Chesapeake Log Perch soon Federally Endangered? PSU’s Dr. Stauffer highlights threat of invasive predators

Fish Sticks

Fish Sticks

Well-known member
Joined
Mar 19, 2022
Messages
3,194
Location
Central PA
www.wtaj.com

One-of-a-kind: Penn State research team studies rare Susquehanna fish

Pa. (WTAJ) — A Penn State University research team is sharing new findings about a rare darter fish that they believe only lives in the Susquehanna River. It’s called the Chesapeake log…
www.wtaj.com www.wtaj.com

Stauffer warns against adding more invasive predators


Of note PA fish and boat stocks some of the last few streams on earth containing this rare species with invasive hatchery trout as well as manages for wild invasive brown trout populations in or very near them.

If Feds list the species PFBC might be forced to clean up their act. We will see.
 
Fish Sticks said:
www.wtaj.com

One-of-a-kind: Penn State research team studies rare Susquehanna fish

Pa. (WTAJ) — A Penn State University research team is sharing new findings about a rare darter fish that they believe only lives in the Susquehanna River. It’s called the Chesapeake log…
www.wtaj.com www.wtaj.com

Stauffer warns against adding more invasive predators


Of note PA fish and boat stocks some of the last few streams on earth containing this rare species with invasive hatchery trout as well as manages for wild invasive brown trout populations in or very near them.

If Feds list the species PFBC might be forced to clean up their act. We will see.
Click to expand...
Since the only management of wild brown trout in that part of SE Pa is with statewide regulations, then by extension the application of statewide regulations would be categorized as managing Pa wild brook trout as well.

Again, as for the stocking of catchable trout in logperch streams, the stocking in one occurs at least 5 mi and one waterfall upstream from the logperch, and that logperch population may be a river-based population. In the other case, but based on old logperch data, the present most downstream stocking point appeared to be upstream from where logperch had been found in the past. At present, the logperch are sympatric with a small wild brown trout population if I recall the more recent wild trout survey correctly. In a third case, one of the two (re)introduction efforts described in the article is occurring in a stream that has two stocked tribs. If there was concern about stocking in a basin with logperch but not directly over them, I doubt that stream would have been selected for introduction of logperch.


Finally, it can’t be emphasized enough that the largest logperch population in a stream in SE Pa is sympatric with a very good wild brown trout population and that the logperch are the most numerous of the “forage size fish” in the stream segment where the populations are sympatric. Wild brown trout have been known by me to have been there since at least the late 1950’s or early 1960’s, so if logperch were also there at that time, sympatry has occurred for numerous fish generations.
 
Last edited:
Mike said:
Since the only management of wild brown trout in that part of SE Pa is with statewide regulations, then by extension, the application of statewide regulations is managing Pa wild brook trout as well.
Click to expand...
I suspect he's talking about the special regs (to protect trout) on two tributaries.
 
Mike said:
Since the only management of wild brown trout in that part of SE Pa is with statewide regulations, then by extension the application of statewide regulations would be categorized as managing Pa wild brook trout as well.

Again, as for the stocking of catchable trout in logperch streams, the stocking in one occurs at least 5 mi and one waterfall upstream from the logperch, and that logperch population may be a river-based population. In the other case, but based on old logperch data, the present most downstream stocking point appeared to be upstream from where logperch had been found in the past. At present, the logperch are sympatric with a small wild brown trout population if I recall the more recent wild trout survey correctly. In a third case, one of the two (re)introduction efforts described in the article is occurring in a stream that has two stocked tribs. If there was concern about stocking in a basin with logperch but not directly over them, I doubt that stream would have been selected for introduction of logperch.


Finally, it can’t be emphasized enough that the largest logperch population in a stream in SE Pa is sympatric with a very good wild brown trout population and that the logperch are the most numerous of the “forage size fish” in the stream segment where the populations are sympatric. Wild brown trout have been known by me to have been there since at least the late 1950’s or early 1960’s, so if logperch were also there at that time, sympatry has occurred for numerous fish generations.
Click to expand...
It is a well known fallacy in fisheries science that looking at observational presence data in a sympatric population with brown trout is just a wild guess and that unless you control for independent variables you can get correlation without causation. This was the case, and highlighted I believe in a recent study of the presence of small minnow and darter species with brown trout in northwestern PA.
You cannot just look at data and make assumptions without testing them. Would it be so surprising if a cold clean stream with good habitat sustained a higher amount of two species despite the one harming the other?
 
