Diet Characterization in Immature, Neritic Green Turtles, Chelonia mydas, Using Gut Contents and Stable Isotope Analyses

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Diet Characterization in Immature, Neritic Green Turtles, Chelonia mydas, Using Gut Contents and Stable Isotope Analyses
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english
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Williams, Natalie C
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Degree:
Master's ( M.S.)
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University of Florida
Degree Disciplines:
Wildlife Ecology and Conservation
Committee Chair:
Carthy, Raymond R
Committee Co-Chair:
Bjorndal, Karen
Committee Members:
Brockmann, H. Jane Jane
Lamont, Margaret

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Subjects / Keywords:
chelonia -- diet -- foraging -- green -- gut -- isotope -- mydas -- stable -- turtle
Wildlife Ecology and Conservation -- Dissertations, Academic -- UF
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Wildlife Ecology and Conservation thesis, M.S.
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Abstract:
Recent developments in open water research have refined our understanding of green turtle, Chelonia mydas, foraging ecology, but diet characterization among populations remains understudied. Previous hypotheses state that once young green turtles recruit to shallow water habitat they shift rapidly from an omnivorous to herbivorous diet. Supporting evidence has primarily been derived from traditional gut content analysis that only provides a small window in time to perceive the diet of an animal. In contrast, stable isotope analysis explore show a consumer uses its resources over a broad temporal scale. We tested the dietary shift hypothesis using gut content and stable isotope analyses to assess the nutritional ecology of a juvenile green turtle aggregation in the northern Gulf of Mexico. We examined the gut contents of 65 green turtles collected from 2008 and 2011 hypothermic stunning events in St. Joseph Bay,Florida. Gut contents were evaluated using volume, dry mass, percent frequency of occurrence, and index of relative importance (IRI). Juvenile green turtles showed omnivorous feeding behavior, feeding on a variety of animal and vegetal items with a bias towards seagrass and tunicates. In addition, we evaluated feeding consistency by stable isotope patterns from epidermis tissue. We measured the stable carbon (d13C)and nitrogen (d15N)isotope values in epidermis of 43 green turtles, ranging from 22.5 to 72.7cm in curved carapace length (CCLmin), and eight known prey items (e.g., algae,seagrasses, invertebrates) collected in 2011. Our study provides a foundation for characterizing the foraging ecology of green turtles in St. Joseph Bay and highlights the value of utilizing isotopic ecology for further foraging studies.
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Statement of Responsibility:
by Natalie C Williams.
Thesis:
Thesis (M.S.)--University of Florida, 2012.
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Adviser: Carthy, Raymond R.
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Co-adviser: Bjorndal, Karen.
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RESTRICTED TO UF STUDENTS, STAFF, FACULTY, AND ON-CAMPUS USE UNTIL 2014-08-31

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1 DIET CHARACTERIZATION IN IMMATURE, NERITIC GREEN TURTLES, CHELONIA MYDAS USING GUT CONTENTS AND STABLE ISOTOPE ANALYSES By NATALIE CHRISTINE WILLIAMS A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTERS OF SCIENCE UNIVERSITY OF FLORIDA 2012

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2 2012 Natalie Christine Williams

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3 To my Dad, who is with me every day

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4 ACKNOWLEDGMENTS Firstly, I would like to thank my committee members Dr. Raymond R. Carthy, Dr. Karen A. Bjorndal, Dr. H. Jane Brockmann and Dr. Margaret M. Lamont for their support, guidance, time and patience. I received much appreciated support from the following: Brittany Burtner, Jean Olbert, Sheri Johnson, M egan Shabram, Sarah Reintjes Tolen, Jame McCray, Anthony Lau, Jason Fidorra, Kyle Pias, Matt Smith, Andrew Hein and Daniel Sasson. I thank Larisa Avens, Brian Stacy, Alan Bolten, Peter Eliazar, Michael Frick, Melania Lopez Castro, Mariela Pajuelo, Joseph Pfaller, Luciano Soares, Hannah Vander Zanden, and Patricia Zarate for pro ject and creative assistance. I also thank Seth Farris, Caitlin Hackett, Jessica McKenzie, Jean Olbert, Kyle Pias, Kate Simon, and Brail Stephens for fie ld and laboratory assistance. I especially thank Seth Farris, Mariela Pajuelo, and Brail Stephens for the collection of gastric contents. Numerous volunteers helped during the cold stunning event and helped make this work possible. I am grateful for support and assistance from the Un iversity of Florida, namely Caprice McRae and Claire Williams of the Department of Wildlife Ecology and Conservation. I would also like to thank J. Curtis at the Stable Isotope Lab (University of Florida) for assistance with stable isotope analyses. I am f orever thankful for the emotional support and words of wisdom provided by Franklin Percival of the Florida This project would not have been possible without Meg Lamont, to whom I am forever grateful. Her continuous encouragement, support, and advice kept me going during times of doubt and taught me many valuable lessons. I am especially grateful for

