Raibow Trout Question on Reproduction

[Wmass]

I was wondering what it takes for stocked rainbows to reproduce in streams? I was fishing my home waters up in Massachusetts this past weekend and managed to catch two beautiful rainbow holdovers. This water has a good supply of food and manages a good population of brookies and browns, but I can't figure out why the rainbows can't reproduce there.

Good fun this weekend though, also managed a nice 8" brookie. All were caught on #12 Olive Crystal Wooly Buggers.

 

[troutbert]

In PA there are a great many streams that have wild brown and wild brook trout. But there are just a comparatively few streams that have wild rainbow trout. I don't think it has anything to do with the stream conditions. I think it has to do with the strain of trout.

The strain of rainbow trout stocked in PA is a highly domesticated hatchery strain. It does well in the hatchery environment, but not does not establish wild populations.

The places that have wild rainbows in PA, such as Falling Springs and Delaware River were apparently stocked with other strains of rainbow that are just better equipped genetically for living in the wild.

The situation is probably similar in the Mass. stream you fished. If the stream is capable of supporting browns and brookies, it is probably capable of supporting rainbows.

Whether that would be a good thing or not is another question. In the Smokies, wild rainbows eliminate native brook trout in freestone streams. They just displace them completely. Which creates a very messy fish management problem.

In PA freestone streams, brown trout compete with brookies, but they don't eliminate them. Even freestoners that are dominated by brown trout, such as Cedar Run, still support brookies.

 

[Squaretail]

I'm no biologist mind you. However the one thing in common with any streams I've caught wild rainbows in (Falling Springs,Trindle Springs,Big Springs) is they're true limestone springers. Limestone is sometimes used to help equalize acid levels in water. Though browns, brooks amd rainbows are very close in whats required to support them there are differences in tolerance to water temps, ruggedness, and tolerance to acidic levels in water and rainbows are the least tolerant to the latter. That would be the problem in my book. Did you ever notice how at some streams you will catch a rainbow and it will seem like theres hardly any slime on them? The acid levels are a big factor in the fish ciommission determening wether to stock brooks/browns or rainbows/browns in any particular stream. Big answer from a man that cant promise its 100% correct.
Good question thats probably ran through the mind of any average flyfisherman.

 

[JackM]

Squaretail wrote:
Good question thats probably ran through the mind of any average flyfisherman.

Actually, I am betting the average fly angler is unaware of the existence of wild rainbows in Pennsylvania. :-D

There are some small freestone streams that support rainbows as well. The one I have in mind does test out with a relatively good total alkalinity, which would buffer the acid rain that the watershed receives. Does anyone know if the reproducing populations in PA are all Spring spawners?

 

[Bamboozle]

Like JackM; I too know of some freestoners with wild bows which I HAVE to believe are hatchery fish that somehow figured out how to reproduce since one of the streams happens to be a Class A brown trout fishery, while the other one USED to be a Class A brook trout fishery.

One of these streams was stocked many moons ago and is a feeder to an AT stream although the mouth of this Class A feeder is NOT dumping into a stocked section. I have caught several bows that have all the earmarks of wild fish including color, size, markings and large perfectly formed fins.

If I am correct about these fish being wild, I have to believe they are of the elusive Benner Spring strain known for their stubby fins, washed out color and receptiveness to anything that remotely looks like food. How they turned out to be related to the beautiful believed-to-be wild fish I caught I'll never know. This unnamed stream is definitely NOT a limestoner but has an abundance of riffles and highly oxygenated water.

I also have caught what I believed to be wild rainbow trout on the Saucon Creek in the Trophy Trout/non-stocked section once or twice and on Cross Fork which now is stocked. Again in both of these cases the fish I caught were gorgeous specimens, perfect in every way; a far cry from the stockers I also caught at Cross Fork and the occasional stocker I catch in the open water of the Saucon.

Of course the Saucon is considered a limestoner although it has the characteristics of a freestoner. In other words it doesn't look like either Trindle or Falling Springs. Cross Fork is a freestoner all the way.

As far as the spawning dates; in all of these streams the population is way too small to have noticed anything.

