cycle. This is interesting because the result of decreased flux through the TCA cycle which results in lower levels of NADH, GTP and other reducing equivalents ultimately leading to a decrease in available ATP.
Sorry for long winded answer, hope this is more clear on my thoughts.
Edited by bbeaupre 12/8/2017 12:19 PM
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