Conservation Corner
How to Keep What We Have
Ian Anderson
Fly Tier and Webmaster
Notes on Catch and Release
 Most fly
fisherman these day practice some form of catch and release.
It is a simple notion actually. Simply put you do not
keep then fish you catch; you release them to be caught
another day. In theory this is a great idea.
Stream keep native species, the populations are not
depleted, not as many fish stocking and plenty of fish for
everyone to enjoy. The reality is a bit different.
There is much research and discussion these day concerning
playing the fish, hooks to use, leaders to use, how to
handle the fish and how the stress of being hooked, played
and released effect the fish.
I recently ran across a great article on the
Indiana
Smallmouth Alliance forum on this very subject.
Without going into to much detail the author covered all of
the bases concerning appropriate catch and release practice.
I would like to thank David Votaw for his permission to reproduce
this article here in our newsletter.
C&R --Again
by David Votaw
The Cooke Fish Ecology and Conservation Physiology Lab of
Carleton University, Canada, has been a leader in research
on C&R (Catch and Release) and tournament fishing implications. They note that
only five species of freshwater fish have been sufficiently
studied to allow an understanding of recreational C&R
impact: largemouth bass, walleye, striped bass, Atlantic
salmon, and rainbow trout; stripers, salmon, and rainbows
are anadromous, of course. Initial studies of these species
have attributed C&R mortality to hooking injuries, water
temperature, and cumulative stress. Additional studies have
focused on non-lethal behavioral effects, including changes
in activity patterns, swimming speed, movement, and habitat
use. Physiological disturbances produced by C&R are
osmoregulatory imbalances, depletion of energy stores,
build-up of metabolic wastes, tissue damage, hormonal
changes and cardiovascular disturbances. Finally, sub-lethal
fitness effects (i.e., lifetime reproductive success) impact
gamete size, quality, and quantity, parental care ability,
mating success, and reproductive success. Thus you can see
that the potential impacts of C&R fishing may reach far
beyond simple hooking mortality.
Based on the research conducted on these five widely
divergent species, the Cooke Lab makes the following five
general recommendations for conserving recreational
fisheries through correct C&R.
Angling Duration: The length of time a fish
is ‘played’ increases physiological disturbances and
recovery time due to depletion of energy stores and
accumulation of lactate with other physiological imbalances.
During recovery, the ability of fish to cope with stress,
for example from air exposure or predator avoidance, is
diminished.
Recommendation: Anglers should attempt to land fish
as rapidly as possible to minimize the duration of exercise
and the concomitant physiological disturbance. Anglers
should choose optimal equipment matched to the size of fish
that are expected to be encountered. Efforts to
intentionally prolong the angling event through the use of
light line or rods should be dissuaded.
Keep them in the water as much as possible
Air Exposure: During air exposure, gills collapse and
the individual filaments adhere to one another, leading to
the rapid decline of blood oxygen bound to hemoglobin and
anoxia. Cardiac variables will require significantly more
time to return to basal levels; the recovery correlates with
duration of air exposure. Extended air exposure, for example
during removal of barbed hooks, measuring and photography,
can result in permanent tissue damage and eventually death;
38% of exhausted trout exposed to air for 30 seconds died,
compared to 72% mortality following 60 seconds of exposure.
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Recommendation: Whenever possible, anglers should
attempt to eliminate air exposure by handling fish that are
to be released in the water. When fish must be exposed to
air, we urge that anglers do everything possible to minimize
the air exposure duration due to the overwhelming negative
consequences associated with that action.
Not just for freshwater fish
Water Temperature: Fish taken at high
water temperatures, an environmental variable that differs
in impact among different species, suffer increased
physiological stress, greater oxygen debt, and increased
mortality rates. In addition, the quantity of dissolved
oxygen in water decreases with increasing water
temperatures.
Recommendation: When water temperatures are their
highest, both the duration of the fight and handling time
should be minimized. Ideally, fishing should be restricted
during extreme water temperatures. For Atlantic salmon in
eastern Canada, Atlantic salmon rivers are temporarily
closed to recreational angling during excessive water
temperatures. Extreme water temperatures are undoubtedly one
of the periods where fish are particularly susceptible to
mortality.
Bait Type, Terminal Tackle, and Hooking Injury:
An obvious determinant of potential injury and mortality is
the use of barbed hooks. Studies of barbless hooks found
that they allow a more efficient release of the fish and
produce less tissue damage, thus resulting in less
mortality. In addition, artificial lures and flies tend to
hook fish in the mouth, compared with live or organic bait
which is more often ingested deeply and thus closer to vital
organs, making hook removal more difficult and harmful.
Recommendation: Barbless hooks should be widely
adopted by anglers. Anglers using barbless hooks and
reducing the emphasis on the use of organic baits will
generally lead to minimal injuries, reduced handling time,
and lowered chance of mortality.
Angling and The Reproductive Period: The
benefits of minimizing stress during reproductive activity
are obvious – increased offspring to contribute to
subsequent year classes. Studies of largemouth bass found
that removal of males from the nest quickly resulted in
predation of the unprotected offspring. Even after returning
to the nest, males exhibited impaired swimming behavior for
the next 24 hours, and provided less care to surviving
offspring. Studies also suggest that largemouth bass caught
immediately prior to the spawning period in a simulated bass
tournament format produced fewer and smaller offspring.
Recommendation: Based upon the negative
consequences associated with angling during the reproductive
period, it is only prudent to avoid capturing fish during
the reproductive period.
Possible the best reason to use barbless hooks
Additional Catch and Release Information
Catch-and-Release Fishing By Erik Williams and Malia
Schwartz
Catch-and-Release From Wikipedia
Catch and Release Fishing Effectiveness and Mortality
The Impact of Recreational Catch and Release |