 

[FarmerDave]

Squaretail wrote:
I'm no biologist mind you. However the one thing in common with any streams I've caught wild rainbows in (Falling Springs,Trindle Springs,Big Springs) is they're true limestone springers. Limestone is sometimes used to help equalize acid levels in water. Though browns, brooks amd rainbows are very close in whats required to support them there are differences in tolerance to water temps, ruggedness, and tolerance to acidic levels in water and rainbows are the least tolerant to the latter.

Actually squaretail, I am pretty sure this is incorrect. Brown trout are less tolerant to acid, but not by a whole lot. I'm not absolutely positive on this, but am pretty sure both from reading and from my own experience. One year we put a bunch of stocked trout that we had caught in a spring at my brother's place to keep them fresh. most of them were brook trout. Relax, we were not stocking a stream. These went into a metal tank that was fed with a spring that I would guess was PH challenged because of the geology in that area (all sandstone). The brown trout didn't last more than a half hour, and I would guess it was from low PH. The rainbows did better (but were not put in there at the same time), but the brook trout did well no matter when we put them in. Had fresh fish until the spring got too low. Think about where they all originated. Browns thrive in the limestoners because they are closest to the chalk streams where they were originally taken from. Rainbows are from out west, and I am guessing they evolved in streams that were not high in PH. Not much limestone in the rockies (somewhat of a guess).

It's very true though that the acidity level is used by the PF&BC to determine what to stock. One thing for sure is that the brook trout are quite a bit more tolerant than the other two. In NW PA you can tell which streams have low PH because they receive only brook trout.

Also, I have caught numerous wild rainbows from a couple freestone streams. Not saying where though in a public forum, but they are not secret. I will tell you that there are wild browns and brookies in the same streams. In all of them, the further upstream you go, the more these streams are dominated by brookies. Browns and rainbows are further down.

I don't have the answer on why there are not more wild rainbows. My guess is that there are several reasons why we don't have many streams with wild rainbows. Some of them have already been stated. Climate could be part of it. One would think they would do well in the limestone streams, but maybe they aren't cold enough in the spring. However, if they are only stocking inferior strains, they just don't stand much chance of getting established. I'd guess that the streams that do have wild rainbows have had them for a very long time, since before the PF&BC perverted the strain.

Jack

 

[FarmerDave]

JackM wrote:

Squaretail wrote:
Good question thats probably ran through the mind of any average flyfisherman.

Does anyone know if the reproducing populations in PA are all Spring spawners?

My best guess is some do spawn in the fall, especially if you count steelhead. I'm pretty sure some of the fall spawners are successful.

I believe some of the wild stream rainbows spawn in the fall. The rubber PF&BC rainbows originated as wild fish a long time ago, and through selective breeding, they developed ones that spawn mostly in the fall. If it wasn't there originally, I doubt they could have developed this without genetic engineering, and they didn't use genetic engineering, only selective breeding. Still just a guess. I typically don't fish stream trout in the fall.

 

[FarmerDave]

To elaborate on something i said earlier... I think climate has something to do with it, too. The wild rainbows I would guess are mostly spring spawners, even in PA. Unfortunately, we get a boatload of rain in the spring which cause a bunch of problems with developing trout eggs and fry. If the stream gets muddied up, kiss the eggs goodbye. The streams where i catch wild rainbows, although they are freestone, they don't tend to get that silted even when the water flow goes way up, and they also recover very quickly from high water conditions.

 

[JackM]

FarmerDave wrote:
To elaborate on something i said earlier... I think climate has something to do with it, too. The wild rainbows I would guess are mostly spring spawners, even in PA. Unfortunately, we get a boatload of rain in the spring which cause a bunch of problems with developing trout eggs and fry. If the stream gets muddied up, kiss the eggs goodbye. The streams where i catch wild rainbows, although they are freestone, they don't tend to get that silted even when the water flow goes way up, and they also recover very quickly from high water conditions.

Dave, this is the theory I was pursuing when I asked that question. It may be the stream geology and flow "habit" during the typical Spring spawning period that determines the likelihood of a viable reproducing rainbow population.

 

[Wulff-Man]

……And many places out west they get a boatload of runoff in the spring.

