Speculation/Question about migrating brown trout

[salvelinusfontinalis]

In the past 2 months, I have been fortunate enough to land 4 brown trout (19-23") on limited trips, that I believe are brown trout that migrate from cold water streams to large warm water rivers. That is to say, at least I believe that is what they do.

However now I am not so sure. I know for certain that some of these fish return to 1 of 2 cold limestone streams in the summer because I witnessed it. However I always assumed that they stayed until after the spawn. In one of the limestone streams the spawn is going on full force but I caught large browns in the warm water river already, one of which was a large female full of eggs.

So my questions are:

Is it possible limited spawning habitat has them trying to breed in the large warm water river?

Do you think they are successful and if so do those hatchlings migrate to cold water come early summer or are they just Bass food?

Is it possible I have the imprinting backwards? I always figured they were imprinted to return to the limestone stream to breed. Is it possible the fish only seek the limestone stream for cold water in the summer and are imprinted to return to the large river?
and if so,
Is it possible the reproduction in the large warm water river IS successful which is why they are imprinted to return to it?

If they don't wait for the spawn to be over to return to the warm water river, then when exactly do they return?

Obviously no one can answer these questions 100% but I found this very interesting. We know little about these fish but I am having great luck targeting them as of late. Just thought I would share. I absolutely love chasing these fish.

 

[Chaz]

It is possible the browns were imprinted in the ww streams. That being said, It's also possible that they simply haven't moved to cold water streams yet, maybe a cold water spring in the WW river where you caught them. Some trout including brookies don't spawn until January so anything is possible.
We simply don't know enough about this subject. Instead of PFBC wasting money on stocked trout residency they ought to finding out more about migration of all wild trout.
They will always make more stockies.

 

[Maurice]

Is it also possible that the egg laden female was a stocked brood fish and has no imprinting?

 

[salmonoid]

I've read a number of places that browns don't imprint. And also a number of studies that suggest they do. Regardless, I doubt we'll solve this mystery on an Internet message board

The female with eggs could just be a wayward, lost brown that hasn't found what it's looking for. The suggestion on another thread that these big browns are sometimes in a habitat suitable for spawning as little as one day and then they're gone might support the idea that the egg-laden fish you caught is just biding its time and you could catch it the next day and it might be egg free.

All speculation on my part and I've come to realize that I understand very little about where and how big browns end up, how much movement they may have in a year and even what their tolerances may be to survive in water that I might think they can't survive in.

 

[salvelinusfontinalis]

Maurice,
0% chance. The fish was a strain of wild brown trout for sure

 

[salvelinusfontinalis]

Chaz and Sal,
Appreciate the comments, some angles i have not thought of before

 

[troutbert]

salvelinusfontinalis wrote:
In the past 2 months, I have been fortunate enough to land 4 brown trout (19-23") on limited trips, that I believe are brown trout that migrate from cold water streams to large warm water rivers. That is to say, at least I believe that is what they do.

However now I am not so sure. I know for certain that some of these fish return to 1 of 2 cold limestone streams in the summer because I witnessed it. However I always assumed that they stayed until after the spawn. In one of the limestone streams the spawn is going on full force but I caught large browns in the warm water river already, one of which was a large female full of eggs.

Some of them may move up in the summer to find cool water.

Then drop back down in the fall as soon as river water temps warrant.

Then move back up to spawn.

On Spring Creek in central PA I've seen trout on the redds as late as Dec. 10. In southern PA limestone streams, trout probably continue spawning considerably later, as spring water temps are warmer, and air temps.

So the trout you caught in the river that still had eggs may simply not have moved up to spawn yet.

 

[krayfish2]

Look at the biggest / most obvious in our area, the Susky. The temps typically stay cool enough for trout from September through June. Maybe not ideal but not lethal. That leaves only a few weeks for the fish to seek refuge or tolerate the warm.

Rivers like the lower Delaware and Lehigh are known to support wild fish populations....but the water temps often soar into the 80's. How is this possible when most studies show exposure to temps of 75+ for a few hours is lethal to trout?

Is it possible this data is incorrect? Is it possible the fish have morfed into a strain that can withstand much higher temps?

Back to the OP, that female may have not moved into her spawning trib yet. It's also possible that she had already returned to where she was hatched. Was the suitable spawning habitat close to where you caught her? It's a truly fascinating topic. We know so little about these fish. Most reports indicate they exist in very low numbers but I believe they are out there in larger numbers than we think. Those that do find them are pretty tight lipped.

 

[pcray1231]

Ditto. In this situation I've always thought the purpose of ascending cold trib is most often thermal rather than spawning. Reason being is they stage off the mouths in mid summer, and ascend in late summer (at least where I've seen it).

Some may stick around to breed before returning. But it's not necessary. We make the assumption that it's a migratory "population", where the next generation is the offspring of those that migrated before them. Not that it can't be true (certainly is true with steelhead), but with browns I've never been convinced. It's not an "organized" enough run. I just think as long as there's normal resident browns in tribs, a few end up in the river downstream. And when that river warms, they seek the nearest cold water, which may or may not be the stream they were born in, and they may or may not stay well into the fall. Wherever they are at breeding time, there they will try to breed, regardless of whether there's any hope for their offspring in that environment.

The migratory browns don't have to breed successfully to make more migratory browns. If they don't breed successfully, that's ok, come spring millions more fry will be born in those tribs. The offspring of ordinary 10 inch residents. And a few will end up down in the river to make up the next generation of "migratory" browns.

