University of South Florida Scholar Commons Graduate Theses and Dissertations Graduate School 2-19-2020 Isotope-Based Methods for Evaluating Fish Trophic Geographies Julie L. Vecchio University of South Florida Follow this and additional works at: https://scholarcommons.usf.edu/etd Part of the Biology Commons, Ecology and Evolutionary Biology Commons, and the Natural Resources Management and Policy Commons Scholar Commons Citation Vecchio, Julie L., "Isotope-Based Methods for Evaluating Fish Trophic Geographies" (2020). Graduate Theses and Dissertations. https://scholarcommons.usf.edu/etd/8306 This Dissertation is brought to you for free and open access by the Graduate School at Scholar Commons. It has been accepted for inclusion in Graduate Theses and Dissertations by an authorized administrator of Scholar Commons. For more information, please contact [email protected]. Isotope-Based Methods for Evaluating Fish Trophic Geographies by Julie L. Vecchio A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy with a concentration in Marine Resource Assessment College of Marine Science University of South Florida Major Professor: Ernst Peebles, Ph.D. Steve Murawski, Ph.D. Linda Lombardi-Carlson, Ph.D. Chris Stallings, Ph.D. Brad Rosenheim, Ph.D. Date of Approval: March 31, 2020 Keywords: Fish eye-lenses, carbon isotopes, nitrogen isotopes, fish movement, fish diets Copyright © 2020, Julie L. Vecchio DEDICATION This work is first and foremost dedicated to my family. Chris has been my rock for many years. He always supports every crazy idea that I have. He’s always up for adventure and I love him for that. Joseph has been as patient as he can be with his mom being a student his entire life. He is still afraid of fish, but I hope to help him get over that fear. My mom was incredulous when I said I wanted to go back to school for a PhD after nine years in the workforce, but she and my dad have both been incredibly supportive throughout the whole process. My sister, Lindsay, showed me that a Vecchio can complete a Ph.D. and has been a sympathetic ear when I feel like walking away. Additional contributors to my mental health throughout this process include the students who have accepted me into their ranks, specifically Kelly Vasbinder, Ryan Venturelli, Imogen Browne, Alex Illich and members of the 2015 cohort. Dr. Mya Breitbart, Dr. Amelia Shevenell, and Sami Francis where extremely supportive and helped me navigate completing my degree. Community contributors to my mental health include Tanks-a-Lot dive charters (Ryan Nelson, owner-operator), my close friends Larry and Lori Smith, who let me crash at their place whenever I need to escape, St. Petersburg Yoga, coffee, and Pass-a-Grill beach. ACKNOWLEDGEMENTS The science contained herein required a huge team effort. My major advisor Dr. Ernst Peebles spent countless hours talking through theory and interpretations with me over the past five years and gave helpful feedback on all drafts and presentations. He was instrumental in collecting the first specimens for this project, volunteering his boat, his time and his local knowledge of YOY Red Grouper. Each of my committee members was also instrumental in various facets of the project. Dr. Chris Stallings contributed ideas, data, and writing expertise for several chapters. Dr. Steve Murawski provided all Tilefish and many of the Red Grouper samples. He also was a consistent, calm presence while I was in the throes of writing. Dr. Linda Lombardi was instrumental in the collection of the Red Snapper for the project, is the world’s leading expert on Tilefish and Red Grouper life history and was incredibly supportive throughout the entire dissertation process. Dr. Brad Rosenheim jumped onboard in the middle of my dissertation and brought a true isotope perspective to an otherwise fish-heavy group. His notes and conversation about isotopic process and terminology used in a variety of fields has been invaluable. Members of the Peebles lab assisted me in a variety of ways. Amy Wallace taught me the finer points of eye-lens peeling and IRMS preparation. Jen Granneman invented the submersion method for peeling eye-lenses without them flying away. Briana Michaud, Vi Nguyen, and Jeremy Browning assisted with many fish dissections. Kaitlyn Rivers was a rock star intern who helped weigh otoliths, package IRSM samples, and do general lab work. Catherine Bruger was a fantastic technician who assisted in all lab tasks for several months. FWRI’s fisheries groups, under the guidance of Dr. Luiz Barbieri, provided a number of invaluable services. Luiz suggested that I become a FWRI volunteer and was a great help to my dissertation process. The Fisheries Independent Monitoring (FIM) Program provided many of the fish for this study. I put in a request and they delivered in a big way. FIM also provided the stomach contents data used in chapter 5. FWRI’s age and growth lab provided otolith preparation, aging and measuring facilities. Jessica, Alison, Kristen and Kristen all provided invaluable assistance in otolith preparation and aging. Mike Schram aged and measured the increments on most of the fish otoliths except for the Tilefish, which were aged by Greta Helmueller. NOAA Fisheries laboratory in Panama City contributed fish collected from routine reef fish monitoring. I specifically thank Chris Gardner for keeping track of the fish I needed and getting them to St. Pete. Tilefish were collected on the Mud and Blood cruises aboard the R/V Weatherbird II and processed by Jenny Ostroff. All stable isotope values were produced by Ethan Goddard in the Paleoceanography lab at the College of Marine Science, USF. I also thank the avid fishers and fishing guides who contributed time, fish, and livelihood to this project. Andrew Herzog of Big Bully Outdoors, Larry Smith of BucketList Charters, and Charles Sobczak, volunteer captain from Sanibel Island all contributed time and vessels. Fishing guides on the east coast of Florida kept Red Grouper after Hurricane Irma and donated them to the project. Tom Herzhouser, the owner of the Tavern at Bayboro, always gave me Red Grouper carcasses once he was done filleting fish. These fish provided my practice eyes for learning the peeling technique. Funding has come in various forms over the past four and a half years. I have been supported by the NOAA/NMFS Marine Resource Assessment fellowship program, the Roche/ARCS fellowship program for college scientists, the Florida Sea Grant Guy Harvey fellowship, the Jack and Katherine Ann Lake fellowship, the Gulf Oceanographic Charitable Trust Fellowship, and the Spawning Habitat and Early Life Linkages (SHELF) project. TABLE OF CONTENTS List of Tables ...................................................................................................................................v List of Figures ............................................................................................................................... vii Abstract .......................................................................................................................................... ix Chapter 1: Introduction and Background .........................................................................................1 Stable isotope ecology: general background ........................................................................1 Geographic and isotopic setting ...........................................................................................3 Muscle and liver δ15N differential .......................................................................................6 Fish eye lenses as records of diet and movement over the lifetime .....................................7 Chapter summaries...............................................................................................................8 Chapter 2: Offset between muscle and liver δ15N for short-term site fidelity .........9 Chapter 3: Eye-lens cores as records of geographic location in fish postlarvae .........................................................................................................10 Chapter 4: Eye-lens profiles as indicators of movement and diet shifts ................10 Chapter 5: Integrating eye-lens isotope data with traditional fisheries data ..........12 Objectives ..........................................................................................................................13 Literature Cited ..................................................................................................................13 Figures................................................................................................................................19 Chapter 2: The δ15N values in muscle and liver of marine Teleosts differ predictably and can be used as an indicator of site fidelity ........................................................................21 Abstract ..............................................................................................................................21 Introduction ........................................................................................................................22 Isotopic offsets between body tissues ....................................................................22 Isotopic and geographic setting for wild fish in study ...........................................23 Objectives ..............................................................................................................25