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More Muskie Fishing -> Muskie Biology -> Late fall fatties
 
Message Subject: Late fall fatties
esoxaddict
Posted 12/19/2017 3:20 PM (#887461 - in reply to #887460)
Subject: Re: Late fall fatties





Posts: 7034


Could be a result of how their diet changes throughout the season. We know they eat a lot of ciscoes late in the fall on lakes where they are available. We know half those ciscoes are as full of eggs as they get. Eat different foods = your matabolism changes = so does your poop. Makes sense to me.
Glaucus_
Posted 12/19/2017 3:52 PM (#887463 - in reply to #887460)
Subject: Re: Late fall fatties




Posts: 131



1) Due to a slowed digestive process in the fall (through whatever mechanism), the digestive enzymes have a longer period of time to work on the prey eaten by the fish, resulting in more calories being absorbed...and thus more calories being made available to be converted into musky biomass.

2) Due to a (relatively) more rapid digestive process in the warmer/summer months, the digestive enzymes simply don't have as much time to work on the ingested prey, and thus digestion isn't as complete. Thus there are undigested "lumps" of prey remaining in the fecal matter of the musky.


While acknowledging that this is all just mental masturbation by a non-expert, I'll point out that you got my idea exactly backwards.

I was suggesting:
- same rate of peristalis year-round. (constant)
- a slower enzymatic process in the cold water period (independent variable)
- less efficient digestion in cold water period (dependent variable) resulting in more wasted food as observed by chunkier feces with more identifiable parts (ie., it pushed out before being completed digested)
- under this hypothesis a fish would need to eat more food in the fall to obtain the same amount of calories
- and there are obviously other variables at play, such as reduced need for calories when metabolism is slower due to the cold and increased need for calories to provide energy to the growth of reproductive cells, etc.

tcbetka
Posted 12/19/2017 4:52 PM (#887467 - in reply to #887463)
Subject: Re: Late fall fatties




Location: Green Bay, WI
Glaucus_ - 12/19/2017 3:52 PM


1) Due to a slowed digestive process in the fall (through whatever mechanism), the digestive enzymes have a longer period of time to work on the prey eaten by the fish, resulting in more calories being absorbed...and thus more calories being made available to be converted into musky biomass.

2) Due to a (relatively) more rapid digestive process in the warmer/summer months, the digestive enzymes simply don't have as much time to work on the ingested prey, and thus digestion isn't as complete. Thus there are undigested "lumps" of prey remaining in the fecal matter of the musky.


While acknowledging that this is all just mental masturbation by a non-expert, I'll point out that you got my idea exactly backwards.

I was suggesting:
- same rate of peristalis year-round. (constant)
- a slower enzymatic process in the cold water period (independent variable)
- less efficient digestion in cold water period (dependent variable) resulting in more wasted food as observed by chunkier feces with more identifiable parts (ie., it pushed out before being completed digested)
- under this hypothesis a fish would need to eat more food in the fall to obtain the same amount of calories
- and there are obviously other variables at play, such as reduced need for calories when metabolism is slower due to the cold and increased need for calories to provide energy to the growth of reproductive cells, etc.



Yes, but their feces isn't as "chunky" in the fall, remember? It's more bird-crap-like: Pasty and sticks to everything. It's the summer feces that's chunkier, according to the reports in this thread. This would suggest to me that their digestive process might possibly be more efficient in the fall--due to prolonged period of digestive action. But I guess it depends upon the composition of the chunks I suppose. Since they are pretty much eating the same sorts of foods (proteins, fats and bones), without much "fiber" in their diets, the bulk-forming components of their diet wouldn't be as variable as you and I have. It's the changes in non-digestible fibers in our diet that (largely) tends to change the consistency of our stool. Eat more fiber, your gut tends to become more "regular" and your feces tends to be more solid and well-formed. Eat less fiber and your stools tend to be more irregular and softer in consistency. That said, there are other things that tend to cause our stools to be firmer for instance, like cheese...which constipates many people when eaten in significant quantities. Also, a rapid transit time like caused by conditions like irritable bowel syndrome or a viral infection would tend to cause soft stools and (ultimately) diarrhea.

