Electrical phase angle as a new method to measure fish condition

Cox, Keith W. and Heintz, Ron (2009) Electrical phase angle as a new method to measure fish condition. Fishery Bulletin, 107(4), pp. 477-487.

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In this study, phase angle (the ratio of resistance and reactance of tissue to applied electrical current) is presented as a possible new method to measure fish condition. Condition indices for fish have historically been based on simple weight-at-length relationships, or on costly and timeconsuming laboratory procedures that measure specific physiological parameters. Phase angle is introduced to combine the simplicity of a quick field-based measurement with the specificity of laboratory analysis by directly measuring extra- and intracellular water distribution within an organism, which is indicative of its condition. Phase angle, which can be measured in the field or laboratory in the time it takes to measure length and weight, was measured in six species of fish at different states (e.g., fed vs. fasted, and postmortem) and under different environmental treatments (wild vs. hatchery, winter vs. spring). Phase angle reflected different states of condition. Phase angles <15° indicated fish in poor condition, and phase angles >15° indicated fish that were in better condition. Phase angle was slightly affected by temperatures (slope = – 0.19) in the 0–8°C range and did not change in fish placed on ice for <12 hours. Phase angle also decreased over time in postmortem fish because of cell membrane degradation and subsequent water movement from intra- to extracellular (interstitial) spaces. Phase angle also reflected condition of specific anatomical locations within the fish.

Item Type: Article
Title: Electrical phase angle as a new method to measure fish condition
Personal Creator/Author:
Cox, Keith W.
Heintz, Ron
Refereed: Yes
Journal or Publication Title: Fishery Bulletin
Volume: 107
Number: 4
Page Range: pp. 477-487
Date: 2009
ISSN: 0090-0656
Issuing Agency: United States National Marine Fisheries Service
Subjects: Biology
Item ID: 8778
Depositing User: Patti M. Marraro
Date Deposited: 10 Jun 2012 09:00
Last Modified: 10 Jun 2012 09:00
URI: http://aquaticcommons.org/id/eprint/8778

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