Thermal Considerations
BrianF.
Posted 11/7/2014 2:38 PM (#738867)
Subject: Thermal Considerations




Posts: 284


Location: Eagan, MN
One of my fishing partners recently said something to me in passing that has me thinking.

"Probably ninety percent of your musky catches are thermal related."

So, what did he mean by that? What do we know of the musky and thermal needs or regulation? Is there any research in this area? What about your anecdotal observations? If there is a thermal connection, how can we, as anglers, use this to our advantage?

Tell us what you know about muskies and thermal needs.

Brian
esoxaddict
Posted 11/7/2014 3:37 PM (#738875 - in reply to #738867)
Subject: Re: Thermal Considerations





Posts: 8719


Hi Brian.

I've noticed a few things over the years that might be related to this. When fishing cooler water in the spring and early summer, we find most of our fish activity in the warmest water. The same thing happens in the fall prior to turnover. If you can find a spot on the lake that's been in the sun for most of the day, even if that water is only 2 degrees warmer than everywhere else, that's where the fish seem to be.

Early to mid summer as the fish are transitioning from the shallow weedy areas to the bars and points, we've found a lot of back and forth movement, but once the surface temps get over about 72 across the board, the fish are out deeper, now presumably looking for cooler water. A buddy and I had a discussion recently about fishing rocks during the transitions during the 68 - 72 degree water period, and how a cold night can push them back into the weeds. Conversely, a hot day seems to push the weed oriented fish onto the rocks. An interesting discovery for both of us was that the very first rock-oriented fish that turn up after a cold spell during this time seem to show on on the dark colored bars and points - black rock. Our theory there is that the dark colored rock absorbs a lot of heat from the sun, effectively giving them a nice warm place to hang out.

So I think the thermal related theory holds some merit. It seems to me that water temps under 68 leave muskies looking for warmer water, and over 72 has them looking for cooler water. In between is where we see the most variety on where we're finding fish from day to day. When you find 70 degree water is often where you will find fish on all different types of structure.

That could all be related to baitfish movements, though. Maybe their food seeks out those temperatures and they just follow.

Either way, it seems to me that the range of 68-72 is what they're looking for. If the water is significantly warmer than that, they are looking for cooler water. If it's significantly cooler than that, they are looking for warmer water.

I don't know of any research to that end, but it would appear that they do have a "comfort zone"...



Edited by esoxaddict 11/7/2014 5:57 PM
Larry Ramsell
Posted 11/8/2014 9:45 AM (#738975 - in reply to #738867)
Subject: Re: Thermal Considerations




Posts: 1275


Location: Hayward, Wisconsin
On a related note, during my tracking work on Eagle Lake, I learned that the bigger fish feed mostly in deep water where Cisco's were and then went to the warmer shallow weedy bays...to digest? Likely...the water in the weedy bays was as much as 10 degrees warmer than where they were feeding on Cisco's!

During the hot month of July, the big girl I followed made a 10 mile circle from deep to shallow and back every 3 days!
sworrall
Posted 11/8/2014 1:56 PM (#739016 - in reply to #738867)
Subject: Re: Thermal Considerations





Posts: 32791


Location: Rhinelander, Wisconsin
Interesting. Do you think we are catching those shallower muskies on Eagle as the are up digesting their last meal, and are triggering them to strike when they really have no need to eat?
Larry Ramsell
Posted 11/8/2014 2:21 PM (#739021 - in reply to #738867)
Subject: Re: Thermal Considerations




Posts: 1275


Location: Hayward, Wisconsin
During the summer, yes Steve I believe that may be the case. Triggering them by a lure landing close by and instinct taking over or they have finished digesting and not yet left the shallows or are on the way out.

In attempting to catch them (to enable us to sedate them and pump their stomach) with a barbless single hook lure, I was never able to get one to hit in the shallows. They would follow (except for the large males) but never hit.

In the late fall when the cisco's move in to spawn, all bets are off.

Also, I found in mid September, they started moving back toward the spawning areas...closest to them that they had been all season. Two other tracking studies that I am aware of showed that females moved to the spawning areas late in the year, near to where they would spawn the following spring.
BrianF.
Posted 11/8/2014 6:00 PM (#739050 - in reply to #738867)
Subject: Re: Thermal Considerations




Posts: 284


Location: Eagan, MN
Larry, I have a theory about those sunbathing muskies that are trying to warm themselves. I think the warming may serve a dual purpose; that is, to perhaps aid digestion and/or to prepare them for foraging. Other cold blooded animals warm themselves prior to foraging in cold water. Why not muskies? I have found that there is research about thermo regulation in fish and apparently warmer water allows fish to swim faster. Would muscles warmed in the shallow sun baked water provided an advantage to the muskies vs. cooler holding prey fish when foraging? Do they warm themselves in anticipation of this activity? While not proof of this, I have witnessed muskies feeding on open water forage very close to where they have been sunbathing, so wonder if there is a connection to warming stations and key foraging locations. Did you see any evidence of this in your tracking efforts? Do warming stations tend to be in close proximity to where they forage as I have observed? A 10 mile round trip wouldn't seem to support this BS theory.

EA, are your observations that muskies attempt to remain in their preferred temp range, as best they can, and regulate themselves accordingly by changing their location? I'm thinking Larry's tracking studies may also suggest this to some degree? The dark rock observation is very interesting. Do you find current to play into the dark rocks they use? Are they in calmer areas to help preserve the heat? Or is that not necessary?

Curious too about how seasonal water temps affect thermo regulation in muskies. They sure don't seem to have the same type of behavior relative to warming themselves in the shallows in the mid- to late-fall like they do in the summer months.

Brian
mnmusky
Posted 11/9/2014 9:19 AM (#739145 - in reply to #738975)
Subject: Re: Thermal Considerations




Larry Ramsell - 11/8/2014 9:45 AM

On a related note, during my tracking work on Eagle Lake, I learned that the bigger fish feed mostly in deep water where Cisco's were and then went to the warmer shallow weedy bays...to digest? Likely...the water in the weedy bays was as much as 10 degrees warmer than where they were feeding on Cisco's!

During the hot month of July, the big girl I followed made a 10 mile circle from deep to shallow and back every 3 days!