Muskies obviously don't eat cheese--well maybe the ones in Green Bay might, but I'm betting not. But my point is that what they do eat is fairly consistent. Even though the species of prey might change throughout the year, it's still most likely to be some sort of fish species with protein, bone and a varying degree of fat content (the last of which can probably change stool consistency to some degree, I'd bet). Thus I think it's quite possible that the variations being seen/reported in stool consistency throughout the season might be more a function of transit time through the gut, and quite possibly also then as a function of degree of absorption of nutrients. I'm also betting that their digestive enzymes are able to break down bony tissue as well--although likely at a slower rate than soft tissues. Given that they have muscle tissue, they must have calcium ions--both for the action of their own muscles as well as for their own bone growth and development. That calcium has certainly to come from somewhere.

Finally, in humans a slow transit time through the gut usually means constipation, while a faster time usually means loose stools. But you're talking about an animal with over 15 feet of bowel--most of which is small bowel. Our large intestine is largely for the re-absorption of water...which will pretty much determine if your stool is softer or hard. Animals that are herbivorous (or partially so) tend to have a longer alimentary tract (gut) than carnivorous animals, and to my knowledge muskellunge would qualify as the latter. So I would expect their gut to be must shorter than ours is, relatively speaking.

Therefore although it's possible that softer stools might be caused by rapid transit times through the fish's GI tract, I bet it's actually the other way around. Since their gut is relatively short compared to their body length, it's likely that the consistency of the stool is indeed a function of 1) the food they're eating, and (I'll bet) more so 2) transit time through the alimentary tract. Also keep in mind that humans drink liquids, which will aid peristalsis and help keep stools more mobile. Freshwater fish are hypertonic compared to their environment, so they actually tend to have to expel water that gets absorbed across their skin through osmosis. In contrast, salt-water fish tend to lose fluids, as their blood is hypotonic with respect to their environment--so those fish have to "drink" water, which then gets desalinated by their gills. Point being that dietary liquid isn't likely going to influence the consistency of musky poop.

Anyway, that's enough. My head hurts and all this talk has made me hungry!
Larry Ramsell
Posted 12/20/2017 7:16 AM (#887514 - in reply to #884189)
Subject: Re: Late fall fatties




Posts: 1054


Location: Hayward, Wisconsin
How about if they loose calories by expelling food before it is completely digested, it is compensated for by the additional intake of forage that is forcing it out???
Glaucus_
Posted 12/20/2017 9:58 AM (#887557 - in reply to #887514)
Subject: Re: Late fall fatties




Posts: 131


tcbetka - 12/19/2017 4:52 PM
Yes, but their feces isn't as "chunky" in the fall, remember? It's more bird-crap-like: Pasty and sticks to everything. It's the summer feces that's chunkier, according to the reports in this thread.


Tom, I think you might have mis-read or mis-remembered the earlier posts?

For example:

Will Schultz - 12/8/2017 1:45 PM
Could they be crapping all over your boat because the rate of digestion had slowed so much that they're eating beyond their digestive rate? Late fall muskie poop is very different from summer muskie poop and appears to be less digested (more scales, bones, etc).


That's my experience too - visibly less digested in the fall.

Larry Ramsell - 12/20/2017 7:16 AM
How about if they loose calories by expelling food before it is completely digested, it is compensated for by the additional intake of forage that is forcing it out???


Yes, that's the hypothesis that Will put forward and we are exploring, Larry: that if their rate of (chemical? enzymatic?) digestion is slowed in cold water periods, but the movement in the digestive tract remains the same, then they'd possibly be passing through food items before they can be completely digested. To make up for lost calories, especially to provide energy to their growing reproductive cells, they would actually need to eat more in the fall in spite of generally lower activity levels.

Observationally, the fall brings short, intense feeding windows, and not nearly as much of the following and other energy "wasting" behavior that you might see in the summer. Spawning baitfish concentrations would help this, as muskies wouldn't need to move as much to find the food.
Larry Ramsell
Posted 12/20/2017 10:04 AM (#887558 - in reply to #884189)
Subject: Re: Late fall fatties




Posts: 1054


Location: Hayward, Wisconsin
But...they metabolize so fast in the summer, that it is impossible to know just how much forage is going thru their system...a real conundrum!
tcbetka
Posted 12/21/2017 9:32 AM (#887674 - in reply to #887557)
Subject: Re: Late fall fatties




Location: Green Bay, WI
I've clarified the post I had here--please see below.

