Wild Trout Stream Survey

[tomgamber]

Brookies have survived for a very long long long long long long time. Way before we were around.....i think if they can withstand pressure from Dino's then i think humans won't be a problem.

That's all very Jiminy Cricket of you. I think your half-full glass is overflowing though. I'm not so sure dinos and the eastern brook trout had an overlap and if they had, I don't think the dinos were targeting these fish or dumping mine waste into their streams.

TWEEK wrote:
yes there are those people out there that like to kill every trout in sight, but i think "we" out number them....

Unfortunately, thats just not true. I wish it were.

 

[Wulff-Man]

TWEEK wrote:
....yes there are those people out there that like to kill every trout in sight, but i think "we" out number them.....

To add to what Tom has said, and to reiterate what I and others have been saying about the possible fallacies of the wild trout survey conclusions....... It doesn't matter if "we" outnumber "them" 20 to 1, or 50 to 1 for that matter, it just may be very possible that "they" can still severely impact many wild streams.

 

[LehighRegular]

Guys
As Mike said, the data they have collected is good. In fact any data collected is usually good data to some extent. What makes a difference is how one interprets that data.

It is obvious that the PFBC is interpreting it as basically saying "all is well in PA". I (being in the scientific field myself) see it a bit differently. For example, the creel survey discussed that the majority of trout creeled were brook trout. To me, that says, brook trout must be protected. But, the PFBC has basically said that regulations aren't necessary. Its a matter of interpretation of the data.

And as Wulff man said above, it doesnt take many anglers willing to creel trout to impact a wild trout fishery for years to come, especially under the current regulations.

 

[Mike]

Lehigh Regular:

That the majority of trout harvested were brook trout does not mean in and of itself that brook trout need protection. Whether or not "protection" is needed depends upon what portion of the population that is subject to legal harvest is actually being harvested. In Pennsylvania, on a statewide basis, that portion is low, amounting to approx. 7 brook trout per stream mile. This is approximately 10% of the avg. number of legal brook trout in a 76 stream sub-sample of the creel survey streams. Are you really that concerned that slightly over one creel limit per mile is being harvested? If so, ask yourself what the true motivation is behind that concern. If it is a value judgement, you are certainly entitled to your values, but if it is a biological or population concern, that is going to be a tough sell to fisheries managers and the general angling public.

 

[LehighRegular]

In Pennsylvania, on a statewide basis, that portion is low, amounting to approx. 7 brook trout per stream mile. This is approximately 10% of the avg. number of legal brook trout in a 76 stream sub-sample of the creel survey streams.

Mike....in your scientific opinion...what is the reason for this "low" number?

 

[Wulff-Man]

Assuming the experts did a masterful job of designing a study that accounts for the possibilty of 1 out of 50 anglers taking their limit repeatedly over a short period of time in a few streams, 7 brook trout per stream mile is an average. Is this 7 trout per season, or what? It seems very little per season. But it's an average, so it's hard to get a feeling for it. Because it's an average, it still could mean that some streams near populated areas could be cleaned out, while those in remote areas have little or no harvest. Just saying that you have to be careful with averages. And I have to go back to the argument that if so few people are harvesting, what's the harm in protecting streams that could be overharvested by having lower creel limits (or bigger size limits)? It would only impact a few anglers who may be "taking more than their share" to the detriment of the majority of anglers. This just seems to be what the PFBC would want to do, maximize the fishing experience for the greatest number of people, as opposed to making it possible for a few to severely negatively impact a stream if that's their style.

 

[troutbert]

Wulff-Man wrote:
Assuming the experts did a masterful job of designing a study that accounts for the possibilty of 1 out of 50 anglers taking their limit repeatedly over a short period of time in a few streams, 7 brook trout per stream mile is an average. Is this 7 trout per season, or what? It seems very little per season. But it's an average, so it's hard to get a feeling for it. Because it's an average, it still could mean that some streams near populated areas could be cleaned out, while those in remote areas have little or no harvest. Just saying that you have to be careful with averages.

