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Fish use of dugouts (livestock watering holes) in stream floodplains was evaluated for the first time in this study. Twenty-two fish species were found in 13 of 20 dugouts near a stream, while 20 species were captured from the adjacent stream reach. Relative species composition in stream and dugouts was similar but fish were more abundant in dugouts. Both assemblages were dominated by fathead minnow (Pimephales promelas), black bullhead (Ameiurus melas), orangespotted sunfish (Lepomis humilis), green sunfish (L. cyanellus), and brook stickleback (Culaea inconstans) in decreasing order of magnitude. The endangered Topeka shiner (Notropis topeka) was found in seven dugouts. The presence of several length groups of Topeka shiners indicated reproduction in two dugouts that were close to the stream (<15.2 m) but remained disconnected from the stream throughout the study. Our results suggest that dugouts separate from the stream within frequently inundated zones can provide off-channel habitat for fishes. [ABSTRACT FROM AUTHOR]

We have developed a set of eight polymorphic microsatellite markers for the endangered Topeka shiner, Notropis topeka. Allelic diversity at each of these loci was assessed in a single isolated population from eastern South Dakota, USA. The allelic diversity ranged from four to 15 alleles. These are the first microsatellite markers to be reported for this species. These markers are being used in a more thorough study of the population structure throughout the remaining range of this species. [ABSTRACT FROM AUTHOR]