How are muskies tracked? A 10 mile circle is interesting.. is there some sort of electronic device attached to them like ive seen on sharks where they bolt an electronic data recorder/gps unit to their dorsal? thanks.
Larry Ramsell
Posted 11/9/2014 9:20 AM (#739146 - in reply to #738867)
Subject: Re: Thermal Considerations




Posts: 1275


Location: Hayward, Wisconsin
BrianF: What you have stated is basically what I said with the exception of the 10 mile round trip...that trip covered several "feeding stations" and I don't think that in the warmer waters of summer that too excessive. Also, this was the largest muskie I tracked...the smaller ones didn't travel that far. However, it was probably only 4 or 5 miles in a direct line from the shallows, but the was considerable distance compared to "next to".

My suspicion is that muskies feed most in summer/hot months when digestion is much faster than fall. Yes, they "bulk-up" in the fall, but I believe that to be a factor of easy prey and slower digestion and not because they are feeding more than in the summer. Only thing I have seen slow them down in the summer...at times...is when it gets too hot. But even then they still feed to their own detriment as thermal stress does kill some in very hot weather/water. I just don't think they can help themselves in the "too hot" water and that is why many don't fish them when the water temps get over 80 degrees and the southern guides move north.
esoxaddict
Posted 11/10/2014 12:10 PM (#739381 - in reply to #739050)
Subject: Re: Thermal Considerations





Posts: 8719


BrianF. - 11/8/2014 6:00 PM

EA, are your observations that muskies attempt to remain in their preferred temp range, as best they can, and regulate themselves accordingly by changing their location? I'm thinking Larry's tracking studies may also suggest this to some degree? The dark rock observation is very interesting. Do you find current to play into the dark rocks they use? Are they in calmer areas to help preserve the heat? Or is that not necessary?

Brian


Brian, it sure seems like it. On the rocks, in the weeds, on the rocks, in the weeds, back and forth from day to day. It's happened enough times where I started looking at the previous day's/nights weather and current surface temps trying to figure out why "they were here yesterday, and today they are over there." Multiple sightings of the same fish over the course of a week confirmed my suspicions that it was the same group of fish moving in between those areas.

The black rock fish? That was something that we only noticed in the morning. As the sun got higher and the day (and surface temps) warmed up to 71, they scattered a bit.

As for current, I think that always comes into play. They are going to relate to structure based on natural current and wind induced current no matter what.

But there seems to be a direct correlation to water temperature and what areas they will be inhabiting, and why they move around in the same area over the course of several days.

A good spot is a good spot, and they're going to use it. It's just a matter of figuring out when they are likely to be moving up onto it to feed, and when they might be 30 yards away in the weeds or 30 yards out on a hump. I'm thinking water temperature plays a big role in that.
jlong
Posted 11/11/2014 9:52 AM (#739554 - in reply to #739050)
Subject: Re: Thermal Considerations





Posts: 1937


Location: Black Creek, WI
BrianF. - 11/8/2014 6:00 PM
Curious too about how seasonal water temps affect thermo regulation in muskies. They sure don't seem to have the same type of behavior relative to warming themselves in the shallows in the mid- to late-fall like they do in the summer months.

Brian


Post turnover the lake is generally the same temperature top to bottom. Thus, I think the need to sunbath in the summer months may be indicative of the need to travel through temperature gradients to find the food they prefer (cisco can be below the thermocline). Cold Blooded creatures need stability and even a few degrees can be significant. Thus, I'm sure they still sunbath to some extent in the cooler water periods, but probably not as intensely when a LARGE temperature gradient exists in their homeland like that found during the summer.
MstrMusky
Posted 11/11/2014 10:34 AM (#739558 - in reply to #739016)
Subject: Re: Thermal Considerations




Posts: 156


sworrall - 11/8/2014 1:56 PM

Interesting. Do you think we are catching those shallower muskies on Eagle as the are up digesting their last meal, and are triggering them to strike when they really have no need to eat?

Steve, not sure how much you've fished Eagle, but this is what Steve Herbeck has been saying for years. "You gotta pee em off, cause they aren't eating where we are fishing."

Larry, in your study on Eagle, what was the average depth of the ciscoes and feeding muskies during the day out in the open water in July/August on relatively sum days? And then was there a "usual" time they started rising in the water column later in the day? If one were to troll the "abyss" out there on sunny days, how deep would you run the baits?

Edited by MstrMusky 11/11/2014 10:35 AM
Larry Ramsell
Posted 11/11/2014 12:49 PM (#739597 - in reply to #738867)
Subject: Re: Thermal Considerations




Posts: 1275


Location: Hayward, Wisconsin
MstrMusky: found cisco's at all depths (max basin depth was 50 feet but most was less than 33 feet). Even saw muskies feeding on them on/near the surface. During tracking, if a transmitter muskie was not moving, there was usually a school of bait nearby, otherwise they were always on the move across the abyss. They certainly didn't need to follow structure to go from point A to point B! When in the bay areas, they usually followed the 18 foot contour and deeper in the bays the 13 foot weed edge. I didn't attempt to monitor the times the cisco's came up to the surface, but they didn't have to be there to be fed on by the muskies.

Made an interesting observation one day after a severe cold front. A small weed bed that the day before had been on the surface was GONE! Actually "sunk" a few feet by the cold...and guess what? One of the transmitter fish was buried under those weeds. Fun/interesting stuff.
jlong
Posted 11/11/2014 1:16 PM (#739601 - in reply to #739597)
Subject: Re: Thermal Considerations





Posts: 1937


Location: Black Creek, WI
Do muskies exhibit behavioral thermoregulation? Is this what those MN Sunbathers are doing? Check this link out: http://www.earthlife.net/fish/tregulate.html

Recognizing that fish are Ectotherms tends to explain many of the fish movements that I've observed over the years. Or at least "I" think so....

http://esi.stanford.edu/temperature/temperature3.htm

The feeding aspect of muskies has been in the limelight for most anglers, however that is a pretty small window of opportunity. Thus, I've spent a good portion of my fishing experimentation around identifying other locations that muskies use the majority of the time... which in many cases is NOT related to feeding. Or, to recognize locations that they may not use for long periods of time, but makes them more vulnerable to angling (in a general sense, this usually means shallow).
14ledo81
Posted 11/11/2014 3:01 PM (#739630 - in reply to #739558)
Subject: Re: Thermal Considerations





Posts: 4269


Location: Ashland WI
MstrMusky - 11/11/2014 10:34 AM

sworrall - 11/8/2014 1:56 PM

Interesting. Do you think we are catching those shallower muskies on Eagle as the are up digesting their last meal, and are triggering them to strike when they really have no need to eat?