Yes, you have to be pretty careful when you are smushing the data together from unlike streams and creating an overall average. Supposedly 7 brookies per mile were harvested and the streams contain an average of 70 legal brookies per mile. But some of the streams have very low numbers of legal size brookies per mile. The data is in the report. Some streams have numbers like 23, 11, 5 or even 0 brookies per mile.

Even worse some of the streams used in creating the average that have high numbers of legal brookies per mile, are under special regulations!
Lyman Run and Slate Run for example. And Kettle Creek was under special regs beginning in 2004, the year they took the data.
So these population numbers, taken from special regs streams, inflate the average numbers used.

We've been discussing brookies here, but the same thing is true when looking at brown trout. They also used population data from some special regs streams when coming up with their average wild brown trout populations. For example Saucon Cr, Spring Cr, Penns Cr, Rauchtown Cr, and Slate Run. Some of these special regs areas have populations that are WAY above what's typical (which supports the argument for special regs BTW). But they are using the data from these special regs streams to inflate the overall averages for wild brown trout pops per stream.

So they're are saying that special regs aren't necessary, but they are using population data from special regs streams to support the argument that the trout population is thriving under general regs!

More generally, the streams they took the harvest data from, and the streams they took the population data from, are not the same set of streams! You can read through the study and see what I mean.

They are taking HARVEST data from one set of streams. And POPULATION data from a different set of streams, some of which are special regs streams, then comparing the harvest levels vs population data.

So, those of you with a science background, what do you think? Is this as bad science as it appears or am I missing something?

 

[LehighRegular]

ONe thing I forgot to add about harvest. The grassroots group I am working assisted the PFBC with a creel survey last season. Of the participants (29) who sent survey cards back to me there were 442 trout caught in approximately 353 hours of fishing. Of those reported catches 29 trout were harvested. About 7% of the trout caught were harvested (actually, that % might be a tad higher since there were some smallies counted in the total # of fish caught, none harvested). In addition, anglers noted on their survey cards that they witnessed other anglers creeling trout. Did those anglers participate in the survey...don't know for sure. FYI - I have not seen the PFBC survey info yet.

But what that leads me to believe is that I think there is much more harvest going on than what is portrayed by the PFBC.

Is the data good - yes

Is it bad science - no

Is it a bad interpretation of the data....For you to decide.

 

[Mike]

Troutbert,

You made a very good point about the brook trout population data including some special reg sections. I had not noticed that before, so I quickly eliminated those special reg areas (Kettle, Slate, Lyman, Penns, Rauchtown, Big Spring) and ran the averages again for streams that contained brook trout. As it turns out you should have quit when you were ahead. By removing the special reg areas the new average number of legal brook trout per mile would be 83 per mile instead of the 76 per mile that I reported earlier. I would not expect you to know this, but having worked with the statewide trout dataset one can add or subtract waters and not really change the data very much because the data set is so robust. That is probably the case here as well. Take out some high numbers, take out some low numbers, and it all comes out the same. But your point is well taken from a scientific standpoint...those special reg area population data should not have been included when I compared harvest per mile with population per mile in my previous post. I made the human error of not having looked very closely at the list. Fortunately, the special reg areas were not included in the harvest per mile figures.

This exercise should point out the bias that exists when special or conservative reg. proponents assume that special reg waters drive up the average number of legal trout per mile. They didn't do that for brook trout in this case, which lends support what I have been saying all along. And by the way, the difference between 76 and 83 legal brookies per mile is probably not statistically significant.

I am not going to play with the brown trout numbers because there is no point. Brown trout harvest is so low that it doesn't matter whether the special reg streams are included or not in the population data. Frankly, that is also true for brook trout. A little more than a creel limit of brook trout harvested per mile over an entire trout season is nothing to be concerned about. As I have said before, there may be unusual streams that are being overharvested, but they are not the norm and they will be relatively difficult to find. If that were not the case, the creel study would have shown it.

 

[Mike]

Lehigh Regular:

You said: In addition, anglers noted on their survey cards that they witnessed other anglers creeling trout.

