Relative Selectivities of Miller High-Speed Samplers and Light Traps for Collecting Ichthyoplankton

Publisher Website
Google Scholar
Abstract
Comparative studies on the relative selectiveness of Miller high-speed samplers and light traps in Chemung Lake, Ontario [Canada] were made over 29 "site-nights" from May 13 to June 25, 1982. Yellow perch (Perca flavescens), Iowa darter (Etheostoma exile), and pumpkinseed sunfish (Lepomis gibbosus) constituted 97.2% of the 4376 specimens collected. A percent similarity index indicated a high uniformity in the size and species composition of the catch (.apprx.70% for much of the study); similarity was least on the earliest sample date (May 13, 3.5%). Smaller darters (< 6.0 mm total length) were excluded from the Miller sampler catch. We suggest that extrusion of prolarval and early postlarval darters through the two nets is responsible for low percent similarity index values in early May. We propose that investigators consider a mixture of passive and active sampling techniques to alleviates existing selectivity biases.