Question regarding Wild Brook Trout Enhancement Program

[wildtrout2]

JackM wrote:
The whole program failed to produce expected results and, yes, harvest restrictions failed as well.

What were the expected results that weren't produced? In what respect did restrictions fail? Try to be specific.

 

[afishinado]

wildtrout2 wrote:

JackM wrote:
The whole program failed to produce expected results and, yes, harvest restrictions failed as well.

What were the expected results that weren't produced? In what respect did restrictions fail? Try to be specific.

From the study link above:

we found that there were no changes in the mean CPE
of Brook Trout ?100 mm or ?175 mm from before to after experimental
CR regulation implementation for treatment or control
streams (Table 2; Figure 3). We also found that there were no
differences in mean Brook Trout/100 m2 ?100 mm or ?175 mm
between treatment and control streams during any time period
(Table 2; Figure 3). In addition, although there were some differences
in mean CPE between streams with and without road
access (e.g., treatment stream posterior means [95% credible
intervals] before the regulation change for those with and without
road access were 2.4 Brook Trout/100 m2 [1.2–4.3] and
18.8 Brook Trout/100 m2 [9.3–33.9], respectively), there were
no differences after the regulation change when compared with
before the regulation change for control or treatment streams
regardless of access category...

 

[wildtrout2]

OK, thanks for that info. It gives a fairly good picture of what did and didn't take place, but I wouldn't call the program a failure if it provided important info about our native brook trout populations.

 

[troutbert]

This experiment does not prove that C&R regulations are ineffective on brook trout streams.

What it shows that it is very difficult to determine the effects of fisheries management regulations on freestone streams, because of many other factors that also influence the trout populations.

And we already knew that.

The fact that it is difficult to determine the effect of a particular factor does not equal proof that the factor has no effect. It simply shows the limitations of an uncontrolled experiment with many confounding factors.

 

[Eccles]

troutbert wrote:
This experiment does not prove that C&R regulations are ineffective on brook trout streams.

What it shows that it is very difficult to determine the effects of fisheries management regulations on freestone streams, because of many other factors that also influence the trout populations.

And we already knew that.

The fact that it is difficult to determine the effect of a particular factor does not equal proof that the factor has no effect. It simply shows the limitations of an uncontrolled experiment with many confounding factors.

I take a different view on what this paper says - in fact I take what it says at face value.

The paper does show that C&R makes no difference (is "ineffective") at enhancing brook trout size or CPE in comparison to statewide regulations.

And it is not correct to say that the study was "uncontrolled". It was nicely controlled by comparing streams with C&R to seven similar streams that maintained statewide regulations for the duration of the study. They even had "before and after" data on the streams that went C&R - a nice added bonus for what are often difficult field studies.

And it really shouldn't be much of a surprise that C&R makes bugger all difference on short-lived populations where only 30% of the fish survive each year. C&R may have some 'benefits' but it is not a panacea for all situations.

 

[Chaz]

salmonoid wrote:
It was on the agenda at the January meeting under "the Amendments to Chapters 61, 63 and 65 to Simplify and Consolidate Fishing Regulations." The recommendation by staff was to remove WBETP (section 65.13).

"Staff propose eliminating § 65.13 (relating to wild brook trout enhancement) in its entirety because based on peer reviewed and published scientific research on the waters within this program, staff have determined that this regulation is ineffective. If the program is eliminated, waters currently in the program will be distributed to other programs."

Unlike some other proposals, I didn't see a press release issued by the PFBC, so I'm not sure if the proposal carried or not.

Then they go and complicate other regulations and add new ones, what kind of logic is that?

 

[k-bob]

Eccles: "shouldn't be much of a surprise that C&R makes bugger all difference on short-lived populations where only 30% of the fish survive each year."

effects of a 70% total annual mortality rate = 30% total annual survival rate for age 1+ fish:

"The bottom figure shows the effect of a 70% total annual mortality rate on a fish population. In such circumstances, don't expect fish to live much past age 5."

https://www.sdstate.edu/nrm/outreach/pond/upload/Fish-Biology-101-Mortality-Rates-Sep-Oct-2005.pdf

 

[RLeep2]

I wasn't aware that there ever were any real biologically-based expectations presented by Commission staff for implementing this program anyway. I was under the impression that it was something that a subset of the angling public lobbied for and, not finding any compelling reasons not to give it a try, the Commission went ahead and gave it a shot. But I thought I remembered some chatter at the time that the entire thing was much more of a social than a biological experiment. I dunno.. Maybe I remember wrong.

In any event (and mostly for the reasons cited in this thread having to do with annual mortality, etc.), I certainly agree that it can be very difficult to actually determine just how successful (or unsuccessful for that matter) a program like this has been. The small freestone setting has far too many highly mercurial variables that can skew the results in one direction or the other. After all, if there were an unusual string of mild winters and good flow years that produced strong year classes and good carryover of these fish, we might now be saying that the WBTEP regs were a "success". Habitat and natural factors can fool us in either direction. My view is that it very difficult if not nearly impossible to use regs to stockpile fish in the small freestone setting.