Steve, not sure how much you've fished Eagle, but this is what Steve Herbeck has been saying for years. "You gotta pee em off, cause they aren't eating where we are fishing."

Larry, in your study on Eagle, what was the average depth of the ciscoes and feeding muskies during the day out in the open water in July/August on relatively sum days? And then was there a "usual" time they started rising in the water column later in the day? If one were to troll the "abyss" out there on sunny days, how deep would you run the baits?


The $1,000,000 question for me then is "What is the best way to tick them off?"
sworrall
Posted 11/11/2014 6:02 PM (#739666 - in reply to #738867)
Subject: Re: Thermal Considerations





Posts: 32791


Location: Rhinelander, Wisconsin
According to Herbie in a conversation in Herbie's Lund he and I had, he feels it's motion, and lots of it. MOVE that lure...even a sucker..and hope the Muskie plays, in Herbie's words, "Cat and mouse". The mouse stops moving, and the cat loses interest. It doesn't have to EAT the mouse, only bite it.

I have direct evidence that fish sometimes react exactly as Herbie claims (basically a strike response) on hundreds of hours of Ice video.
esoxaddict
Posted 11/11/2014 9:29 PM (#739702 - in reply to #739666)
Subject: Re: Thermal Considerations





Posts: 8719


They are programmed to eat. They are programmed to chase down their prey and make sure it doesn't get away. I spent my youth fishing clear water, watching fish of all species eat and get eaten. The one thing I noticed that stuck with me is that fish seldom eat anything that just sits there, or moves very slowly. There was a good population of bass that liked to hang out in the milfoil around the boat slips. We spent entire days digging crayfish out from the rocks and feeding those bass. What we learned was that if you drop a crayfish in the water, and they freeze, they can sink to the bottom without much attention from surrounding fish. When we dropped them in the water and they immediately swam, none of them got far.

It's the same reason that the best live bet is fresh caught. Be it shiners, suckers, dace, red tail chubs, the best bait is the bait that swims like mad trying to get away.

Translating that into musky fishing, if it's "getting away", it's getting eaten. There are times when you need to slow down and put a lure right in their faces and give them a chance to eat it. But for the most part, the second a musky senses that your lure is "getting away", it's gonna eat that lure.
jlong
Posted 11/12/2014 11:35 AM (#739786 - in reply to #739702)
Subject: Re: Thermal Considerations





Posts: 1937


Location: Black Creek, WI
If you believe fish are using a location for reasons OTHER than to feed... then of course your presentation may require some alterations.

Before moving on to a discussion about presentation... I'd like to further understand why fish may be using some very PREDICTABLE locations for reasons other than to feed... so I can identify more opportunities to target.

You can't catch what isn't there... so let's not rush ahead to the "P" in the In Fisherman Equation (Fish + Location + Presentation = Success). I'd like to connect F and L together.... for when a fish is NOT feeding... as the majority of their life is spent digesting, not consuming. Digesting periods are a much LARGER window than actual feeding windows.
BrianF.
Posted 11/12/2014 12:16 PM (#739797 - in reply to #738867)
Subject: Re: Thermal Considerations




Posts: 284


Location: Eagan, MN
Jason, I prefer the modified and improved version of the In-Fish formula...F+L+P+T=S. The 'T' stands for timing. You can't catch what IS there, but not inclined to chase or eat. Seen it all too often! Fish when the fish are feeding to improve on the success formula.

Sorry for the distraction. Carry on...



Brian
jlong
Posted 11/12/2014 12:53 PM (#739807 - in reply to #739797)
Subject: Re: Thermal Considerations





Posts: 1937


Location: Black Creek, WI
BrianF...... agreed.
esoxaddict
Posted 11/12/2014 1:30 PM (#739819 - in reply to #739797)
Subject: Re: Thermal Considerations





Posts: 8719


Here's a fun analogy on finding the fish:

A good spot is like a restaurant on a Saturday. During the "feeding windows", they're all in the restaurant eating. After that? They're still hanging around, and some will eat more just because it's there. Once they've gone home to lie on the couch, (the sunbathers) feeding time is over. There are a few that show up early, and a few that come late, so there's a time before and after "feeding time" where some are eating. While we like to think the feeding windows happen in a flash, it's more of a bell curve. You start seeing a few lazy fish, and a few more, and then they really start chasing your lures, then they start eating. And it tapers off gradually after that.

It's the time PRIOR to that that we largely ignore. The restaurant is empty, but they are starting to hang around in the parking lot. They're hungry, and they will feed. They're still relating to that structural element, they're just off it a ways. But casting into the restaurant while they're behind you in the parking lot isn't getting you a fish in the net. It's those times where I think we'd be better served to work our spots from a cast length out in deeper water, or even inside-out. They're hanging around the food, but they're not in it or on top of it yet.

Prior to the "parking lot" phase, they're on the move. They're on their way to the restaurant. If you can pinpoint the likely travel routes between the main lake basin/deep water and the "restaurant", you should contact some fish.

An interesting side note:

We've had days where nearly every fish we saw followed our lures, didn't make a turn, went under the boat and just kept right on going. We ran out of daylight before we figured out where they were going, but they were going somewhere. Spot after spot after spot, we were just pulling them off of points and bars. I don't think one turned around and went back.

Edited by esoxaddict 11/12/2014 1:36 PM
jlong
Posted 11/12/2014 1:46 PM (#739826 - in reply to #739819)
Subject: Re: Thermal Considerations





Posts: 1937


Location: Black Creek, WI
EA,
Nice analogy. However, in some lakes... I think you have your restaurant and parking lot backwards.

In some lakes, they feed in the basin (parking lot) and lounge/digest on the couch (shallow structure).

In lakes where the basin is so massive it is almost futile to fish for the feeding muskies out there... your only option is to find structures where the basin dwelling food makes contact with structure on a regular basis.... or to learn how to catch muskies that are NOT actively feeding (target them in the parking lot).