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5 the friendship of Brail Stephens, who has supported me through many trials, both professional and personal, and given me hope, motivation, and confidence. I am thankful to Alison Hodges Steverson, Heather Blanton, Mackenzie Kay, and Lindsay Branciforte, who have always list ened and supported me endlessly Finally, I thank my parents, who have provided love, support, and encouragement to me throughout my life, in all my endeavors. I thank my Dad, whose wisdom and guidance helped me through much of graduate school, and whom I know is proud of this accomplishment. I thank my Mom, who is a lways there when needed and is the most caring, loving and selfless person I know. I would also like to thank my Uncle Tom and Aunt Jeri for providing wisdom and support. The Florida Sea Turtle Grants Program, Knight Vision Foundation, and Jennings Scholar ship funded this research All p roject work was performed under MTP # 094 and MTP # 016.

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6 TABLE OF CONTENTS page ACKNOWLEDGMENTS ................................ ................................ ................................ .. 4 LIST OF TABLES ................................ ................................ ................................ ............ 7 LIST OF FIGURES ................................ ................................ ................................ .......... 8 LIST OF ABBREVIATIONS ................................ ................................ ............................. 9 ABSTRACT ................................ ................................ ................................ ................... 10 CHAPTER 1 DIET OF GREEN TURTLES WORLDWIDE ................................ ........................... 12 2 DIET CHARACTERIZATION IN IMMATURE, NERITIC GREEN TURTLES, CHELONIA MYDAS USING GUT CONTENTS AND STABLE ISOTOPE ANALYSES ................................ ................................ ................................ ............. 17 Introduction ................................ ................................ ................................ ............. 17 Materials and Methods ................................ ................................ ............................ 21 Study Area ................................ ................................ ................................ ........ 21 Sample Collection ................................ ................................ ............................ 22 Stable Isotope Analyses ................................ ................................ ................... 24 Statistical Analyses ................................ ................................ .......................... 25 Results ................................ ................................ ................................ .................... 25 Discussion ................................ ................................ ................................ .............. 27 APPENDIX A JANUARY 2008 DIET COMPOSITION ................................ ................................ ... 35 B JANUARY 2011 DIET COMPOSITION ................................ ................................ ... 37 C 2011 DIET AND BODY SIZE ................................ ................................ .................. 39 D 2011 15 N AND BODY SIZE ................................ ................................ ................... 41 E DIET OF THE GREEN TURTLE, CHELONIA MYDAS ................................ ........... 42 LIST OF REFER ENCES ................................ ................................ ............................... 62 BIOGRAPHICAL SKETCH ................................ ................................ ............................ 68

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7 LIST OF TABLES Table page 2 1 Diet composition of juvenile green turtles in St. Joseph Bay, Florida ................. 31 E 1 Diet of the green turtle, Chelonia mydas ................................ ............................ 42

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8 LIST OF FIGURES Figure page 2 1 Conceptual model of patterns of isotope values represe nting resource use through time ................................ ................................ ................................ ........ 32 2 2 Plot of stable isotope ratios of nitrogen and carbon from epidermis samples and major p rey items of juvenile green turtles ................................ .................... 33 2 3 Chelonia mydas. Epidermis 13 C vs. curved carapace length in St. Joseph Bay, Florida in 2011 ................................ ................................ ............................ 34 A 1 Diet composition in 12 juvenile green turtles from the cold stunning event in St. Joseph Bay, Florida in January 2008 ................................ ............................ 35 A 2 Diet composition in 12 juvenile green turtles from the cold stunning event in St. Joseph Bay, Florida in January 2008 ................................ ............................ 36 B 1 Diet composition of 31 juvenile green turtles from the cold stunning event in St. Jos eph Bay, Florida in January 2011 ................................ ............................ 37 B 2 Diet composition of 31 juvenile green turtles from the cold stunni ng event in St. Jose ph Bay, Florida in January 2011 ................................ ............................ 38 C 1 The relationship between green turtle body size (CCLmin) and seagrasses (P seagrasses = 0.3 127) in St. Joseph Bay, Florida ................................ ................... 39 C 2 The relationship between green turtle body size (CCLmin) and tunicates (P tunicates = 0.2 215) in St. Joseph Bay, Florida ................................ ..................... 40 D 1 Chelonia m ydas 15 N vs. curved carapace length in St. Joseph Bay, Florida in 2011 ................................ ................................ ............................ 41

