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USER'S MANUAL
RECOMMENDED ADJUSTMENTS
Quick Setup adjusts the LR-24 to produce 30 Hz, 12%
duty cycle at 25 watts average output power. This
is only a suggested starting point, and any or all of
the output settings may be changed by the user at
any time. Duty cycle and frequency can have a huge
impact on taxis. In general, lower frequencies are
safer for fish than higher frequencies. If you are not
getting any response from fish, change the LR-24
settings as follows:
a. Increase the voltage in 50 volt increments. Stop
increasing voltage when you begin getting a forced
response (twitch), from the fish when pressing the
anode pole switch.
b. If fish are not showing taxis, lower the voltage to
the original level and increase the duty cycle by
5%, press the Enter key and try again. If neces-
sary, repeat step “a” from above until you elicit
taxis in the fish. If the voltage is increased to
maximum and taxis is still not achieved, reduce
the voltage and increase duty cycle by 5% again.
If no response after increasing duty cycle, lower
all settings and proceed to step "c".
c. Increase the frequency by 5Hz, press the Enter
key and try again. If necessary, go back to step
“a” before increasing frequency again.
Observe the collected fish closely. In general, if it
takes more than 5 seconds for a fish to recover, it
may have been shocked too much. If it takes more
than 15 seconds for a fish to recover, it was definitely
shocked too much; reduce the frequency, duty cycle,
and/or output voltage of the LR-24.
SECTION 5: SETUP AND OPERATION (CONT.)
TAXIS AND TETANY
There may be some confusion
between taxis and tetany. Taxis is
an induced swimming action. The
nerves have time to repolarize and the
muscles have time to relax between
output pulses of the electrofisher.
Tetany is locking up the muscles. The
fish is stiff and there may be some
slight quivering in the fins. While
the fish may move toward the anode
(positive electrode), this is not taxis.
The output of the electrofisher should
be reduced.
“Rolling fish over” should be avoided
when electrofishing. With settings
high enough to quickly knock fish out,
injury rate is higher than it should be.
Ideally, fish will swim into the net while
following the anode. Recovery time
should be quick and the fish should
be able to swim normally immediately
upon being placed in the holding
tank. It should not take more than
5 seconds for a fish to recover after
being placed in the holding tank. If it
takes 15 seconds or more for fish to
recover after being placed in the tank,
then reduce the output settings of the
electrofisher.
BEFORE ELECTROFISHING:
The most experienced members of
the electrofishing crew should be
doing the netting. They know what
to expect, what to look for, and where
to look. The next most experienced
member should be running the LR-24,
looking for likely habitat. The next
most experienced member of the crew
should be taking care of the recovery
tank. The tank should be kept out of
the sun, water temperature checked
regularly, and oxygen levels in the tank
checked if the fish are held very long
before being worked up and released.
Never electrofish with unauthorized
people standing on the bank. Under
certain conditions, the field of the
electrofisher can travel long distances.
Things to look for include sheet piling,
metal culverts, buried pipes, suction
lines for irrigation, etc.
SECTION 5