Early Life History of Fishes in the San Francisco Estuary and Watershed

Evaluating Aspects of Larval Light Trap Bias and Specificity in the Northern Sacramento River System: Do Size and Color Matter?

Michael P. Marchetti, Elaine Esteban, Michael Limm, and Ryon Kurth

doi: https://doi.org/10.47886/9781888569599.ch18

Abstract.—Light traps have been used to study the distribution and ecology of fish larvae in a variety of waters. Yet the physical and taxonomic limitations of light traps have been little studied, particularly in lotic systems. The purpose of this study was to examine aspects of light trap use, bias, and specificity in a natural stream setting. We sampled fish larvae using light traps in the upper Sacramento River watershed in April (2001, 2002) and June (2002) using five different color light sources and two trap sizes. Our results suggest that (1) small traps are as effective at sampling fish larvae as large traps, (2) color of light and/or relative intensity of light have strong effects on numbers of larvae collected, and (3) environmental factors play a role in the number of larvae collected over short time periods.