Questions about trout and warm weather

[Atlas]

As a newbie this year I have never been through a warm water period while fly fishing for trout so I have a few questions...

1) What water temps are too warm to fish for trout without killing or hurting the fish? Are there guidelines for this?

2) Do limestone streams typically reach temps that put them "off limits" or is it pretty safe to fish these streams during the summer?

3) Are there other ways, besides water temp, to determine if the fish are too stressed from the heat or water levels to safely catch and release?

 

[jayL]

I try not to fish streams that are running over 70, and refuse to fish them over 72. That seems to be the generally accepted range of when c&r trout fishing is off limits.

I worry less about stocked fish, as they were stocked for a reason.

Limestone streams usually have less variance in temperature, but not all of them are fishable in the summer. Penns, for example, is not fishable right now. It is among the finest limestone wild trout streams, too. The only real way to be sure is to take a temp for yourself.

You may find stretches of water that are less than 70 or 72 degrees in certain streams. Feeder streams are a a likely spot. I don't think it's ethical to fish these sections either, but have made exceptions on stocked waters. The fish are stacked up for thermal refuge, and it's not really sporting, nor responsible to harass them.

 

[PatriotFly26]

Warm Weather Trout is an oxymoron in some cases. Trout do not live in nor will they survive in waters over 70 degrees. They prefer upper 30's to 50's. Brown trout can survive in temperatures warmer than Rainbows can survive. This makes your question difficult.

Trout will manage to find cold water whether it be a tributary or a permanent water drainage system.

If you are fishing an area where water is let out regularly there is a good chance that with new water there will be good trout populations. If not a system look for where fresh springs trickle into a stream and a smaller stream can hold large fish in these hot summer months, so don't be afraid to cast where you can't see over a rock, they like to hide, and they like to eat, so don't give yourself up, and don't pass up any pools.

Summer trout fishing is an art, and should be treated as such. Good luck.

 

[afishinado]

Great questions Atlas.



Atlas wrote:
As a newbie this year I have never been through a warm water period while fly fishing for trout so I have a few questions...

1) What water temps are too warm to fish for trout without killing or hurting the fish? Are there guidelines for this?

Most believe (myself included) if the stream temp reaches 70*, it is too warm to fish. Some say wait until it cools a degree or two, but my feeling is that it's time to give the trout a break. Stressing them when the water temps are up is not a good thing. I suggest you find a cooler stream or fish for warmwater species

2) Do limestone streams typically reach temps that put them "off limits" or is it pretty safe to fish these streams during the summer?

The main source of Water from Limestone/Spring comes from deep under the ground. The temperature underground does not change with the seasons, therefore, in nearly every limestoner or spring creek, the water remains cool enough to fish in the summer. It's not a bad idea to test the stream with a thermometer before fishing.

3) Are there other ways, besides water temp, to determine if the fish are too stressed from the heat or water levels to safely catch and release?

Fish that lay close to the bottom and are lethargic and/or are all huddled up in a confined area is a sure sign of stressed fish. It is likely they are holding close to a spring or colder trib to survive the warmer water temps.

The way I look at it, I fish for trout 10 months a year and can skip July and August. I try to give them a break, especially with the low water and high temperatures we've been having this summer. I pursue warmwater fish in July and August (SMBs mostly) and actually look forward to fishing for them each summer. If I get the trout bug, I choose a tailwater fishery or a cool limestoner for trout.

Good fishing.

 

[pcray1231]

The other answers were all good. I'll add my own.

1) What water temps are too warm to fish for trout without killing or hurting the fish? Are there guidelines for this?

Generally, 70 degrees is a good measure. It can be a bit more complicated than that. Browns seem to handle warm temps better than brookies or bows. Amount of flow matters a bit, they'll handle temps better if the water is fast and aerated. Streams go up and down by the day, some considerably and others not as much. So if its 70 for a brief time at the peak of the day, but dropping to 62 at night, you might be alright, but if its staying at 70 thats a different story.

2) Do limestone streams typically reach temps that put them "off limits" or is it pretty safe to fish these streams during the summer?