10 years ago while fishing Lake Vermilion for the Simply Fishing Tournament... there was a group of VERY experienced Canadian Trollers staying at the same resort I was using. They trolled the lake for 10 days prior to the event... and didn't catch a single musky. I was shocked to learn this as I firmly believe that the majority of musky feeding activity occurs out in the basin on this lake. If fishing where they feed is the most productive approach... why did these guys fail so miserably? Their own assessment was that they spent too much time dragging baits too deep (below the muskies) but even after making adjustments to fish higher in the water column they never contacted a musky.

No doubt, I'd much prefer to target feeding muskies as they are the most vulnerable to angling. However, if you can't predict where they are going feed you may want to look for some other options. Thermal Considerations.
esoxaddict
Posted 11/12/2014 3:19 PM (#739841 - in reply to #739826)
Subject: Re: Thermal Considerations





Posts: 8719


Jason,

You make a very good point about those types of lakes. I will admit that other than Eagle, the other lakes I fish are typical Northern Wisconsin fisheries - less than 900 acres, small basins, and plenty of structure adjacent to what little open water basins are present. If the fish aren't in the bays in the weeds, they're out on the bars and points. If they aren't on the points and bars, you look to the humps. And open water that is lacking major structural elements you can cover with a few deep water presentations and be assured that most of the fish in the lake have seen your lures today.

My guess as to the Canadian trollers (and this is only a guess as I don't fish those types of lakes) is that whatever lures you're putting out there in the main basin of a lake like Vermilion don't come close to a size of what the fish that feed in those areas are eating. If they're out there eating lake trout, a depth raider or a 10" Jake isn't going to get their attention very often. If there are large schools of pelagic bait fish, they can basically just hang around them and eat whenever they feel like it. You're out there looking for the needle in a haystack fish that may decide to eat a lure when it's surrounded by actual food.
BrianF.
Posted 11/12/2014 3:39 PM (#739844 - in reply to #738867)
Subject: Re: Thermal Considerations




Posts: 284


Location: Eagan, MN
Why do larger sized muskies seem more driven to get and stay warm? Some speculation I've heard/read is that warming increases metabolism, which increases speed of digestion, which increases growth rate. What is the advantage of additional growth when the musky is already, say 55", and large enough to tackle the some of the biggest forage species in the lake? Is it an increase in egg mass, which increases the chance of successful propagation of their genetics?

Even if we never know the answer to these questions, knowing that BIG fish are driven by thermo regulation is a key for us anglers, is it not?

Brian

Edited by BrianF. 11/12/2014 3:40 PM
esoxaddict
Posted 11/12/2014 4:17 PM (#739845 - in reply to #739844)
Subject: Re: Thermal Considerations





Posts: 8719


BrianF. - 11/12/2014 3:39 PM

Why do larger sized muskies seem more driven to get and stay warm? Some speculation I've heard/read is that warming increases metabolism, which increases speed of digestion, which increases growth rate. What is the advantage of additional growth when the musky is already, say 55", and large enough to tackle the some of the biggest forage species in the lake? Is it an increase in egg mass, which increases the chance of successful propagation of their genetics?

Even if we never know the answer to these questions, knowing that BIG fish are driven by thermo regulation is a key for us anglers, is it not?

Brian


I'd agree that when it comes to big fish, it's likely related to egg production in the females at least. At that size, I'm not sure fueling growth applies as much as simply needing to eat and metabolize a larger volume of food.
Larry Ramsell
Posted 11/13/2014 7:19 AM (#739899 - in reply to #738867)
Subject: Re: Thermal Considerations




Posts: 1275


Location: Hayward, Wisconsin
Brian: I too believe, as does EA, that the big girls "need" to eat more due to body size to maintain mass, but ALSO, these bigger girls produce more (and perhaps) larger eggs and need more food to that end as well.
esoxaddict
Posted 11/13/2014 12:54 PM (#739936 - in reply to #739899)
Subject: Re: Thermal Considerations





Posts: 8719


So Jason...

If the fish are feeding out in the main basin of the lake in deep water where targeting them is futile, it stands to reason that we're catching fish that just aren't hungry. What's your theory on why they are biting? Is it just a genetic response to the movement and vibration of our lures? Is it nature telling them to take advantage of a meal when one presents itself? Or perhaps they are sitting there quietly digesting their meal, and the presence of our lures is just plain annoying enough for them to want to chase them off with force if necessary?

Edited by esoxaddict 11/13/2014 1:01 PM
jlong
Posted 11/13/2014 1:30 PM (#739939 - in reply to #739936)
Subject: Re: Thermal Considerations





Posts: 1937


Location: Black Creek, WI
Good question EA. One I've pondered for many years.

If you believe that the ONLY type of strike is one for the purpose of feeding, then TIMING is everything. You want to present a lure to a digesting fish that is reaching the end of its digestion period and preparing to go on the hunt again (leave its comfort spot). Thus, you can get a feeding strike in a NON-feeding location by being there at the right time.

However, I believe there is another type of bite. One some people call an EXCITEMENT bite. One can speculate for eternity if it truly exists or why it happens. Could be instinctive (linked to the lateral line?). Could be the predator behavior like many referencing the cat&mouse deal. I don't know. Or... when I think I've achieved an excitement bite... perhaps I just got lucky in my timing and actually got a feeding strike from a fish that was just about to vacate the area in search of its next meal? We'll never know for sure....
esoxaddict
Posted 11/13/2014 1:46 PM (#739941 - in reply to #739939)
Subject: Re: Thermal Considerations





Posts: 8719


As I alluded to earlier, there are periods leading up to and away from active feeding windows when they will still eat. Given the opportunity to consume a meal with little energy expended, I believe that they will take that opportunity more often than not. I firmly believe that instinct plays into this with fish that are not actively feeding, and will still whack a lure just because it's there. How many times have you had a fish follow your lure from a distance, obviously not interested enough to eat it (or it would have already) that sort of hangs around watching your figure 8, and suddenly comes completely unglued when you make the right move?? That's not feeding in my opinion.

You're right, we will never know. I also suspect that there's always a few fish that simply didn't score during "feeding time". No predator is successful 100% of the time.

So back to thermal considerations... Outside of the periods of feeding, and the dead time of digesting when they won't even turn to watch a lure go by, why do you think they are seeking out certain temperatures? I can see it in the summer when the warmest water holds a lot less oxygen. But what about the rest of the time?

jlong
Posted 11/14/2014 8:55 AM (#740051 - in reply to #739941)
Subject: Re: Thermal Considerations





Posts: 1937


Location: Black Creek, WI
EA, I think its that simple. Feeding locations... and digestion (comfort) locations. Anything in between would simply be a travel route.