Edited by tcbetka 12/21/2017 10:40 AM
tcbetka
Posted 12/21/2017 10:21 AM (#887677 - in reply to #884189)
Subject: Re: Late fall fatties




Location: Green Bay, WI
I had another thought (or two)...

First of all, I think that I was mistaken regarding the degree of decrease in gastric enzymatic activity as the water cools. If their preferred water temperature is around 70F, and we're fishing for them (in the fall) in water temperature of about 40F, then it's a swing of about 30F of cooling. So if enzymatic activity is cut in half for every 10F or so, then the rate of activity in the fall would be about 1/8th of that in the summer...give or take.

70F --> 60F = 1/2
60F --> 50F = 1/2
50F --> 40F = 1/2

Therefore: 1/2 * 1/2 * 1/2 = 1/8

So in all likelihood, they probably have a gastric enzyme rate of around 1/8th the rate of summer, when we're fishing for them in the fall. I didn't go back through the entire thread and read all my posts, but I believe I did the math wrong before. So I wanted to correct myself. This being said, it certainly supports a slowed rate of digestion in the fall.

Now then, in terms of the amount of feces we see them crapping out--I think that their intestines are more full in the fall, due to a combination of them 1) eating more (due to the opportunity) and 2) a *possible* delay in transit time through the bowel. I'm not convinced yet that their bowel slows significantly, for the reason(s) I mentioned in my post immediately proceeding this one. I think that the gastrocolic reflex is simply too strong for them to get (essentially) constipated because their body temperature is dropping. That wouldn't be good from an evolutionary standpoint.

Regarding how "chunky" their stool is or isn't in the fall, compared to the summer... I checked just now with my friend Jerry, and he indicated that he didn't see them crap in the boat as much in the summer as in the fall. That's my experience as well. I think they are eating more in the fall, so they have more waste in their intestine--so they crap more when they're handled. In terms of the consistency of said crap, I guess I can't really comment because I just haven't seen that much of it in the summer. In fact I also see more of it in larger fish, and I'm not used to catching larger fish in Green Bay in the summer. I think my average fish in the summer months out here is probably in the 42-43" range? I've never really kept track. But I will admit that when I was fishing a lot in the summer, it was NOT in the areas where guys have been catching big fish the past several years. I was sort of late to that party, and was concentrating more on the fall fishing areas, which (in my personal experience) didn't seem to have the bigger fish until Sept-Nov.

Edited by tcbetka 12/21/2017 10:24 AM
esoxaddict
Posted 12/22/2017 4:26 PM (#887814 - in reply to #887677)
Subject: Re: Late fall fatties





Posts: 7034


Do you suppose egg mass they are devolving in the fall could be compacting the digestive tract to the point where it effects the digestion process, so what whatever they eat is pushing out what they ate last time before it spends enough time in there to be fully digested?
Sudszee
Posted 12/23/2017 8:57 AM (#887840 - in reply to #887814)
Subject: Re: Late fall fatties




Posts: 19


Does a higher rate of dissolved oxygen in cold water vs summer months play a role in any of this?
tcbetka
Posted 12/23/2017 5:57 PM (#887913 - in reply to #887814)
Subject: Re: Late fall fatties




Location: Green Bay, WI
esoxaddict - 12/22/2017 4:26 PM

Do you suppose egg mass they are devolving in the fall could be compacting the digestive tract to the point where it effects the digestion process, so what whatever they eat is pushing out what they ate last time before it spends enough time in there to be fully digested?


Sort of the "pregnant women can't eat as much" idea? Hmmm, I suppose it's possible. To be honest I really don't know at what point the egg mass descends to the point where that might happen. I've never studied dead muskies throughout the egg-development cycle, so I can't say. I think my Larry would be the better guy to answer that question, as he's undoubtedly had more experience than me with that sort of thing.



Sudszee - 12/23/2017 8:57 AM
Does a higher rate of dissolved oxygen in cold water vs summer months play a role in any of this?


I'm not really sure I know what you're asking, but my take on it is that (to the degree possible) the fish will likely seek out water temperatures more to their liking in regards to the DO levels. In other words, I doubt they'll stay in water with low DO levels if they can help it. So in that sense, my answer would likely be "probably not".
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