Hardly. Given the characteristics of exotic fish invasions and their population reproductive trends, if an invasive predatory fish (and sometimes a competitor of the forage fish) has not substantially reduced a forage fish population in relatively short order (a few fish generations) in a given water body or a segment thereof where the invader is most abundant, it’s not likely to do so unless there is a second substantial increase in that predatory fish population, which could occur with changes in habitat/water quality.

One doesn’t need to know about independent variables within a given population of wild BT and logperch to know that each is thriving at a point in time based on their abundance index values. You don’t have to know the cause to know that a fish is abundant, but it’s helpful if you would like to try to duplicate that elsewhere. For example, logperch were scarce in a silty stream upstream from two impoundments, but was it the silt in the creek or the blockage by the impoundments preventing upstream migration from the river that was the problem? Given the age of the impoundments, I’m betting on the silt. Studying it doesn’t change the fact that they are scarce.

Even when reproduction in the year of the survey has been poor, evidence of previous strong year classes is suggestive of a thriving population. We know that reproductive success varies from yr to yr in fish populations. Furthermore, some forage fish are so abundant in some streams that even an index of abundance value seems unnecessary at the time unless it is used in the future for comparison. Sometimes it is obvious to the trained eye that the species is abundant, but measuring that abundance assigns a number to the population for future comparative work. Even if a species’ abundance has declined over time, prior to any surveys, the species may still score high in an abundance index.
 
silverfox said:
I suspect he's talking about the special regs (to protect trout) on two tributaries.
Click to expand...
There are no special regs to protect wild brown trout in any tribs to the lower Susquehanna in the stream drainage basins where logperch have been found or in the other near-by wild brown trout streams to those logperch streams. In the entire Area 6 region there is only one special reg area targeting BT. My observation stands; if BT can be said to be “managed” with statewide regs, so can ST.
 
Last edited:
Mike said:
There are no special regs to protect wild brown trout in any tribs to the lower Susquehanna in the stream drainage basins where logperch have been found or in the other near-by wild brown trout streams to those logperch streams. Even the Codorus mouth is probably at least 20 river miles and separated by at least one power dam from one of those tribs.
Click to expand...
When you stock the species into recovering lancaster county streams you can expect wild reproduction ergo PFBC management is promoting a brown trout fishery
 
Mike said:
Hardly. Given the characteristics of exotic fish invasions and their population reproductive trends, if an invasive predatory fish (and sometimes a competitor of the forage fish) has not substantially reduced a forage fish population in relatively short order (a few fish generations) in a given water body or a segment thereof where the invader is most abundant, it’s not likely to do so unless there is a second substantial increase in that predatory fish population, which could occur with changes in habitat/water quality.

One doesn’t need to know about independent variables within a given population of wild BT and logperch to know that each is thriving at a point in time based on their abundance index values. You don’t have to know the cause to know that a fish is abundant, but it’s helpful if you would like to try to duplicate that elsewhere. For example, logperch were scarce in a silty stream upstream from two impoundments, but was it the silt in the creek or the blockage by the impoundments preventing upstream migration from the river that was the problem? Given the age of the impoundments, I’m betting on the silt. Studying it doesn’t change the fact that they are scarce.

Even when reproduction in the year of the survey has been poor, evidence of previous strong year classes is suggestive of a thriving population. We know that reproductive success varies from yr to yr in fish populations. Furthermore, some forage fish are so abundant in some streams that even an index of abundance value seems unnecessary at the time unless it is used in the future for comparison. Sometimes it is obvious to the trained eye that the species is abundant, but measuring that abundance assigns a number to the population for future comparative work. Even if a species’ abundance has declined over time, prior to any surveys, the species may still score high in an abundance index.
Click to expand...
What this simply conclusion fails to account for is source sink dynamics. You say they are both there so whats the problem but the log perches life history is such that it migrates into these streams from the river. So their could be a negative interaction in one of the streams with brown trout and log perch from another stream could be coming in because of the habitat quality.

The other thing is your assessment is highly static based on when you surveyed it long ago. Invasive species don’t just gobble up native fish immediately as the sole mechanism of negative impact. Often slow progressive changes in size structure of the impacted native species can take away size based refuge from predation, or changing thermal characteristics can for a native species into a habitat type where conflict happens more readily, Or conservation genetics can be effected over periods of time by changes in behavior.