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9 LIST OF ABBREVIATION S C Carbon CCL MIN Minimum curved carapace l ength delta GI Gastrointestinal IRI Index of Relative Importance N Nitrogen SIA Stable Isotope Analysis SJB St. Joseph Bay

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10 Abstract of Thesis Presented to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Masters of Science DIET CHARACTERIZA TION IN IMMATURE, NERITIC GREEN TURTLES, CHELONIA MYDAS USING GUT CONTENTS AND STABLE ISOTOPE ANALYSES By Natalie Christine Williams August 2012 Chair: Raymond R. Carthy Cochair: Karen A. Bjorndal Major: Wildlife Ecology and Conservation Recent develop ments in open water research have refined our understanding of green turtle, Chelonia mydas foraging ecology, but diet characterization among populations remains understudied. Previous hypotheses state that once young green turtles recruit to shallow wate r habitat they shift rapidly from an omnivorous to herbivorous diet. Supporting evidence has primarily been derived from traditional gut content analysis that only provides a small window in time to perceive the diet of an animal. In contrast, stable isoto pe analysis explores how a consumer uses its resources over a broad temporal scale We tested the dietary shift hypothesis using gut content and stable isotope analyses to assess the nutritional ecology of a juvenile green turtle aggregation in the norther n Gulf of Mexico. We examined the gut contents of 65 green turtles collected from 2008 and 2011 hypothermic stunning events in St. Joseph Bay, Florida. Gut contents were evaluated using volume, dry mass, percent frequency of occurrence, and index of relati ve importance (IRI). Juvenile green turtles showed omnivorous feeding behavior, feeding on a variety of animal and vegetal items with a bias towards seagrass and tunicates. In addition, we evaluated feeding consistency by

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11 stable isotope patterns from epide rmis tissue. We measured the stable carbon ( 13 C) and nitrogen ( 15 N) isotope values in epidermis of 43 green turtles, ranging from 22.5 to 72.7cm in curved carapace length (CCLmin), and eight known prey items (e.g. algae, seagrasses, invertebrates) colle cted in 2011. Our study provides a foundation for characterizing the foraging ecology of green turtles in St. Joseph Bay and highlights the value of utilizing isotopic ecology for further foraging studies.

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12 CHAPTER 1 DIET OF GREEN TURTLE S WORLDWIDE The g reen turtle, Chelonia mydas is an endangered marine species that inhabits tropical and subtropical regions worldwide. Understanding the fora ging ecology of this species is key to its conservation, as diet influences reproduction, survivorship, growth rate s and ultimately, population demography ( Bjorndal 1982 ) For these reasons, studies have focused on diet characterization, ran ging from descriptions of gut contents to detailed, quantitative examinations of nutritional content ( Carr 1952 B jorndal 1980 Gilbert 2005 ) The life history of green turtles can be described as a series of ontogenetic ha bitat shifts where use of habitats and resources varies depending on life history stage. Gree n turtles maintain omnivorous diets in some habitats and herbivorous diets in other habitats. The literature on the foraging ecology of green sea turtles was reviewed and characterized the green turtle as an herbivore that may also eat animal matter ( Mortimer 1976 1982 ) ( 1982 ) our knowledge of the diet of green turtles worldwide has expanded. The literature on the diet of green turtles as post hatchlings, juveniles and adults is summarized in the first section of this review. The remainder of this review is a table of reported diet species (see Appendix E ) of green turtles representing four life history stages ( O = oceanic, post hatchling, J = juvenile, sub adult, A = adult and U = unknown or not s tated ) in the Atlantic and Pacific /Indian Oceans. N on nutritive ite ms (debris, feathers, etc.) are not included in the table. they recruit to neritic habitats (water depth s < 200 m) as greater than 20 cm juveniles ( Reich et al. 2007 ) Relatively little is kno wn of the ecology of post hatchling green

