Stocked browns spawn successfully

[Mike]

Embedded in the wild trout discussion was a comment (paraphrased) that stocked brown trout do not spawn successfully, with some reference to poor spawning site selection.
That is certainly not the case in Pa., and I will support that comment with just two observations. Long term studies by a power company on the East Branch Perkiomen Creek, a (very) warmwater stream, had never found wild trout or fingerling trout, nor had the PFBC. Following the first fall stockings of adult browns, fingerling browns were found in the same stretch at the historical sampling sites by the consultants. As expected in this warmwater stream, they did not survive the summer. The point is, however, the the stocked adults spawned successfully. Another case is that of the Class A Codorus Creek. The best available information is that the Codorus population's "founders" were spring stocked adult brown trout planted after the creation of the cold water producing Lake Marburg dam. Before construction of the dam, Codorus Creek was also a warmwater stream in the stretch that now supports the thriving trout population. I am unaware of any wild brown trout streams that were present in the upper Codorus or West Branch basins prior to the dam's construction.

 

[Stone_Fly]

I'll agree that there may be some reproduction, but I don't think I'd call it successful spawning if the fingerlings can't survive the summer. If there were more stocked brown trout reproducing then we wouldn't have any brookies left in our streams.

 

[tomgamber]

I think the fact that we have any wild brown trout in our waters (heck theres a list on the pfbc website full of them) tells me that they reproduce just fine, since they are not a native species.

 

[Philly]

What about Valley Creek? That would be a prime example of stocked browns spawning successfully. There are always reports of small wild fish being caught in Ridley Creek and the Wissahickon Creek. I've seen stocked browns attempting to spawn in the latter. It would seem that enough might be surviving to a size large enough to take a fly. The question might be is the spawn capable of producing a sustainable population of browns without additional stocking.

 

[Wulff-Man]

This is an interesting subject. I think there are (at least) 2 questions here:

1. Are stocked trout biologically capable of reproducing? Are they biologically capable but maybe not as fertile as wild trout? Do they become more biologically capable of reproducing if they hold over and become more wild? Tomgamber makes a good point that all wild brown trout in North America came from stocked trout, but it's possible that stocked trout today are not as fertile as those stocked a hundred years ago.

2. If stocked trout are biologically capable of reproducing to some extent, is this greatly restricted by other disadvantages? For example, studies like Bachman's have shown that stocked trout disappear from wild trout streams in a fairly short period of time. Some may argue this "theory" but the point is that stocked trout may not be able to survive or compete in even good trout water well enough to reproduce to an appreciable extent.

I don't have any answers, just questions, and I'm interested to hear what more knowledgeable trout experts might think or know about this.

 

[Padraic]

For example, studies like Bachman's have shown that stocked trout disappear from wild trout streams in a fairly short period of time.

Wulff-mann,

I've heard Dr. Bachman speak on his study a couple times. Granted 90% of it went over my head. Still, I don't believe that Dr. Bachman claims that all stocked trout die out of wild trout streams. I think, he rails on stocking wild trout streams for much the opposite reason. When trout are stocked over wild fish, both the stocked trout and the wild trout die off owing to territorial fighting, which expends energy and exposes fish to predators. Stocked trout die off at a greater rate than the wild fish, and I believe in the study group, all the stocked trout died off. There has to be a die off, because the wild fish will rise to a population level that completely fills the carry capacity for the stream (even if this population level is very low, such as a Class D or so).

I can well imagine a scenario where 1,000 adult fish are stocked over wild fish, year after year. The first years, the stockies may die off completely, but the wild population also suffers adult die off (which would take time to naturally replenish) and fry might fill the increased need for forage. So the stocked trout eventually find some footholds as the wild trout population is eroded. In that case, the stocked trout would eventually take over the stocked section of the stream.

 

[Wulff-Man]

Thanks, Padraic. I kind of remember reading that Bachman said something like "What happened to the stocked trout?" and kind of leaving it open that they may have gone elsewhere, at least the ones that survived. But even then they would have just run up against more competition in a stream filled to its capacity. Maybe some (many?) eventually find a spot where they can kick out a smaller/weaker wild fish. But I hope they can't totally take over a stream section.

As a footnote, I think I experienced an example of Bachman's findings at Spring Creek. I get there 3 or 4 times a year for a few days of fishing each trip. After the great hatchery breakout a year or two ago, at least 50% of the fish I caught in a section downstream of the Benner Springs hatchery were escaped rainbows. I'm talking about lots of small to medium sized stockies. This also was true my next trip, maybe 6 months later, and the rainbows seemed to be getting bigger and stronger. But my last 2 trips I don't think I caught or saw a single rainbow. "What happened to them?" Has anyone else experienced this on Spring Creek?

 

[MKern]

At my local creek, the browns have had a couple of good years lately. This year I caught about 10 little browns all under 8". Most of which are in areas that a stocked trout wouldn't hold, such as under the point of an overhung tree branch. This shows that the little ones are smart and know hte lay of the land. Plus, i like it when the strike indicator goes down and I reel in a 8" brown -- quite a plessant surprize.
P.S. I would attach pics, but my friend cam never take good ones.

 

[SlumpBuster]

I thinkn I can answer some of these questions you guys have.

Wulff-Man,
Stocked trout are definitly just as biologically able to reproduce as wild trout. They are not sterile by any means and could reproduce as long as they are healthy enough to do so. Saying that they can reproduce and are healthy they definitly will. So far as i know, trout have not lost any ability to reproduce in comparision to older stocks. I hope this answered your question and hopefully you'll believe me. I do know a little about fish adn managment practices.

Pardaric,
Good point I think you understood more than you think. You are right on stocked trout can have a huge effect on wilds when stocked over them. Stocked fish live in an enviremotn with almost no competition. They are fed every day and are use to sitting on top of each other. When stocked with wild trout they quickly destroy the system of strongest survives. Even though stocked trout may be finless they are usually fatter and have all thier food requirements met while in the hatchery.

Another good example of a stream that has reproduction of browns from stocked fish is the South Branch of the Codorus. I grew up on the stream my entire life and not lucky enough to have a dam at the top of it, it gets very warm during the summer. This past year I caught wild browns in it that were age 1. Its amazing to think they even survived.

Also a good stream to watch for the effects of stockies on wilds would be cross forks in potter. May the fishing gods have no mercy on the sole of the man who gave the go ahead to allow stocking that stream.

 

[troutbert]

Re: "May the fishing gods have no mercy on the sole of the man who gave the go ahead to allow stocking that stream."

Or the flounder either.

 

[vcregular]

It took two years the fin clipped fingerling stockies to dissapear. I think it was 2003 when 17,000 browns were planted. None if any are left. This pic is from April 2005.

 

[Chaz]

Which fin was clipped? I can't tell from the photo that any of them were the clipped fin but they sure are not the fins of a wild trout.

 

[LehighRegular]

Adipose fin is clipped. That is a fingerling that was stocked in Penns Cr. Those fingerlings grew at a nice rate....but once they hit 14" or so, they started to become very scarce. Not sure if the summer of 2005 or this recent summer took a toll on them and they died off because they couldnt find cold water. Or they just died off because they are stupid stockies??? Or both?

 

[Chaz]

The easiest answer is they subimitted to predation by anglers in the TT section of Penns Creek. I did notice the adipose fin looked strange.