7116 ‎(2)‎

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

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Hydrobiologia 173: 9-43, In9
@ 1989 Kluwer Academic Publishcrs. Printcd in Belgium

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Electrofishing - Theory and practice with special emphasis on
salmon ids

Torgny Bohlin I, Stellan Hamrin2, Tor G. Heggberget3, Gorm Rasmussen4 & Svein Jakob Saltveit5
I Dept. of Zoology, Univ. of Gothenburg, P.O. Box 25059,5-40031 Gothenburg, Sweden; 2Dept. of
Ecology-Limnology, Univ. of Lund, P.O. Box 3065,5-22100 Lund, Sweden; 3DirectorateJor Nature
Management. Fish Research Division, Tungaslella 2, N-7000 Trondheim, Norway; 4Danish Institute for
Fisheries and Marine Research, Inland Fisheries Laboratory, Lysbrogade 42, DK 8600 Silkeborg,
Denmark; 5Laboratory for Freshwater Ecology and Inland Fisheries, University of Oslo, Zoological
Museum, Sars gt. 1, 0562 Oslo 5, Norway

Received 18 March 1987; in revised form 15 October 1987; accepted 12 December 1987

Key words: electrofishing, population estimation, sampling design, salmonids

Abstract

This report attempts to establish guide-lines for electrofishing in population studies and is the result of
literature studies and experience from electrofishing in Denmark, Finland, Norway and Sweden. Equip-
ment, safety and training, sampling design and precision requirements for various types of investigations,
population estimation and fishing practice are discussed. The results are put forward in the form of
recommendations. Special attention is paid to the sampling design of surveys in streams of different types
and for different purposes, Examples of the computation procedures are also included.

Introduction

The breakthrough of electrofishing in the 1950's
and 60's opened new horizons for fishery bio-
logists. Quantitative investigations of fish popu-
lations in running water, previously regarded as
nearly impossible, were now within the realm of
possibility. The electrofishing apparatus also per-
mitted careful trapping of fish for later use in
breeding, marking and release experiments, Elec-
trofishing has also been carried out as a supple-
ment to traditional trapping methods in lakes,
mostly in areas near the shore. In this manner, the
electrofishing gear has become a common tool for
fishery biologists, and is today used by most

persons and institutions engaged in freshwater
fish research.
In Nordic countries electrofishing is primarily
used in running waters. Conflicts between fisher-
ies and other interests are increasing at the same
pace as the ever growing use of rivers and streams
for drainage of agricultural, residential and in-
dustrial waste. Stream regulation and acidifi-
cation have also increased the need for quantify-
ing fish populations in running water.
Meanwhile, using electrofishing creates several
problems. These are partially associated with a
lack of 'biological' understanding (limited knowl-
edge about how fish populations fluctuate in time
and space), but are primarily attributable to the