Wild Rainbows, why aren't they more common in PA/NY/NJ?

[Underdog]

Any thoughts on why there aren't more naturally reproducing wild rainbows? Why are they usually small when there are? Seems like it's all about brown, brook trout mostly. Or am I very wrong.

 

[Kyle]

i have caught plenty in the ken lockwood gorge over the years. although like you said they are small. that gorge is a year round trout conservation area though. some common factors of not many wild bows or large ones could be.

polluted waters.
rivers that dont stay cool all year.
rivers that are not restored to host ample bug life.
fishing pressure.
predators, like mink, otter, eagles.
poor fishing habits.

 

[Mike]

Rainbow trout: sensitivity limits reproductive success in Pa/adult survival

The subjects of limited RT reproduction in Pa and temperature sensitivity come up periodically here. Yesterday, I happened to be doing some research and stumbled across two scientific publications that refreshed my memory. Here is the long and short of it: Primary limits on reproduction...

www.paflyfish.com

Farther down in the thread you will find that I answered the NW Pa population and Smoky Mtn question as well….spring spawners.

 

[krayfish2]

There aren't a lot of streams I fish where wild RT are possible. Mike, I read your old post and the two rivers I can think of far exceed the temperature requirements you outlined. For sure, the Delaware contains wild RT and temperatures exceed 75 for extended periods most years. The other is the Lehigh where I suspect that we have small pockets of wild RT. The temps on that system usually get into the upper 70's / low 80's during the summer.

How the streams dramatically differ is what I was find interesting. Lehigh has many more riffle sections that aerate the water all summer.

The Delaware is quite gentle in flow with virtually no riffle sections, feeders dry up in summer but there might be more spring seepages. The same rainbow strain lives in the neversink and esopus. The only similarity is that the fish were a pure strain that learned to survive in the conditions they were handed. I see most of what the PFBC stocks to be multiple generations deep in hatchery life and ill suited for survival.

 

[FirstLight]

Rainbows are very sensitive to PH levels. Unless conditions are right with PH the eggs will not be successfully fertilized. There is limited natural reproduction in a few Pennsylvania streams per articles in the Pennsylvania Angler magazine. Here is another reference that explains some…

Rainbow Trout | Vermont Fish & Wildlife Department

Native to the West Coast and introduced to Vermont in the late 1800s, Rainbow Trout (Oncorhynchus mykiss) are the most habitat-sensitive of the trout species and are stocked and bred extensively in state fisheries. Rainbow Trout will live in high- to moderate-gradient streams and rivers, as well...

vtfishandwildlife.com

 

[Nymph-wristed]

All the other valid points raised aside, I wonder what percentage of stocked rainbows are actually males?

If there were more males stocked, would that make a difference? Do we even want that?

Most of the males I tend to catch are brood stock sent out to pasture in PA it seems.

 

[PennKev]

All the other valid points raised aside, I wonder what percentage of stocked rainbows are actually males?

If there were more males stocked, would that make a difference? Do we even want that?

Most of the males I tend to catch are brood stock sent out to pasture in PA it seems.

When fished fall stocked fish more often, I recall many of them expelling the white stuff when they were handled.

So I would say quite a few.

 

[Nymph-wristed]

When fished fall stocked fish more often, I recall many of them expelling the white stuff when they were handled.

So I would say quite a few.

But they are spring spawners aren't they? Isn't that one of the issues? And the ones that do go wild adapt to fall spawners from what I have heard.

 

[PennKev]

Rainbow trout: sensitivity limits reproductive success in Pa/adult survival

The subjects of limited RT reproduction in Pa and temperature sensitivity come up periodically here. Yesterday, I happened to be doing some research and stumbled across two scientific publications that refreshed my memory. Here is the long and short of it: Primary limits on reproduction...

www.paflyfish.com

Farther down in the thread you will find that I answered the NW Pa population and Smoky Mtn question as well….spring spawners.

So if spring spawners were introduced more widely in PA, do you think wild bows would be more widespread? Is that the implication?

 

[PennKev]

But they are spring spawners aren't they? Isn't that one of the issues? And the ones that do go wild are fall spawners from what I have heard.

I believe hatchery fish are fall spawners. If I am reading the other posts and linked posts correctly, wild bows in PA are spring spawners.

FWIW, I've never caught hatchery bows dumping eggs or milt over the winter or in the spring.

 

[Nymph-wristed]

I believe hatchery fish are fall spawners. If I am reading the other posts and linked posts correctly, wild bows in PA are spring spawners.

Yeah, I could def have the whole thing reversed, but I am curious what Mike says about that too. It just seems like most stocked fish and the vast majority of holdovers I catch are female.

