Our goal was to identify habitat, fish species, and fish assemblages associated with the occurrence of Topeka Shiners Notropis topeka in stream and off-channel habitat (OCH) of west-central Iowa. Fish assemblages and habitat characteristics were estimated in 67 stream and 27OCHsites during 2010-2011. Topeka Shiners were sampled in 52% of OCH sites, but in only 9% of stream sites, which supports the hypothesis that OCH is an important component of their life history. Fish assemblages containing Topeka Shiners were different from those that did not contain Topeka Shiners in OCH sites, but this was not evident in stream sites. Results from logistic regression models suggested that Topeka Shiner presence was associated with increased submerged vegetation and abundance of Fathead Minnow Pimephales promelas. Contrary to the findings of other studies, the abundance of large piscivorous fishes was not associated with the occurrence of Topeka Shiners. Our results provide new information about the biology and life history of the Topeka Shiner that will guide habitat restoration and other recovery efforts. KeywordsTopeka Shiner, Notropis topeka, piscivorous, off-channel habitat RightsWorks produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted. AbstractOur goal was to identify habitat, fish species, and fish assemblages associated with the occurrence of Topeka Shiners Notropis topeka in stream and off-channel habitat (OCH) of west-central Iowa. Fish assemblages and habitat characteristics were estimated in 67 stream and 27 OCH sites during 2010-2011. Topeka Shiners were sampled in 52% of OCH sites, but in only 9% of stream sites, which supports the hypothesis that OCH is an important component of their life history. Fish assemblages containing Topeka Shiners were different from those that did not contain Topeka Shiners in OCH sites, but this was not evident in stream sites. Results from logistic regression models suggested that Topeka Shiner presence was associated with increased submerged vegetation and abundance of Fathead Minnow Pimephales promelas. Contrary to the findings of other studies, the abundance of large piscivorous fishes was not associated with the occurrence of Topeka Shiners. Our results provide new information about the biology and life history of the Topeka Shiner that will guide habitat restoration and other recovery efforts.

1. In the agricultural landscape of the Midwestern USA, waterways are highly altered.Oxbows are among the few remaining off-channel habitats associated with streams, supporting fish assemblages that include the endangered Topeka shiners Notropis topeka in portions of their remaining range. Oxbow restorations seek to increase the number and quality of oxbows for Topeka shiners. For oxbows to provide optimal habitat, periods of isolation from streams and connection with streams during floods are necessary. Water levels and patterns of drying and hydrological connectivity between 12oxbows and their neighboring streams in West Central Iowa were continuously monitored from May to October 2011, and fish assemblages were assessed for responses to the differing hydrodynamics using dynamic occupancy modelling.3. The 12 oxbows exhibited varied hydrodynamics and connectivity with streams.Two oxbows never contained fish; these oxbows never flooded and were among the three oxbows that were dry for the longest periods. 4. Occupancy modelling suggested that connection with the stream via floods significantly increased the probability of colonization, and low water level increased the probability of local extinction from oxbows. Thirteen of the 16 fish species encountered had detection probabilities over 60%, and eight had detection probabilities over 90%, including Topeka shiners. 5. None of the five previously restored oxbows flooded; all five contained fish, but only one contained Topeka shiners. Three of the four oxbows containing Topeka shiners flooded and all four dried at least once.6. These results suggest that planning for future oxbow restorations should consider:(i) sites that flood frequently; and (ii) construction methods promoting alternating periods of isolation from and connection with streams.

Quist for their guidance and instruction. Their expertise in scientific research, writing, and communication was invaluable to this project and to my growth as a student and fisheries professional. Much thanks also to Dr. Philip Dixon, who served on my committee and provided valuable insight. This project would not have been possible without the faculty, staff, and students of Iowa State University, the Department of Natural Resources, and the Iowa Cooperative Fish and Wildlife Research Unit. I would like to thank fellow graduate students Michael Colvin, Jesse Fischer, Timothy Parks, Tony Sindt, for their contributions to this project and my overall experience in Iowa. Without them, I would have never realized the awesomeness of Program R, shot my first goose, played drums in a rock band, or discovered the joy of sitting silently in a tree stand, respectively. I would next like to thank my family for their unwavering support and encouragement. I would especially like to thank my wife, Jennifer, for leaving mountains of Montana to follow her future husband to the flatlands of Iowa. I would never have made it through this experience without her love, understanding, and friendship. Lastly, I would like to dedicate this thesis to the memory of my grandfather, George Bakevich Sr., who took me fishing before I learned how to walk. Because of him, I grew up to appreciate the beauty, complexity, and value of watery places.

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