Electrofishing Effort and Fish Species Richness and Relative Abundance in Ozark Highland Streams of Arkansas

Abstract

We sampled 15 stream sites in the Ozark Highlands ecoregion of Arkansas and examined the effect of increased backpack electrofishing effort on the richness and relative abundance estimates of fish species. Each site was 75 mean stream widths (MSWs) long and was divided into 15 consecutive segments that were each 5 MSWs long. For each site the percent of empirical and theoretical species richness and the percent of relative abundance similarity to the entire fish assemblage were calculated by adding consecutive segments using an approach that resulted in 15 accumulation curves per assemblage character for each stream site. On average, a distance of 53.8 MSWs (SD ϭ 7.4) was needed to sample 95% of empirical species richness at a stream site, which was equal to an area of 2,722.0 m 2 (SD ϭ 1,967.0). For sampling 95% of theoretical species richness, an average of 101.8 MSWs (SD ϭ 34.5), or 5,055.7 m 2 (SD ϭ 3,667.4), was needed. Obtaining 95% relative abundance similarity required an average sampling effort equivalent to 24.0 MSWs (SD ϭ 8.9), or 1,269.7 m 2 (SD ϭ 932.1). Mean stream width explained more variance in the reach lengths and areas needed for estimates of species richness and relative abundance than did riffleϪpool sequence length or watershed size. Our results should offer insight into species richness and relative abundance accumulation rates when using a one-pass backpack electrofishing sample in Ozark Highland streams of Arkansas.

An Evaluation of Qualitative Indexes of Physical Habitat Applied to Agricultural Streams in Ten U.S. States1

“…(2006) and Hughes and Peck (2008). Sites of that length were generally found adequate for assessing fish species richness in wadeable streams throughout the U.S. (Lyons, 1992; Angermeier and Smogor, 1995; Paller, 1995; Dauwalter and Pert, 2003b) and for repeatable index of biotic integrity (IBI) estimates (Dauwalter and Pert, 2003a; Reynolds et al. , 2003).…”

Assemblage level monitoring of stream fishes: The relative efficiency of single-pass vs. double-pass electrofishing

“…These results suggest considerable differences in sampling efficiency-species richness relationships even among small wadable lowland streams from the same region. Although shorter sections may be sufficient for catching all species for some sites, in other cases electrofishing a minimum of 30-40 stream widths or even longer sections is necessary for the reliable determination of species richness (Lyons, 1992;Angermeier and Smogor, 1995;Paller, 1995;Dauwalter and Pert, 2003a).…”

Evaluation of electrofishing efficiency in a stream under natural and regulated conditions

“…However, when one run is consistently applied using a constant unit of effort, its efficiency may be of some value in comparative studies (Lyons and Kanehl 1993;Matthews 1998;Simonson and Lyons 1995;Bravo et al 1999;Penczak et al 2000;Maunder 2001). The underlying assumption of this method is that the number of fish obtained by the single run (in our study termed C 1 ), which is also termed the "relative abundance" or "index abundance" (Lyons and Kaneh 1993;Angermeier and Smogor 1995;Penczak et al 2000Penczak et al , 2003Dauwalter and Pert 2003;Pine et al 2003), remains as a consistent proportion of all fish present in the studied stream, or even across streams. Unfortunately, the usefulness of this parameter is limited, because even small streams show changes between similar stations (Hankin 1984) when they are monitored over a long time frame (Simonson and Lyons 1995).…”