 

[Eccles]

k-bob wrote:
Eccles: "shouldn't be much of a surprise that C&R makes bugger all difference on short-lived populations where only 30% of the fish survive each year."

effects of a 70% total annual mortality rate = 30% total annual survival rate for age 1+ fish:

"The bottom figure shows the effect of a 70% total annual mortality rate on a fish population. In such circumstances, don't expect fish to live much past age 5."

I don't quite see the point you are making here. The paper says 70% annual mortality, I simply decided to quote it as 30% annual survival.

 

[k-bob]

sorry . my post links an article with a chart showing the consequences of a 30% annual survival rate: very few fish will live 5 years.

striking to see the impact of that low survival rate in the figure. short lives in infertile streams would make pa headwaters st small even w zero harvest.

 

[k-bob]

eccles: "shouldn't be much of a surprise that C&R makes bugger all difference on short-lived populations where only 30% of the fish survive each year. C&R may have some 'benefits' but it is not a panacea for all situations."

thanks for this comment, eccles. it fits well with Behnke's comments in his About Trout book (p 208) on the biological fit of C&R regs with small stream brook trout: "The results of studies on short-lived and slow growing brook trout revealed that annual mortality was so high, none of the trout survived beyond age 3, and if they were caught-and-released they would die of natural causes before the next year." Behnke notes that trout with longer lifespans, faster growth, and lower annual mortality rates (for example, some cutthroats), may show better response to C&R regs.

(Behnke's 1989 article "We're Putting Them Back Alive," reprinted in About Trout, expands on these issues. great info, imho.)

 

[Chaz]

k-bob wrote:
eccles: "shouldn't be much of a surprise that C&R makes bugger all difference on short-lived populations where only 30% of the fish survive each year. C&R may have some 'benefits' but it is not a panacea for all situations."

thanks for this comment, eccles. it fits well with Behnke's comments in his About Trout book (p 208) on the biological fit of C&R regs with small stream brook trout: "The results of studies on short-lived and slow growing brook trout revealed that annual mortality was so high, none of the trout survived beyond age 3, and if they were caught-and-released they would die of natural causes before the next year." Behnke notes that trout with longer lifespans, faster growth, and lower annual mortality rates (for example, some cutthroats), may show better response to C&R regs.

(Behnke's 1989 article "We're Putting Them Back Alive," reprinted in About Trout, expands on these issues. great info, imho.)

Bob,
Thanks for posting that, I remember reading that in "About Trout" and coming from an expert it makes a whole lot more sense to me than the mantra spouted by people that insist C & R saves trout all the time. It's clear it doesn't, it time to move on from that one size fits all statement.

 

[Chaz]

RLeep2 wrote:
I wasn't aware that there ever were any real biologically-based expectations presented by Commission staff for implementing this program anyway. I was under the impression that it was something that a subset of the angling public lobbied for and, not finding any compelling reasons not to give it a try, the Commission went ahead and gave it a shot. But I thought I remembered some chatter at the time that the entire thing was much more of a social than a biological experiment. I dunno.. Maybe I remember wrong.

That is exactly why the program was implemented. I feel it was doomed from the beginning not because of the reasons stated by many. Though Behnke says in his book it would be difficult based on other studies to show improvement, but because with all of the larger brook trout already removed from these streams for 100 years or more the gene pool is very limited for fast growth and late sexual maturity. These are the main factors that determine the maximum size of trout in any population. It's not that the genetic pool is bad, it is just limited.
That and brookies are much more susceptible to mortality due to hooking than the other trout species.

 

[pcray1231]

But I thought I remembered some chatter at the time that the entire thing was much more of a social than a biological experiment. I dunno.. Maybe I remember wrong.

I remember such chatter too, as much of it came from me. Though I was in no way the official voice of the PFBC. It was just my take on it, and others as well.

When it was implemented I didn't think it's help those particular streams. If anything, it'd hurt them. The rationale being that the streams were generally lightly fished to begin with, and among those who fished them, with very high rates of C&R. Harvest simply was not, and is not, the "limiting factor".

That said, I do still see a social benefit, in that the program, the maps, the posters on trees, etc, act to highlight a type of fishery that the public is largely unaware of. Even if you actually hurt those streams, by attracting extra attention and fishing pressure, they are but a handful of thousands of streams that are an awful lot like them. I do believe that overall, if more anglers were aware of the various types of wild trout fishing available to them, close by, it would be a good thing, and a start to moving away from the notion that all PA trout come from a truck. I still believe that, although it is a slow, generational process.

While I do support stocking in PA, I do think the PFBC should do all it can to highlight wild trout opportunities to the public, and promote those fisheries over stocked ones.

