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lycoflyfisher
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Those were the first additions in many years and if I am not mistaken are entirely on state forest land.
Swattie87
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Yeah. Hadn’t seen that. That’s good. Most are tiny, but still. I’m familiar with many of them.
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troutbert
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I agree that this is true. But I guess I assumed that it is obvious, i.e. that it goes without saying that if a stream has a mixed population that this means a loss for the brook trout population compared to if the stream held only brook trout.
What you see on the streams with mixed populations is that the brown trout take the prime lies (depth and cover) where life span and growth rate are greater. And brook trout are relegated to the more marginal habitat, i.e. "thin" water, as we fishermen say.
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troutbert
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Thanks for this good info. Comments on some of these streams:
Black Bear Run was stocked, not all that many years ago.
County Line Branch was stocked by a sportsmens club in the past.
Laurelly Fork has a coop hatchery along it, fed by a diversion from Laurelly Fork. It's not very "wildernessy" from that hatchery down to the mouth.
silverfox
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One of the WTS I alluded to earlier always surprised me because it has a SGL access road that runs right along the one fork for pretty much its entire length. There's quite a lot of activity in that area so its not very "wildernessy" either. I've suspected that people are "moving fish around" there. I suspect they do it as retribution for not being able to stock it.
On one that I fished, I got up to a point and heard people talking and rounded a bend in the creek and there was a cabin, and they had clear-cut all the woods through the holler except for the riparian buffer right on the stream. I didn't have OnX at the time, and maybe the stream stayed on the public land, but it was still very close to their cabin, so I backed out. Kind of wrecked the whole "wilderness" experience.
Another one I was fishing and heard motors which turned out to be several SxS's that had established some trails which crossed the stream upstream of me. That kind of ruined that one too. Another one I discovered had an adjacent landowner who established some 4x4 trails that ran right to the edge of the SGL where the stream was. Looked like it was heavily used but I never saw anyone on that one. They probably use it for access for hunting, but again, not really a "wilderness" feel when you cut fresh ATV trails.
I've fished quite a few of the WTS, and it's really a mixed bag in terms of fishing, from my experience. There are a bunch of streams I think should be WTS that aren't. Some are far more remote than some of the streams that are already listed. Some have been phenomenal, and some I'll never go back to. That's fishing though.
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Mike
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Mike
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Thermal maxima and upper incipient lethal temps (UILT’s) are only part of the cause for trout mortalities related to temperature. Chronic exposure to sub-lethal temps at temps still above the 68 deg F (20 deg C) stress threshold but below both of the above (thermal max & UILT’s) may still eliminate populations depending upon frequency of such excursions or degree days. Mortality is also expected to occur to even greater extent for time periods greater than 7 day UILT’s.
With respect to chronic temp oscillations above 68 deg, mortalities start after a critical number of degree days are reached or as the number of fifteen minute periods per month that temps exceed 68 deg F start to accrue. Even without outright mortality, temperature stressors can lead to population reduction and elimination through reproductive failures. Finally, I strongly suspect that a 3.3 deg F difference, also cited in the mentioned paper, in max weekly mean temperature tolerance limits between ST and BT can favor BT over ST by contributing to in some cases or exacerbating in others the often seen continuum of ST in headwaters, mixed ST BT farther down, and then purely BT even farther downstream.
As for thermal refugia in the form of upwellings in Pa, I have addressed this before by saying they do not appear to be common. Forty-two years of my field surveys on wild trout streams revealed none of these as demonstrated by congregations of fish, BT or ST, around apparent cold groundwater upwellings or upwellings in receiving streams originating from seasonally dry hollows. Once, however, it was clear that all wild BT in Marsh Ck, Chester Co, had been attracted to the cold plume of water discharging from a tiny, flowing trib. and I once found a substantial center channel spring in Willow Ck, Berks Co, a limestoner, at the head end of the Class A stretch. No trout were congregated near that spring and that spring was the starting point of the year around wild trout stretch. Upstream from that point the stream was warm during the summer and with some regularity dried up in areas.