Unlike what you'll hear elsewhere, both limestoners and freestoners generally have a base flow that comes from springs. But most freestoners have many small springs from a wide drainage area. A fair number of limestone springs are much larger, and can represent the majority of the flow in some areas. All springwater comes out at a constant temperature, and once in the stream begins to take on the temperature of the surroundings. So, with a limestoner, it is possible to have a fairly large waterway which is relatively fresh from the ground and thus cold. Thats hard to do with a freestoner, they grow more gradually with a higher number of smaller springs spread out over a bigger area. Small streams will often be plenty cool, but by the time its a large waterway, it's probably warm. That said, even limestoners eventually flow far enough from the spring to warm up. Take the temperature yourself.

3) Are there other ways, besides water temp, to determine if the fish are too stressed from the heat or water levels to safely catch and release?

Well, water temp is the easiest predictor. But a stressed fish will generally feed less and put up a poor fight when hooked. The fight time it takes to overstress a fish is also shorter, so if after release, the fish doesn't dart away very quickly thats a bad sign, and if it turns belly up or needs "reviving", thats a very bad sign.

 

[Atlas]

Thanks everyone!

That is very helpful. Sounds like its time to get a thermometer for the vest. I love to get after trout but want to make sure I am responsible about it.

I have noticed some areas with fish beginning to stack up a bit and wondered what that was about (although I think these are stocked fish so I may have to do them a favor and cull the herd).

I have never really fished for SMB - was actually more of a spinning rod LMB fisherman before this year so I suppose I can turn over another new leaf for a few months and go after the smallies (and maybe even a few of those carp...)

 

[jayL]

Smallmouth on the fly rod are incredible fun.

 

[troutslammer]

fish the first hr or 1-1/2 then last hr or so , water temps here been varying 10 degrees (76 mid day -66 ) remember the thermometer u are holding in your hand takes temperature or first 6" of water which is the warmest , did any of you ever tie a string to your thermometer and stand in the middle ( deep pool ) and drop it 5' to the bottom ? whats the temp difference gonna be ?

 

[PennKev]

6" of water which is the warmest , did any of you ever tie a string to your thermometer and stand in the middle ( deep pool ) and drop it 5' to the bottom ? whats the temp difference gonna be ?

`

The water in a typical trout stream is sufficiently mixed that there is little difference in temperature top to bottom. Large pools and flats might develope a very thin layer of warmer water near the surface, but depth, in a trout stream, does not create cooler water. The logic used by some that says trout go to the deepest pools to stay cool is a flawed. They are most likely going to the most protected spot if they cannot find significantly cooler water.

Generally, 70 degrees is a good measure. It can be a bit more complicated than that. Browns seem to handle warm temps better than brookies or bows. Amount of flow matters a bit, they'll handle temps better if the water is fast and aerated. Streams go up and down by the day, some considerably and others not as much. So if its 70 for a brief time at the peak of the day, but dropping to 62 at night, you might be alright, but if its staying at 70 thats a different story

I agree 100% with the above. It's not the maximum temp that kills the fish, it is how long the water stays at that temperature. if you have a freestone stream that is peaking at 70-72 and staying in the 60's for most of the day, you probably have a pretty decent trout fishery. Trout do not suddenly drop dead at 70 degrees The affects of warm water takes some time to deplete a popualtion of trout.

Kev

 

[jayL]

PennKev wrote:
Trout do not suddenly drop dead at 70 degrees

But many freshly released trout do.

 

[JackM]

I think whether the freshly released trout drop dead at 70 degrees depends on their health before being caught, the length of the fight and the handling when landing and releasing. If "many" of these are dying, then the angler is doing something wrong and needs to fish cooler water where poor practices are less likely to kill the trout.

 

[jayL]

I'm taking the average, and I'd wager that it's more than a few. In my opinion, more than a few is as good as (or as bad as) many in this context. I assert that the average experience of a caught and released trout in temperatures over the generally accepted unfishable range is one that results in a high probability of death.

The moral of the story is that it's tough to justify c&r trout angling in temps over 70ish degrees. It's simply irresponsible. That is undeniable. No rebuttal.

 

[JackM]

Well, I respectfully disagree. If 70 is the peak temperature of the stream, the trouts are going to be healthy, assuming sufficient oxygenation and food supply. If the peaks are in the mid-seventies and lows just below 70, then your predictions of certain demise are accurate, but otherwise, I think not.

 

[jayL]

If you're out there taking a sampling of temps at various hours to get an idea of high and low water temps over the period of a few weeks, be my guest. I don't think one can ever assume that this is the case.

