Some C&R Information

Willi wrote:



If I understand you, your problem is with the 20% figure? ... that five year period
probably shows the cumulative effect.

tough to maintain standards for c&r practices by individual fishermen.
i suspect you would have a lower kill rate than i would have. based on
the rough practices in releases i've observed by the guided "johns" and
other tourists (including me), it's tough to make broad, general
percentage statements about c&r mortality, imo.

"rw" wrote in message
m...
Wolfgang wrote:

"rw" wrote in message
m...

Wolfgang wrote:

No one can
reasonably hope to say anything meaningful about what can be expected
in.....oh, say a century or two....

Oh yes they can. I can say with certainty, for example, that I will be

dead.

I stand corrected. It appears that GOOD news, at least, is more or less
predictable.

YOU will be dead, too.

I was just about THIS close to guessing that.

We won't have to fret about what PETA is up to.

Well, I don't fret much anyway, but I figure that if I'm going to think
about these matters at all I'd best do it some time in the next couple of
decades. It seems unlikely that I'll have much opportunity after that

Or did you miss the point?

It isn't so much that I missed it as that I don't agree that you are the
only person in the history or the future of the planet who matters.

Wolfgang.

Willi wrote in news:40c0d702$0$201$75868355
@news.frii.net:

If I understand you, your problem is with the 20% figure? Or
would it be with any figure? Or they shouldn't study it and make the
results public because PETA might make use of the information or ?

It's tough, cause I haven't seen the study, but my problem is that the 20%
figure comes without any estimate of the precision of the measurement.
It's like the presidential polls that say +/- 4% in the fine print.
Because the study is missing, the fine print is missing. Frankly, I don't
think that a fish population can be measured with that fine precision, and
the 20% might just live in the noise.

Scott

Scott Seidman wrote:
Willi wrote in news:40c0d702$0$201$75868355
@news.frii.net:


If I understand you, your problem is with the 20% figure? Or
would it be with any figure? Or they shouldn't study it and make the
results public because PETA might make use of the information or ?


It's tough, cause I haven't seen the study, but my problem is that the 20%
figure comes without any estimate of the precision of the measurement.
It's like the presidential polls that say +/- 4% in the fine print.
Because the study is missing, the fine print is missing. Frankly, I don't
think that a fish population can be measured with that fine precision, and
the 20% might just live in the noise.

Scott


It was a survey, over a five year period of time, for the purpose of
gaining some information on the effects of the C&R regulations. I doubt
that they even have reliability or validity figures.

It wasn't an experiment and it doesn't PROVE anything. I doubt that was
their purpose. It was an affordable way for them to gain some
information so that can make more intelligent decisions in terms of
regulations. Not perfect but much better than guessing.

Scott, don't you think that a 20% reduction in fish population from five
years of C&R fishing on a heavily fished river seems like a VERY
reasonable number? Don't you think that the study also shows that
individual C&R mortality is VERY low?


Willi

Willi wrote in
:

Scott, don't you think that a 20% reduction in fish population from
five years of C&R fishing on a heavily fished river seems like a VERY
reasonable number? Don't you think that the study also shows that
individual C&R mortality is VERY low?


No, 20% is not an unreasonable finding, but I don't know if their
methods are capable of demonstrating a difference that small. Perhaps
if I read their paper, I'd have a better feeling. However, having
stated that I don't believe that they can accurately assess the
population to raise that 20% figure out of the noise, it would be
inconsistent for me to draw any conclusions about that 20% figure,
except that C&R impact on the region being studied is somewhere between
medium and nothing.

I'm not knocking their finding, and I wouldn't be very surprised if
their assertion turned out to be true, but that's not the issue. I
haven't questioned the interpretation, I've just suggested that the
methodology does not necessarily support the interpretation. Let me try
to frame this up as best I know how. If by happenstance, their numbers
showed a 5% increase in population in the fished region, would you
conclude that C&R actually improved population health? Of course
not--you would begin looking for reasons other that C&R that would have
created that finding. That's all I'm doing here. The scientist in me
doesn't allow me to accept the finding at face value simply because the
study came out the way I expected it to. It's how we're trained. We
consider the methodology before we consider the results. If we don't
like the methodology, we don't weight the results very heavily, whether
they support our hypotheses of what's going on or not.

In this case, whether it was an experiment or not, the data is being
used to establish a relationship between fisheries policy and fish
population. The fact that it wasn't an experiment is a second strike on
the data, not an excuse for loose numbers.

