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Injury to Wild Brook Trout by Backpack Electrofishing
Author(s) -
Hollender Bruce A.,
Carline Robert F.
Publication year - 1994
Publication title -
north american journal of fisheries management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.587
H-Index - 72
eISSN - 1548-8675
pISSN - 0275-5947
DOI - 10.1577/1548-8675(1994)014<0643:itwbtb>2.3.co;2
Subject(s) - electrofishing , salvelinus , trout , fishery , rainbow trout , fontinalis , brown trout , salmo , biology , fish <actinopterygii> , zoology
Most studies of salmonid injuries caused by electrofishing have been conducted on adult brown trout Salmo trutta and rainbow trout Oncorhynchus mykiss in medium‐ or high‐conductivity waters. The objective of this study was to assess internal injuries of wild brook trout Salvelinus fontinalis that were captured with AC and pulsed‐DC backpack electrofishing units in four small, low‐alkalinity streams. We used X rays and autopsies to assess the injury rate of 579 brook trout (95–237 mm total length, TL) captured by electrofishing. Injuries consisted of either internal hemorrhages, spinal misalignment and fracture, or both. We found a total of 74 hemorrhages and 91 spinal injuries. Injury rates of brook trout captured by electrofishing were not significantly different ( P > 0.05) between electrical wave forms: 26% for AC and 22% for pulsed DC. Injury rate increased with fish length, ranging from 14% for fish smaller than 125 mm TL to 42% for fish 175 mm TL or larger. In spinal‐injured fish, damage occurred to an average of six vertebrae, usually ones in the posterior region of the spinal column between the dorsal and anal fins. We also examined 89 brook trout (87–225 mm TL) captured by angling. Less than 7% of the angled fish had injuries, all detected by X ray. We conclude that the incidence of electrofishing‐induced injury can be substantial, even for relatively small brook trout in low‐alkalinity waters. The relation of these injuries to mortality remains to be explored.