Committee Chair

Schorr, Mark

Committee Member

Litchford, Gary; Van Horn, Gene; Fritz, Doug


Dept. of Biology, Geology, and Environmental Science


College of Arts and Sciences


University of Tennessee at Chattanooga

Place of Publication

Chattanooga (Tenn.)


I evaluated the adequacy of different electrofishing approaches for estimating species richness in small Ridge and Valley streams. My study objectives were to determine the effects of the sampling season, reach length, habitat sequences surveyed, and sampling intensity on estimates of fish species richness. Fish assemblages were sampled at 18 sites across five streams in the Chattanooga, Tennessee area, May-June (spring) and July-August (summer) 1998. Reach lengths ranged from 103 to 278 m (30 to 61 times the mean stream width [MSW]). At each site, fish were collected using one or two backpack electrofishers within habitat-specific enclosures (riflle-run or pool). Two and three-pass sampling was conducted at selected sites. Species richness averaged slightly higher (P < 0.1) in the spring than summer; these estimates were positively correlated (r = 0.829; P < 0.0001). Regression analysis revealed a positive asymptotic relationship between species richness and the reach length sampled (r2 > 0.87; P <0.0001). Sampling a reach of 41 times the mean stream width (MSW) yielded 90% of the estimated maximum species richness. Species richness averaged higher (P < 0.1) in samples from two habitat sequences versus one habitat sequence; sampling more than two habitat sequences did not yield significantly greater numbers of species ( P > 0. 1). Estimates of species richness from single- and multiple-pass (two and three collections) electrofishing were statistically similar ( P > 0.1). This study demonstrated that sampling reach lengths equal to at least 41 times the MSW with one electrofishing pass was sufficient to collect 90% of the species present in small streams in the Ridge and Valley ecoregion. Additionally, at least two habitat sequences should be included within this sampling reach.


I would like to express my gratitude and appreciation for everyone who contributed to this research. I would like to thank Dr. Mark Schorr, my major professor, without whose expertise, guidance, and devotion of his time this thesis could not have been completed. Dr. Schorr proved to be an invaluable supporter and friend throughout the entire project. I would also like to thank Drs. Gary Litchford and Gene S. Van Hom for their helpful comments and suggestions. I would also like to thank the city of Chattanooga, Stormwater Management Division for funding the Urban Streams Project. Doug Fritz was an especially helpful liaison between the city and the university and was very receptive to questions and comments. Several Tennessee Valley Authority personnel willingly contributed to the completion of this thesis. Charlie Saylor and Amy Wales shared their expertise on the Index of Biotic Integrity and the calculation of the IBI metrics. Their technical knowledge and years of field experience in the Tennessee Valley are an incredible asset to TVA and the Tennessee River watershed. I would like to thank the UTC students and other volunteers who assisted with the field work involved in the Urban Streams Project. I would especially like to thank Jeannie Long, Paul Freeman, and Jennifer Backer for the numerous hours of time and effort they have contributed to this project.


M. S.; A thesis submitted to the faculty of the University of Tennessee at Chattanooga in partial fulfillment of the requirements of the degree of Master of Science.




Fish populations--Tennessee--Chattanooga; Fisheries--Research--Statistical methods


Environmental Indicators and Impact Assessment

Document Type

Masters theses




viii, 52 leaves



Call Number

LB2369.2 .C738 1999