Researching Thermoregulation in Ectotherms (cold blooded creatures) reveals a lot of cool stuff. Iquanas and how they feed in the ocean and "regulate" on shoreline rocks seems very similar to what I believe many basin feeding muskies are doing.

The connection to thermoregulation and digestion is due to metabolism. However, as you read up on this stuff... you'll also notice that CHANGE in temperature has negative effects on cold blooded creatures and they will relocate in an effort to slow/minimize this change.... or to recover from the change. Thus, in spring and fall when the lakes are changing in temperature most significantly... I feel muskies will do some strange things to avoid this chaos. Some anglers will struggle at these times... while others hit the jackpot.
14ledo81
Posted 11/14/2014 9:47 AM (#740062 - in reply to #738867)
Subject: Re: Thermal Considerations





Posts: 4269


Location: Ashland WI
Ok, so if we feel that muskies are feeding in the basin areas and digesting in shallows, what about shallower reservoir/flowage style lakes?

Do these fish not follow a pattern like that at all?
BrianF.
Posted 11/14/2014 10:10 AM (#740067 - in reply to #738867)
Subject: Re: Thermal Considerations




Posts: 284


Location: Eagan, MN
14ledo81 raises a good question, which also leads to others.

Is there a difference between the various strains of musky in terms of their thermo regulatory and feeding behavior?

Most of what is being discussed here applies to Leech Lake strain muskies found in relatively large lakes having loads of pelagic forage. Would the typical strain of musky found in other states act the same in a similar environment?

What about environments where there is no pelagic forage relating to a big basin, for example in a shallow, small, fast moving river system or, as 14ledo81 asks, in a shallow flow age situation that presumably lacks pelagic forage? Do all muskies, regardless of strain, have this same thermo regulatory need?

I would tend to think so, but my experiences with strains other than Leech Lakers is that they show somewhat different thermo regulatory behaviors. What have others seen?

Brian
jlong
Posted 11/14/2014 10:21 AM (#740070 - in reply to #740067)
Subject: Re: Thermal Considerations





Posts: 1937


Location: Black Creek, WI
I grew up chasing WI Strain muskies. Some lakes has ciscoes, others only sucker/panfish for forage. What is unique about the true MN Sunbathers is there intense movement to shallow structures during peak water temps. I have attributed this to their basin feeding habits... but could be wrong.

The Wisconsin fish, however, is where I've observed some of the better THERMO related fish movements. Two opportunities present themselves:

1. When Preferred water temperatures exist (71F?) muskies will seek this condition out over others.
2. When water temperatures are changing (up or down) they will seek stability (areas with the least change in temperature... or closest to the last stable temperature).

Find these microhabitats that provide either preferred water temps or greater temperature stability... and you'll find more muskies... and arguably bigger muskies too.

These learnings from WI strain muskies has treated me well when applying them to Spotted Strain muskies.
esoxaddict
Posted 11/14/2014 1:09 PM (#740089 - in reply to #738867)
Subject: Re: Thermal Considerations





Posts: 8719


If they are like other cold blooded creatures, one could speculate that they might just move up into the warmer shallow areas to get their metabolism going BEFORE they feed as well as afterwards, as Brian mentioned earlier. That could explain some of the fish we catch shallow. They're not up there to eat, they're up there to warm up and THEN go eat. It's a theory, but it runs contrary to the notion that they need thermal stability as well as a preferred temperature. Seems a quick transition from the warmest shallow water into the colder deeper water might be a bit of a shock to their system.

I've not seen it with muskies, but I have had the experience with other species of fish being physically warm to the touch, or cold to the touch compared to the surface water you are putting them back into. Surface temperatures only tell you part of the story.
MstrMusky
Posted 11/15/2014 8:40 AM (#740177 - in reply to #738867)
Subject: Re: Thermal Considerations




Posts: 156


Lots of good discussion here, and much of it correlated with my own observations. I think sometimes we as musky fisherman try to come up with "rules", but the fact most likely is that not all the muskies are alike or doing the same thing.

Based on some observations this year, I have a new theory I was wondering what some of you thought of it. I think it only is valid late summer once water temps have started to tick down a bit. In or near open water, what if there is such a good spot/structure...that the muskies never actually travel far away. The walleyes are always there, and I believe the ciscoes "come home" every evening/night. As an efficient predator, wouldn't it make more sense for the muskies to just "wait" for the food to come back to them? This is then where the thermal considerations come in. I think the muskies are never far from this structure, and depending on the sun/heat, they just slide down off the structure/bars, or paddle out a bit to open water and suspend. Obviously, wind trumps all. If its really windy and the bait may never come "home" that evening/night, then the muskies will start moving to the next spot or start swimming in search of food.
sworrall
Posted 11/15/2014 12:27 PM (#740201 - in reply to #740070)
Subject: Re: Thermal Considerations





Posts: 32791


Location: Rhinelander, Wisconsin
jlong - 11/14/2014 10:21 AM

I grew up chasing WI Strain muskies. Some lakes has ciscoes, others only sucker/panfish for forage. What is unique about the true MN Sunbathers is there intense movement to shallow structures during peak water temps. I have attributed this to their basin feeding habits... but could be wrong.

The Wisconsin fish, however, is where I've observed some of the better THERMO related fish movements. Two opportunities present themselves:

1. When Preferred water temperatures exist (71F?) muskies will seek this condition out over others.
2. When water temperatures are changing (up or down) they will seek stability (areas with the least change in temperature... or closest to the last stable temperature).

Find these microhabitats that provide either preferred water temps or greater temperature stability... and you'll find more muskies... and arguably bigger muskies too.

These learnings from WI strain muskies has treated me well when applying them to Spotted Strain muskies.


