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What is too warm?

3K views 58 replies 26 participants last post by  Tsar Bulba 
#1 ·
Here in western Washington with the recent hot spell our local lake temperatures after a prolong cool spell are soaring. When do folks say enough is enough and end their lowland lake trout fishing until the fall? What is your temperature thresholds?

I visited Pass yesterday and found that the surface temperature had raised to 71 degrees (at 10 AM) up 5 degrees in the last week. Of more concern Pass is a shallow lake; most less than 20 feet deep. I ran a quick temperature profile and found that 70 degree water extended down to more than 10 feet and even at 20 feet the bottom 4 or 5 feet of water was 66/67 degrees. I did fish but tried to land the fish quickly (actually broke one off and pulled several hooks) and minimize any handling. The fish fought well (several making the backing) and did not appear to be unduly stress. However have decided to call it season for the lowland lake trout season and am ready to move on t0 various warm water species, rivers, and Puget Sound opportunities.

At what point do others make similar decisions?

Curt
 
#3 ·
Even in deeper lakes that have a thermocline, the temperature of the surface layer (the water column from the surface down to the thermocline) won’t change that much. Temperature monitoring has shown as little as 2 degrees depression down to the thermocline from the surface.
 
#4 ·
I generally say that 70 degrees is the high temperature limit for rainbow trout. Above that and the risk of unintentional mortality increases greatly even with careful C&R techniques. But, it depends on the lake too, as some lakes with good depth may provide better conditions for the fish, or strong underwater springs may provide cooler water and more oxygen, or shade from trees or cliffs may help the fish stay cooler. I recommend going higher in altitude where the lakes take longer to warm up (think Leech Lake at 4,000 feet or high altitude BC lakes in the 3,500 to 5,000 feet range). Another alternative is to fish for the Lahontan Cutthroat, as they can tolerate the warm water temperatures a lot better than rainbows (think Omak or Grimes). Or fish for different species (think shad or bass or pink salmon late summer in odd years).

Several years ago a friend had a fish finder that read the temperature at various depths. Here is the chart he produced from Grimes Lake one summer:

Rectangle Slope Plot Parallel Font


I'm sure some lakes are different, depending on a lot of factors, but at least at Grimes Lake, the temperature at the surface was substantially different than the temperature in the thermocline (which was about 24 feet down).
 
#5 · (Edited)
From looking at the graph it looks like the point of inflection of the temperature was about 67-68 degrees which on that day is most likely where the thermocline was. Still only a 5 degree difference from the surface temperature. I agree that different species such as Lahontans can tolerate higher temperatures since they evolved in that environment.
 
#7 ·
I'm sure the thermocline level can change from day to day and even in different parts of the lake, depending on underwater springs or inlet creeks, and maybe wind (as Ira points out, although it seems to me that it would take an awful lot of wind over a fairly long time to change the dissolved oxygen content down at 24 feet). I identify the thermocline layer by not only where most of the fish are holding, but also by the sonar reflection on my fish finder. At least at Grimes on most parts of the lake, that thermocline layer is usually at 24 feet.
 
#6 ·
Stoked trout. I understand wanting to limit your impact, but at the same time these fish, even in Pass are just stoked trout. Yes with higher temperatures, you end up with more evaporation of dissolved oxygen and the fish's metabolism increases, thus creating a need for more oxygen. Windy days will then be better than dead calm days. If I find a time to fish in the Summer at Pass, I will.
 
#8 ·
I have been a lake steward on a small King County lake the last few years. Measured water quality, visibility, temps, etc. every two weeks spring thru fall. It is fairly deep for it's size ~50'. The surface temp (3' down) got up to 75 degrees. At 20' feet down the water stayed at a fairly constant 55 degrees due to depth and all the natural springs. I noticed bringing up the fish from ~15 to 20 feet down was hard on them due to temps and lack of O2. So I quit fishing last season when the near surface temp was above 65 degrees. I will stop earlier in the season this year; especially with this heat wave we are having.

I know each lake is different but when nice, healthy fish show lots of fatigue/stress when fighting before the release it is time to wait until fall when the temps cool down...
 
#15 ·
I have mixed views on this.

1. I don't think people should be fishing for trout in warm water and that temp is somewhere close to 70 degrees.

2. Am am incredibly sick of the type community fly fishing has become everyone telling everyone else what to do. No hero shots , keep em wet, and on and on and on.
Everything you do, if you share it here you get jumped on for something. No more rules formal or informal go fishing and leave everyone else alone.
 
