A Comparison of Sampling Gears for Capturing Juvenile Silver Carp in River–Floodplain Ecosystems

Abstract

Effective management and monitoring programs require confidence regarding basic biological sampling. Gear comparisons are often required to determine the most effective techniques. Such is the case for populations of invasive Asian carps Hypophthalmichthys spp., which have recently occurred in large numbers throughout sections of the Mississippi River basin. We tested five gears (mini-fyke nets, beach seine, purse seine, pulsed-DC electrofishing, and gill net) that targeted juvenile (age 0) Silver Carp H. molitrix at sites along the Illinois River during 2014 and 2015 to determine the most effective ones for age-0 Silver Carp. We considered the most cost-effective gear to be the one that provided the largest catch at a minimal expenditure of labor. Mini-fyke nets were the most effective at collecting large numbers of age-0 Silver Carp, followed in decreasing order by beach seines, pulsed-DC electrofishing, purse seines, and gill nets. The smallest Silver Carp were caught in beach seines and the largest were caught in gill nets, and there was considerable variation in size distributions among gears. However, when we considered cost-effectiveness in terms of labor hours for each gear, both beach seines and mini-fyke nets had similar and overlapping labor expenditures. Gill nets and purse seines were not cost-effective, as they required more labor and had lower overall catch rates.

Received May 23, 2016; accepted September 19, 2016Published online December 21, 2016

ACKNOWLEDGMENTS

This study was supported by the Great Lakes Restoration Initiative, with funding administered through the Illinois Department of Natural Resources (CAFWS-93). We thank K. Irons and M. O’Hara of the Illinois Department of Natural Resources for their assistance in coordinating this project. We are grateful to the numerous individuals who have provided field assistance to make this project possible, including the graduate students and staff of the Kaskaskia and Sam Parr Biological Stations, Illinois Natural History Survey, and the University of Illinois.