REPRODUCTIVE SCHEDULE AND TRAITS OF HYBOPSIS AMBLOPS (BIGEYE CHUB) IN THE FLINT RIVER SYSTEM, HUNTSVILLE, ALABAMA by CRISSY L. TARVER A THESIS Submitted in partial fulfillment of the requirements for the degree of Masters of Science in The Department of Biological Sciences The School of Graduate Studies of The University of Alabama in Huntsville Huntsville, Alabama 2015 ii iii ABSTRACT The School of Graduate Studies The University of Alabama in Huntsville Degree Master of Science College/Dept. Science/Biological Sciences Name of Candidate Crissy L. Tarver Title Reproductive Schedule and Traits of Hybopsis amblops (Bigeye Chub) in the Flint River System in Huntsville, Alabama The goal of this study was to ascertain a reproductive schedule and describe reproductive traits of Hybopsis amblops in the Flint River system in Huntsville, AL. Members of this species were collected from the Flint River from May, 2013 to July, 2014. The standard length (SL) of each fish was measured using digital slide calipers. Gross body mass (GBM) and gonadal mass (GM) were obtained using a digital balance. In adult fish, gonadosomatic indices (GSI) were calculated to aid in determining reproductive timing. Ovaries and oocytes were categorized into developmental stages. Total fecundity (TF) of each female was calculated from the number of oocytes found in each ovary. The average size of oocytes in each stage of development was defined by diameter measurements. A spawning season from March to June with peaks in April and May were indicated by mean monthly GSI values. The primary reproductive month was April as evidenced by a peak GSI value with the retrieval of more than 800 stage III mature and stage IV ripe ova from females collected that month. An absolute fecundity ranged from 90 to 2,566 oocytes. This study examined multiple relationships between SL, GBM, GSI values, GM, TF, and water temperature. GSI values were found to be independent of SL and GBM in both sexes. Total fecundity not strongly correlated to GSI values (R2=0.306; p < .0001). The strongest relationship was seen between TF and GM (R2 = 0.621; p < .0001). Similar trends were noted for the mean monthly water iv v ACKNOWLEDGMENTS This project was made possible by the assistance and support of my mentors, peers, and family. I would like to express my appreciation to Dr. Bruce Stallsmith for his assistance, guidance, and persistence on collection trips during this project. My gratitude extends to Dr. Yong Wang for expanding my knowledge on the application of statistical methods in a biological context. I am grateful to Dr. Luciano Matzkin for all of his lectures on evolution, and for introducing me to JMP 10 statistical software. The completion of this research would not have been possible without the assistance of Kelly Hodgskins, Joshua Mann, Kara Million, Breann Roberts, Ethan Tarver, Roy Tarver Jr., and Jeffrey Warner who helped with the collection of data and fish. Finally, I would like to thank Roy, Ethan, and Victoria Tarver for their assistance and unrelenting support. vi TABLE OF CONTENTS Page List of Figures………………………………………………………………………..….viii List of Tables……………………………………………………………………………...x Chapter One: Introduction 1.1 Rationale.................................................................................................................... 1 1.2 Cyprinids ................................................................................................................... 6 1.3 Reproductive schedules and strategies of cyprinids ................................................ 10 1.4 Hybopsis amblops, Bigeye chub ............................................................................. 15 1.5 Statement of purpose and hypothesis ...................................................................... 19 Chapter Two: Material and Methods 2.1 Study site and sampling........................................................................................... 20 2.2 Laboratory analysis ................................................................................................. 22 2.3 Statistical analysis ................................................................................................... 25 Chapter Three: Results 3.1 Study site data ......................................................................................................... 27 3.2. Sex bias and size structure ..................................................................................... 28 3.3 Reproductive schedule ............................................................................................ 32 3.4 Ovarian development, oocyte counts, and oocyte diameters .................................. 33 3.5 Relationships………………………………………………………………………39 Chapter Four: Discussion 4.1 Study goals and limitations…………………………………………………..…....42 4.2 Size and reproductive schedule ............................................................................... 43 4.3 Fecundity and maturation………...………………………………………….…….44 Appendix……………………………………………………………………..…………..46 Works Cited ...................................................................................................................... 72 vii LIST OF FIGURES Figure Page 1.1 Triangular life history continuum model ...................................................................... 5 1.2 Deep phylogeny of ray-finned fish (Actinopterygii) .................................................... 7 1.3 Distribution map for Hybopsis amblops ..................................................................... 16 1.4 Hybopsis amblops conservation status, United States ................................................ 17 2.1 Flint River location on Oscar Patterson Road in Huntsville, Alabama according to Google maps .............................................................................................................. 21 2.2 Flint River collection site at Oscar Patterson Road access point in Huntsville, Alabama .................................................................................................. 21 2.3 Stages of ovarian development ................................................................................... 23 2.4 Stages of oocyte development .................................................................................... 24 3.1 Mean (±SD) monthly standard length for female, juvenile, and male Hybopsis amblops collected from May, 2013 to July, 2014. No females were collected in January, 2014; no juveniles were collected in July, 2013, January or June, 2014. ............................................................................................... 29 3.2 Mean (±SD) monthly body mass for female, juvenile, and male Hybopsis amblops collected from May, 2013 to July, 2014. No females were collected in January, 2014; no juveniles were collected in July, 2013, January or June, 2014. ............................................................................................... 30 3.3 Standard length vs gross body mass relationship in female Hybopsis amblops collected between May, 2013 and July, 2014. ........................................................... 30 viii 3.4 Standard length vs gross body mass relationship in male Hybopsis amblops collected between May, 2013 and July, 2014. .......................................................................... 31 3.5 Standard length vs gross body mass relationship in juvenile Hybopsis amblops collected between May, 2013 and July, 2014. ........................................................... 31 3.6 Mean monthly gonadosomatic indices (GSI) for adult male and female Hybopsis amblops collected from May, 2013 to July, 2014. No females were collected in January, 2014. Levels not connected by the same letter are significantly different. ............................................................................................... 32 3.7 Mean (±SE) monthly number of oocytes per stages I, II, III, and IV for Hybopsis amblops collected from May to June, 2013, and February to July, 2014. 35 3.8 Standard length vs oocyte counts in developmental stages I-IV for Hybopsis amblops collected from May, 2013 to July, 2014. .................................... 38 3.9 Total fecundity vs GSI values in female Hybopsis amblops collected from May, 2013 to July, 2014. ........................................................................................... 39 3.10 Total fecundity vs gonadal mass in female Hybopsis amblops collected from May, 2013 to July, 2014. ........................................................................................... 39 3.11 Total fecundity vs GBM in female Hybopsis amblops collected from May, 2013 to July, 2014. ........................................................................................... 40 3.12 Common trends for mean monthly fecundity values vs mean water temperatures (ºC) collected from May, 2013 to July, 2014. ...................................... 40 ix LIST OF TABLES Table Page 3.1 Monthly water temperatures and average rate of river discharge (m3/sec) from the U.S. Geological Survey database 03575100 at Brownsboro, AL from May, 2013 to July, 2014. ........................................................................................... 27 3.2 Total number of male, female, and juvenile Hybopsis amblops collected with monthly totals from May, 2013 to July, 2014. No females were collected in January, 2014; no juveniles were collected in July, 2013, January or June, 2014………………….29 3.3 Number of ovaries per month categorized into developmental