#19 ·
The attitude you're complaining about has less to do with people's opinions than something that was borne from caring about trout survival. This discussion is an old one and has been kicked around the site for about a decade. The folks piping up here were not attacking people. They were addressing "practice." Good C&R "practice" increases the survival of temperature sensitive trout, thus contributing to a better future fishery.

I clearly remember past discussions and posts of scientific research on how long does it take a trout to recover in warm water, as well as survival rates based upon various factors. All the points you complained about ("hero shots, keep em wet...") were all touched upon way back then. The point is, as the temps rise, you have to do increasing more to insure survival of the fish. Isn't that the point of the "R" in C&R? After a certain point, the risk of mortality becomes too great to even bother with a given body of water.
 
#16 ·
However have decided to call it season for the lowland lake trout season and am ready to move on t0 various warm water species, rivers, and Puget Sound opportunities.

At what point do others make similar decisions?

Curt
Curt, With the warmer than usual spring and this additional hot spell it appears to me our runoff season is well under way. I'm guessing the rivers may drop into shape earlier this year. It has been my experience that at least some searuns move into the lower portions of the river when this drop occurs. Still few fish compared to later in the year but I seem to be able to find a few fresh fish and having the entire Skagit from Mt. Vernon to the mouth all to myself is awesome.
Water Plant Tree Lake Wood
 
G
#17 ·
Curt, With the warmer than usual spring and this additional hot spell it appears to me our runoff season is well under way. I'm guessing the rivers may drop into shape earlier this year. It has been my experience that at least some searuns move into the lower portions of the river when this drop occurs. Still few fish compared to later in the year but I seem to be able to find a few fresh fish and having the entire Skagit from Mt. Vernon to the mouth all to myself is awesome. View attachment 171408
 
#23 ·
In interest of full disclosure for the first in more than 3 decades this spring I have spend significant amount of time fishing a couple western Washington lakes and attempt in learning more about this game of fishing "mids". Clearly management, fishing methods, and angler view points have changed significantly since the mid-1980s thus some of my questions.

Yes the trout in those lakes are stocked by the State however in the lakes I fished those stocked trout had become "stoked" fish (sorry Ira!). Sticking with Pass lake it currently is managed as a fly only water under strict CnR rules. Those rules coupled with reduced planting levels appear to be designed to foster a higher abundance of larger/older fish; at least that is my assumption. If that is wrong and we are too worried about having lots of carry-over fish should that management approach be re-considered? Maybe for those folks that are interesting in killing a fish or two should be allowed to keep one or two a day. After all they are stocked fish and WDFW will plant some more.

Curt
 
#24 ·
Seems to me the best option for a lake where WDFW wants to encourage a CnR fishery would be to use a native species or introduce a species that will reproduce in the wild.
I agree a lot has changed since the 80s. It used to be teaching people what they could have if they would limit their catch. Now? Shout people down who go against the conservation agenda. I am very ashamed to say i used to do that very thing knowing full well i was so right in doing it..
I may be overreacting slightly to this particular thread and for that i apologize.
We really need to live and let live. A guy who holds a fish out of the water or fishes when the water is hot is not an enemy.
 
#25 ·
I'm not sure I know of a lake in western Washington where there were native rainbow and/or brown trout prior to hatchery introduction. So how does conservation fit in? These fish are planted purely for recreational purposes and the limits on harvest do not ensure eternal life for them. They all eventually die (from something).

We are just concerned that our catching (and providing a near death experience for them) does not cause an early death. We want to catch a "big" fish and that's the real reason we release- so they will get bigger. Issues of lifting a fish out of water fit in here as well. We like to think we do no harm.

Reality is we all know that higher temps cause fish mortality, and that the stress of capture under low DO/high temp conditions is not good for them. The state even shuts down certain lakes in the summer for that reason. For those few lakes the decision whether to fish in warm water is a legal issue, rather than a moral decision. But for the majority of lakes it's just a moral decision and up to us.

And it's morals that we fight over all the time as we follow our passions.
 
#32 ·
I disagree. We pay for lakes to be stocked with the hope of creating quality fishing. If we fish when the lake warms up and we kill most of the fish we hook or catch, those fish won't be there in the fall when the water cools and quality fishing could again be available. It isn't always the case that only a wild trout is too valuable to be caught just once. Hatchery fish stocked to make for good spring fishing can also provide us with good fall fishing if they are still alive then.

Sg
 
#34 ·
Salmo g.

I think that as "dinosaurs" that have recently re-entered the lowland lake fishing game you and I have miss read where the fly fishing is coming from in their management desires. Based on what I have read on this site I had assumed that a major interest was the development and maintaining of fisheries with access to "quality" (larger) fish with reason catch rates. Typically the management tools used to create those kinds of fisheries has been lower planting levels (yielding faster growth rates) and limited harvest (dead fish) through gear restrictions, strict CnR, or low bag limits with larger size limits. It appears that the majority of the community desires those types of management approach but seem less inclined to walk that talk when it comes to their own fisheries.

