7705

• UCREFRP Catalog Number: 7705
• Author: Gunstrom, G. K. and M. Bethers
• Title: Electrical Anesthesia for Handling Large Salmonids
• USFW Year: 1985
• USFW - Doc Type: Progressive Fish-Culture
• Copyright Material: YES

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TECHNICAL NOTE

Electrical Anesthesia For Handling La ge Salmonids

Tagging studies are essential to the man-
agement of chinook salmon in coastal waters
of Southeast Alaska. While being handled for
marking and release, these large fish must be
temporarily immobilized for their own safety,
Unable to use standard fish culture anes-
thetics for fish immobilization because of FDA
restrictions, we modified an "electronarcosis"
procedure used in Great Britain in the mid-
1960's (Hartley 1967) for a tagging program in
northern Southeast Alaska in 1981. The pro-
cedure employed an electrified "landing bas-
ket" with positive and negative electrodes
near opposite ends, the power emanating from
a 12 volt car battery, When the troll-caught
salmon were lifted from the water in the bas-
ket, contact was made with the electrodes,
which immediately caused their muscles to
undergo tetanus. The fish thus became im-
mobilized without chemical anesthesia. Han-
dling procedures were then conducted, usually
in less than one minute, while the fish lay
quietly in the basket. We did not wear rubber
gloves and an electrical "tingling" could be felt,
in our fingers as we worked toward the center
of the fish during the tagging procedures.
When the electricity was turned off, recov-
ery was instantaneous; salmon held in live
tanks on-board showed no after effects and,
indeed, one tagged fish was recaptured within
three days of its handling and release. The
return of7,59% of the tagged, released chinook
salmon (58/764) from the commercial and
sport fisheries over the ensuing 18 months
from as far south as northern Oregon is consid-
ered acceptable and validates the use of
electrical anesthesia when chemical anes-
thetics cannot be used.
To the best of our knowledge, this was the
first employment of this technique on pacific
salmon, Advantages of immobilizing salmon
with the electric basket, as opposed to chem-
ical anesthesia, which were apparent in this
study were:

Prog, Fish-Cult. 4701, .January, 1985

Fig,!, Lifting a chinook salmon aboard in the electri-
fied basket,
"

\

Fig, 2. Electri control box with a spool of Petersen
tags on top.

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