 

[troutbert]

k-bob wrote:
eccles: "shouldn't be much of a surprise that C&R makes bugger all difference on short-lived populations where only 30% of the fish survive each year. C&R may have some 'benefits' but it is not a panacea for all situations."

thanks for this comment, eccles. it fits well with Behnke's comments in his About Trout book (p 208) on the biological fit of C&R regs with small stream brook trout: "The results of studies on short-lived and slow growing brook trout revealed that annual mortality was so high, none of the trout survived beyond age 3, and if they were caught-and-released they would die of natural causes before the next year." Behnke notes that trout with longer lifespans, faster growth, and lower annual mortality rates (for example, some cutthroats), may show better response to C&R regs.

(Behnke's 1989 article "We're Putting Them Back Alive," reprinted in About Trout, expands on these issues. great info, imho.)

How big is a 3 year old brookie in PA freestone streams? (Maybe Mike can help here.)

Probably 6 inches long, 7 inches tops?

So, what's the explanation of all the 8 inch brookies, which are pretty common in some PA streams? And we catch fair numbers of 9 inchers, and some 10 inchers every year. And occasionally larger.

All of those brookies from 8 inches and up are surely older than 3 years.

What Behnke is describing here doesn't seem to fit PA freestone streams.

 

[pcray1231]

All of those brookies from 8 inches and up are surely older than 3 years.

Disagree.

How big is a 3 year old brookie in PA freestone streams? (Maybe Mike can help here.)

Probably 6 inches long, 7 inches tops?

Varies wildly from stream to stream and perhaps pool to pool. But my take has always been that your average, everyday brookie that we catch in the 5-9" range is 2 years old. My take (generally for 1st and 2nd order freestoners) would be this (based on a typical summertime excursion):

1/2 year: 3-6" "dinks"
1 1/2 year: 5-9" "average fish"
2 1/2 year: 6-11" "big to exceptional fish"
3 1/2 year: very rare, 7-13" "trophy in the PA brook trout world"

Of course, limestone is a different ball game, as are fish that grow up in lakes or large rivers and return to small streams.

I base this on observed size classes, and having occasionally caught the same fish in consecutive years which fits this narrative. Also, regarding the 1/2 year size, it's pretty valid based on all the dinks that, in the first spring, are hardly big enough to drown a fly, but sometime mid-summer become catchable on non-midge sized flies.

In general, up to 2 years growth rate seems fairly consistent. Thereafter, it's highly stream dependent, in that some streams pretty much top out and growth rate slows to a crawl. Those "old" hook-jawed spawned out 7 inch brookies are always interesting to look at, but they do exist! In other streams, they continue growing.

 

[troutbert]

pcray1231 wrote: My take (generally for 1st and 2nd order freestoners) would be this:

1 year: 3-6" "dinks"

One year old brookies, small freestone streams, 6 inches long?

 

[pcray1231]

As an upper size range, yeah. I'm throwing numbers out there, and yeah, a 6 inch first year fish is unusual, but not unheard of.

The streams where it happens are likely the same ones where you can perhaps hit the upper end of the rest of the ranges.

I'd say 3" is about where a fish becomes "catchable" without resorting to unusual methods. Even then, we often pick larger flies with the sole purpose of excluding them. The first spring, these are essentially "minnows" playing with a fly that's way too big for them. Sometimes there's dozens on the fly each cast! By the end of that summer, you start catching them, and yes, they are 3, 4, 5". I have zero doubt these are fish that were just born in the spring.

You're standard "not big, not tiny" brookie at 6 or 7 inches is 1 year older than that. You're "fairly big" for this stream are either the same age and just on the larger size of average due to having found a good holding lie, or another year older. You're "truly" big fish are 2 1/2 (on their 3rd summer), and your "fish of a season" type brookies may be the upper end of the 2 1/2 range or else the rare example of a 3 1/2 year old fish.

 

[Chaz]

Many of the streams where I find larger brookies are streams that are more fertile than most brookie fishermen fish. The ones that aren't fertile have a combination of very low angler use and or an impoundment of some type on it.Even very small impoundments seem to make a difference.
If you want to see how big brookies can grow, go to a freestone stream that has an impoundment on it during the spawn. You'd be amazed.
As for sizes, year 0 fish, up to 3 inches; year 1, 2 to 5 inches; year 3, 4 to 6 inches; year 4, 5 to 8 inches; anything larger is anyones guess.
I know of a stream or 2 that have no or very low populations of small fish, but good populations of fish in the 6 to 10 inches size range. My only explanation is that the small fish use the tributaries of these streams and only migrate to the larger water after surviving to the larger sizes.

 

[pcray1231]

Many of the streams where I find larger brookies are streams that are more fertile than most brookie fishermen fish. The ones that aren't fertile have a combination of very low angler use and or an impoundment of some type on it.

Yup. Which is why I put this line in there:

Of course, limestone is a different ball game, as are fish that grow up in lakes or large rivers and return to small streams.

Growth rates can be much higher in those situations. I doubt that age is any higher, though.