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13 turtles while in the oceanic phase. Hypotheses ( Reich et al. 2007 ) suggest that neonate green turtles spend time in the ope n water, feeding primarily as carnivore s Parker et al. (2011 ) examined gut contents in 10 oceanic neonate green turtles from the northern Pacific Ocean and found the turtles to be primarily carnivorou s The main diet constituents are zooplankton, pelagic crustaceans an d mollusks with coelenterates such as Pyrosoma sp. also present in large amounts (see Appendix E ; for all cited diet spe cie s hereafter, refer to Appendix E ) Davenport and Balazs (1991 ) posit that pyrosomas may be targeted as prey not due to their gelatinous structure but for their stomach contents which are of high nutritional value being composed of phytoplankton zooplankton, and detritus. In Australia, two hatchlings were tethered for 4.5 months to o bserve their feeding behavior; m ain diet items included hydrozoans, cte nophores and oceanic tunicates ( Booth & Peters 1972 ) Many factors (i.e. tag retention, sightability) contribute to the difficulty in studying the oceanic phase, but r ecent advances in satellite telemetry ( Mansfield 2012 ) and stable isotope technology ( Reich e t al. 2007 ) have improved our ability to gain insight into this elusive phase in sea turtle life history. Four size classes of green turtle (8, 30, 48, 66 kg) in the Bahamas ( Bjorndal 1980 ) reportedly have diets consisting of mostly seagrass. In the Atlantic, Mendona (1983 ) found that green turtles foraged selectively on Rhodophyta and Ch lorophyta in Mosquito Lagoon Florida. In contrast, Gilbert (2005 ) found immature turtles to be grazing exclusively on seagrasses and avoiding the abundant algae species on Ambersand Reef, Florida Ju venile green turtles off the coast of Long Island, New York feed primarily on the seagrass Zostera sp. and marine algae ( Burke et al. 1992 ) study represents one of the few available studies that examine s green turtle diet at the

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14 edge of their range. Few reports are available on green turtle diet in the Gulf of Mexico. In the northern Gulf of Mexico Foley et al. (2007 ) found the primary diet constituent of stranded turtles to be seagrass ( Thalassia testudinum ). There are a number of studies available on the diet of immature green turtles in Pacific waters. Studies on juvenile C. mydas diet in Australia ( Read & Limpus 2002 Arthur et al. 2009 ) and Hawaii ( Balazs 1980 ) reported a diet primarily composed of seagrass red algae and green algae In Oman, smaller green turtles (30 to 50 cm) feed on the bases of seagrasses such as Halophila and Halodule spp as well as marine algae ( Ross 1985 ) However, in the relatively dense seagrass beds of Shark Bay, Australia, recent research has revealed that animal matter accounts for 76 99 % of the nutrients for turtles between 29 a nd 59 cm CCL and for 53 76 % of the nutrients for turtles > 59 cm CCL. The authors suggest that despite the abundant seagrass, intraspecific competition may drive individual specialization in this habitat, with some turtle s foraging heavily on seagrass ( Burkholder et al. 2011 ) In the Pacific Oc ean green turtles have been documented consuming molluscs, crustaceans and sponges ( Garnett et al. 1985 Balazs et al. 1987 ) Off the coast of Ecuador, the stomach of a large, immature female con tained fish eggs attached to a small amount of sargassum ( Fritts 1981 ) Gut content analyses have shown that animal prey continues to be consume d by green turtles after entering the neritic habitat off southwestern Colombia, the Galapagos Islands, western Mexico, and in San Diego Bay ( Seminoff et al. 2002 Amorocho & Reina 2007 Carrin Cortez et al. 2010 Lemons et al. 2011 ) As adults, green turtles in the western Atlantic feed primarily on seagrasses and algae (Appendix E ) Mortimer (1981 ) examined the stomach contents of 24 3 adult and

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15 subadult turtles in Caribbean Nicaragua. The main diet items, in decreasing order of importance, comprised: Thalassia other species of seagrass, 40 different algae species, benthic substrate, and animal matter. Turtles were found to modify their diet opportunistically, based on the composition of available prey sources For example, during migrations to breeding grounds, where turtles travel near sho re, they consume more red algae and lignified terrestrial debris ( Mortimer 1981 ) In northern Brazil, Ferreira (1968 ) documented that green turtle diet is composed of approximately 88% marine algae and less than 10% animal matter in an area where seagrass is not abundant. The following types of animal matter were found: as cidians, molluscs, sponges, bryozoans, crustaceans, and echinoderms. Seminoff et al. (2002 ) found the diet of sub adult and adult green turtles in the Gulf of California, Mexico to be primarily composed of marine algae and some animal matter in a regi on lacking in seagrass habitat Frazier (1971 ) collected stomach samples from adults and subadults in the Aldabra Atoll and found the species to be pri marily herbivorous. R ecent studies ( Hatase et al. 2006 ) in Jap an have used satellite telemetry and stable isotope analysis to reveal that females remain in the carnivorou s, oceanic phase into their adult years. An area of research that calls for further examination involves combining gut content and stable isotope an alyses for a long term picture of diet composition Lemons et al. (2011 ) used stable isotope mixing models to determine that animal matter contributed to the diet of green turtles in San Diego Bay over the course of the six year isotope series study. Mixing mo dels determine the contribution of different prey groups bas ed on their isotope value relative to the isotope value of the consumer ( Phillips & Greg g 2003 ) The authors recommend that future studies should account for seasonal

