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4 INFORMATION AND TECHNOLOGY REpORT--2003-0002 Results - Historical Overview Electricity has been used by humans to kill, anesthetize, capture, drive, draw, tickle (arouse), guide, or screen (block, repel) fish since the mid 1800's (Vibert, I 967b; Halsband and Halsband, 1975, 1984; Hartley, 1990). Fishery researchers and managers often rely on electrofishing as their principal capture method for researching, monitoring, and managing stocks of freshwater fishes, especially salmonids (e.g., Weber, 1997). In 1863, a British patent was granted to Isham Baggs for electric fishing, but widespread development and use of the technique did not occur until the 1950's (Hartley, 1990; Reynolds, 1995). Halsband and Halsband (1975, 1984) provided a particularly detailed history of research on fish in electric fields, especially with regard to German contributions. However, man's technological developments are often modifications or imitations of nature's own. Before the evolution of modem man, certain species offish developed powerful electric organs which were probably used much like their modem descendants to detect and capture prey or ward off predators (Marshall, 1966; Hyatt, 1979). The stunning or narcotizing effects of electric fishes were known and used for medical purposes by the ancient Greeks, and study of electric fishes during the 18th and 19th centuries was instrumental in our understanding 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 English-language European symposia publications edited by Vibert (l967a, from 1966 FAO symposium, United Nations Food and Agriculture Organization, Belgium), Cowx (1990, from 1988 EIFAC symposium, European Inland Fisheries Advisory Council, England), and Cowx and Lamarque (1990-also from 1988 EIFAC symposium); a German text by Halsband and Halsband (1975, English translation 1984); a Russian reference book by Sternin et al. (1972, English translation 1976); and a manual for a course on electrofishing offered nationwide through the National Conservation Training Center (formerly Fisheries Academy) of the U.S. Fish and Wildlife Service (latest version, Kolz et aI., 1998). A book by Meyer-Waarden and Halsband (1975, German) 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. 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 of the information therein should be treated as fact; there are too many uncertainties and gaps in knowledge. Although this book is treated by distributors as a replacement for Vibert's (1967a) Fishing with Electricity, Vibert's book includes much information not in the new book. Halsband and Halsband (1975, 1984) is also a fine text on electro fishing, but it is based largely on German perspectives, experience, and research, and like Vibert (l967a), it is somewhat dated. Sternin et al. (1972, 1976) includes marine applications and is a very detailed treatise on the theory and practice of electrofishing based on Soviet research and summaries of world literature. Its Appendices 4 and 5 are tabulated summaries of fish response thresholds (without source references) and aftereffects on fish (reproduced in Snyder 1992a as Appendices III and IV, respectively). The manual for the U.S. Fish and Wildlife Service classroom and correspondence course on Principles and Techniques of Electrofishing (Kolz et aI., 1998) is a loose-leaf, periodically updated volume in semi-outline format with a CD-ROM disk of supplemental simulations and exercises. 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 Sternin et aI. (1972,1976), Halsband and Halsband (1975, 1984), and Kolz et al. (1998), the matter of electrofishing injury and mortality was not discussed extensively in any of these books or manuals. Recognized authorities on electro fishing have long emphasized its benign qualities. For example, Halsband (1967) stated that "the harmlessness of electric current to fish and their food organisms has already been proved on several occasions." And in the foreword to their book, Sternin et al. (1972, 1976) suggested that the theory and practice of electro fishing in recent decades had put to rest concerns about deleterious effects on normal activ- ity and natural reproduction in fish. More emphatically, Halsband and Halsband (1975, 1984) stated that "today we are convinced that electrical collecting, repelling, and stunning methods neither cause pain to animals nor in- jure them internally or externally, (apart from unavoidable exceptions)." However, these conclusions were prema- ture because we now have considerable evidence that electrofishing injuries may have been more common than they appeared or were reported. Spinal injuries in particular were not widely recog- nized because most are not externally obvious and can only be detected by X-ray analysis or necropsy. When present, even brands (temporary dark markings on the body; Fig. 2) were seldom associated, as they frequently are now, with at least moderately severe spinal injuries or hemorrhages. If captured fish had no notable external injuries, aside from occasional brands, and appeared to recover sufficiently to swim away, they were typically considered "unharmed" and expected to continue to be- have, grow, and reproduce normally. As a result, electrofishing had often been considered not only the most efficient but the least-damaging collection technique available.