I'll maintain that it's irresponsible to fish streams over the 70-72 mark, for most situations. My interpretation of the original questions was that general information was requested. I'll also propose that it's irresponsible to suggest that a beginner fish streams over that range, unless they're willing to do the temperature study mentioned above.

 

[JackM]

I stand by my position that your statement in reply #10 is way overbroad. You do not have to do a temperature study, just use common sense. If the last 5 days were air temps in the high 80s and the 9:00 AM temperature is 70, then you know full well that the stream was too warm a good portion of the day before. On the other hand, if the temperature at 5:30 PM on the fifth extremely hot day is 70, I wouldn't hesitate to fish the stream, morning noon or night. I think it is irresponsible to give inaccurate or incomplete information in response to an inquiry.

 

[greenghost]

Two weeks ago I was fishing the Little J above Spruce Creek. The air temperature reached the upper 70s, the night time temperature was in the mid 60's. I was surprised to see that by 4 p.m., the water temperature was about 69 degrees... borderline for me. I was ready to pack it in after temping the water when I noticed across the river a young man hooked a nice fish. He fought it for over 5 minutes, netted it walked it up the bank to show a group of older anglers. Measurements were taken. (Heard one man say "21 inches, nice!") Pictures were taken, handshakes were exchanged... the whole time the fish was out of water... I'm thinking, "That fish is DOA." Sure enough, he tried to revive it but after 15 minutes it was still rolling on its side... I left and he was still working on the fish in faster water. I decided to lower my limit to 68 degrees.

 

[JackM]

I think if you pull a trout out of water after 5 minutes of struggle, then keep it out of water for another minute or more, you are going to have a dead fish even if the water temperatures were in the mid-50s.

 

[pcray1231]

Agreed. Nomatter what the temperature, if you have a fish out of water for too long as described, especially after a 5 minute fight, then water temperature is not the reason that its going to die.

Anytime you need to "revive" a fish is a bad sign. The fish may seem as if its revived, and swim off looking apparantly fine. But there's a good chance that fish is going to die from acidosis within a few days.

Biologically speaking, trout are similar to humans in their metabolism. Muscles need energy to move, which is usually supplied by aerobic metabolism (requires oxygen and sugar to create energy). But we have systems for anabolic metabolism too. This occurs when there is not enough oxygen, either from lack of actual oxygen available or strenuous exercise which exceeds the heart and arteries' ability to transport oxygen to the muscle. Anabolic metabolism does supply the energy required to do the job, however a side effect is hydrogen ions being produced, which lower the pH, i.e. acidosis. It's why we get sore muscles, for instance. And like sore muscles, the peak effects are often a day or so later. And in order to recover, you must consume more oxygen at rest than is otherwise typical.

All the same is true in fish. If we have an extended fight, the fish is undergoing anabolic metabolism to supply its energy, and moreso if the water is warm and the available oxygen low. Holding it out of the water requires more anabolic metabolism just to keep the fish's organs functioning. And upon release, that fish needs more oxygen to survive than it did prior to being hooked. If that oxygen isn't available, more anabolic metabolism will take place, until the blood is acidic enough to kill some of the organs in the fish and the fish dies.

Bottom line: The warmer the water, the shorter the fight and quicker the release must be for the fish to survive. In water that remains above 70 degrees for any length of time, there is very little leeway for any fight or release to take place, and the fish is unlikely to recover due to lack of oxygen in the hours and days AFTER the fight. Just because it looks fine when it swims away does not mean it will live. But if that same fish swims away fine in the warmer water, and the water overnight cools to more comfortable levels, enough oxygen may be available for the fish to rest and recover from its ordeal.

 

[Atlas]

Thanks for all of the input. This discussion has been helpful. I always try to handle the fish as little as possible and bring it to hand as efficiently as possible but just wanted to make sure that I am being responsible. The purpose of the post was really to see if there were general guidelines and I think that I have some basic ones that will help me to judge the specific situations that I find myself in.

So, if I can summarize, my takeaways are:

1) Get a thermometer for the vest
2) If I am fishing for trout during the hot months try to do it first thing in the am or in the evening, minimize fight time and release ASAP
3) Be careful if the temp is creeping toward 70
4) If its higher than 70 pretty much stand down on the trout and fish for smallies

 

[PatriotFly26]

When the water heats up what do you guys prefer to use if you decide to go for trout? Dries, wets, nymphs, or streamers?