Florida State University Libraries Electronic Theses, Treatises and Dissertations The Graduate School 2014 Distribution and Abundance, Community Structure, and Trophic Ecology of Sharks and Teleost Fishes in the Florida Big Bend Cheston Thomas Peterson Follow this and additional works at the FSU Digital Library. For more information, please contact [email protected] FLORIDA STATE UNIVERSITY COLLEGE OF ARTS AND SCIENCES DISTRIBUTION AND ABUNDANCE, COMMUNITY STRUCTURE, AND TROPHIC ECOLOGY OF SHARKS AND TELEOST FISHES IN THE FLORIDA BIG BEND By CHESTON THOMAS PETERSON A Thesis submitted to the Department of Biological Science in partial fulfillment of the requirements for the degree of Master of Science Degree Awarded: Spring Semester, 2014 Cheston Thomas Peterson defended this thesis on April 2, 2014. The members of the supervisory committee were: Dean Grubbs Professor Directing Thesis Joe Travis Committee Member Walter Tschinkel Committee Member The Graduate School has verified and approved the above-named committee members, and certifies that the thesis has been approved in accordance with university requirements. ii I dedicate this to my grandfather, Chester ‘Pop’ Onks, and my dear friend, Troy Billington. “Fare thee well, fare thee well I love you more than words can tell Listen to the river sing sweet songs to rock my soul” - Robert Hunter, Brokedown Palace “Flight of the seabirds, scattered like lost words Wheel to the storm and fly” - John Perry Barlow, Cassidy iii ACKNOWLEDGMENTS Many people have contributed this work, and it is impossible to list them all. First, I would like to thank my advisor, mentor, and friend Dean Grubbs, whose remarkable intelligence, gentle guidance, and strong patience saw me through this entire process. I thank my committee members, Joe Travis and Walter Tschinkel, for their thoughtful comments and suggestions which improved both this research and my ability to think about science and statistics. Many people provided assistance in the field for this work, and without them this work would not have been possible. Specifically, I thank Travis Richards, Ale Mickle, Matthew Kolmann, Lisa Hollensead, Mariah Pfleger, Erica Holdridge, and Johanna Imhoff. Countless undergraduate and outside volunteers gave up their time for this work, and I am profoundly grateful for their help. This work was part of the Gulf Shark Pupping and Nursery (GulfSPAN) survey conducted by the NOAA/NMFS fisheries lab in Panama City, Florida. I thank Dana Bethea and John Carlson for annual funding of the survey, gillnets, and shark tags; all of which facilitated this research. I had a great group of colleagues with whom I could discuss my research with, both formally and informally: Travis Richards, Johanna Imhoff, Matthew Kolmann, Lisa Hollensead, Mollie Taylor, Robert Ellis, as well as the many EERDG participants. This work funded by through GulfSPAN funding provided by NOAA/NMFS, as well a research awards granted through Florida Sea Grant and funded by the Guy Harvey Ocean Foundation, as well as a grant awarded to Dean Grubbs by the Guy Harvey Ocean Foundation. Finally, I thank my family and friends for their continued love and support. iv TABLE OF CONTENTS List of Tables ................................................................................................................................ vii List of Figures .............................................................................................................................. viii Abstract ..........................................................................................................................................xv 1. ABUNDANCE, DISTRIBUTION, AND COMMUNTIYCOMPOSTIION OF SHARKS AND TELEOST FISHES IN THE FLORIDA BIG BEND ....................................................1 1.1 Introduction ....................................................................................................................1 1.2 Materials and Methods ...................................................................................................3 1.2.1 Study Area ........................................................................................................3 1.2.2 Survey Design ...................................................................................................3 1.2.3 Sampling ...........................................................................................................4 1.2.4 Abundance and Distribution of Dominant Species ...........................................5 1.2.5 Community Composition and Environmental Correlates .................................6 1.3 Results ............................................................................................................................8 1.3.1 General Results .................................................................................................8 1.3.2 Abundance and Distribution of Dominant Species ...........................................9 1.3.3 Community Composition and Environmental Correlates ...............................12 1.4 Discussion ....................................................................................................................16 1.4.1 Ubiquitous Species..........................................................................................16 1.4.2 Sexual Segregation in Sharks..........................................................................17 1.4.3 Regional Faunal Zones ...................................................................................18 1.4.4 Community Composition and Environmental Correlates ...............................19 1.4.5 Conclusion ......................................................................................................22 2. STABLE ISOTOPE ECOLOGY AND TROPHIC STRUCTURE OF SHARK AND TELEOST FAUNAL ASSEMBLAGES IN THE BIG BEND .............................................70 2.1 Introduction ..................................................................................................................70 2.2 Materials and Methods .................................................................................................71 2.2.1 Sample Collection and Preparation .................................................................71 2.2.2 Stable Isotope Analysis ...................................................................................72 2.2.3 Statistical Analysis ..........................................................................................73 2.3 Results ..........................................................................................................................74 2.3.1 General Results for All Taxa ..........................................................................74 2.3.2 Ontogenetic Shift in Dominant Taxa ..............................................................77 2.3.3 Regional Variation in Stable Isotope Values ..................................................77 2.4 Discussion ....................................................................................................................78 2.4.1 General Results for All Taxa ..........................................................................78 2.4.2 Ontogenetic Shifts in Dominant Taxa .............................................................82 2.4.3 Regional Variation in Stable Isotope Values ..................................................83 2.4.1 Conclusion ......................................................................................................84 v APPENDICES .............................................................................................................................105 A. RANK ABUNDANCE CURVES AND OMISSION OF RARE SPECIES .......................105 B. NMDS DIMENSIONS AND STRESS ...............................................................................106 C. STATION COORDINATES AND CLUSTER DESIGNATIONS .....................................107 D. ACUC LETTER OF APPROVAL ......................................................................................112 REFERENCES ............................................................................................................................113 BIOGRAPHICAL SKETCH .......................................................................................................122 vi LIST OF TABLES 1 Summary of environmental parameters of sites sampled within each survey region. Means and standard deviations are shown with ranges in parentheses. Mean depth included maximum and minimum depths of each site. For salinity, temperature, and dissolved oxygen, each line represents surface, mid, and bottom values from top to bottom, respectively ...........................................................................................................23 2 Summary of elasmobranch fishes; longline CPUE ([catch/100 hooks]/hours soaked *100), gillnet CPUE (catch/hours soaked); SE = standard error; m = male, f = female; YOY = young-of-the-year, Juv = juvenile, Mat = mature, FL = fork length, TL = total length, DW = disc width, Individuals for which sex and/or life stage were not recorded were omitted for calculation of sex and maturity ratios ....................................................24 3 Summary of bony fishes in taxonomic order by family; LL CPUE ([catch/100 hooks]/hours soaked*100), GN CPUE (catch/hours soaked); SE=standard error; FL=fork length..................................................................................................................................25 4 Diversity