Mortality =40%

[Chaz]

Jack,
Except that when they select trout for breeding for the hatchery environment they select out all the instinctive behaviors and select the behaviors desireable for survival in a hatchery where they are handfed every day. Stocked trout don't survive to spawn, this is well documented, except in a few instances where the conditions are favorable.

 

[tomgamber]

As dsicussed the 40% figure is for wild trout streams and is the statewide average.

Chaz's post is like a Bizarro world newspaper where there is a headline and then the story is just a re-statement of the headline with no more detail than the headline....imagine a newspaper like that... pages and pages of headlines, with no stories...so we make the stories, right or wrong, fact or fiction.

Care to add anything to that Chaz? Is it bunk? Is it a fair assessment? What is the major reason its 40 intsead of say 20 or 80?
Its like Costello without Abbott...theres a punchline but no straight man to set it up. If you are just letting us know its 40%, well then thanks, I guess. If you'd like to share some insight to that number, as we've come to expect, I know i'd welcome it. Was this something someone just said to you? Was there a report? Was this a creel survey? Where did they get 40%? Did they defend the number or just blurt it out and walk away like you did?

 

[Chaz]

“Chaz's post is like a Bizarro world newspaper where there is a headline and then the story is just a re-statement of the headline with no more detail than the headline....imagine a newspaper like that... pages and pages of headlines, with no stories...so we make the stories, right or wrong, fact or fiction.

America...what a great city!”

Maurice,
It is a great country and isn’t that what we get in newspapers anyway? Again I though I had the % right, but Mike says it is even higher. The reason for my post was something to do with what others were saying in a post earlier this week. They have a misconception about trout mortality in streams, it is very high whether or not it is a stream under special regs or not. On stocked streams it is so high as to be 100%.

 

[JackM]

Chaz wrote:
Jack,
Except that when they select trout for breeding for the hatchery environment they select out all the instinctive behaviors and select the behaviors desireable for survival in a hatchery where they are handfed every day. Stocked trout don't survive to spawn, this is well documented, except in a few instances where the conditions are favorable.

Chaz, you are really just guessing with an agenda by stating that instinctive behaviors are "selected out" in the hatchery cycle. Survival instincts can't be eliminated through selective breeding; even if you were trying to do so, it would be a near impossible task. Hatchery trout are not planted into favorable environments in the first place-- and when they are, as you say "rarely," they are not significantly handicapped with respect to survival skills nor the ability to reproduce.

 

[Mike]

Maurice,

A favorable response in the context that I presented would be a significant increase in the number of adult trout or in the number of large trout, or both, depending upon your definition of large. To use an example that gets away from trout, many lakes that have gone from the statewide 12 inch size limit for largemouth bass to the 15 inch "Big Bass" special regulation have shown substantial increases in the number of 12-15 inch bass in response to the reg. Additionally, some have shown substantial increases in bass greater than 15 inches long in response to the reg. I would classify these responses as "favorable."

Regarding a 50% angling mortality rate, it has apparently been suggested in a peer reviewed scientific paper that this is the pre special regs. fishing mortality rate at which special regulations when applied will begin to produce a favorable response in a trout population. At a fishing mortality rate that is somewhat below 50% the anticipated benefits of special regs with respect to the impact on population abundance or size structure will not likely occur. To go further than this in this discussion would probably get us back to the topic of "compensatory mortality" and I really don't want to go there again at this time.

Mike

 

[Mike]

Troutbert said: Here's a quote from a Fisheries Manager in Virginia in their publication Virginia Trout Guide:

"The major management problem associated with Virginia streams appears to be excessive fishing pressure on many of the more popular wild trout streams resulting in over-exploitation.

In MD, the state-wide, general regulations on wild trout streams is 2 fish per day. That's not a SPECIAL regulation, it's the general regulation on wild trout streams. Then there are also C&R regulations on certain wild trout waters.

In Shendandoah Park, some streams are C&R, the others are 2 fish, 9 inch limit (as compared to 7 inches in PA). When I fished there, 8 inch brookies were very common.

Most of Yellowstone Park is managed as C&R.

PA is becoming isolated, out of the mainstream of fisheries science. Maybe everyone else has it wrong, and the PFBC has it right. You have to decide that for yourself.

Mike's response:
The Virginia fisheries manager said "apparently" and specified " on many of the more popular wild trout streams." I don't have a problem with that.

As for Md., I assume Md. had biological or harvest info. to justify its use of such conservative regs.

And in the case of the Shenandoah, more recent evaluation of the regs and their necessity by the park's biologists paints a different picture. Check the news release from a year or two ago. I admire the biologists there for challenging their own previous assumptions and, in effect, those of many anglers.

As for Yellowstone, it is hardly a system that is comparable to Pa.

 

[JeffK]

The 40% for wild trout seems pretty good to me, but mileage does vary. Remember the old saw about a female trout needing 1500 eggs to produce a breeding pair to replace it and it's mate? Those numbers don't jive with low mortality rates. Very few wild trout get beyond 5 years old. When looking at shocking data the 0, 1, and 2 year classes show up pretty clear, but everything past that is in a blur generally (and doesn't make up that many individuals).

Year to year variation in recruitment is enormous. For example, droughts can prune out the adults and the fingerlings can thrive. Some good years for adults are tough on the fingerlings. That adds up to tons of year by year and year class to year class variation. 20% seems to be a good year and a real bad year can practically wipe out a vulnerable year class. The 40% mortality seems reasonable, but very much simplified. Trout streams are pretty dynamic environments. (As an aside, nice sized 15" to 18" smallies can be 8 to 10 years old and many poorly fished largemouth lakes are dominated by some ancient monsters that are very fertile but are tough on the youngsters and make recruitment rates low so the mortality rate for the population is high. However, the fish you catch are the survivors that can be quite old).

I think that practically no regulation stocked trout are in the water a year after they are stocked.