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Current PA Brook Trout Population as Percentage of Original?

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What do you all estimate the current brook trout population in PA is, as a percentage of the original brook trout population, i.e. pre-European settlement?

Of course there is no way to know this exactly, but just what would be your rough estimate? (I will give my own ideas later, after hearing from others.)

Posted on: 3/6 9:00


Re: Current PA Brook Trout Population as Percentage of Original?

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Interesting question. I guess this can be looked at two ways, as numbers of fish or as poundage of fish. I'm sure they were probably bigger back then because there was less settlement and more foliage hence more food.

I would say numbers, maybe 30% of what it used to be.

Poundage, I would guess maybe less than 10%.

Posted on: 3/6 9:35


Re: Current PA Brook Trout Population as Percentage of Original?

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Quote:

Foxgap239 wrote:
Interesting question. I guess this can be looked at two ways, as numbers of fish or as poundage of fish.


Biologists typically use poundage, i.e. weight, i.e. biomass to assess trout populations, and that's probably the best measure, so let's go with that.

Posted on: 3/6 10:03


Re: Current PA Brook Trout Population as Percentage of Original?

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Come on TB, you know me. I'd have a hard time spelling "biologist". Fortunately you spelled it for me!

Posted on: 3/6 10:08


Re: Current PA Brook Trout Population as Percentage of Original?

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Pre-Euro brook trout population? Gosh, I dunno. I am younger than some of you guys, so I wasn't fishing back then :)

I have read early 20th C fishermen accounts of 20" wild brookies, but not sure what these mean? After all, I know some guys who still catch them! :)

of course if you go back some tens of thousands of years, much of today's brookie habitat was choked with ice and snow-- wait a minute, is it happening again?

Ok I'll stop ... my guess is 30% by # of fish. biomass a bit less.

Not sure what all this means.. much of deforestation etc cant be reversed in reality .. historical range doesnt really tell you about about current viability. black bears greatly reduced from original range included N indiana for example, but that doesn't mean they are doing badly in PA now:

https://www.bear.org/website/bear-page ... /37-black-bear-range.html

Posted on: 3/6 10:08


Re: Current PA Brook Trout Population as Percentage of Original?

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ebtjv 'brook trout health map' below. I am not saying that it is wrong, but I saw this when I started fishing and got the impression that wild brookies would be hard to find in PA. very little of PA listed as intact, mostly reduced, greatly reduced, etc ... think it is based on historical range. coded colors may be right based on present versus historical. but I get the feeling there may be good and stable brookie populations in some pa watersheds -- even if they are in fact reduced from some historical peak.

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Posted on: 3/6 14:06


Re: Current PA Brook Trout Population as Percentage of Original?

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FWIW, I'd add another inquiry to the nature of the question. You could also look at it by % of brook trout holding streams with respectable populations, compared to the original.

By number of streams, I'd estimate we're still at 70 or 80% of the original.

By number of fish, we're probably more like 20% of the original.

And by lbs of fish, probably more like 5%.

Guestimates, of course.

The discrepency is mostly about which streams. The brookies still exist, in often relatively healthy populations, in MOST smallish headwater streams where they always did. But they've been lost or largely lost in the bigger waters. In many cases due to those larger streams being much warmer than they once were, in other cases due to brown trout taking them over.

To clarify, if every little hop across sized headwater stream counts as 1 stream just like Big Pine Creek counts as 1 stream, we really have only lost a small % of the brook trout holding streams.

That said, 1 stream like Big Pine, over 30+ miles, held enough trout to populate several hundred, if not thousand of those little streams, which are much smaller and usually only a few miles in length.

And the average weight of one of those Big Pine fish is probably 5 times as heavy as the average trout from those little streams as well.

Using Big Pine as an example. You could replace it with a number of the largish streams in PA which don't have wild trout, or virtually ANY of the streams which currently hold brown trout and no respectable brookie populations. Streams with primarily brook trout outnumber streams with primarily brown trout over 10 to 1 in this state. But the brown trout streams are generally larger and richer, and more significant to us fishermen.

Posted on: 3/6 14:24

Edited by pcray1231 on 2014/3/6 14:40:54


Re: Current PA Brook Trout Population as Percentage of Original?

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P.S. That post kind of explains why I'm not sure how to take the map that k-bob showed.

i.e. yes, almost all "watersheds" are impaired. The big stream that defines the watershed probably is severely impaired, as well as any larger tribs it may have. But in more forested areas, the little tribs in the system are often in better shape.

Posted on: 3/6 14:36


Re: Current PA Brook Trout Population as Percentage of Original?

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right so loss of brookies by stream-mile is not so much but by biomass is major. brookies probably fairly stable where they are. bambi came roaring back, but he can live in the burbs:


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Posted on: 3/6 14:40


Re: Current PA Brook Trout Population as Percentage of Original?

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Breakdown from the map above:

Percent of watersheds where brook trout were once present that still hold brook trout.
-Green: 1% relatively intact (~90% occupied)
-Yellow: 9% present in reduced percentages (50-90% occupied)
-Red: 39% existing but greatly reduced (<50% occupied)
-Gray: 34% extirpated

Posted on: 3/6 14:41


Re: Current PA Brook Trout Population as Percentage of Original?

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Interesting curve. I'd also point out on that curve that modern whitetail populations, where healthy, are actually much larger than pre-European Settlement, at least here in the temperate eastern US.

The reason is that after the logging days, the forests came back with a higher % of hardwoods, which support much larger populations. And also farms, which also support larger populations.

But on a graph like that, those observations have to be combined with the fact that there are not healthy populations in many areas due to development. So more deer in less area = about the same number of deer.

The devil is always in the details.

Posted on: 3/6 14:45


Re: Current PA Brook Trout Population as Percentage of Original?

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ebtjv map: right only 10% of PA _watersheds_ are that once had brook trout are now 50% or more occupied by brook trout.

do that by PA streams, not entire watersheds, and you'd get a very different picture.

Posted on: 3/6 14:50


Re: Current PA Brook Trout Population as Percentage of Original?

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Please do not divert this thread to whitetail deer. If you wish to discuss that, please start another thread.

Posted on: 3/6 14:51


Re: Current PA Brook Trout Population as Percentage of Original?

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deer chart is relevant ... basic issue is that some species do better in changed post deforestation envt than others. also issues of # of animals versus weight of total stock.

Posted on: 3/6 14:53


Re: Current PA Brook Trout Population as Percentage of Original?

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Quote:

KenU wrote:
Breakdown from the map above:

Percent of watersheds where brook trout were once present that still hold brook trout.
-Green: 1% relatively intact (~90% occupied)
-Yellow: 9% present in reduced percentages (50-90% occupied)
-Red: 39% existing but greatly reduced (<50% occupied)
-Gray: 34% extirpated


Ken,
What do those percentages mean? Does it mean:

stream miles now occupied by brookies / stream miles originally occupied by brookies?

Do you know if the people who did that research every tried to come up with an answer to the question in my OP? That is a rough estimate of the present brookie / population vs the original.

A stream stretch may be occupied, i.e. brookies are present, but in numbers far less than originally, because of various changes, that greatly reduced the brookie population, but did not go so far as to totally eliminate them.

Posted on: 3/6 15:03



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