 

[FarmerDave]

JackM wrote:

It may be the stream geology and flow "habit" during the typical Spring spawning period that determines the likelihood of a viable reproducing rainbow population.

Jack, I'll be honest. I vaguely remember reading or hearing something along those lines many years ago, but don't remember the details, so I was just trying to tie it in to my personal experience. I personally think it is a big part of why they aren't established more places, but not the only reason. They have stocked a lot of rainbows for a long time in this state, so i don't think the poor strain had as much to do with it in the past, but it fits why the curent rubber fish don't take hold.

 

[FarmerDave]

Wulff-Man wrote:
……And many places out west they get a boatload of runoff in the spring.

Very true Wulff-Man, but the characteristics are quite different when you are talking runoff from snow vs spring rains. I think the variation of flow is what is hardest on them (along with silt). In those western streams, the flow, although much higher in the spring, stays relatively constant well into summer compared to PA streams. this is because most of the flow is from snow and ice melt. in PA, the stream levels vary considerably because it is mostly from spring rains. In the west, the rainbows spawn in this higher flow. The flow stays up and is highly oxygenated. In the PA Springtime the streams are up and down all the time. If they spawn when the stream is relatively down, then with a big rain they get washed out and/or covered with silt. Stream drops, and the eggs die from the silt. Or, if they spawn when the crick is up, they are left high and dry when the level drops.

Take my favorite wild rainbow stream in PA. Like i said earlier, it recovers very very quickly from rain, and usually doesn't get very muddy. This stream passes through a fairly deep valley which is heavily shaded by hemlock. You need a flash to take pictures, even in the middle of the afternoon. Also, there are rock outcroppings that get covered in ice in the winter. Lots of ice. I've seen ice still along thos rock walls clear into June. I think this helps maintain consistant flow which would help spring spawners.

Like I said, I don't remember the details so this is somewhat of a guess, as to why some streams have reproducing rainbows and some don't.

 

[troutbert]

In the past, I don't think PFBC stocked rainbows established populations at all, because they were are a highly domesticated strain.

But, just a few years ago, the PFBC began buying rainbows from a private hatchery down south somewhere. These fish are very likely of a different genetic strain.

The question is, are these imported rainbows of a strain that can establish wild populations? It does seem like there are more little, wild-appearing rainbows popping up in unexpected places in the last couple years. I've noticed this and so have others.

 

[FarmerDave]

I can't answer your question, but ...

When I was speaking of "in the past," I didn't mean in the past couple decades. I meant way back when they started stocking rainbows (probably about 100 years). Back then, they were basically transplants from out west, and it took several years before the PF&BC perverted the strain to what they are today. That is why I speculated that the streams that have wild rainbows have had them for a long time (as in many decades).

 

[FarmerDave]

Not sure what happened there, but my point is, the rainbows we have now, had to come from PF&BC stocking at some time. They have been around for decades, but aren't native to PA.

 

[TimMurphy]

Wulff-Man wrote:
……And many places out west they get a boatload of runoff in the spring.

Dear Wulff-Man,

That isn't entirely accurate. Out west the rainbows spawn primarily in March and the high water from run-off doesn't occur until late June or early July in most years. They have the benefit of spawning and having the eggs hatch during generally low flows during the "Mountain" winter.

Fish spawning in PA at that same time are usually met with the highest flows of the entire year since that time period is generally when whatever snow we have melts and the Spring rains begin. I think that makes it awfully difficult for a Spring spawning fish to be successful.

Regards,
Tim Murphy

 

[RLeeP]

The paucity of self-sustaining RT pops. in PA streams has always been a curiousity to me. Most of the other states in the NE have significantly more wild RT pops than PA. Even NJ has a higher percentage of such waters as a component of their total cold water mileage than PA.

I think there are a lot of factors involved, from spawning difficulties to existing wild BT and ST pops that have simply been too much for introduced RT to successfully compete with long enough to establish a breeding population and so on and so forth.
Water chemistry so far as alkalinity, etc. *may* be a factor, but my giess is that it is not much of one. Rainbows do just fine in an awful lot of low alkalinity streams all uo and down the Appalachian spine, from VT to GA.