After being locked in a room for a day, reviewing 60 million dollars of
NIH grants to assess their fundability, my thresholds are extremely
high. The quality of every proposed measurement needs to be assessed.
When you assess a grant, you think "If their data turn out to be just
what they think it will be, do you believe it?" If you can't believe
the finding given the methods, you assign a low priority, and the grant
writers try again. It's a tough standard, but it clears up the
riffraff. My personal belief is that if DEC's and the like were held to
a very high level of science, two things would happen: a) There would be
less studies done, and b) the studies that are done would have more
money available to them, and they would have the resources they need to
get the study right.

Scott

I'd like to see the same study done with a control section established in the
no fishing area furthest away from the C&R area. This area would be required to
have the same amount of human activity as the C&R area, but with no actual
fishing. In other words, people would put in the same number of man hours
wading and walking the bank of this section as in the C&R section, without
actually fishing. I'm thinking that the amount of human activity in the C&R
section is causing some fish to move out in numbers high enough to be a
significant component of the 20%.


George Adams

"All good fishermen stay young until they die, for fishing is the only dream of
youth that doth not grow stale with age."
---- J.W Muller

On 07 Jun 2004 17:45:17 GMT, ojunk (George Adams)
wrote:

I'd like to see the same study done with a control section established in the
no fishing area furthest away from the C&R area. This area would be required to
have the same amount of human activity as the C&R area, but with no actual
fishing. In other words, people would put in the same number of man hours
wading and walking the bank of this section as in the C&R section, without
actually fishing. I'm thinking that the amount of human activity in the C&R
section is causing some fish to move out in numbers high enough to be a
significant component of the 20%.


George Adams

Excellent point George, hadn't considered that simple traffic would
cause a shift but it could have an effect. I know that Grand River
dinks become very tolerant of wading fishermen but you rarely see a
larger fish actively feeding close to a human.

Peter

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"Peter Charles" wrote in message
...


Excellent point George, hadn't considered that simple traffic would
cause a shift but it could have an effect. I know that Grand River
dinks become very tolerant of wading fishermen but you rarely see a
larger fish actively feeding close to a human.

Probably has a lot to do with options. There are many places where
fish simply cannot entirely escape human presence. Those familiar
with Penns in May will recognize it as a pretty good example. Where
they CAN escape, the bigger fish will naturally take up the best lies
in less trafficked parts of the stream, driving out what smaller fish
were already there. Oddly, this may actually be beneficial for the
smaller fish. Given a choice between human interference and the jaws
of concentrated cannibals up or down stream, those who opt for the
former may enhance their chances for survival. Then too, a small fish
probably does better competing against others more or less its own
size.....even against many others.....than against a smaller number of
larger competitors.

Wolfgang

Scott Seidman wrote:
... My personal belief is that if DEC's and the like were held to
a very high level of science, two things would happen: a) There would be
less studies done, and b) the studies that are done would have more
money available to them, and they would have the resources they need to
get the study right.

You cannot hold fisheries research to a very high level of science.
Real life streams and lakes are not, and cannot be, laboratories
where variables are held constant. It's messy science by nature and
that's just the way it has to be done if it's to be done at all.

Psychology is messy science too. Think how research in psychology
would be different if scientists could euthanize and dissect some
of the human subjects. ;-)

--
Ken Fortenberry

Scott Seidman wrote in message .1.4...

Frankly, I don't
think that a fish population can be measured with that fine precision,

Sure it can. Antimycin would be my first choice...

and
the 20% might just live in the noise.

See, e.g.,

http://afs.allenpress.com/afsonline/?request=get-abstract&doi=10.1577%2F1548-8659(1987)116%3C768:BFSFUI%3E2.0.CO%3B2

for an example as to why noise is probably not generally 20%.

I think you're being a little too scientifically hardheaded here.
Are their results journal-quality in their rigor? Maybe not. But,
odd as it may sound, I wouldn't necessarily require journal-quality
rigor on results that I might use in the field. Most especially if
the results match common sense in the first place.

BTW, if you _really_ do want to know the details, I'm sure you
could find plenty of reading material at your local university
library. Fish population surveys have been done for a long, long
time, and I lean towards believing they know what their methods
are telling them. Sure you won't get the details of this particular
study, but you'd learn enough to answer many of the questions
you're asking. If you wait for it to show up on ROFF, well....

Jon.