So what makes you think that the anglers who were seen creeling trout creeled them on average over the course of the creel survey at a rate that exceeded the 7% rate that you just reported?

 

[OhioOutdoorsman]

For all of you arguing to change regs -

So how does "saving" a brook trout that was going to die from stress, starvation, or non-human predation by limiting creels protect brook trout populations?

I just don't get these endless regulation arguments. Stocking arguements I understand to a degree, but not regulation arguments. I'm not entirely ignorant, I was an ecology major as an undergrad and have been fishing all of my life. Maybe this makes me part of the PFBC-stocking industry complex. Oh well.

While everyone intentions (I think) are good (and not just an excercise in fly-fishing myopia), I think the emphaisis in your conservation efforts would be MUCH better spent in areas other than second guessing fisheries professionals and arguing over regulations that have a modest, if any, affect on a POPULATION.

Yes, you are taking a FISH, but another slightly smaller fish swims into its prime lie and now has a chance to thrive that it didn't before. This is why a POPULATION can tolerate a certain creel.

Lets deal with reality and not worst case scenarios.

 

[Maurice]

OhioOutdoorsman wrote:
For all of you arguing to change regs -

So how does "saving" a brook trout that was going to die from stress, starvation, or non-human predation by limiting creels protect brook trout populations?

I just don't get these endless regulation arguments. Stocking arguements I understand to a degree, but not regulation arguments. I'm not entirely ignorant, I was an ecology major as an undergrad and have been fishing all of my life. Maybe this makes me part of the PFBC-stocking industry complex. Oh well.

While everyone intentions (I think) are good (and not just an excercise in fly-fishing myopia), I think the emphaisis in your conservation efforts would be MUCH better spent in areas other than second guessing fisheries professionals and arguing over regulations that have a modest, if any, affect on a POPULATION.

Yes, you are taking a FISH, but another slightly smaller fish swims into its prime lie and now has a chance to thrive that it didn't before. This is why a POPULATION can tolerate a certain creel.

Lets deal with reality and not worst case scenarios.

Double O,

While I fully understand this harvest rationale, my problem with it is the time of harvest. Although the harvested trout will be replaced by younger ones from this year, it is my opinion that by taking them so early in the season jeoprodizes my opportunity to fish for them. We later season anglers are relegated to the "whats left" population. The same population used to quality a stream for classification.

The system used to qualify streams looks at them from a specific view. For instance, small (

 

[Mike]

Troutbert:

I reran the trout per mile population estimate numbers shown in the wild trout creel survey table this morning for two reasons. 1) I was curious about the brown trout per mile and 2) it dawned on me that perhaps I ran the brook trout numbers differently last night than they were done in the report. Regarding 2), it turn out that I was comparing apples to oranges last night because I only included a stream in the averages if it actually had brook trout present. The report, it turned out, counted those with and without brook trout present in calculating the average number of brook trout per mile.

So, let me revise the numbers again...this time using only those stream segments that actually harbor a brook trout population or a brown trout population...........

avg. legal (7"+) brook trout per mile including the special reg segments = 94
avg. legal brook trout per mile minus the special reg segments = 83

avg legal (7"+) brown trout per mile including the special reg segments = 257
avg legal brown trout per mile minus the special reg segments = 304

My comments in my previous post still stand for the most part except that you were correct in that the emperical number of wild brook trout per mile is slightly inflated when the special reg areas are included. My comment about that, however, still applies....I sincerely doubt that there is any statistical difference between 83 and 94 legal brook trout per mile. More importantly, a fishing rod is not a technique that will allow an angler to detect a difference that is so small. Furthermore, my comments about statistical significance and the inefficiency of a fishing rod in detecting population differences of the magnitude shown can be applied to the brown trout numbers as well.

The bottom line remains the same: harvest of brook and brown trout in the creel study was low in comparison to the avg. number of legal trout that were available in a subsample of the study streams.