Regarding upwellings being used by trout in Pa, a WCO found one of these groundwater upwellings in the warmer stretch of the W Br Perkiomen, Montgomery Co, as indicated by a “ball” of wild BT hovering around a non-descript spot in the middle of a channel. Likewise, when I asked if anyone on the Board had ever seen one, only Afish responded in the affirmative. Clearly they exist in Pa, but I have not seen or heard (from fellow biologists, WCO’s, or anglers) of them as being common. In contrast, reports of congregations of stocked trout around trib mouths as stocked streams warm are fairly common. Likewise those Penns Ck congregations of wild BT that occasionally occur under low flows and warm temps. I wouldn’t hang my hat on cold upwellings being a major factor in BT or ST population distributions in Pa until it is shown that they are.
With respect to chronic temp oscillations above 68 deg, mortalities start after a critical number of degree days are reached or as the number of fifteen minute periods per month that temps exceed 68 deg F start to accrue. Even without outright mortality, temperature stressors can lead to population reduction and elimination through reproductive failures. Finally, I strongly suspect that a 3.3 deg F difference, also cited in the mentioned paper, in max weekly mean temperature tolerance limits between ST and BT can favor BT over ST by contributing to in some cases or exacerbating in others the often seen continuum of ST in headwaters, mixed ST BT farther down, and then purely BT even farther downstream.
As for thermal refugia in the form of upwellings in Pa, I have addressed this before by saying they do not appear to be common. Forty-two years of my field surveys on wild trout streams revealed none of these as demonstrated by congregations of fish, BT or ST, around apparent cold groundwater upwellings or upwellings in receiving streams originating from seasonally dry hollows. Once, however, it was clear that all wild BT in Marsh Ck, Chester Co, had been attracted to the cold plume of water discharging from a tiny, flowing trib. and I once found a substantial center channel spring in Willow Ck, Berks Co, a limestoner, at the head end of the Class A stretch. No trout were congregated near that spring and that spring was the starting point of the year around wild trout stretch. Upstream from that point the stream was warm during the summer and with some regularity dried up in areas.
Regarding upwellings being used by trout in Pa, a WCO found one of these groundwater upwellings in the warmer stretch of the W Br Perkiomen, Montgomery Co, as indicated by a “ball” of wild BT hovering around a non-descript spot in the middle of a channel. Likewise, when I asked if anyone on the Board had ever seen one, only Afish responded in the affirmative. Clearly they exist in Pa, but I have not seen or heard (from fellow biologists, WCO’s, or anglers) of them as being common. In contrast, reports of congregations of stocked trout around trib mouths as stocked streams warm are fairly common. Likewise those Penns Ck congregations of wild BT that occasionally occur under low flows and warm temps. I wouldn’t hang my hat on cold upwellings being a major factor in BT or ST population distributions in Pa until it is shown that they are.
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Fish Sticks
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Thermal Refugia is just referring to a slightly to significantly cooler area and can be on a micro scale, using visually observed large congregations of fish is going to vastly underestimate the thermal heterogeneity of streams in PA.
I understand your point about sublethal temperatures but again measuring temps and mortality can be correlation without direct causation if your not controlling for displacement from thermal refuge. This thermal heterogeneity has been documented in shavers fork (a free stoner) in corey tregos study using scuba surveys and displacement did occur from thermal microhabitat 2c colder
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Mike
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The behavior of trout in thermal and chemical refugia that I have seen would be easily detected whether it was one fish or a pod. The fish were unwilling to move out of the refugia even when one walked through them or if they did attempt to move they immediately turned back when hitting the thermally or chemically different water. Given this extreme affinity for the refugia, even single fish holding in a refuge would be easy to spot when wading up a stream channel where clarity was such that the bottom and the fish were reasonably visible. They would be unusually approachable. Fish population surveys provide ample opportunity to observe such behavior if it occurs because of the single to multiple, thorough wading trips through sampling sites, both forward and laterally. With 42 years of stream surveys in Pa, if within channel refugia associated with upwellings were common, I should have seen trout behavior which indicated that the refugia existed.
Fish Sticks
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Id imagine one is not be able to see thermal Refugia well enough to quantify it, especially if small and a single fish is in it. Wether the fish bolts or bot seems like it gets into behavioral characteristics to an extent. Sounds like Trego et al used a thermometer in their study/snorkel survey.
sixfootfenwick
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Well maybe a few times, but maybe not also, sampling sites are 300m right? That is only 0.19 miles rounded up.