 

[FirstLight]

May depend on where you are fishing. For many years Maryland DNR stocked mostly all female rainbows. The eggs came for a source on the West Coast that “cold shocked” the eggs to product female only
trout. The advantage of raising females - grow faster / larger then males in the same time period. Also, males become more aggressive and territorial in the raceways during the spawning season and start attacking each other (i was told this by a private fish hatchery owner. I do not know the male to female ratio of what Maryland stocks now. I think they stopped importing West Coast eggs due to disease concerns. Not that the West coast hatchery had disease, just out of an abundance of caution.

 

[tomgamber]

I lived in ID for a while and remember a lot of spawning areas were closed to fishing in late spring, early summer for spawning areas. Thinking about the timing I'd say it's water temps and flows that makes it difficult.

 

[troutbert]

The reason there are few populations in PA is that the strain of rainbow raised and stocked by the PFBC is a highly domesticated strain that tends not to establish wild populations. Which is a good thing because wild rainbows can out-compete native brook trout far into the headwaters, as they do in the Smoky Mountains.

In other states, their hatcheries have different strains of rainbow trout, that can establish wild populations.

The rainbow populations in PA were mostly introduced through private stockings. A few streams in NW PA have populations that are usually attributed to stocking by a federal hatchery.

The reason there are few rainbow trout populations in PA is not because of stream characteristics. There are rainbow trout in both limestone and freestone streams in PA, and streams similar to ours in other states in our region.

 

[Nymph-wristed]

The reason there are few populations in PA is that the strain of rainbow raised and stocked by the PFBC is a highly domesticated strain that tends not to establish wild populations. Which is a good thing because wild rainbows can out-compete native brook trout far into the headwaters, as they do in the Smoky Mountains.

In other states, their hatcheries have different strains of rainbow trout, that can establish wild populations.

The rainbow populations in PA were mostly introduced through private stockings. A few streams in NW PA have populations that are usually attributed to stocking by a federal hatchery.

The reason there are few rainbow trout populations in PA is not because of stream characteristics. There are rainbow trout in both limestone and freestone streams in PA, and streams similar to ours in other states in our region.

That makes sense. Another reason to regulate club stockings more closely. In my experience, the best looking bows and the majority of males also appear to be different fish than those provided by the Commish.

 

[Mike]

So if spring spawners were introduced more widely in PA, do you think wild bows would be more widespread? Is that the implication?

I think it’s likely enough that I wouldn’t want to try it unless I was attempting to or didn’t object to creating a wild RT fishery.

On the other hand, and a bit in contrast to Troutbert’s comment, I wouldn’t want to stock fall spawning RT in or near specific sections of limestoners that maintain the appropriate water temps, both summer and winter, that I listed in my links if I did not want to take a chance on establishing a wild RT population, assuming that physical habitat was also appropriate.

Somewhat in support of Troutbert’s comment as well has been my observation that even when PFBC RT successfully reproduce in freestone or limestone influenced streams (not the same as limestoners) they seldom survive for more than a year, if that, and they rarely produce many young fish…certainly not enough to result in a desirable fishable“population” even if they were to survive that long. In my experience what one usually finds is one or two yoy RT in a stream survey every 4-8 yrs. I could count on two hands the number of different streams of the types I’ve mentioned in this paragraph where my crews and I saw them.

 

[Mike]

That makes sense. Another reason to regulate club stockings more closely. In my experience, the best looking bows and the majority of males also appear to be different fish than those provided by the Commish.

Given the opportunity, the “Commish” RT will look exactly like a wild RT once the fingerlings are in the stream for a few months. You will see this for yourself if fishing a fingerling stocked stream. The PFBC uses the same brood stock to produce the fingerlings as it does for the adults. When the Tully was fall fingerling stocked in the 1980’s/1990’s the fish looked to be wild bymthe time the spring fishery rolled around.

To answer the other question, PFBC brood RT were all fall spawners during my career. I have not heard that anything has changed in that regard.

 

[Mike]

There aren't a lot of streams I fish where wild RT are possible. Mike, I read your old post and the two rivers I can think of far exceed the temperature requirements you outlined. For sure, the Delaware contains wild RT and temperatures exceed 75 for extended periods most years. The other is the Lehigh where I suspect that we have small pockets of wild RT. The temps on that system usually get into the upper 70's / low 80's during the summer.

How the streams dramatically differ is what I was find interesting. Lehigh has many more riffle sections that aerate the water all summer.

The Delaware is quite gentle in flow with virtually no riffle sections, feeders dry up in summer but there might be more spring seepages. The same rainbow strain lives in the neversink and esopus. The only similarity is that the fish were a pure strain that learned to survive in the conditions they were handed. I see most of what the PFBC stocks to be multiple generations deep in hatchery life and ill suited for survival.

I can’t speak with direct knowledge regarding RT in those rivers. I suspect, however, that if there is successful reproduction occurring within those rivers rather than in the tribs the RT must be finding a cold water source during the times when the rivers are warm and the productive redds must be in micro-habitats that don’t get too cold in winter.

 

[rustbeltwilds]

I think some rainbows stocked are triploids....although triploids look like females


T