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16 and annual fluctuations in prey isotope values. Stable isotope technology is a valuable tool in reconstructing the diet of individuals; however, future research should fully i ts explore its limitations to avoid misinterpretation of results. My review also pointed out the need for studies that examine changes in diet composition by season. For example, Lpez Mendilaharsu et al. (2008 ) showed that juveni le green turtles fed preferentially on species that showed high fluctuations in availability and abundance throughout the year. Diet preference and diet diversity changes coincided with seasonal changes in prey biomass. These results underscore an area of mostly unexplored res earch: what does a tropical green turtle do in c ooler temperatures with dynamic resources? Further research is needed to quantify the nutritional an d energetic consequences of augmenting a herbivorous diet with animal matter. Our best insights into the foraging ecology of green turtles are from studies conducted in range habitats with dense seagrass beds and algal communities while relatively little is known of foraging grounds at the extremes of the species range. In habitats where foliage is not present year round, animal matter may play an important role in nutrition. Studies in these habitats may provide insight into how animals modify the ir diets with variable resource availability and influence management and conservation planning.

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17 CHAPTER 2 DIET CHARACTERIZATIO N IN IMMATURE NERITIC GREEN TURT LES, C HELONIA MYDAS USING GUT CONTENTS A ND STABLE ISOTOPE AN ALYSES Introduction The life hi story of green turtles ( Chelonia mydas ) involves a series of habitat and resource shifts depending on the life history stage ( Bolten 2003 ) After completing an initial oceanic life stage, small juvenile green turtles (20 to 35 cm curved carapace length) become resi d ents of neritic habitats, where they feed primarily on seagrasses and/or macroalgae, but may also consume animal matter ( Mortimer 1981 Bjorndal 1 997 ) Variation in feeding patterns is thought to be dependent on prey abundance and availability ( Guebert Bartholo et al. 2011 ) but may also be affected by feeding selectivity ( Bjorndal 1985 Fuentes et al. 2006 Lpez Mendilaharsu et al. 2008 ) Variation in feeding patterns has been observed in sub tr opical systems ( Guebert Bartholo et al. 2011 Nagaoka et al. 2012 ) where resource availability is rel atively stable. In temperate systems, resource availability is more variable ; changes in seasonal biomass of vegetation and animal material may lead to greater variation and plasticity in feeding patterns. For these reasons, i t is critical to understand ho w tropical/subtropical species at the latitudinal extremes of their range cope with environmental variation. Studies on immature green turtles in the western Atlantic have reported a primarily herbivorous diet augmented with small amounts of animal matter Juveniles in the Caribbean (Bjorndal 1980) reportedly have diets consisting of mostly seagrass and algae. Mortimer (1981 ) examined the stomach contents of 243 adult and subadult turtles in Caribbean Nicaragua. The main diet items, in decreasing order of importance, comprised: Thalassia three o ther species of seagrass, 40 different algae species, benthic substrate, and animal matter. Turtles were found to modify their diet

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18 opportunistically, based on the composition of available prey sources. For example, during migrations to breeding grounds, w here turtles travel near shore, they consume more red algae and lignified terrestrial debris ( Mortimer 1981 ) Studies in several foraging grounds along the coast of Bra zil have reported varied diets between locations, with some diets dominated by algae and others by animal matter. For example, i n northern Brazi l, Ferreira (1 968 ) documented that juvenile and adult (31 120 cm curved carapace length, CCL) green turtle diet is composed of approximately 88% marine algae and less than 10% animal matter in an area where seagrass is not abundant The following types of animal mat ter were found: ascidians, molluscs, sponges, bryozoans, crustaceans, and echinoderms. In a lagoon complex in southeastern Brazil, main diet items were ranked by frequency of occurrence as follows: 87.5% terrestrial plants and algae, 50% invertebrates and 12.5% seagrasses ( Nagaoka et al. 2012 ) In the western Atlantic, Gilbert (2005) found that green turtles foraged selectively on Rhodophyta and Chlorophyta on Ambersand Reef, Indian River Coun ty, Florida. In contrast, Mendona (1983) found immature turtles to be grazing exclusively on seagrasses and avoiding the abundant algae species in Mosquito Lagoon, Florida. Juvenile green turtles off the coast of Long Island, New York, feed primarily on t he seagrass Zostera s p. and marine algae (Burke et al.) New York waters provide a seasonal foraging ground for several sea turtle species from June through November ( Burke et al. 1993 ) research represents one of the few available studies that examine green turtle d iet at the edge of their range. During a three year study in South Padre Island, Texas, Coyne (1994 ) reported subadult (22.2 81.5 cm straight carapace length, SCL) green turtles feeding selectively on algae ( Ulva fasciata Rhod ymenia pseudopalmata Family Ceramiaceae,