Leaving more that 80 percent of every mile not sampled, provided there is even a Sampling site for every mile of a watershed. Usually there isn't. Sometimes I also imagine more than 1.
That is a poor sample to determine if upwelling refugia exists, even after 42 years and multiple surveys.
I would also imagine only a percentage of the surveys would meet the criterion of observing the behavior. Many streams, when purposely surveyed for trout, stay cool enough the refugia isn't needed, unless an extreme occurrence of drought and heatwave. In others it is, but chances are the sample size surveyed is small when compared to the mileage in the basin.
Using that kind of sample to determine if something is common is like using a fly rod to determine fish populations.
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Fish Sticks
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Yea agreed and I think thermal microhabitat is different than what mike is picturing, finding 20 trout piled up on an obviously large cold water discharge into the stream. We could be talking about a pocket half the size of a shoe box. When you put the circle on the end of an electrofisher against a slightly undercut bank where rock formations intercept channel and a few fish turn up hard to say why they were there as opposed to sane feature 50 yrds up. Tiny seeps have to be near impossible to select visually and the temperature does bit have to be 55 deg F vs surrounding 76 to be thermal refugia
It doesn’t have to be anywhere near as dramatic as pine creek running into Penns creek
silverfox
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The largest upwelling I've found is mind-boggling. I only discovered it floating the river when it was extremely low and clear. The hole in the stream bottom was roughly the size of a manhole cover, and what caught my attention at first was the white sand surrounding it. It was pumping so much water that the surface of the river bulged where the upwelling is. The trout (BT) were scattered downstream of it for a good 25 yards or so. Upriver of that one about 1/2 a mile is a series of smaller ones and there are always trout (BT) tucked in against them in the summer when the river is 80F. Then another 1/2 mile up from that complex is a spring that erupts about 50 yards off the mainstem and forms a small stream before joining the river. One I discovered because my daughter and her friends innertube on the river and she told me about hitting a freezing cold section when the rest of the river was "hot" and I had her show me where it is. I found another one last year quite a ways upstream of those springs and I only noticed it because I was exploring the area closely and noticed water gushing out of the bank.
Outside of all of that a mile or so in either direction there is nothing like that one section. So I'd imagine that would all be easy to miss unless you went to that exact area.
Outside of all of that a mile or so in either direction there is nothing like that one section. So I'd imagine that would all be easy to miss unless you went to that exact area.
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Mike
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When you and/or your crews have sampled let’s say up to 1000 sites in wild and mixed stocked/wild streams, if refugia are all that important at the population level then by chance alone you are going to run into some (or at least one), just like all of the other rare events that one runs into in 42 yrs in the field because you were at the right place at the right time. Not only do you spend a lot of time in good water, you also spend a lot of time in marginal water. In fact, despite the occasional criticism here of the stream sectioning system, that system, as well as the unassessed waters program, encourages a crew to search out the marginal water/identify the break points between habitat types predominated by coldwater and transitional or warmwater fish communities. There are other reasons as well for establishing section limits, but fish communities determined by water temps can be one of them. Section limits are often established close to these areas and wild trout stream lower geographical limits are as well for designations and descriptions on the statewide list. As some like to point out, the majority of the sampling is done in the summer
You will note that I have not questioned the existence of the occasional refuge, especially the seeps coming out of riparian areas, the hyporheic inflows from tribs or hollows, the obvious occasional cold surface flows from some tribs, or for that matter (adding this one based on new recollection of another experience) the larger springs or groups of seeps where limestone bedrock crosses streams, but I’m not convinced that these are commonly important at the population level in PA streams, given the variability in geology from region to region and state to state. It reminds me to some extent of what I like to refer to as the “phantom anglers” who we are to believe harvest so many wild brook trout limits from Pa streams and those “phantom poachers” who, according to some anglers, are apparently to blame for so many of their bad days of fishing in special reg areas. As with the phantom anglers, the upwellings are rarely seen, but I am to believe that they exist in such quantity or volume that they are critical at the population level. Not only do I need to see some proof of that from Pa, but I would welcome it.
