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Re: Electroshock procedures


"James E. Johnson" <[log in to unmask]>


Academic forum on fisheries ecology and related topics <[log in to unmask]>


Thu, 5 Dec 1996 08:57:14 -0600





TEXT/PLAIN (1 lines)

Glen - I have electrofished northern hogsuckers (Hypentelium nigricans)
and white suckers (Catostomus commersoni) for spawning many times and have
noticed no problems with egg viability. Jim.

James E. Johnson
[log in to unmask]
Arkansas Cooperative Research Unit
Department of Biological Sciences
University of Arkansas
Fayetteville, AR 72701
  phone (501) 575-6709

On Wed, 4 Dec 1996, Glenn Parsons wrote:

> Fish Folk,
> I have a question that is related to the discussion of electrofishsing. We
> use electroshocked crappie (Pomoxis annularis and P. nigromaculatus) for
> strip spawning
> in my lab. Is anyone aware of any effects of electroshock on egg viability,
> that is, could our problems with successfully strip spawning crappie be due
> to the fact that the female was electroshocked?
> Glenn Parsons
> University of Mississippi
> [log in to unmask]
> >>Date: Mon, 2 Dec 1996 14:40:55 -0800
> >>From: Craig Fusaro <[log in to unmask]>
> >>Subject: Electroshock procedures
> >>
> >>"Do (sic) to the irregular or rocky conditions electrofishing may be
> >>required... Fish will be collected using pulsed direct current with
> >>voltage set at 200-300 volt and 0.1 to 2.0 amps output... Pulse frequency
> >>and pulse width will be set to induce involuntary swimming action with
> >>minimum harm to fish."
> >>
> >>1. Is electrofishing really effective in five to ten foot water depth?
> >>
> >>2. Are the pulse voltage and current settings specified appropriate for
> >>these water depths?
> >>
> >>3. Would mortalities reasonbly be expected under the regimen described
> >>above, and, if so, what could be expected in terms of percent deaths?
> >>
> >Pulsed direct current electrofishing from a boat is definitely the safest
> >method from the fish's point of view. We have had considerable success
> >using our boat-mounted electroshocker (Model 7.5 GPP, Smith-Root, Vancouver,
> >Washington) in river water 5-10 feet deep. In fact we were pulling 6-8 lb
> >steelhead out of the Columbia River a couple of years ago. The key to
> >effective electrofishing is knowing the conductivity of the water you will
> >be fishing. We have fished with 900 W (300 volts at 3 amps) without any
> >significant mortality to larger fish. Keep in mind, however, that many of
> >the potential adverse effects of electrofishing are manifested over a
> >relatively long period of time. Since most of our work has been
> >catch-and-release, we have been unable to calculate a true mortality rate.
> >Good luck!
> >
> >Tad Deshler
> >Tetra Tech, Inc.
> >[log in to unmask]
> >
> >

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