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<br />Meyer and Miller, 1990; Wyoming Game and Fish
<br />Department, 1991; Fredenberg, 1992; Hollender and
<br />Carline, 1992, 1994; Newman, 1992; Roach, 1992; Taube,
<br />1992; McMichael, 1993; Zeigenfuss, 1995; Dalbey et al.,
<br />1996; Grisak, 1996; Thompson et al., 1997a).
<br />The results of Sharber and Carothers' (1988) study
<br />also alarmed regional biologists and managers of the
<br />National Park Service and U.S. Bureau of Reclamation
<br />about continued use of electro fishing to monitor endan-
<br />gered humpback chub in the Grand Canyon. In a memo-
<br />randum to the Glen Canyon Ecological Studies program
<br />manager (12 July 1990), the superintendent of Grand Can-
<br />yon National Park, J.H. Davis, suggested that until con-
<br />cerns over potential adverse effects could be resolved,
<br />electrofishing in Glen Canyon National Recreation Area
<br />and Grand Canyon National Park should be kept to a
<br />minimum and be used in such a way as to minimize pos-
<br />sible stress and injury to humpback chub. Concern also
<br />increased about the use of electrofishing to study en-
<br />dangered Colorado pikeminnow, humpback chub,
<br />bony tail, and razorback sucker in the Upper Colorado
<br />River Basin. As a result, the U.S. Bureau of Reclamation
<br />sponsored the three-phase study described in the Pref-
<br />ace of this report.
<br />The objectives of the original Phase I report (Snyder,
<br />1992a) and this update were to: (I) review and synthesize
<br />the literature on electro fishing including the nature of
<br />electric fields in water, responses of fish to those fields,
<br />its harmful effects on fish, and the factors (specific as-
<br />pects of electrofishing fields and fish) potentially affect-
<br />ing injury and mortality in fish; (2) answer specific
<br />questions regarding the use of electro fishing to capture
<br />threatened, endangered, and native fishes in the Colo-
<br />rado River Basin; and (3) provide recommendations for
<br />interim policy and future research to avoid or minimize
<br />the harmful effects of electrofishing on those fishes. AI.
<br />though specifically intended to facilitate evaluation of
<br />current electrofishing policies by Colorado River Basin
<br />agencies, the review and synthesis is broad in scope and
<br />should be useful wherever the impacts of electrofishing
<br />are a concern. As author, I have brought little practical
<br />electrofishing experience to this project but also no prior
<br />biases or vested interests.
<br />
<br />Methods
<br />
<br />Publications up to year 2000 on electrofishing and
<br />particularly its effects on fish were identified primarily
<br />through electrofishing bibliographies (especially Burridge
<br />et al., 1990), electronic databases ofliterature (e.g., Fish
<br />and Fisheries Worldwide, Aquatic Science and Fisheries
<br />Abstracts, Biological Abstracts, Fish and Wildlife
<br />Reference Service, and Uncover), and the Literature Cited
<br />
<br />SNYDER 3
<br />
<br />sections of published papers. Copies of most English-
<br />language and translated literature and many foreign-
<br />language papers were obtained, scanned for content, and,
<br />if pertinent, reviewed for inclusion in this report. Literature
<br />identified for the earlier version of this report (Snyder,
<br />1992a) was catalogued with keywords and content codes
<br />in a bibliographic database (Reference Manager, Institute
<br />for Scientific Information, Philadelphia, Pennsylvania).
<br />An indexed bibliography was generated from this
<br />database (Snyder and Johnson, 1991) and appended to
<br />the original report (Snyder, 1 992a). Both that bibliography
<br />and Burridge et al. (1990) were expanded upon and
<br />updated by Miskimmin and Paul (1997a).
<br />Information derived from published literature and
<br />limited-distribution reports was supplemented by data,
<br />observations, theories, and recommendations in
<br />unpublished manuscripts and anecdotal personal
<br />communications. ] Contributions regarding unpublished
<br />and ongoing work, as well as personal observations,
<br />experiences, and suggestions, were solicited through a
<br />request printed in the American Fisheries Society
<br />magazine Fisheries, vol. 16, no. 3, p. 52, May-June 1991)
<br />and several other fishery-related bulletins and
<br />newsletters. Approximately 30 responses were received.
<br />Several recognized authorities and electrofishing gear
<br />manufacturers also shared their knowledge, views, and
<br />unpublished manuscripts. Some contacts were made and
<br />information exchanged during special sessions on
<br />electrofishing injuries that were held as part of annual
<br />meetings of the Western Division of the American
<br />Fisheries Society in 1991 (Bozeman, Montana) and 1992
<br />(Fort Collins, Colorado). Finally, a questionnaire was
<br />prepared to solicit local observations and
<br />recommendations on electro fishing (Appendix II in
<br />Snyder, 1992a). The survey forms were distributed to
<br />researchers working in the Colorado River Basin and to
<br />faculty and students in fishery biology at Colorado State
<br />University.
<br />Scientific names and families of fishes referenced by
<br />common names herein are given in Appendix A and fol-
<br />low Robins et al. (1991a,b). When known, fish lengths
<br />are specified as total length (TL), fork length (FL) or stan-
<br />dard length (SL), conductivity as ambient or standard-
<br />ized to 250 C, and electrical output and field intensities as
<br />mean (m), root-mean-square (nns), or peak (p)' In many cases
<br />these important distinctions were not reported. Except
<br />when directly pertinent to the text, readers are referred to
<br />Appendix B for environmental and electrical parameters
<br />associated with electrofishing investigations discussed
<br />herein.
<br />
<br />lUnpublished manuscripts and personal communications are
<br />fully identified on page 125 after "Literature Cited."
<br />
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