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19 Bryocladia sp., Hypnea musciformis ) and shoal grass ( Halodule wrightii ). Few reports are available on green turtle diet in the Gulf of Mexico. In the northern Gulf of Mexico, Foley et al. (2007) found the primary d iet constituent of stranded turtles to be seagrass ( Thalassia testudinum ). Tunicate species ( Styela ; Molgula; unidentifiable pieces) were also found in small quantities ( Lessman n 2002 ) Some of the reported variation in diet composition of juvenile green turtles may arise from changes in habitats used by these turtles among years or between seasons. core te mperature for digestion and other physiological processes. Sea turtles may display seasonal movements related to changes in temperature emigrating from areas that become seasonably cold ( Witherington & Ehrhart 1989 ) In hab itats with abrupt changes in temperature, behavioral strategies are necessary to survive a dynamic environment. To deal with cold water temperatures, juveniles in neritic habitats can either migrate to warmer waters or overwinter in the neritic habitat. In temperate climates, adult turtles migrate long distances to overwinter in warmer waters ( Meylan 1995 ) However, juvenile turtles foraging in shallow, neritic habitats m ay face rapid decreases in water tempe rature and be unable to escape due to limited exit access, creating a trapping effect ( Mendonca & Ehrhart 1982 ) A t te mpe ratures less than 10 C turtles often become stunned and enter a torpid state ( Foley et al. 2007 ) in which they are unable to swim and they float to the surface. On average, t he risk of being susceptible to cold fronts a ppears to be an acceptable trade off for the benefits of inhabiting northern, temperate habitats during the summer ( Ultsch 2006 )

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2 0 Bec ause juvenile turtles reside year round in St. Joseph Bay, Florida, this area provides an interesting site to ob serve foraging behavior of green turtles at the edge of their range. St. Joseph Bay is at the northern edge of the range of year round foraging grounds of the tropical/subtropical green turtle. St. Joseph Bay has historically been susceptible to cold stunn ing events, with 401 turtles stranding in December 2000/ January 2001 ( Foley et al. 2007 ) and 1,733 turtles stranding in 2010 ( Avens et al. 2012 ) Foley et al. (2007 ) reported a diet dominated by seagrass and macroalgae prior to the 2000/ 2001 cold stunning event. However, seagrasses are known to experience decreases in abundance during the winter in St Joseph Bay ( Leonard & McClintock 1999 ) T he behavioral modifications of how tropical green turtles behave in temperate forag ing grounds, especially during winter foliage reductions, remain unknown. What do herbivorous green turtles do during this time? Analysis of stomach contents from cold stunning events allows the opportunity to reconstruct turtle diet prior to stranding and begin to create a picture of winter behavior I investigate the diet of green turtles during winter in St Joseph Bay using two approaches. Stomach contents, that give a direct measure of diet, but only for a short window of time, and stable isotopes. Stable isotope analyses of epidermis samples can be used to evaluate consistency of diet over a broader temporal scale because isotopes reflect the average dietary record ( Dalerum & Angerbjrn 2005 ) I ncorporation of new protein into tissues is a combination of turnover and growth. Protein turnover is related to the metabolic rate of the tissue, so tissues with fast metabolic rates have high protein turnover rate Therefore, tissues with different turnover rates reflect average dietary records over different lengths of time ( Hobson & Clark 1992 ) Figure 2 1 presents a

