7116 ‎(2)‎

• UCREFRP Catalog Number: 7116
• Author: Baxter, G. and J. Simon
• Title: Editor
• USFW Year: Series
• USFW - Doc Type: 1970
• Copyright Material: YES

10

fact that electrofishing is carried out by a variety
of techniques with different kinds of equipment.
Therefore applied usage of large amounts of elec-
trofishing data previously collected is sorely
limited.
In spite electrofishing's many promising quali-
ties (effectivity, simplicity, relative harmlessness
for captured fish), we have today a much more
limited knowledge of the relationships and the
effects of environmental disturbance than would
otherwise have been the case had electrofishing
techniques been more uniform, with the precision
and reliability of results better understood. There-
fore, the goal of the present report is that future
electrofishing methods as well as the processing of
data shall conform to specific standards. A
standardization of procedures used in different
watercourses will result in comparable data,
greater fishery biologicial understanding and an
increased significance of results which may be
useful in a variety of contexts.
This work started at the University of Oslo in
1981, at a meeting attended by the foremost
authorities on electrofishing in the Nordic
countries. The meeting concluded that an attempt
at standardizing electrofishing in the Nordic
countries was essential, and a resolution was
. made for the establishment of a small study group
for further investigations. The group was com-
posed of the following persons: Torgny Bohlin

(Sweden), Stellan Hamrin (Sweden), Tor G.
Heggberget (Norway), Eero JutiIa (Finland),
0sten KarlstrOm (Sweden), Albert Lillehammer
(Norway), Jan Nielsen (Denmark), Gorm
Rasmussen (Denmark) and Svein Jakob Saltveit
(Norway). The leader of the work has been Tor G.
Heggberget.
This work is largely based on 'Quantitative
electrofishing for salmon and trout - views and
recommendations' (Bohlin, 1984). We have, how-
ever, expanded the contents to include some of
the most common situations in Nordic countries
and elsewhere, regarding physical (water type,
watercourse size) and biological (fish species, fish
size) conditions.

Electric fishing in fresh waters: equipment and
efficiency

Equipment

Electric fishing gear consists of three main parts,
a power unit device (generator or battery), a trans-
former and electrodes (Fig. 1). The power unit
generally produces alternating current and the
effect of the unit determines the maximum voltage
in the water. The transformer converts the original
current to direct current of different voltage and
produces the shape, length and frequency of the

TRANSFORMER
CONDUCTOR
, WIRE DRUM

-.r:=

Fig.], Equipment used for electrofishing with stationary (left part) and mobile systems.

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