Record Display for the EPA National Library Catalog


Main Title Calibrated Mask-Bar for Underwater Measurement of Fish.
Author Swenson, W. A. ; Gobin, W. P. ; Simonson, T. D. ;
CORP Author Wisconsin Univ.-Superior. Center for Lake Superior Environmental Studies.;Environmental Research Lab.-Duluth, MN.
Publisher c1988
Year Published 1988
Report Number EPA-R-812215 ;EPA-R-810934; EPA/600/J-88/461;
Stock Number PB90-147836
Additional Subjects Fishes ; Measuring instruments ; Underwater equipment ; Calibrating ; Diving suits ; Breathing masks ; Reprints ;
Library Call Number Additional Info Location Last
NTIS  PB90-147836 Some EPA libraries have a fiche copy filed under the call number shown. 07/26/2022
Collation 5p
The paper describes a method for measuring fish under water by using a diving mask equipped with a calibrated mask-bar. The calibrated mask-bar consists of a plexiglass strip with calibration marks spaced 3.22 mm (1/8 in) apart, mounted to a diver's mask by aluminum straps. Relationships between calibration mark counts made by underwater observers and the length of objects were described by regression analysis. Measurements of stationary objects were accurate to within + or - 5%. Estimates of fish length under field conditions were generally accurate to within + or - 10%. Mean lengths calculated from multiple mask-bar measurements were consistent with those calculated from measurement of captured fish. (Copyright (c) by the American Fisheries Society 1988.)