Just fun I took a closer look at one of the lakes I have been fishing - Pass Lake and its management. In response to angler concerns about the quality of the trout available; larger and more robust fish WDFW has made some management adjustments. Those adjustments took the form of reducing the number of trout planted. Just looking at the rainbow program that lake is now planted with 5,000 fry last spring (about a month ago). As of early June this year those fish were 14 to 16 inches long and decent mix of larger carry-overs. While those fish were strong and active unfortunately the reduced planting levels the standing crop of available trout. My best guess is that given the planting levels and high survival rates that current standing crop is likely less than 2,500 rainbows. Just for the heck let's assume that anglers fishing during the warm water periods might be killing a single trout a day due to elevated stress. Over an expected warm water period of 90 days with an angler effort of 5 to 10 anglers/day we could expect to see an reduction in that standing crop of 18 to 36% above and beyond normal mortalities. Apparently those losses are not of significant concern.

Clearly having develop a conservation ethic of the last 50 years fishing on wild salmonid population had colored my view when it came to fisheries support by hatchery production; even those gear to producing higher quality fisheries. This thread has been educational and I'm glad I asked the question and will spend my energy/time on other issues.

While I will not speak for you it is clear on this and other issues this "dinosaur" is out of step with much of the fly fishing community.

Curt
 
#38 ·
Ira,

Yes, all fishing license buyers pay the same, and WDFW manages some lakes for higher quality fishing than others, based in part on angler input. In addition, some of us do pay more than others in the case where my local fly fishing club pays WDFW to stock additional and larger trout in Munn Lake. Like a lot of lowland lakes, it is shallow and gets warm in the summer. Trout can survive only because of some groundwater springs that feed it. I don't fish it during the summer, but some anglers do because it also offers good bass and crappie fishing. My point is that every trout that survives the summer is an additional 3 or 4" larger come fall, and can provide some very rewarding fishing.

As for fishing mortality, I don't know what the rates are. However it's nearly impossible to kill a trout through lactic acid build up when the water temperature is 50* or lower, but somewhere around 70* it becomes difficult to avoid that excessive acid build up. I've read that 68* might be a good cut off for avoiding mortality from fishing, but I don't know for sure. I do know that I had one experience of good trout fishing where I wasn't paying attention to the temperature until I noticed that several trout I caught were laying on the bottom of the small lake I was fishing. So I took the water temperature, and it read 72*. I'm pretty good at handling fish safely, so I took that result to mean that trout can die from lactic acid build up very rapidly when the water is 72*. So I make a point to avoid fishing for trout in water that is 70* or higher. If I was fishing for the skillet, I guess it wouldn't matter, but I rarely keep trout.
 
#40 ·
Ira -
Could not agree more that every lake is different! I had been told by reliable sources that both Pass (the example lake for this discussion) and Lone lake do not normally form a thermocline; being too shallow. Being one that likes to check such things out and this being the first season that I consistently fished either Lone or Pass I monitored the temperature profiles of both since early May. As I mentioned in my first post last week more than 1/2 of the water volume in Pass was 70 degrees or more and the rest was between 66 and 69 degrees with no evidence of a thermocline. In short there did not appear to be any cool oxygenated refugia available to the trout in either lake once they warmed.

I suspect that the information on temperature stress and related mortality that you have found on streams would be a fair representative of what you might expect on Pass. The only difference between Pass and say the Stillaguamish is that the Pass would not provide the consistent oxygenation provided from the riffles that streams provide, the diurnal temperature swings one see on streams (cooler temperatures in early mornings hours) and fewer site specific temperature refuge from spring seeps and/or tributaries.

BTW -
A salmonid that is accustomed to the cool waters of a deep lake thermocline (temperature typically in the low to mid 50 degree range) that experience prolong stress in temperatures that maybe 20 degrees or more than accustomed temperature can be experience higher handling mortalities; and in some cases mortalities higher than if they were accustomed to temperatures that were closer to the surface temperatures.

But as others have posted the choice is and should be driven by individual angler ethic. I just asked what choices other anglers were making and attempted to provide information to aid those who had not made a determination of there was decision point in their temperature consideration in making informed decisions.

In regard to my personal choice I recognize that the trout in lakes are typically of stocked origin and am willing risk impacts from my handling of fish at temperatures that are several degrees warmer than am willing to fish in streams on wild trout.

Curt
 
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