Electric-induced mortality of newly transformed juvenile fishes in waters of different conductivity

Theodore B Henry, John M Grizzle

    Research output: Contribution to journalArticle

    Abstract

    In three experiments, each with three species of newly transformed juvenile fishes, the immediate mortality was determined after electrical exposure to 60 Hz pulsed DC in waters of different conductivity (C-w). With a constant applied power density (D-a; 1.0-4.9 mW cm(-3) depending on species) over a range of C-w(10-1020 mu S cm(-1)), the results predicted that the highest fish mortality would occur at C-w of 65 mu S cm(-1) for bluegill Lepomis macrochirus, 74 mu S cm(-1) for largemouth bass Micropterus salmoides and at 140-175 mu S cm(-1) for channel catfish Ictalurus punctatus. In experiment 2, the voltage gradient (E) was maintained constant (2.5-8.0 peak V cm(-1) depending on species) over the same range of C-w, and fish mortality increased with current density (J) or D-a, which are directly related to C-w. In experiment 3, fish mortality did not differ when peak E(3 or 8 V cm(-1) depending on species) and mean J(0.09 or 0.24 mA cm(-2) depending on species) were held constant by changing pulse width in waters with different C-w(99, 165 or 495 mu S cm(-1)). Fish mortality in this experiment was not significantly related to peak or mean transferred power density, and the 'power transfer theory for electrofishing' was not useful for predicting electrofishing mortality. Overall, the results of the present study indicated that mortality caused by exposure to electricity can be predicted more accurately with the variables peak E and mean J than with models requiring determination of effective conductivity of the fish.

    Original languageEnglish
    Pages (from-to)747-758
    Number of pages12
    JournalJournal of Fish Biology
    Volume68
    Issue number3
    DOIs
    Publication statusPublished - Mar 2006

    Keywords

    • power transfer
    • fish mortality
    • electrofishing
    • water conductivity
    • ELECTROSHOCKING
    • stunning

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