Nailed it, I think. Spotted muskies like to travel very shallow, and it may be as much environmental as strain related. I tried to use the shallow water patterns I identified on the Goon in WI, and was very successful. Small areas, JL's microhabitats, I believe. We caught fish in 1 to 3' of water all year this season maybe because temps allowed them to be where they are most comfortable.
Larry Ramsell
Posted 11/16/2014 8:29 AM (#740311 - in reply to #738867)
Subject: Re: Thermal Considerations




Posts: 1275


Location: Hayward, Wisconsin
Sworrall: I believe, after tracking muskies on both "the Goon" (Wabigoon) and Eagle, that your identified shallow water patterns on the Goon were more a factor of water clarity than thermo related. Light penetration there is very limited due to the suspended clay particles in the water, hence the weeds don't grow very deep and when the muskies there go to the weeds to warm-up, they are naturally in shallow water.

I did track muskies there that were either traveling or feeding in deeper water, but when they were shallow, they were really shallow...cover & warmth? More food for thought.
BrianF.
Posted 11/16/2014 10:39 AM (#740326 - in reply to #738867)
Subject: Re: Thermal Considerations




Posts: 284


Location: Eagan, MN
On the shield lake I fish, there was a thick four acre weed bed in a shallow sand bay that used to hold all kinds of summer muskies, big ones included. At the mouth of this sand bay, perhaps 100 yards from the weedbed, was a rock pike that also consistently held muskies right up on top. When the rusty crayfish moved in to the area and ate ALL the weeds, the spot no longer held muskies. While not surprising as the weeds were the attraction there, what was something of a surprise was that the rock pile also stopped holding fish. I'm unclear about the connection between these two spots, but think thermal considerations were a factor. Any one care to venture a guess why a rock spot would die when an associated weedbed disappeared? Not sure I 'get it'.

Brian

Edited by BrianF. 11/16/2014 10:42 AM
sworrall
Posted 11/16/2014 7:13 PM (#740448 - in reply to #740311)
Subject: Re: Thermal Considerations





Posts: 32791


Location: Rhinelander, Wisconsin
Wabigoon cleared considerably over the years and the pattern stayed very shallow. And the shallow pattern we have been working in WI has been on some relatively clear water. One of the really effective 'Goon patterns is current and sand cuts, really shallow.

Regarding what are commonly referred to as 'complexes'...I saw the same thing in Wisconsin where rocks and weeds, separated by a fair distance but part of a 'complex', changed when Rusties showed up.
Travis A.
Posted 1/29/2015 9:52 PM (#750935 - in reply to #740326)
Subject: Re: Thermal Considerations





Posts: 157


Location: Lincoln, NE
BrianF. - 11/16/2014 10:39 AM

On the shield lake I fish, there was a thick four acre weed bed in a shallow sand bay that used to hold all kinds of summer muskies, big ones included. At the mouth of this sand bay, perhaps 100 yards from the weedbed, was a rock pike that also consistently held muskies right up on top. When the rusty crayfish moved in to the area and ate ALL the weeds, the spot no longer held muskies. While not surprising as the weeds were the attraction there, what was something of a surprise was that the rock pile also stopped holding fish. I'm unclear about the connection between these two spots, but think thermal considerations were a factor. Any one care to venture a guess why a rock spot would die when an associated weedbed disappeared? Not sure I 'get it'.

Brian


Makes sense. The muskies could have been feeding in the weedbed and then going over to the rock spot to warm/digest. Once the weedbed disappeared the baitfish it held moved and the muskies probably followed. Once they moved to a new food and correlating thermo/digestion spot nearby that feeding spot, they probably had no reason to travel farther back to the old rock spot. The next question would be to check it out again the following year and see if they are using it again up until the weeds disappear again, assuming the crayfish eat it up again.

This is thread is a gem of great information and ideas. I hope the discussion continues.

I'll add my experience with this. On the reservoir I fish dam is like a zero wade swimming pool. In March, April and May the muskies are stacked in there like sardines in a can. I see a lot of pictures on Facebook of people catching them from the shore during this time. My theory is that the concrete warms up and heats that water first. Along with nearby baitfish spawning area and constant wind blowing into the area. It is a good spot up until Memorial Weekend. After that we haven't raised a single musky there in June, July, August, until the temps switch back to the fall pattern. The pictures of random people catching them also stop after that time. At first I was thinking it was because the baitfish left the area after spawning but now I also think it has to do with the water temp. They probably hang out there in spring since it warms sooner but then once it reaches above that 70 degree sweet spot I'm thinking something clicks and they start to roam and find the cooler water.
esoxaddict
Posted 1/30/2015 1:15 PM (#751016 - in reply to #750935)
Subject: Re: Thermal Considerations





Posts: 8719


We've seen the same thing on a few lakes up in Vilas. Rusties devour the "good" weeds, and some of the adjacent rock spots just sort of.... die.

It makes sense if those areas are what I like to call "transitionary" meaning the muskies will use the weedy areas at certain times of the year and adjacent rock structure at others, or even move between the two.

Another aspect that a lot of folks talk about is the oxygen produced by those weeds. Having found fish in weed beds that are pretty well dead I'm not sure that's a determining factor, but green weeds do seem to be a fish magnet. Thick weed beds provide ambush points, cover, shade, and they attract baitfish. It makes sense to me that if the rusties destroy a weed bed, that baitfish and muskies will vacate the area completely.

The good news is that they haven't left the lake. They've gone somewhere. You just have to figure out where somewhere is.

As Travis said above, 70 seems to be the magic temperature. To me that's a combination of 1. the fish needing to feed more because their metabolism has basically sped up as the temperature rises. #2 is that when you're finding that magic 70 degree mark, muskies will be in more places across the lake. When the water is hot, they seek cooler water, thus limiting the areas where they will likely be. The same goes for cold water in the spring, and the cooler water you find in the fall prior to turnover. They're looking for warmer water.

jlong
Posted 1/30/2015 2:19 PM (#751030 - in reply to #751016)
Subject: Re: Thermal Considerations





Posts: 1937


Location: Black Creek, WI
BrianF,
The rockpile in your example may have been a DickP "Holding Pen" type situation. A spot they hung up on as they traveled between two destinations (weedbed for oxygen/digestion/recovery and basin for feeding). Once one of the two destinations were eliminated... the fish no longer traveled the route that put fish in the holding pen (rock pile).
FlyPiker
Posted 2/18/2015 12:18 PM (#754593 - in reply to #738867)
Subject: Re: Thermal Considerations




Posts: 386


Sorry if this already posted in this thread, didn't see it here though.

http://www.tnfish.org/MuskyMeltonHillLakeTennessee_TWRA/files/Seaso...

