LR-24 Electrofisher - Field Environmental Instruments

SET UP & OPERATION
USER'S MANUAL
Set up and Operation (Cont.)
8. Place the anode ring and cathode cable approximately 12 inches
(30 cm.) apart in ankle deep water.
9. Press the anode pole switch and listen to the audio alarm. If
it is beeping on and off 1 time per second, release the anode
pole switch and increase the output voltage 50 volts and press
the Enter key. Press the anode pole switch again and listen
to the tone. If the audio alarm is beeping on and off two or
more times per second, release the anode pole switch and begin
electrofishing. If not, repeat this step until the audio alarm
begins beeping on and off faster than one time per second.
Fig. 6.15
10. Begin electrofishing.
NOTE:
Duty cycle and frequency can have a huge impact on taxis. In
general, lower frequencies are safer for larger fish than higher
frequencies. If you are not getting any response at all from fish,
change the LR-24 settings as follows:
a. Increase the voltage 50 volts, press the Enter key and try again.
Stop increasing voltage when begin getting a forced response,
(twitch), from the fish when press the anode pole switch.
b. If fish are not showing taxis then increase the duty cycle by
10%, press the Enter key and try again; if necessary repeat this
step until elicit taxis in the fish. If increase the duty cycle to
maximum and still are not getting taxis then reduce the duty
cycle back to 12% and go to the next step.
c. Increase the frequency by 10 Hz, press the Enter key and try
again. Go back to step “a” before increasing frequency if
necessary.
Observe the captured fish closely. In general, if it takes more
than 5 seconds for a fish to recover, it may have been shocked too
severely. If it takes more than 15 seconds for a fish to recover,
it was definitely shocked too much; reduce the power limit, duty
cycle, frequency, or output voltage of the LR-24.
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