Small fertile freestone brown trout population: size structure, abundance

[Mike]

Presented below are Brown Trout data from a small, fertile freestoner that was surveyed today. The stream is essentially unfished, with rare exception at a couple of locations. It has excellent larger fish habitat for a stream that is on average 5.3 m wide under the good flows that are occurring right now.

One can tell that the habitat is fairly good for larger trout based on the abundance of 11 and 12 inch fish. Typical small freestone BT streams have fewer fish of that size, but also typically have at least some fish up to 12 inches and if there is good habitat perhaps a 14-18 inch fish in 300 meters. I have not run the numbers yet, but given the abundance of "larger" fish I am fairly confident that is a Class A equivalent population.

What you will see is practically all fish from a 320 m long sampling site. There were probably two dozen more fingerlings that would have been collected in a few more electrofishing passes. These data come from three electrofishing passes through the site with a total three pass time of 102 minutes.

The stream is in Berks Co, was never surveyed before, and has thousands of vehicles passing it daily.

Note that this stream was out of its banks a few times this summer, including the recent weeks, but YOY abundance is excellent by any measure (2-4" fish).

Trout lengths, abundance
2", 2
3", 78
4", 16
5", 0
6", 1
7", 1
8", 18
9", 5
10", 3
11", 7
12", 4
15", 1

 

[Dave_W]

Very interesting to see results from studies like this.

The data tends to support the conventional wisdom of carrying capacity in light of habitat and food supply. Also of note is the evidence of good year classes with different age cohorts with good flood survival this year.

Perhaps the stream took a hit during the 2016 drought based on the gap in 5-7" fish(?) Hhmmm....

Anyway, more good news on the SEPA wild trout stream front.

 

[Mike]

Could be a missing yr class, but they are through much of their second growing season and were probably growing quite fast due to the ideal water temps and forage abundance (earthworms) this summer. Plus it is a fertile freestoner, as is Codorus Ck, for example. The missing year class may not be missing. The abundant 8" fish and those two 6-7" fish are possibly from the fall, 2016 spawning period and just growing like crazy.

 

[Eccles]

Neat. A fertile base with an abundance in the 2-4 year class. A rapid switch to piscivory by fish in the 10-12 inch group?

 

[troutbert]

Mike,

What do you think is the age breakdown for those trout?

 

[Acristickid]

It’s not stocked and the wild trout are thriving?

 

[Fly-Swatter]

It's not stocked and the fish are left alone (by anglers) so the wild trout are thriving.

Mike: I'm curious to learn if this stream has mostly public or private access. I don't have a slue where it is and I don't live in the area, but this info may shed light on why it's not fished much.

 

[Millsertime]

If this stream was surveyed utilizing tax payer's money, shouldn't he just state the name and location of the stream?

 

[FarmerDave]

No.

You might ask why.

1. It probably was paid for with PF&BC funds which don't come out of the general tax funds.

2. This sight is not owned by the PF&BC.

3. It will appear on the PF&BC list of streams with natural reproduction if it isn't there already (likely is). It also sound like it may be in consideration for class A listing. Definitely not a wilderness stream. ;-)

 

[wildtrout2]

Millsertime wrote:
If this stream was surveyed utilizing tax payer's money, shouldn't he just state the name and location of the stream?

What, so a bunch of fishermen can converge on it? Then, the next thing you know it's laden with trash and damned near fished out. I'm OK not knowing it's location. It's just nice to hear of a newly classified wild stream that's doing well!

 

[salvelinusfontinalis]

I'm 99 percent certain I know the stream.
There are only a few access points on it open to the public, what is open , isn't pleasant to fish.
Fairly urban.

I could be wrong but I'm sure I'm not. Fished it twice and found it to be not worth it, even had good fish back then. Just not as good as some others in the area.

 

[jifigz]

Brown trout are truly adaptive and thriving. I'm glad to hear about their increasing populations around the state. PA is truly blessed with a lot of fantastic water.

 

[Swattie87]

Millsertime wrote:
If this stream was surveyed utilizing tax payer's money, shouldn't he just state the name and location of the stream?

Here, on a public forum? Probably not.

If you email or call the PFBC, and ask politely to talk to the biologist who did the survey and will be writing the report (in this case, Mike), they will likely tell you. My experience is the biologists are good guys/gals and like to talk streams with knowledgeable anglers.

 

[Swattie87]

Mike - What delineation do you use to define a "fertile freestoner?" My assumption has been that as freestoners grow in size, they tend to become more fertile. Problem is as they grow in size, they tend to get warmer, and at some point (usually while still rather infertile) they become too warm for Trout.

This stream seems pretty small from your notes though. What makes it fertile at such a small size?

 

[salvelinusfontinalis]

If Iam correct on my location swattie,
It's part limestone and feeds a reservoir.

 

[FarmerDave]

Swattie87 wrote:
Mike - What delineation do you use to define a "fertile freestoner?" My assumption has been that as freestoners grow in size, they tend to become more fertile. Problem is as they grow in size, they tend to get warmer, and at some point (usually while still rather infertile) they become too warm for Trout.

This stream seems pretty small from your notes though. What makes it fertile at such a small size?

Sewage treatment plant. ;-)

 

[gulfgreyhound]

Down stream fro a farm and the effluent from the barnyard? GG

 

[timmyt]

"If this stream was surveyed utilizing tax payer's money, shouldn't he just state the name and location of the stream?"

The guy who accuses others of 'needing a spoon' now wants one himself, isnt that IRONIC

 

[wildtrout2]

timmyt wrote:
"If this stream was surveyed utilizing tax payer's money, shouldn't he just state the name and location of the stream?"

The guy who accuses others of 'needing a spoon' now wants one himself, isnt that IRONIC

You have a good memory (post #12 of that thread) timmyt.

 

[troutbert]

Swattie87 wrote:
Mike - What delineation do you use to define a "fertile freestoner?" My assumption has been that as freestoners grow in size, they tend to become more fertile. Problem is as they grow in size, they tend to get warmer, and at some point (usually while still rather infertile) they become too warm for Trout.

This stream seems pretty small from your notes though. What makes it fertile at such a small size?

Freestone streams of similar size can vary greatly in fertility depending on differences in the soils and rocks the streams are flowing through.

Everybody knows that some soils are more fertile than others. So it makes sense that water draining from those soils also have different chemistries.