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The Life History of the Southern Lanternshark, Etmopterus Granulosus, from the Southwestern Indian Ocean

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The Life History of the Southern Lanternshark, Etmopterus Granulosus, from the Southwestern Indian Ocean San Jose State University SJSU ScholarWorks Master's Theses Master's Theses and Graduate Research Spring 2019 The Life History of the Southern Lanternshark, Etmopterus granulosus, from the Southwestern Indian Ocean Melissa Nehmens San Jose State University Follow this and additional works at: https://scholarworks.sjsu.edu/etd_theses Recommended Citation Nehmens, Melissa, "The Life History of the Southern Lanternshark, Etmopterus granulosus, from the Southwestern Indian Ocean" (2019). Master's Theses. 5011. DOI: https://doi.org/10.31979/etd.bdm2-twwy https://scholarworks.sjsu.edu/etd_theses/5011 This Thesis is brought to you for free and open access by the Master's Theses and Graduate Research at SJSU ScholarWorks. It has been accepted for inclusion in Master's Theses by an authorized administrator of SJSU ScholarWorks. For more information, please contact [email protected]. THE LIFE HISTORY OF THE SOUTHERN LANTERNSHARK, ETMOPTERUS GRANULOSUS, FROM THE SOUTHWESTERN INDIAN OCEAN A Thesis Presented to The Faculty of Moss Landing Marine Laboratories San José State University In Partial Fulfillment of the Requirements for the Degree Master of Science by Melissa C. Nehmens May 2019 © 2019 Melissa C. Nehmens ALL RIGHTS RESERVED The Designated Thesis Committee Approves the Thesis Titled THE LIFE HISTORY OF THE SOUTHERN LANTERNSHARK, ETMOPTERUS GRANULOSUS, FROM THE SOUTHWESTERN INDIAN OCEAN by Melissa C. Nehmens APPROVED FOR THE DEPARTMENT OF MARINE SCIENCE SAN JOSÉ STATE UNIVERSITY May 2019 Dr. David A. Ebert Moss Landing Marine Laboratories Dr. Scott L. Hamilton Moss Landing Marine Laboratories Dr. Kenneth H. Coale Moss Landing Marine Laboratories ABSTRACT THE LIFE HISTORY OF THE SOUTHERN LANTERNSHARK, ETMOPTERUS GRANULOSUS, FROM THE SOUTHWESTERN INDIAN OCEAN by Melissa C. Nehmens The Southern Lanternshark, Etmopterus granulosus, is a deep-sea shark that associates with seamounts and ridges between 220-1500 m throughout the southern oceans. Though not a targeted species, it is frequently incidentally caught in several fisheries, and comprises the highest amount of bycatch by number in the Orange Roughy (Hoplostethus atlanticus) fishery in the Southwestern Indian Ocean. Despite how frequently this species is encountered, surprisingly little is known about it beyond basic biology. The lack of life history information is partially attributed to the difficulty in obtaining samples and is compounded by a lack of methods to appropriately assess traditional life history parameters, such as age and growth. To better understand the life history of this species, genetic techniques were used to examine its mating system and to assess whether an alternative ageing method could be developed. The use of microsatellite markers to examine the mating system showed that polyandry was present in 33% of the litters. However, the frequency of multiple paternity and its comparison to other aspects of the breeding biology of this species do not fit within the usual elasmobranch paradigms. The use of qPCR to measure telomere length showed that telomeres appear to shorten with increased length (p= 0.0007). Though more work will need to be done to develop this as an ageing method, it may help to develop understanding of elasmobranch life history outside of traditional parameters. ACKNOWLEDGMENTS I greatly thank all of the organizations that financially contributed to the successful completion of my thesis and the presentation of my findings at conferences which included Moss Landing Marine Laboratories (MLML) (Wave Award), Dr. Earl H. Myers and Ethel M. Myers Oceanographic and Marine Biology Trust, CSU COAST, and the American Elasmobranch Society. I thank my thesis committee, Dr. David Ebert, Dr. Scott Hamilton, and Dr. Kenneth Coale for all of your invaluable feedback on my thesis and each of your unique approaches in fostering my academic growth. I am grateful for your investment in me to ensure my success as a graduate student and your perspectives and guidance that have and will continue to contribute to my professional and personal development. I appreciate it more than I can express. I thank my collaborators, Dr. Alexis Janosik, Rebecca Varney, and Dr. Kevin Feldheim for each your contributions to the success of my thesis and furthering my knowledge base. Thank you, Rebecca, for your friendship and guidance through a new area of study to me and for your unwavering moral compass. Thank you, Kevin, for your mentorship, support, kindness, and patience and willingness to answer my never-ending questions. Your involvement in my thesis was transformative and for that I am forever grateful. Thank you to everyone at MLML. This institution has made a lasting impression on me and the things I have learned and experiences I have had I will take with me always. A special thank you to my lab mates at MLML in the Pacific Shark Research Center and v in the greater ichthyology lab. Help was always given when it was asked for and I am happy to have had such an amazing group of people to go through graduate school with. To my friends both at MLML and beyond, I am incredibly lucky to have your support and friendship. It took a team to get me through to the other side, and I am so honored to have you all on mine. To my family, thank you for your lifelong support and encouragement to pursue my chosen career path. Thank you to my sisters Stephanie and Angela for never getting too upset when I had to miss an event or birthday due to my travels for school or needing to write my thesis. And last, but not least, I thank my dad for always being my biggest cheerleader. You have taught me so much about the type of person I want to be and how to apply hard work and compassion to all aspects of my life. You have taught me to always find the silver lining, especially when I found it hard to find it myself. Thank you for always believing in me. vi Table of Contents List of Tables ................................................................................................................... viii List of Figures .................................................................................................................... ix Background ..........................................................................................................................1 Chapter One: Understanding What We Cannot See: A Genetic Approach to the Mating System of The Southern Lanternshark, Etmopterus granulosus ...................................6 Introduction ....................................................................................................................6 Materials and Methods ...................................................................................................9 Results ..........................................................................................................................16 Discussion ....................................................................................................................24 Summary ......................................................................................................................28 Chapter Two: Telomere Length and Longevity: An Exploratory Study Using the Deep- sea Shark, Etmopterus granulosus ...............................................................................30 Introduction ..................................................................................................................30 Materials and Methods .................................................................................................36 Results ..........................................................................................................................39 Discussion ....................................................................................................................42 Summary ......................................................................................................................45 Conclusion .........................................................................................................................45 Literature Cited ..................................................................................................................46 vii List of Tables Table 1. PCR Information for Each Locus ........................................................................14 Table 2. Summary Statistics for All Microsatellite Loci Amplified from Etmopterus granulosus ...........................................................................................................17 Table 3. Results from Paternity Reconstruction ................................................................18 Table 4. STORM Results from Internal Relatedness Analysis..........................................20 Table 5. Compilation of Multiple Paternity Studies in Sharks (Study Species in Bold) ...27 Table 6. Examples of Methods for Band Enhancement with References..........................31 Table 7. Examples of Methods Used for Validation and Verification in Ageing Studies .32 viii List of Figures Figure 1. Dorsal View of Etmopterus granulosus ..........................................................8 Figure 2. Map of the Sampling Locations ...................................................................10 Figure 3. Individuals Displayed on the Map are Ones that Showed IR Values ...........19 Figure 4. Examples of the Discrepancy of Gestational Stages and Embryonic Development .................................................................................................21 Figure
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