Winter Behavior of Stream Trout: Temps, Light, and Ice Cover

[LeTortAngler2]

With such cold temps recently I was looking for some info on the behavior of trout in the winter, regarding when our freestoners (and a couple Limestoners) get completely iced over and how it affects their habitat here in PA. After doing some research into this I found that in these extreme conditions, its not always a bad thing, but there are other variables to this. Also, I am also concerned about the aquatic insect life and how these frigid temps affect them. After the bad winter we had last year, I had heard that it had affected certain streams hatches?
Here's a link to a study I found
http://www.diva-portal.org/smash/get/diva2:613889/FULLTEXT02.pdf

 

[BrookieChaser]

Thanks for posting the link. I look forward to reading the paper.

 

[geebee]

interesting. thanks for sharing.

i was recently reading a blog of a guy who snorkels streams in winter - he has spooked numerous trout under the ice.

life carries on it seems.

 

[pcray1231]

Will have to have a look.

In freestoners, anyway, the water temperature is pretty much 32-33 degrees when there's ice on the surface. This happens every winter, and trout and bugs live up in Alaska and Canada, so I'm not real "concerned", per se. And it's not like winters like this are all that uncommon here.

That said, for bug life, absolutely, they grow faster in even slightly warmer temps. Ice cover delays the warming of the water. The longer the water stays cool, the less growth occurs in the bugs and trout. And even if temps recover in spring, it can delay hatches. That's the main effect, I think. Late hatches and smaller fish. But since the water temp isn't actually reduced below 32, what matters is whether it extends the time it's at that temp. i.e. a warm snap could completely offset it.

Although how early or late the hatches are, I think, depends on the total growth throughout their lives, so the temperatures from being laid as eggs right up to hatch day. A few weeks of below average temps is not going to have a large effect. Plus, the least growth always occurs in winter, so a cold snap in winter may have a lesser effect than it would in fall or spring, for instance.

I'd assume limestoners are similar, except warmer, so the cold snap actually does reduce water temps. A cold winter may have a larger effect on the timing of hatches, and may also have a larger effect on the growth rate of the trout as well.

 

[geebee]

pc -why smaller fish ? - trouts are cold water beasties. sure, there are less hatches but the same number of nymphs no ? not to mention baitfish, fish eggs etc

I used to fish up in NH on the Cocheco right through the winter and those fish were fat all winter even though the average temps were below freezing from early december to april.

looking at their natal geographic range - northern europe basically, sub zero winter months are the norm not the exception.

Just my .02.

Mark.

 

[AkDan76]

Pc, our largest skeeters are early spring, gradually getting smaller come fall throughout the hatches..though faster and more devious, the early boys are slow and easy to kill. They are substantially bigger after spending a winter under the ice as larvae/pupae.

Midges will be fine, as will your caddis....we don't have real prolific mayflies, but do on a few rivers, one in particular is a spring fed river (with giant green drakes and giant grayling that eat them oooolala!)

One thing we notice up here and I don't fully understand why, is from year to year, different species of insects seem to be more prolific than others, and it never seems to be the same. Well minus the amount of skeeters and midges, there is a consistent amount of them! Bees included, it could be paperwasps, ground hornets, or bald face hornets, its substantial difference from year to year what does well......why? That I don't know.

I cant speak for your browns, or how they will react to crazy cold, but your bows/brookies will be more than fine. I'd guess they'll really key in on midges more than anything smaller than fry. There's always something in some stage of spawning, fall spring which means eggs/flesh/fry at various stages.

We had a warm shot here recently and I've heard of a few midges being reported mostly near some form of heat source (cabins), buy mid to late april the skeeters will be out, the grayling will be sucking midges on the surface as the creeks open up, and did I mention the skeeters will be coming out LOL!

You need to get up here Andrew! see you in April!

 

[Chaz]

One of the reasons why we don't see more reproduction of RT in PA. The cold keeps them from growing over the winter and producing viable eggs due to low fat reserves.

 

[geebee]

Chaz wrote:
One of the reasons why we don't see more reproduction of RT in PA. The cold keeps them from growing over the winter and producing viable eggs due to low fat reserves.

how do they manage in Alaska, Kamchtka then ?

I'd think its the opposite - not enough cold water and food in the summer to gorge themselves ahead of winter.

 

[AkDan76]

I would also disagree with the water temperature being the sole factor on them not being able to successfully reproduce on their own.

Food base is usually the number one factor. What you'll quickly notice up here is rivers that do NOT have salmon DO NOT have rainbows! There is no river farther north than the gulkana that has wild bows or wild steelhead (in the USA anyways), it also has a good run of sockeye (red salmon) and king (Chinook) salmon. These rivers are fed by two LARGE lakes and a glacier in the beginning. Very common for Red fisheries is the lake. Its also very common to have rainbows in both the lake and the river system, or any river system with the reds running up them.

Without the large food bases these rivers wouldn't be as prolific as they are for trout. A lot of the better known rivers up here for bows have all 5 species of salmon running. Along with char, grayling, whitefish and suckers. That's spring summer and fall spawning cycles....TONS of dead salmon summer/fall and part of winter...giant smolt out migrations in the spring and more holding over (kings) in some river systems for 2 years. Plenty of sculpins along with midges, caddis, mayflies. That's an endless super sized French fry for us not so skinny types. we keep eating them and keep on getting fat, hmmmm. LOL!

I just don't believe we'd have the size, or amount of trout we do if they had to survive on midges, caddis, or mayflies.

That said the grayling do very well though most rivers have salmon in them to a lesser degree, their main focus is midges in all river systems. Obviously the larger grayling are found in rivers with the better salmon returns....eggs/flesh/smolts all winter = Fat guy buffet! Last summer we got on some dandies lined out behind sockeyes ready to spawn, lines of grayling almost invisible to your eye, chock full of fish! A couple days of sailfish mania and not a site of another person around but us! Spoiled maybe LOL! Right off the road system as well, nothing remote about it!

It reminded me of the day with a forum member, seeing a couple large browns ready to spawn (or finishing not sure which), with a zillion suckers hounding them like piranhas. When theirs eggs in the water you can bet EVERYTHING is eating them!

One other thing we have in some river systems (think naknek), is andromous rainbows. They live in river in the winter, but will fall back into the brack generally early in the spring, and than follow the salmon back up river as the migrations progress. Its a guess but I'm guessing they're following the out migrating smolts AND lampreys in the spring (and hanging out in the lower sections of the river in winters). If you ever come up here dig in the mud on almost any river and you'll find them. I'd be shocked if the trout don't feed on them.

Without food, you have nothing. With poor food sources you'll have a poor fishery no matter how hard you stock it!