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21 conceptual model comparing the isotope values of individuals in a population with inconsistent and consistent feeding patterns. If individuals in a population have not fed consistently, their stable isotope values will not be associated with the stable isotope value of the major diet item from the stomach contents (Figure 2 1a). If individuals in a population have maintained a relatively consistent diet over the previ ous months, th e ir epidermis stable isotope value s should fal l above the major diet item from the stomach contents, the distance representing the discrimin ation value (Figure 2 1 b ). To answer the question, what is the diet of primarily herbivorous green turtles during the winter in a temperate region, I analyzed st omach contents from 64 green turtles that died during cold stunning events in St. Joseph Bay, Gulf County, Florida in 2008 (n = 12) and 2011 (n = 52). Epidermis stable isotope values from 39 green turtles from 2011 were used to evaluate consistency of the diet over the preceding months. Materials and Methods Study Area St. Joseph Bay, Florida (29.76 N, 85.35 W), in the northeastern Gulf of M exico, covers an area just less than 30,000 hectares. The study site is a coastal habitat located along the Florida panhandle in Gulf County. St. Joseph Bay is approximately 21 km in length, with a maximum width of 8 km The maximum depth is 13.3 m in the northern end, with a minimum depth of 1.0 m in the southern end (McMichael 2005). The site has a tidal range of app roximately 0.47 m, a very low current flow and highly organ ic sediments. The salinity in the bay is usually identical to the Gulf of Mexico ( Stewart & Gorsline 1962 ) and averages 35.0 ppt ( DEP 2008 ) Annual w ater temperatures range from 4 to 35 C ( McMichael 2005 ) Wind direction is usually north in the winter and south in the summer. The bay is productive due to its salt marsh and

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22 seagrass habitats; seagrass beds are a prominent feature in the southern end and cover appr oximately one sixth of th e bay ( DEP 2008 ) The local, do minant seagrass species include Thalassia testudinum, Halodule wrightii and Syringodium filiforme. St. Joseph Bay is susceptible to cold stunning events because water temper ature can decline to less than 10 C under which torpor and cold stun ning can occur ( Schwartz 1978 Witherington & Ehrhart 1989 Morreale et al. 1992 ) Sample Collection In J anuary 2008 and 2011, volunteers collected green turtles (n = 64) that st randed dead during cold stunning events in St. Joseph Bay, Florida. Cold stunned turtles become lethargic and float to the sur face, and can be easily retrieved from the water or after they wash ashore ( Witherington & Ehrhart 1989 ) Minimum c urved carapace length (CCLmin; cm) was measured u sing a tape measure ( Bolten 1999 ) Body mass (kg) was measured using a hanging spring scale. Stomach contents were removed from the gastrointestinal (GI) tract and fro zen pending analyses. Epidermis tissue from the dorsal surface of the neck was collected using a 6 mm biopsy punch and preserved in dry NaCl until analysis. For analysis, epidermis samples were rinsed with distilled wate r to remove the NaCl and the outermost epidermis w as separated from the dermis tissue using a scalp el blade. Known prey items identified from stomach contents were opportunisti cally collected from SJB in fall 2011 for stable isotope analysis. This collect ion period was chosen to b est represent the time period in which diet item isotope values would be incorporated and represented in epidermis tissue. The following known prey items were sampled: seagrasses ( Thalassia testudinum Halodule wrightii and Syrin godium filiforme ), macroalgae ( Gracilaria sp and Enteromorpha s p ), and tunicates ( Botrylloides

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23 sp ). The sample size was two for each species. Samples were put in a cool box for transport, rinsed with distilled water and then frozen at 20 C pending ana lysis. Frozen stomach contents were thawed and separated to species or the lowest identifiable taxon using a dissecting scope when necessary Each diet item was q uantified using percent frequency of occurrence, volume, mass, and index of relative imp orta nce (IRI). Percent volume was evaluated by water displacement using graduated cylinders; diet items less than 0.2 mL Diet items were dried at 60 C for 24 hours and then weighed to calculate mass. The index of relative importance wa s modifi ed from Hyslop (1980 ) by Bjorndal et al. (1997 ) for application to herbivores. Each diet category was calculated by the following equation: (2 1) where F is percent frequency of occurrence, V is percent volume, and n is th e number of diet categories. E ach of these measures (volume and frequency) in isolation can yield misleading interpretations ( Hyslop 1980 Bjorndal et al. 1997 ) For example, a diet item with a 100 % frequency of occurrence may only be present in each stomach in trace amounts. The IRI provides a better interpretation for ranking the relative importance of diet ca tegories because both fre quency and volume are included ( Bjorndal et al. 1997 ) Of the total individual samples (n = 52) collected for 2011, only individual total sample volumes greater than 9.0 mL were included as representative sample s of turtle diet (n = 31). I compared results from all sample s with those from samples > 9.0 mL to test for an effect of volume on estimates of diet composition. Small sample volumes occurred only in 2011.

