7784

• UCREFRP Catalog Number: 7784
• Author: Snyder, D. E.
• Title: Impacts of Electrofishing on Fish.
• USFW Year: 1992.
• USFW - Doc Type: \
• Copyright Material: NO

4 Review

18th and 19th centuries was instrumental in our
recognition of the electrogenic nature of nerves and
muscles (WU 1984).
Most of our knowledge of electrofishing practice,
theory, and effects on aquatic organisms is well
represented in three European books edited by Vibert
(1 967a), Cowx (1990), and Cowx and Lamarque
(1990); a Gennan volume by Halsband and Halsband
(1975, English translation 1984); and a Russian book
on electrofishing by Stemin et al. (1972, English
translation 1976). A book by Meyer-Waarden and
Halsband (1975, Gennan) and a symposium
publication edited by Maiselis (1975, Russian with
English summaries) also should be included in the
list, but English translations are not available. The
three European books comprise the published reports
and papers of special F AO (United Nations Food and
Agriculture Organization, Belgium, 1966) and
ElF AC (European Inland Fisheries Advisory Council,
England, 1988) symposia. Fishing with Electricity,
edited by Cowx and Lamarque (1990), can serve as
a relatively up-to-date academic text and basic
reference but not all the infonnation therein should
be treated as fact; there are just too many
uncertainties and gaps in our knowledge. Although
the book is treated by distributors as a replacement
for Vibert's (1967) Fishing with Electricity, the latter
includes much infonnation not in the new book.
Halsband and Halsband (1975, 1984) is also a fine
text on electro fishing, but it is based largely on
Gennan perspectives, experience, and research and,
like Vibert (1967a), somewhat dated. The Russian
book is a very detailed treatise on the theory and
practice of electrical fishing, including marine
applications, based on Soviet research and summaries
of world literature. Its appendices include tabulated
summaries of fish response thresholds (without
source references) and aftereffects; copies of these
summary tables are reproduced in Appendices m and
IV. A text-type manual is planned for the Principles
and Techniques of Electrofishing course offered
through the Fisheries Academy of the u.s. Fish and
Wildlife Service (Temple pers. commun.). Except
for the article by Sharber and Carothers (1990) in
Cowx (1990), a four-page synopsis in the article by
Lamarque (1990) in Cowx and Lamarque (1990), and
a few pages in Halsband and Halsband (1975, 1984)
and Steroin et aI. (1972, 1976), the matter of

Impacts of Electroflshing on Fish

electrofishing injury and mortality was not discussed
extensively in any of these books.
Since the 1988 Elf AC symposium and
concurrent publication by Sharber and Carothers
(1988), some researchers have begun to verify and
further investigate the extent, conditions, and causes
of electrofishing-induced spinal injuries (e.g., Sharber
et al. unpubl. ms. 1989, unpubl. ms. 1991; Holmes et
aI. 1990; Wyoming Game and Fish Department
1990, 1991; Fredenberg 1992; and others cited in the
introduction). Many biologists across the continent,
and probably abroad, now acknowledge that the
incidence of electrofishing injuries in otherwise
nonnal appearing specimens might be a serious
concem, at least for some environmental conditions,
equipment, and species. They are asking: what
species and size groups are affected; to what degree
are they affected; what equipment, electrical
parameters, and techniques are responsible; what
specific mechanisms are involved; and what can be
done to eliminate or minimize the problem?
Most of these are not new questions. Spinal
injury has long been associated with AC fields
(Hauck 1949). But in spite of electrofishing's
prominent role in fishery research and management,
well-designed investigations in response to many of
these questions and others regarding the general
reactions of fish in electric fields are scarce, often
very limited in scope (frequently a by-product of
another investigation), and difficult to compare
because of differing gear, techniques, environmental
conditions, fish, and tenninology. With regard to
tenninology, many researchers and authors fail to
make critical distinctions such as those between PDC
and continuous, non-pulsed, direct current (DC), peak
and mean voltages or voltage gradients, and narcosis
and tetany. The design, methodology, and
interpretation of results in some studies suggest that
the researchers had an inadequate understanding of
basic physics and electricity (Sharber pers.
commun.). Also, many reports of adverse effects are
anecdotal or lack critical data on the circumstances
of the observations or experiments. Perhaps mostly
as a result of these limitations and deficiencies,
publications and reports sometimes seem so
contradictory that they appear to follow the law of
physics which states that for every action (report),
there is an equal and opposite reaction (counter
report).

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