Some of the Factors Affecting the Calibration Number of the Clarke‐Bumpus Quantitative Plankton Sampler1

Abstract

Calibration values obtained by standard “field” calibration procedures are in error because a portion of the water encountered during the tow is rejected. A method is described by which the actual volume of water passing through the sampler is measured without disrupting normal flow characteristics around or through the meter. Depending upon net attachment and towing velocity, the percentage of water accepted varies from 90–94 per cent. An attempt has also been made to evaluate the effects of net clogging on calibration values.