You will note that I have not questioned the existence of the occasional refuge, especially the seeps coming out of riparian areas, the hyporheic inflows from tribs or hollows, the obvious occasional cold surface flows from some tribs, or for that matter (adding this one based on new recollection of another experience) the larger springs or groups of seeps where limestone bedrock crosses streams, but I’m not convinced that these are commonly important at the population level in PA streams, given the variability in geology from region to region and state to state. It reminds me to some extent of what I like to refer to as the “phantom anglers” who we are to believe harvest so many wild brook trout limits from Pa streams and those “phantom poachers” who, according to some anglers, are apparently to blame for so many of their bad days of fishing in special reg areas. As with the phantom anglers, the upwellings are rarely seen, but I am to believe that they exist in such quantity or volume that they are critical at the population level. Not only do I need to see some proof of that from Pa, but I would welcome it.
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silverfox
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In the example I posted above, those seeps are an anomaly. I had (incorrectly) attributed the presence of large wild BT to some extensive migratory behavior. The Eureka moment only happened because I realized I was catching these fish in one relatively small area, and exploration of upstream and downstream of those areas by even a small amount didn't produce the same fish. In the winter, if it was really some migratory behavior and these fish were held up in some inaccessible tributary during the summer and then spread out in the large river in winter, you'd think any "trout-friendly" habitat in the large river would produce trout, but it didn't. It wasn't until I really started trying to understand the river by exploring it thoroughly in the heat of summer that I discovered the seeps and subsequently caught the same fish in the same places when the river was 80 degrees F.
So yes, it's an anomaly. Is it important at the population level? That depends on the definition of "population." I believe (now) that this "population" is nothing more than several dozen to maybe 100 or so individuals within a complex of about a mile and a half and halfway up a tributary. The thermal situation isn't only "important," it's necessary. Without it, the "population" wouldn't exist. We're not really talking about a "fishable" population here, though. I dumbed on them on a hunch, and it played out how I imagined (sort of), but that doesn't mean it's important. Its just an example of how things aren't always cut and dry when it comes to identifying important habitat for trout.
The "phantom" harvest, on the other hand, I've seen that with my own two eyes in the form of a 5-gallon bucket full of brook trout. That gentleman has moved on, though, and I think he was an anomaly too. Though I know his protege has been pinched multiple times for a whole variety of wildlife violations, so his proclivity to disregard bag limits lives on to some extent, regardless.
pcray1231
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I have found thermal refugia with my feet. Woo, that's cold right there. Even in freestone streams. And backed up by thermometers.
But not at times that thermal refugia are actually required because I don't generally fish a stream when the bulk water temperature would require fish to seek out such places. So I have not observed fish stacked up at them much.
More commonly, though, they are tributaries. Often the spring might be only a few dozen yards from the stream, but tributaries nonetheless. Even some really dinky tribs, sometimes actually appearing dry on the surface, actually flow decent water underground. Especially in the rockier areas, what you see on the surface of a small stream or trickle is only part of it.
But not at times that thermal refugia are actually required because I don't generally fish a stream when the bulk water temperature would require fish to seek out such places. So I have not observed fish stacked up at them much.
More commonly, though, they are tributaries. Often the spring might be only a few dozen yards from the stream, but tributaries nonetheless. Even some really dinky tribs, sometimes actually appearing dry on the surface, actually flow decent water underground. Especially in the rockier areas, what you see on the surface of a small stream or trickle is only part of it.
silverfox
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In case the OP is still paying attention here through the sidebar conversations, this list shows all the WTS and includes the biomass of the streams.
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troutbert
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Which river is this, and what do you think are the hydrogeological explanations?
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troutbert
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Small thermal refuges can be created where water flows from the stream channel into the floodplain substrates, where it cools, then flows back into stream channel.
Geek out, if you wish: https://en.wikipedia.org/wiki/Hyporheic_zone
Geek out, if you wish: https://en.wikipedia.org/wiki/Hyporheic_zone
Fish Sticks
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Well thats what I am saying, Trego found a significant amount to study in an infertile free stone shavers fork but i am to believe there are not a significant enough amount in PA the land of limestone for brown trout occupying to matter for native brook trout?
42 years of you not specifically looking for them and saying is not going to convince many there are not enough to matter at all at the population level.