Most of the info confirms what has already been said but has a built in control (as much as can be done in a non-lab setting) for dissolved oxygen and forage base due to the unique conditions at Melton Hill. Definitely worth a read on a cold winter day.

Edited by FlyPiker 2/18/2015 12:20 PM
BrianF.
Posted 2/18/2015 1:40 PM (#754613 - in reply to #738867)
Subject: Re: Thermal Considerations




Posts: 284


Location: Eagan, MN
Interesting...

So, to summarize, when available, muskies in Melton Hill tend to seek and remain in a preferred temperature range, avoiding temperatures above and below that range. During the cold water period, when the preferred temperature range is not available, they tend to seek the warmest water available.

In the warm water period, they spread out more, which tells me that once the temperature preference is met other factors (e.g. forage, DO, current, spawning) probably begin to take on more importance. In the cold water period, the Melton muskies congregated in the warmest water section of the lake. So, in the cold water period, finding the warmest temperature seems to take precedent above the other basic needs?

Just wondering how we anglers correlate this info into more fish in the boat.

B.

Edited by BrianF. 2/18/2015 1:59 PM
jlong
Posted 2/18/2015 2:15 PM (#754624 - in reply to #754593)
Subject: Re: Thermal Considerations





Posts: 1937


Location: Black Creek, WI
Wow, great read! Thanks for sharing FlyPiker!

It seems to confirm that muskies will relocate to stay in their preferred water temperature of 22.4 Deg. C (72.3 Deg. F) and prefer STABILITY in water temperatures. As seasons progress, different areas and structures of the watershed will provide that for them. This certainly agrees with my angling experiences.
jlong
Posted 2/18/2015 2:19 PM (#754626 - in reply to #754613)
Subject: Re: Thermal Considerations





Posts: 1937


Location: Black Creek, WI
Brian... note that the fish avoided the high current areas. These areas of the system were cooler on average and had more daily temperature fluctuations.

Thus, I suspect that if we as anglers treat ALL current equally... our results will be sporatic. Gotta look for the "right" current... which in this case is water with a stable temperature... and ideally of the right temperature (72.3 Deg. F).
BrianF.
Posted 2/18/2015 2:46 PM (#754631 - in reply to #738867)
Subject: Re: Thermal Considerations




Posts: 284


Location: Eagan, MN
Good points, J.

What I think needs to be highlighted is how artificial the cold-water environment is on Melton Hill, with the power plant discharge pumping out warm water during the normally cold water period. Still, studying how the muskies respond in that environment I think only helps to shed light on how important temperature is to these creatures when in natural lakes, rivers, or reservoirs not having a warm-water discharge. Actually, I should probably say the importance of 'comfort' vs. temperature, which leads me to another thread.

B.
Reef Hawg
Posted 2/18/2015 9:24 PM (#754723 - in reply to #738867)
Subject: RE: Thermal Considerations




Posts: 3518


Location: north central wisconsin
Good read. Having been fishing systems with warm water influences and cold water inlets since a child, these areas always seem to be seasonal fish 'pens', especially during extremes. Half the fish population of one huge fishery used to run miles in fall for thermal reasons almost exclusively. Now that the lions share of the thermal draw is gone, the same portion of the fish no longer show up. That brings me to my question with regards to these isolated thermals: Is there imprinting once a fish finds/stumbles upon these places(are the same fish returning?)? From how far away can a fish detect and more importantly, be drawn to one of these 'zones'? For example, a cool water inlet on lotw that is otherwise featureless, holds fish only during the spawn then during heat. What are the factors that determine the return if they're coming from a distance further than they can feel it? Is it a revolving door area being refreshed with new fish, or does the same set of fish that utilize this area, return each year? I know I'm referenceing the more obvious artificial and small natural spots, but can we expand it to the large natural systems? Do the same fish find comfort in the same areas each year when the need is greatest(coldest and warmest periods) and do they show up based on the 'memory', the pull of the comfort, or the push from the extreme?

Edited by Reef Hawg 2/18/2015 9:34 PM
jlong
Posted 2/23/2015 11:04 AM (#755685 - in reply to #754723)
Subject: RE: Thermal Considerations





Posts: 1937


Location: Black Creek, WI
Reef Hawg - 2/18/2015 9:24 PM Do the same fish find comfort in the same areas each year when the need is greatest(coldest and warmest periods) and do they show up based on the 'memory', the pull of the comfort, or the push from the extreme?


Good questions, Jason. Wish I could answer them. For now, I'm keeping it simple and assuming they find these "micro habitats" by avoiding the extremes.
Chemi
Posted 2/23/2015 12:32 PM (#755700 - in reply to #751030)
Subject: Re: Thermal Considerations





jlong - 1/30/2015 3:19 PM

BrianF,
The rockpile in your example may have been a DickP "Holding Pen" type situation. A spot they hung up on as they traveled between two destinations (weedbed for oxygen/digestion/recovery and basin for feeding). Once one of the two destinations were eliminated... the fish no longer traveled the route that put fish in the holding pen (rock pile).
This sounds exactly like what Buck Perry called a "migration route" between the feeding area and the "sanctuary". Kind of a rest area on the turnpike.
Travis A.
Posted 2/24/2015 7:13 PM (#755933 - in reply to #738867)
Subject: Re: Thermal Considerations





Posts: 157


Location: Lincoln, NE
Thanks for the link FlyPiker, some very good information in there.

Here are some thoughts and analysis:

It appears that the bigger muskies have less tolerance/preference to the upper limit of comfortable temperature range. This would lead one to believe that they would be the first muskies to leave a good shallow spot once it heats up going from spring into summer or as summer progresses and head out into the main lake basin in search of cooler waters. Applying this theory one could also make the assumption that the bigger muskies might be the first ones to move out of the cooler waters of the basin back into warmer waters of the shallows in the spring, or during other times that they switch temperature locations. This could be part of the reason why they are so elusive. They are always slightly ahead of the pattern. This could be why the big ones sometimes get caught on the "wrong spot" or opposite location of the rest of the population of muskies.

