Salinity Tolerance of Juveniles of Four Varieties of Tilapia Robert Welsh Nugon Louisiana State University and Agricultural and Mechanical College
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Louisiana State University LSU Digital Commons LSU Master's Theses Graduate School 2003 Salinity tolerance of juveniles of four varieties of tilapia Robert Welsh Nugon Louisiana State University and Agricultural and Mechanical College Follow this and additional works at: https://digitalcommons.lsu.edu/gradschool_theses Recommended Citation Nugon, Robert Welsh, "Salinity tolerance of juveniles of four varieties of tilapia" (2003). LSU Master's Theses. 566. https://digitalcommons.lsu.edu/gradschool_theses/566 This Thesis 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 Master's Theses by an authorized graduate school editor of LSU Digital Commons. For more information, please contact [email protected]. SALINITY TOLERANCE OF JUVENILES OF FOUR VARIETIES OF TILAPIA A Thesis Submitted to the Graduate Faculty of the Louisiana State University and Agriculture and Mechanical College in partial fulfillment of the requirements for the degree of Master of Science in The School of Renewable Natural Resources by Robert Welsh Nugon, Jr. B.S., Millsaps College, 1997 May 2003 ACKNOWLEDGEMENTS I thank Dr. C. Greg Lutz and Dr. Charles Weirich for their direction, mentorship, and patience demonstrated throughout my master’s program. I thank Dr. Robert P. Romaire and Dr. Terrence R. Tiersch for serving on my graduate committee and for guidance while finishing my master’s program. I also thank Dr. Luis A. Escobar for statistical expertise and Dr. John Hawke for advice and instruction. I thank Dr. Manuel Segovia and Dr. Allen Rutherford for friendship, advice, and support while I completed my degree. I thank Jennifer Spencer and Derrick Groat for help with initiating salinity trials. I thank Bo Liu for help with statistical programming and Kenneth Riley for advice and assistance in reviewing my work. I thank Mr. Steve Abernathy and the staff at Til-Tech Aqua Farm of Robert, Louisiana for their donation of tilapia broodstock, without which this research could not have taken place. I thank the staff of the LSU Aquaculture Research Station, particularly Marla Jones and Jay Stander, who keep the station running daily and who I cannot thank enough. This research was funded in part by the United States Department of Agriculture. Finally, I thank my family: Peggy, Katie, and Elisabeth for their support and encouragement to pursue my dreams. Additionally, I dedicate my thesis in memory of my father, Robert W. Nugon Sr., who taught me persistence and was instrumental in my decision to pursue this degree. ii TABLE OF CONTENTS ACKNOWLEDGEMENTS................................................................................................................... ii LIST OF TABLES...............................................................................................................................v LIST OF FIGURES ........................................................................................................................... vi ABSTRACT..................................................................................................................................... vii CHAPTER 1-INTRODUCTION............................................................................................................1 References............................................................................................................4 CHAPTER 2- JUVENILE SALINITY TOLERANCE OF FOUR TILAPIA VARIETIES .............................6 Methods..............................................................................................................10 Experimental Design .................................................................................10 Physical Description of Trial Layout.........................................................11 Collection of Tilapia and Preparation for Treatments ...............................13 Description of Acclimation and Salinity Trials .........................................14 Data Analysis ............................................................................................16 Results................................................................................................................18 Preliminary Stocking Density Study..........................................................18 Blue Tilapia................................................................................................18 Florida Red Tilapia ....................................................................................19 Mississippi Commercial Tilapia ................................................................20 Nile Tilapia ................................................................................................20 Statistical Analysis.....................................................................................21 Discussion..........................................................................................................24 References..........................................................................................................27 CHAPTER 3- A REVIEW OF THE POTENTIAL FOR FOUR COMMERCIAL TILAPIA VARIETIES TO ADAPT TO SALINITIES FOUND IN THE COASTAL WATERSHEDS OF LOUISIANA................................................................................31 Geographic Considerations................................................................................34 Regulation of Tilapia in Louisiana ....................................................................37 Salinity and Temperature and the Role they Play in Tilapia Survival..............................................................................................................38 References..........................................................................................................44 CHAPTER 4- GENERAL CONCLUSIONS..........................................................................................49 References..........................................................................................................52 APPENDIX A- OUTLINE OF PROCEDURES USED DURING SALINITY CHALLENGES .....................54 iii APPENDIX B- DATA OF: TRIAL, VARIETY, SALINITY, AND SURVIVAL USED IN CHAPTER 2.............................................................................................................56 APPENDIX C- REGULATION OF TILAPIA SPECIES IN LOUISIANA.................................................62 VITA ...............................................................................................................................................69 iv LIST OF TABLES Table 2-1. Physical layout of the experimental design used to determine salinity tolerance of four tilapia strains. Twenty-four containers were divided into groups of three and fish of two varieties were stocked accordingly...............11 Table 2-2. Dates salinity challenges were initiated and completed. Challenges began in September 2001, with completion of two challenges per month through November 2001.............................................................................11 Table 2-3. Mean weights and (+ SD) of four varieties of tilapia acclimated for salinity challenges..................................................................................................14 Table 2-4. Relationship between stocking densities and water quality for juvenile (mean 4 g) Mississippi commercial tilapia (MCT), Florida red tilapia (FRT), Nile tilapia (NT), and blue tilapia (BT) held in 20 l of freshwater for 96 hours. .........................................................................................18 Table 2-5. Probability (P) values expressing no significant differences in survival among replicate containers and P values expressing significance (P < 0.01) in the interaction between replicates and salinities. .....................................21 Table 3-1. Five distinct salinity zones found in coastal Louisiana. ........................................38 Table 3-2. Percent survival recorded from Chapter 2 in which juvenile (mean 4 g) tilapia of four varieties were investigated for salinity tolerance by exposure to four regimes (0, 10, 20, 35 ppt) over a 97-h period. ..........................39 v LIST OF FIGURES Figure 1-1 Photographs of adult Mississippi commercial tilapia (a), Florida red tilapia (b), blue tilapia (c), and Nile tilapia (d) , bar = 15 cm (Lutz, 2002). ......................................................................................................................2 Figure 2-1. Description of procedures implemented during salinity challenges. Tilapia were acclimated to transition salinities for 8 hours. Water changes increasing salinity by 5 ppt were performed every 9 hours until prescribed salinity was achieved. At 45 h and 97 h ammonia was recorded in control containers and tilapia fed in all containers. All tilapia reached target salinity by 63 h, after which observations were made at 75 h, 87 h, and 97 h. .................................................................................17 Figure 2-2. Survival of juvenile blue tilapia exposed to four salinity regimes (0, 10, 20, 35 ppt) during a 97-h period ......................................................................19 Figure 2-3. Survival of juvenile Florida red tilapia exposed to four increasing salinity regimes (0, 10, 20, 35 ppt) during a 97-h period.......................................19 Figure 2-4. Survival of juvenile Mississippi commercial tilapia exposed to four salinity regimes