Louisiana State University LSU Digital Commons LSU Doctoral Dissertations Graduate School 2003 The ecology of two estuarine-dependent tonguefishes, the blackcheek tonguefish (Symphurus plagiusa) and the offshore tonguefish (S. civitatium), in coastal Louisiana Theodore Scott wS itzer Louisiana State University and Agricultural and Mechanical College, [email protected] Follow this and additional works at: https://digitalcommons.lsu.edu/gradschool_dissertations Part of the Oceanography and Atmospheric Sciences and Meteorology Commons Recommended Citation Switzer, Theodore Scott, "The ce ology of two estuarine-dependent tonguefishes, the blackcheek tonguefish (Symphurus plagiusa) and the offshore tonguefish (S. civitatium), in coastal Louisiana" (2003). LSU Doctoral Dissertations. 1305. https://digitalcommons.lsu.edu/gradschool_dissertations/1305 This Dissertation is brought to you for free and open access by the Graduate School at LSU Digital Commons. It has been accepted for inclusion in LSU Doctoral Dissertations by an authorized graduate school editor of LSU Digital Commons. For more information, please [email protected]. THE ECOLOGY OF TWO ESTUARINE-DEPENDENT TONGUEFISHES, THE BLACKCHEEK TONGUEFISH (SYMPHURUS PLAGIUSA) AND THE OFFSHORE TONGUEFISH (S. CIVITATIUM), IN COASTAL LOUISIANA A Dissertation Submitted to the Graduate Faculty of the Louisiana State University and Agricultural and Mechanical College In partial fulfillment of the Requirements for the degree of Doctor of Philosophy in The Department of Oceanography and Coastal Sciences by Theodore S. Switzer B.S., Clarion University of Pennsylvania, 1995 M.Ap.Stat., Louisiana State University, 2002 August, 2003 ACKNOWLEDGEMENTS First of all I would like to thank my major professor, Don Baltz, for his guidance and support throughout the past several years, without which this dissertation would not have been possible. I also want to thank committee members Chuck Wilson and Ed Chesney for their meaningful advice on this research as well as access to laboratory space and materials. Committee member Jay Geaghan mentored my development as a statistician and his guidance through the statistical analyses was invaluable. Additionally, committee members Larry Rouse and Ken Brown offered insightful comments that greatly improved the quality of this dissertation. Thanks to Bob Allen for access to his flatfish collections. Tom Munroe provided stimulating comments regarding the ecology of tonguefishes in coastal Louisiana. Thanks to Andy Fischer and Lori Benson for instructing me in techniques for age and growth analysis. I would like to thank Hiram Li and Phil Rossignol for their informative tutorial on loop analysis. Thanks to John Fleeger for assisting with the identification of copepods collected from stomach contents. Several graduate students and research associates assisted in various stages in the field and laboratory: Guillermo Duque, Cara Miller, Alex Arrivillaga, Robert Jones, Mark Stead, Murt Verburg and Cody Short. Additional thanks to all the individuals involved in the various sampling studies from which I borrowed several data sets. The support staff at the Louisiana Universities Marine Consortium (LUMCON) was extremely helpful during my time in Cocodrie. Sarah Frias-Torres provided words of wisdom during the writing process of this dissertation. Thanks to the secretarial and administrative staff in the Coastal Fisheries Institute, the Department of Oceanography and Coastal Sciences and the Graduate School, for guiding me through all the paperwork and deadlines required for the completion of my degree. I also want to ii thank all of my friends from the Department of Oceanography and Coastal Sciences and the greater Louisiana State University community for making the past seven years truly enjoyable. Please forgive me for not mentioning each of you individually, but there are so many individuals that I would undoubtedly forget some of you. Finally I wish to acknowledge the support of my other friends and family, especially my parents Ted and Judy Switzer and my sister Robin Hanna. I could not have accomplished this without your love and support. Thank you all! iii TABLE OF CONTENTS Page ACKNOWLEDGEMENTS ---------------------------------------------------------------------------------ii LIST OF TABLES -------------------------------------------------------------------------------------------vi LIST OF FIGURES ----------------------------------------------------------------------------------------viii ABSTRACT -------------------------------------------------------------------------------------------------xii CHAPTER I. INTRODUCTION: WETLAND DYNAMICS, NURSERY HABITAT AND THE ECOLOGY OF TONGUEFISHES ---------------------------------------------------------1 