 

[Mike]

Maurice:

I always have to hold one back for you in case you respond. Here goes. Electrofishing examinations of wild trout streams just before opening day and then repeated during the mid to late summer revealed that more legal size wild trout were present in the summer samples. Your point I believe is that the fish may have moved into the sampling sites from below seeking thermal refuge. That may be so, but the sites were probably located a variety of distances from any thermal problems. But I'll give you that point as being pretty reasonable. Here is the kicker though. One of the sites in NE Pa. was immediately above a substantial waterfall, high enough that no trout was going to go up even in high water. Even at that sampling site the number of legal size trout was greater in the summer. I can't explain it, but that was the case. So, there remains no evidence that late season anglers should have a poorer success than early season anglers based upon the numbers of legal size wild trout that are present.

 

[JackM]

I don't know much about trout ecosystems and biology, but wouldn't there be a "growing season" for trout where they would add most of their yearly growth in comparison to other parts of the year? And if so, I would think that would be the time when food is most plentiful and water temperatures more "prime," i.e. April thru July.

 

[LehighRegular]

So what makes you think that the anglers who were seen creeling trout creeled them on average over the course of the creel survey at a rate that exceeded the 7% rate that you just reported?

Mike

What I'm saying is that there are more anglers out there creeling trout. I dont know the percentage because they may not have participated in the creel survey. The anglers noted that 5 trout were creeled on the cards by the "other anglers".

I think it would be foolish and under conservative to suggest that the rates were lower. In my profession we use groundwater contaminant models and project them to be over conservative for the protection of human health. Based on the Wild Trout Survey, it appears under conservative in a variety of ways. That is just how I interpreted the information that was presented in the report.

 

[LehighRegular]

One of the sites in NE Pa. was immediately above a substantial waterfall, high enough that no trout was going to go up even in high water. Even at that sampling site the number of legal size trout was greater in the summer. I can't explain it, but that was the case

What kind of stream did this Stream with the water fall flow into?? And could have fished came up from lower reaches of this stream or even a river/stream this creek flowed into?? Maybe that explains the increase in #s? Just a thought.

Mike is that possible in this case?

 

[Maurice]

Maybe Mike could provide the breakdown of spring +legal size and sub-legal (within an inch). that may be the crux, In the three months between, some fish may have grown to above the legal size because this is when they put on size. (length and weight). With the right fertility, trout can grow fast. But we don't know these details, maybe Mike does.

Maurice

 

[OhioOutdoorsman]

Using regs to alter the size of the fish is another matter all together.....

What about a slot limit? Would that work...maybe not on brookie streams but maybe with browns and rainbows?

If we want to alter regulations to give us the type of fishery that we want - large, wild fish in a C and R FFO environment, thats fine. But lets be honest and say its self-derving......

I'm out of here, going to the smokies for a week of fly fishing.....look forward to everyone's conclusions when I get back.

 

[Mike]

Maurice, Jack, and LR,

Growth may have played some role, but as I recall it could not have explained much of the results. I expected that upstream movement into the sites was a likely source of the additional legal fish plus some growth, but the upstream movement theory took a major hit when the waterfall case appeared.

LR, what I was trying to say about that was that the sampling site being used was above the waterfall, so any fish moving upstream toward the sampling site could not have gotten to the sampling site because of the blockage.

Lastly, Jack is correct that there are a few prime months for growth of wild trout on some streams. A recent paper on some Appalachian streams concluded that brook trout in the study waters grew for only two months out of the year (during the spring) corresponding with an exceptionally high availability of terrestrial insects (a particular terrestrial insect group, in fact). During summer and fall food availability was limited to the extent that all energy derived from the available food went into fish body maintenance and none went into growth. This helps explain what we have seen in some mining affected streams where there is a pausity of aquatic macroinvertebrates yet the brookies are robust and growing well. In our limited gut analyses in the summer and in a student's gut analysis of the fish in the fall terrestrials were a large part of their diets. The volume of terrestrials that are available for brook trout is probably at least in part determined by the species of vegetation that surround the streams.