Freshwater Fisheries
Title:	An approach to evaluating the combination of gear that representatively samples fish assemblages in small coastal streams
Author(s):	Sarah P. Wells, Joseph M. Smith, Martha E. Mather, Robert M. Muth, John T. Finn, University of Massachusetts
Date:	Tuesday, April 27, 2010
Time:	1:25 pm - 1:45 pm
Room:	Salon C
Abstract: Scientists are often faced with the challenge of sampling fish assemblages at locations with limited baseline data. In these locations it is difficult to know what combination of gear will provide a representative sample. As a result, a systematic approach for determining the appropriate sampling protocol would be useful. Relative to this goal, we asked the following questions: 1) are species and sizes sampled using three gear types different?; 2) how much gear is needed for a representative sample?; and 3) does random resampling help determine the best sampling regime? In June of 2009, we compared catches from single-pass backpack electrofishing, hoop nets, and minnow traps in Fish Brook, MA. We divided a 90 m homogeneous reach into 30 m blocks in which we randomly assigned one, two, and three units of gear (one unit = 10 m backpack electrofishing, one 0.6 m diameter hoop net, and 5 minnow traps). We then compared species richness for 1-3 gear units across four replicate samples. These catches were randomly resampled using bootstrapping techniques. Overall, 11 species and 103 individuals were caught. As expected, catches from the three gear types differed in species richness, numbers, and sizes. Two-gear units caught 76% of the cumulative species pool, providing a representative sample of the existing fish assemblage. In summary, use of a combination of the gear types was most effective. This approach may be useful to other researchers in designing plans for accurately sampling fish assemblages.
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