The exception to the rule with the Okaboji muskies was when they stayed in the water temperature waters of shallow bays with vegetation. They stayed in the warmer water of the weeds pushing the threshold of their upper limit of water temperature tolerance even though there was cooler water available nearby. This got me thinking about my home waters that I fish and comparing the one end of the lake with the hot rock bite next to the main lake basin vs the big weedbed bite on the other end of the lake. We have also caught numerous muskies in the weedbed area later into the summer whereas the rock spot absolutely shut off before the summer got too hot. Now why would they stay in the warmer shallows with weeds available but not on the rocks in the warmer shallows? This got me thinking. Perhaps the weeds offer more benefits to the musky. The weeds offer shade, cover/security, more oxygen, and baitfish. The rocks offer some solar heat to warm up the water in the springtime so they are a hotspot then. That same warming effect could probably be the reason why baitfish come into the rocky area also. So it's good early on. There is warm water and baitfish. But then once the temps get higher as summer goes on the warming effect isn't needed. The baitfish don't need it then either so they leave. So what's left for benefits? Nothing. Result: Rock muskies head out into the basin earlier. Now the weeds are in less comfortable water but still offer 4 benefits compared to the rock water. It doesn't mean the muskies on that half of the lake like warm water better. I think they stay DESPITE the water temperature because there is just too much else to offer to leave the area. Maybe they slip off a little ways and check back in depending on weather but I doubt they pickup camp and head to the other end of the lake. So this kind of explains why the rocks are good in the cold and can be good early in the year and again in fall. Plus in the fall when the weeds die off there goes the oxygen and there goes the baitfish so back to the rocks they go.

Now I'm not saying I have it all figured out but it does tie together a lot of the questions I've had about where did they go and why did they leave one area so soon when it was such a great bite a few weeks before. My ultimate goal is to try and pattern them throughout the seasons and stay on top of them. The first part of doing this is being able to leave a spot that was hot but isn't producing now, rather than wasting all day on that spot hoping. Now I can use this information to try and figure out where they are going next and cut them off and migrate with them. So when the whole crowd is pounding that spot that was on fire 2 weeks ago but is a ghost town today, I can be over on that spot that looks like nothing that's really a travel route to their next seasonal hotspot. If these theories are right I can save a lot of time by not fishing waters that don't hold fish and instead be on the spots that do when the fish turn on.

Any thoughts on this?
Sidejack
Posted 2/24/2015 11:40 PM (#755955 - in reply to #755933)
Subject: Re: Thermal Considerations





Posts: 1080


Location: Aurora
An additional factor in favor of their preference for weeds despite water temp could be better water quality.
Weeds = more surface area = increased colonization of beneficial microorganisms = better water
jlong
Posted 8/27/2015 2:54 PM (#782206 - in reply to #755955)
Subject: Re: Thermal Considerations





Posts: 1937


Location: Black Creek, WI
The Fall cool down is beginning. Who is watching their temp gauges and making decisions based on it? Anyone finding new successes after "digesting" all the theories shared on this thread and trying something new? Would be nice to know if any of our winternet discussions help put more/bigger fish in the boat for some of you.
jaultman
Posted 8/27/2015 3:03 PM (#782207 - in reply to #782206)
Subject: Re: Thermal Considerations




Posts: 1828


Haven't been out in 9 days, but...
Saturday before last, had classic pre-frontal conditions. Water temp was about 76. found a couple fish but not much. Slight cold front came through, air temps dropped 10 deg for the next couple days and water temp fell to 72-73 by Tuesday. Tuesday, found a bunch of fish on the same (shallow) spots and caught a few of them. Tuesday was also pre-frontal as another small high pressure system landed.

Not saying those fish suddenly showed up and got so active based on water temp alone.
ulbian
Posted 8/28/2015 6:45 AM (#782244 - in reply to #782207)
Subject: Re: Thermal Considerations




Posts: 1168


Over the past few years I've been paying much closer attention the when fish really pack up into the shallows and pay attention to other things that might be a tip-off (besides temp) that it is about to occur.

It's remained fairly consistent that once water temps surpass that 72-73 mark you can find fish holding shallow when water temps are cooling down. Once that sun pops up and water starts warming they leave. The past few years this has opened up many more skinny water opportunities besides just this late summer/early fall cool down. Earlier in the summer the windows are not very big and might only be 30-45 minutes but as more extreme temp fluctuations occur these windows get bigger. It does mean that you will have to be on the water before sunrise. Once the sun gets above the trees on the horizon she shuts down.

As the summer progresses into "early fall"" that window opens more and more until a more significant temp drop like we've had over the past few days. That opens the window up to an all day type of deal for a few days or a couple of weeks. So....this isn't just something that you have to wait for to happen in late August/early September. These cooling shallow water opportunities can start showing up as early as June. It just depends on what your water temp range and fluctuations are.
jlong
Posted 8/28/2015 7:31 AM (#782249 - in reply to #782244)
Subject: Re: Thermal Considerations





Posts: 1937


Location: Black Creek, WI
Agreed. It occurs all year long. However, the fall seasonal cool down is the most predictable... as it ALWAYS cools down in the fall.
BrianF.
Posted 8/28/2015 9:39 AM (#782268 - in reply to #738867)
Subject: Re: Thermal Considerations




Posts: 284


Location: Eagan, MN
So, fish hold in skinny water in the early a.m. as the sun begins to warm the shallows. For me, this shallow movement seems to peak a couple of hours after sunrise and last until the noon hour or just beyond. As the day wears on into afternoon, something seems to change. No more fish contacts or the aggressiveness is just not there.

Any one else notice this transition later in the day?? If so, what do you think is going on?? How do you anticipate this transition and proactively change your approach to stay on active fish??

Brian
jlong
Posted 8/28/2015 10:53 AM (#782278 - in reply to #782268)
Subject: Re: Thermal Considerations





Posts: 1937


Location: Black Creek, WI
Not sure why I'm answering BrianF... as we have discussed this theory at length together in the past.

In simple terms... I think comfort AFTER (cool nights, cold front, big winds, etc.) and feeding locations during stability. This could be a daily transition from shallow (morning) to deep(er) in the evening. Also, comfort zones may not always be shallower, especially if there is wind increasing mixing of the water column.

I think fish get into a cycle of FEED and RECOVERY. They may be recovering from feeding (optimize their metabolism in preparation for their next meal) or to recover from environmental changes... in this case... water temperature changes (even a 1/2 degree can be significant).

Just like there are seasonal movements... there are daily movements as well. Understanding what drives those movements is the tricky part.