Effectiveness of Seining after Electrofishing to Characterize Stream Fish Communities

Abstract

The richness and composition of species collected uniquely to electrofishing and subsequent seining efforts were examined at 271 stream sites across the USA by using wadeable electrofishing methods (backpack or barge electrofishing) or boat electrofishing followed by seining. Seining after wadeable electrofishing resulted in the collection of new species at 42% of sites, whereas seining after boat electrofishing resulted in the collection of new species at 87% of sites. Mean percentage of total observed fish species richness that was collected uniquely by seining was 6% (representing one new species, on average) after wadeable electrofishing compared with 18% (four new species, on average) after boat electrofishing. Shannon–Wiener diversity index values were not significantly different between data from combined sampling (electrofishing and seining) and data from wadeable electrofishing (P = 0.490) but were significantly different between boat electrofishing and combined sampling (P = 0.004). Seining efforts after boat electrofishing can provide critical information that allows for a more complete characterization of the fish community. For sampling in wadeable streams, decisions regarding the use of seines should consider the effectiveness of electrofishing at a given site and the use of seines as an alternative primary sampling gear rather than as a supplement to electrofishing.

Received June 22, 2011; accepted November 10, 2011

ACKNOWLEDGMENTS

Many biologists, hydrologists, and technicians—too numerous to name individually—spent their time and effort collecting data as part of the NAWQA Program. I thank Larry Brown, John Lyons, and anonymous reviewers for their helpful comments and suggestions. This study was conducted as part of an ecological synthesis through the NAWQA Program of the U.S. Geological Survey.