But I think my vote for most likely controlling factor goes to the strains historically used by the PFBC. I say this mostly because in at least some of the places where RT have established themselves in freestone water in PA, the source of the original fish very easily might have been other than PFBC. There is or was a scattering of wild RT pops in small freestones in and around the Allegheny National Forest, particularly the western portion of the Forest. Chances are fairly good that the ancestors of these trout were Federal fish. Before they mostly got out of the fish raising biz some years ago, the Feds used to dump a lot of fish in ANF waters.
If a scattering of these same waters have developed self-sustaining RT pops while virtually no long term state managed streams have done so, this *may* (and it's a big maybe) be an indication that the difference is somewhat due to the original strains stocked and their characteristics, etc.

Personally, I really like to fish over small wild freestone RT. They are by far, once hooked the hottest fish of any of the three major species..

 

[tomgamber]

TimMurphy wrote:
Out west the rainbows spawn primarily in March and the high water from run-off doesn't occur until late June or early July in most years.

Actually, Tim, they will spawn anywhere from March thru July. Some of the streams in the area of Idaho, where I lived, were closed from june 15th to july 15 for just that reason. Regardless, There is something different about the flows or temps or chemistry of the water, thats makes them less successful here.

I read one report that said regardless of when they spawn there can be a difference of up to four months as to when the eggs actually hatch based on water temps. And a difference of two months from when the fry will leave the gravel beds and find alternate cover based on flows, so those things may factor in as well.

The last time I was out there it was June 15th. They had a lot of snow in late april and flows were pretty average as the "big" snows hadn't even begun to run off yet.

 

[Maurice]

My theory as to why we don't have more Rainbow reproduction in PA is primarily due to the effects of acid precipitation. After hearing all of the conjecture, allow me to add mine. I like the idea that the strains may have something to do with it...to a point. But there has to be something more to do with water quality.

As discussed before, we have the acid tolerant brook trout. But these fish are mainly tolerant to the more acidic streams in the hemlock forests. Mainly first and second order stream with steeper gradients. The secondary fish for this region is the rainbow trout. I believe they survive well here because of the temperature controlled forests in moderately acidic streams. Some even reproducing here.

Then we have the more warm water tolerant Brown trout that can and does find ways to reproduce in the messiest watercourses the mankind can produce. Many of these stream and rivers are silt laden still waters in the summers. When its all said and done after a warmer summer the Browns are still there but the Bows go away. (well, you will find some in the heaviest pocket water and bouldered pools where spring seeps help a little) Still, reproduction remains the duty of the BT. Still RT are the primary fish stocked for these larger and warmer, more silty streams.

Rainbow trout are the major production product of the state's machine. And that is only going to get worse...or better depending on how you look at it. RT put on weight faster and grow longer than any of the big 3. With the request for fewer but larger fish, expect more rainbows.

Therefor RT cover more ground, so to speak, than the other two species from a stocking standpoint. But their reproduction is limited to limestone streams and small freestones...and the Delaware. (But we will come back to that.) Acid precip has been around since the stocking of RT. Although better now..but getting worse, the operative word is dosage. If you look at the limestone streams they inhabit, they are very small drainage areas. The freestones are small as well. Smaller drainage areas equate to lesser impacts from acid precipitation and siltation.

As for the Delaware, maybe it is a "dilution solution" as to why they thrive there. Or maybe largely due to the strains. (I liked RLP's Federal fish conspiracy theory) The Delaware fish could be NY strains of RT. Less corrupted genes.

KIMIHNIWITA :-D

 

[Chaz]

I think it's a combination of factors, first as Troutbert said it is in their genes to do well in a hatchery environment same as hatchery brookies in fact. Once released to the wild they last in streams only until the last fish is harvested, same as the hatchery brookies there too. If some do escape capture they just die.
Fall spawning fish tend to have better success spawning, in part because of spring floods, having said that though, the stocked rainbows for the most part spawn in the fall, so that might help. I believe that the water chemistry has an impact but it is hard to get this information. As for the number 1 cause I believe it is genetics and believe that the streams that do have wild bows were stocked with a good strain over a hundred years ago.