 

[Fishidiot]

Agree with the above posts.

This is a fascinating topic that is poorly understood and calls out for scientific study.

To be sure, local folks have long known that certain mid to large sized WW creeks and rivers produce very large brown trout during certain times of year, but the habits of these big, mysterious fish with respect to spawning and long term residence, is almost entirely speculation.

 

[pete41]

I thought they were imprinted to move upstream to spawn to keep fish in the rivers-then move downstream to keep fish in the rivers as they would quickly eat up all the fry if they stayed concentrated in the smaller waters and the fry would be meals for all kinds of fish in the bigger waters.Natures game plan.

 

[Midge22]

I have read that browns do NOT imprint. Which tends to make sense to me. Ive caught some big browns in places they shouldnt have been.
i know of a place where there are large fish yearly, but they arent there in the summer. ive caught fish over 20 inches in places that are barren in the summer due to temps. Ive done it for roughly 4 straight years. and as for spawning, that stream was a strict WW until they put in an AMD treatment plant, and the communities switched to waste water treatment plants (10 years ago). Now there is a wild brown population. The cold water fishery is roughly 10 or so miles above (road miles) where im talking about. Thats not that far, but those fish have to be running that far up to escape temps and to potentially spawn.

Its pretty incredible to think about that. Its also pretty incredible that i have never noticed salmonoids "running" (outside of the great lakes tribs).

 

[pete41]

In Montana the spawning runs from the lakes were the best fishing of the year---

 

[JeffK]

Just yesterday I was checking out the Delaware R tribs and came to one where the bar at the mouth was too shallow for most browns to ascend (saw two redds above). However, saw a number of redds on the gravel bar that extended into the Delaware. These gravel bars at the mouths of small tribs are also where walleyes will spawn in late winter.

BTW, caught two 13" to 14" fish in the trib and they looked like pretty beat up post spawn browns.

 

[rrt]

There is presently a study on the LJR about trout movement. It is not confined to spawning time but all year. Some surprising findings so far: about 40% mortality from natural causes, migration of trout seems random so far, etc.

I think if you go to the LJR website, you might be able to find more info.

 

[salmonoid]

rrt wrote:
There is presently a study on the LJR about trout movement. It is not confined to spawning time but all year. Some surprising findings so far: about 40% mortality from natural causes, migration of trout seems random so far, etc.

I think if you go to the LJR website, you might be able to find more info.

http://www.littlejuniata.org/brown-trout-telemetry-study/

Signal can be picked up at 1/2 mile away. Guess you are SOL when the fish move 0.6 miles or more 24 fish to be tagged..

I made the conscious decision to fish the evening that this topic was being presented at the last Spring Creek TU meeting, but I now wish I would have attended.

Here is a study about large brown trout movement in the midwest:

http://savesilvercreek.org/Pdf_files/c8_range_habitat_brown_trout.pdf

This probably require a subscription to access and most fish are 18" or less:

Telemetry-determined Diurnal Positions of Brown Trout (Salmo trutta) in Two South-central Wyoming Streams

http://www.jstor.org/stable/2426390

 

[salvelinusfontinalis]

I'll have to look later but I had found a study on brown trout that showed in one large watershed they will move way more than 10 miles, but certain fish stay in a 300 yard stretch most of the year. Really interesting to try and figure these fish out

 

[JeffK]

NYS did a telemetry study on the Beaverkill a few years back. The browns basically stayed put, except for the two weeks when they spawned and then they went all over. However, they came back. Some browns were seen on very strange trajectories, but they were later discovered to be in the bellies of birds. Rainbows on the other hand migrated a lot going to the tailwaters for summer thermal refuge and then heading up to the freestones when the water cooled.

 

[krayfish2]

Jeff,
Your take on the study is somewhat accurate. Yes, I have no life and read a good portion of the study. They tagged fish on EB, WB, Main and BK. Wild browns, wild bows and stocked browns were tagged. Basically, a majority of the stocked browns stayed put. Even if the water temps exceeded lethal levels....they just sat there and died. The browns did seem to move less but a few did move 20-25 miles. What was interesting is that one fish had a pattern where it would swim down river all the way to Narrowsburg NY for it's summer refuge. There were also several bows that moved 20-50 miles...some up river, some down river. The bows seemed to be on the move quicker than the browns due to rising water temps. Very interesting study.

What was shocking to me was the percentage of the fish that were caught / kept and the tags returned to the university.

 

[geebee]

I have also read and seen studies of brown trout not imprinting.

they are an adaptive fish. they will mate where and whenever they can according to water temp and light levels.

I have seen numerous redds in January and February in their natal range - of which the continental US is not, remember.

they can also be nomadic and/or territorial dependent on food levels, water temps, water levels, cover and ability to transition or not.

they are the most successful trout globally for these reasons.

and they are probably the most studied trout too - to understand this complex beastie look back and East - Ritz, Halford, Sawyer, Skues, Waller Hills, Plunkett Green, RN Stewart, Falkus, etc etc these guys were naturalists and observationists as well as fishermen.

amongst the charming anecdotes and theories, there are many description of the varied natures of individual brown trout.

the strangest I've read was some warm water browns in an urban canal, who would in the fall would leap three feet into the air up into a factories cold water outflow and spawn in its gravel bedded water tanks. they would locate the pipe by its dripping flow and then jump over and over until they landed bang in it then they'd flap along the half empty pipe until they reached the tank and dropped into it.

adaptive you see.

cheers

mark.