Q.
In an earlier response you said that
the cutthroats of the Buffalo Ford [Yellowstone National Park]
area are caught an average of six times a season.
What effects on their population and breeding
are caused by this?
A.
I have an update on the numbers I gave earlier.
The publication Yellowstone Science has an
interesting series (this is Part II) entitled
"A Grand Experiment" that discusses the history
of fishery management in Yellowstone. In this
recent article, the author states, "By the 1980s,
cutthroat between Yellowstone Lake and Sulphur
Caldron on the Yellowstone River were caught an
estimated average of 9.7 times during the 108-day
catch-and-release season, many of them two or
three times in a single day." The author also
states, "The very characteristics that made the
cutthroat so popular as a sportfish--its abundance
and vulnerability to angling--may also have
imperiled it."
The author does not discuss specific aspects of the
impact of catching these fish so many times on their
population and breeding, but reading between the
lines, it surely indicates that such pressure must
contribute to some population impact. Cessation
of egg collection and fish stocking in the 1950s
did not relieve the constantly increasing fishing
pressure, so it appears that this kind of pressure
adversely impacts the population. Even in a
catch-and-release fishery, a certain percentage
of fish will be lost to hooking mortality. However,
it also appears that the very fact that there are
still so many fish to be caught, even if many are
repeaters, that the overall population must be
reasonably healthy. I do not know if reproductive
rate has changed materially; again, there seem to
be a lot of fish in that reach. It also looks like
the newly found problem with lake trout in
Yellowstone Lake may have a more severe impact
on the cutthroat population over time than does
the current fishing pressure.
The above response, gleaned mostly from uncertain
assumptions, seemed a it weak, so I called one of
the fishery biologists in Yellowstone to pursue
your question. First, he said that the study
which determined the 9.7 number and the two or
three times per day was not very rigorous in terms
of real scientific control. So, I'd take them with
a grain of salt. What he did say, that was more
applicable to your original question, is that they
have better evidence to show that disturbance of
trout redds by wading fishermen probably have a
greater detrimental impact on the reproductive
capacity than does the repeated catching of
the trout.
~ C. E. (Bert) Cushing, aka Streamdoctor
105 W. Cherokee Dr.
Estes Park, CO 80517
Phone: 970-577-1584
Email: streamdoctor@aol.com
The 'Stream Doctor' is a retired professional stream ecologist and
author, now living in the West and spending way too much time
fly-fishing. You are invited to submit questions relating to
anything stream related directly to him for use in this Q & A Feature
at streamdoctor@aol.com.
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