Literature Cited -------------------------------------------------------------------------------------10 CHAPTER II. HABITAT SELECTION BY SYMPATRIC TONGUEFISHES (SYMPHURUS: CYNOGLOSSIDAE) IN COASTAL LOUISIANA: UNRAVELING SEASONAL, SPATIAL, AND ONTOGENETIC PATTERNS IN RESOURCE UTILIZATION -------------------------------------------------------------------------------------13 Introduction ----------------------------------------------------------------------------------------13 Materials and Methods ---------------------------------------------------------------------------15 Results ----------------------------------------------------------------------------------------------22 Discussion -------------------------------------------------------------------------------------------37 Literature Cited -------------------------------------------------------------------------------------46 CHAPTER III. UTILIZATION OF MARSH-EDGE HABITAT BY TWO SYMPATRIC TONGUEFISHES (SYMPHURUS: CYNOGLOSSIDAE) IN COASTAL LOUISIANA ---------------------------------------------------------------------------------------51 Introduction ----------------------------------------------------------------------------------------51 Materials and Methods ---------------------------------------------------------------------------53 Results ----------------------------------------------------------------------------------------------60 Discussion -------------------------------------------------------------------------------------------70 Literature Cited -------------------------------------------------------------------------------------75 CHAPTER IV. AGE AND GROWTH OF YOUNG-OF-THE-YEAR TONGUEFISHES (SYMPHURUS: CYNOGLOSSIDAE) IN BARATARIA BAY, LOUISIANA -----------78 Introduction ----------------------------------------------------------------------------------------78 Materials and Methods ---------------------------------------------------------------------------80 Results ----------------------------------------------------------------------------------------------88 Discussion -------------------------------------------------------------------------------------------93 Literature Cited -----------------------------------------------------------------------------------100 iv CHAPTER V. COMPARATIVE PATTERNS OF RESOURCE UTILIZATION OF SYMPATRIC TONGUEFISHES (SYMPHURUS: CYNOGLOSSIDAE) WITHIN THE VERMILION AND BARATARIA ESTUARINE SYSTEMS, LOUISIANA -------------------------------------------------------------------------------------105 Introduction ----------------------------------------------------------------------------------------105 Materials and Methods ---------------------------------------------------------------------------108 Results ---------------------------------------------------------------------------------------------117 Discussion ----------------------------------------------------------------------------------------127 Literature Cited ----------------------------------------------------------------------------------132 CHAPTER VI. QUALITATIVE MODELING OF THE ECOLOGY OF TONGUEFISHES IN COASTAL LOUISIANA ------------------------------------------------------------------137 Introduction ---------------------------------------------------------------------------------------137 Materials and Methods --------------------------------------------------------------------------139 Results ---------------------------------------------------------------------------------------------148 Discussion ----------------------------------------------------------------------------------------156 Literature Cited -----------------------------------------------------------------------------------159 CHAPTER VII. CONCLUSION ------------------------------------------------------------------------162 Literature Cited ----------------------------------------------------------------------------------166 VITA -------------------------------------------------------------------------------------------------------169 v LIST OF TABLES Table 2.1. Seasonal patterns in resource availability estimated by least-square means (± SE) for six environmental variables. Significant differences (p ≤ 0.025) among seasons are indicated by different letters reading horizontally (NS indicates that differences were not significant). Seasonal ranges are reported below the mean for each variable. ---------------------23 Table 2.2. Spatial patterns in resource availability estimated by least-square means (± SE) for six environmental variables. Significant differences (p ≤ 0.047) among strata are indicated by different letters reading horizontally (NS indicates that differences were not significant). Spatial ranges are reported below the mean for each variable. ------------25