Just saying i Surveyed it a couple times but didn’t study means you got a snap shot which is essentially useless in uncovering negative impact. There are mixed class A streams that have alot of brook trout and alot of brown trout but that are in transition with displacement happening the same thing can be true of the log perch.

If PA fish and boat wants to continue to stock with they need to actually study it (not collect observational data and draw conclusions) the thinking that such is not necessary would be torn apart by groups of fisheries scientists peer reviewing such an idea should it make it onto paper.
 
Mike said:
There are no special regs to protect wild brown trout in any tribs to the lower Susquehanna in the stream drainage basins where logperch have been found or in the other near-by wild brown trout streams to those logperch streams. In the entire Area 6 region there is only one special reg area targeting BT. My observation stands; if BT can be said to be “managed” with statewide regs, so can ST.
Click to expand...
You can’t say that because when you stock brown trout or have harvest restrictions on wild brown trout you know they will displace brook trout in most cases(over what time scale is variable)

But if you know brown trout + brook trout = eventually likely just brown trout the. Statewide regs that favor that are just brown trout management as the goal not brook trout. Same with any species brown trout effect negatively like darters or certain cyprinids, you can’t say your managing for them if your state regulations favor promoting the species that you know will win the interaction between the two.
 
Fish Sticks said:
When you stock the species into recovering lancaster county streams you can expect wild reproduction ergo PFBC management is promoting a brown trout fishery
Click to expand...
Wow, if only it were so simple as that. You can hardly “expect it.”

Furthermore, in my view when adult BT are stocked there is no management for BT; the management is with BT.
 
Last edited:
Mike said:
Wow, if only it were so simple as that. You can hardly “expect it.”
Click to expand...
Lol are you saying brown trout swam here from Scotland? Yes i expect stocking in a large karst increasingly partially reforested region to create wild populations ….because where this has been done its already happened
 
Specified in #9 above were Lancaster County streams, not limestoners, and that generalization was what I was responding to. Almost every wild brown trout stream in Lancaster Co is not a true limestoner, although some are limestone influenced. That a true Lancaster Co limestoner would recover to the extent that BT reproduction would occur would certainly be unexpected and a pleasant surprise given the degree of degradation. True limestoners with wild trout are:. Donegal- regularly struggles to maintain a decent wild BT population and Hammer - has both ST and BT, with tribs in Lancaster Co that have nearly entirely or entirely ST populations. The rest of the limestoners in Lanc Co I looked at or surveyed were shot, although there may br an extremely short one west of the airport.
 
Last edited:
I think compromise is what has gotten so many species threatened.

Acting like zealot is a bad word is funny. In things such as convictions, it can be a very good thing.

It seems to me, if we are to treat zealot with negative connotations when referring to stocking or not, it's the stocking zealots that need every trickle stocked that seem uncompromising.


Not a single wild trout water should be stocked.
I would definitely say not a single Class A or B. The stocking zealots have a fit at such a reasonable compromise , like there arent plenty of marginal waters to put rubber fish in.🤷
 
Last edited:
Mike said:
Specified in #9 above were Lancaster County streams, not limestoners, and that generalization was what I was responding to. Almost every wild brown trout stream in Lancaster Co is not a true limestoner, although some are limestone influenced. That a true Lancaster Co limestoner would recover to the extent that BT reproduction would occur would certainly be unexpected and a pleasant surprise given the degree of degradation. True limestoners with wild trout are:. Donegal- regularly struggles to maintain a decent wild BT population and Hammer - has both ST and BT, with tribs in Lancaster Co that have nearly entirely or entirely ST populations. The rest of the limestoners in Lanc Co I looked at or surveyed were shot, although there may br an extremely short one west of the airport.
Click to expand...
I seriously doubt there is more than a handful of brook trout left in Walnut or Kettle. When were these streams last surveyed?
 
Kettle…2 summers ago is my recollection ( when it was being looked at for the possibility of dam removal).
 
You must log in or register to reply here.

Latest posts

Montana Angler Fly Fishing
Montana Angler Fly Fishing
Harman's North Fork Cottages


Real Time Data From
the USGS Site

Share this page

Back
Top