"What it means
Relatively unfished brown trout are less angler-shy and more vulnerable to
capture, But the ''virgin waters' effect is short-lived, As was apparent
in the Ugly river, a single capture dramatically changes a fish's behavior.
Whether this response is learned or has a physiologic al basis - such as
elevated levels of stress homes or the hormones of energy reserves after
capture - is not easily determined but eh effect lasts several days.
There was also the 'chronic' effect of fishing the Owens browns. the trout
were less visible and less catchable. And, while fish occupying visible
feeding stations were less likely to spook, they were also less likely to
take a fly.
Do these findings apply only to brown trout in New Zealand streams? I doubt
it. Fish in small clear streams are highly vulnerable, but dozens of
anglers fishing even a large lake or reservoir day after day can 'educate' a
lot of fish.
I commonly hear fisheries management colleagues who try to maintain large
populations of quality fish lament the effect of 'increasingly skilled
anglers' and how technology has raised angler efficiency.
There is little doubt that angler skill and efficiency is increasing, but we
may be wrong in assuming that the fish don't change too."
