The theoretical effectiveness of towed-net samplers as related to sampler size and to swimming speed of organisms

Abstract

One of the vexing problems which confront the marine biologist is that of evaluating the effectiveness of towed nets as samplers of the marine biota; the obverse of this problem is that of designing towed nets to sample specific portions of the marine community. Studies of sampling effectiveness have thus far been based primarily upon statistical analysis of samples obtained in the field, often on an a posteriori basis; net design has been based upon past experience and trial and error. In the present analysis we shall depart from this pattern to consider, in a rather elementary way, the physical factors which ulimately limit a net's ability to catch a single organism. The results provide a basis for estimating the minimal effectiveness of existing towed nets and for improving net designs. © 1964, Oxford University Press. All rights reserved.