Cyli wrote:
On Thu, 15 Dec 2005 00:36:33 -0600, chas
wrote:

(snipped)

Interesting. I know what you mean, but these disturbances all follow
patterns
that the fish are used to, when the pattern changes I think (but don't
actually
know) they are alerted. It could be much like the way we can pick a familiar
voice out of a throng, or recognize a friend at a distance by some subtle
nuance of motion. I'm going to think about testing this, off hand it seems
like it would be hard to get a good test that wasn't muddled by too many
variables.


Try to walk like a deer? They generally step in the water one slow
step at a time, stop and have a drink, maybe do another bodily
function or two, and then move on a bit or get out of the water. I
don't know what they do between knee level and swimming level, though.
But there are very often deer walking / swimming across trout streams.
Otters disturb the bottom, too. Think of all the things that do
disturb the silt and then try to move like that?

Cyli

What I was concerned about was trying to make only 1 disturbance and trying to
observer the trout at the same time to see if just that one disturbance
bothered them. Just getting close enough to see the trout is often enough to
spook them. Trying to only make noise, but not have them see you or see waves
you make is difficult. I suppose the watching could be done by a second
stealthy observer.

As for the deer, I'm sure they disturb trout often. Trout are often skittish,
but what bothers them is largely a function of what they are used to. The
cutthroat in the Yellowstone in the park in August have seen so many people
wading around that they don't even flinch when you walk in and bend over to
watch them eat tiny nymphs. Those fish wouldn't be the ones to try this test
with. I suspect the opposite end of the spectrum would be steelhead in low
water.

My point is that it's hard to devise a way to determine experimentally what
sort of things disturb trout, and what sort of things are not a problem because
it's hard to all at once 1) observe the trout without them knowing it, 2) make
just one sort of disturbance, and 3) determine if the fish were bothered by
that disturbance. Presuming success in this, then we just know about that one
fish or group of fish, now we need to run the experiment on other fish
populations.

Chas
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