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24 Stable Isotope Analyse s For stable isotope analysis, approximately 0.5 to 0.6 mg of each epidermis sa mple (1.0 15.0 mg for prey samples) was weighed and sealed in a tin capsule. Samples were analyzed for 13 15 N by combustion in a Thermo Finnigan DeltaPlus XL isotope ratio mass spectrometer with a ConFlo III interface linked to a Costech ECS 4010 El emental Combustion System (elemental analyzer) in the Stable Isotope Geochemistry Lab at the University of Florida, Gainesville Sample stable isotope ratios relative to the isotope standard are expressed in the conventional delta ( ) not ation in parts per : sample /R standard ) 1] 1000 (2 2) where R sample and R standard are the corresponding ratios of heavy to light isotopes ( 13 C/ 12 C and 15 N/ 14 N) in the sample and international standard, respectively. The standard used for 13 C was Vienna Pee Dee Belemnite and atmospheric N 2 for 15 N All analytical runs included samples of standard materials that were inserted at regular int ervals to calibrate the system. The reference material USGS40 (L glutamic acid) was used to normalize all r esults. The standard deviation of the reference material w as 0.04 13 C and 0.08 15 N values ( n = 10 ). Repeated measurements of a laboratory reference material, loggerhead scute, was used to examine consistency in a homogeneous sample with similar isotopic composition to the epidermis samples. The standard d eviation of the loggerhead scute was 0.06 13 C values and 0.10 15 N values ( n = 4 ). To evaluate feeding consistency, I assigned each turtle for which I had large stomach values and isotope values (n = 19) to one of three categories based on th eir stomach contents: > 50 % seagrasses, > 50 % macroalgae and > 50 % tunicates. I then

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25 plotted the stable isotope values of these turtles and the prey species. I compared the resulting graph (Figure 2 2) with the conceptual models to determine whether tur tles were feeding consistently. Statistical Analyses To test for annual difference in percent volume of diet items between 2008 and 2011, a two way analysis of variance was conducte d between years and diet constituents. A Tukey HSD multiple comparison tes t for unequal sample size was used when significant difference s were detected from the ANOVA. Volume percentages of diet items were arc sine square root transformed to improve normality and homogeneity of variance. Regression a nalyses were used to evaluate relationship s between turtle size (CCLmin) and primary diet constituents (seagrasses and tunicates) and between turtle size (CCLmin) and 13 15 N values. All data were analyzed using program JMP version 9.0.2 ( JMP 1989 2010 ) Results In total 43 stomach sa mples were collected from 2008 (n = 12 ) and 2011 (n = 31 ). In 2008, c urved carapace length of turtles ranged f rom 23.6 to 35.9 cm CCL (n = 12; mean SD = 30.4 4.34 ) In 2011, c urved carapace length of turtles ranged f rom 22.5 to 72.7 cm in CCL (n = 51; mean SD = 35.9 9.87 ) and body mass ranged from 1.2 to 40.8 kg (n = 50; mean SD = 6.73 6.93 ). Samples were analyzed and t hirteen c ategories were identified: seagrass (n = 3) algae (n = 2), tunicate (n = 2 ) and other materials (n = 6) were identif ied (Table 2 1). The proportion of Botrylloides sp. in the diet of green turtles differed significantly (P = 0.0037) between 2008 and 2011. T herefore data from the two years were analyzed separately. In the 2008 samples (n = 12), three species were conside red major diet items (> 5 % volume in at least one sample;

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26 ( Garnett et al. 1985 ) : Pyrosoma s p Botry lloides s p. and Thalassia testudinum blades (Table 2 1). In the 2011 samples (n = 31) six items were con sidered major diet constituents : Thalassia testudinum Gracilaria s p ., Enteromorpha s p Syringodium filiforme Botrylloides s p ., and Pyrosoma s p There was no significant difference in diet composition between all samples (large + small) and only large samples in 2011 (Table 2 1) In 2011, epidermis samples were collected from 39 turtles for stable isotope analyses. S table isotope values in epid ermis tissue ranged from 16.44 to 8.05 13 C (mean SD: 12.84 2.11 ; Figure 2 2 ) Epidermis 15 N values ranged from 7.05 to 11.97 ( mean SD: 8.95 1.14 ; Figure 2 2 ) Stable carbon and nitrog en values were determined for six prey species : Thal assia testudinum, Syringodium filiforme, Halod ule wrightii, Gracilaria sp ., Enteromorpha s p and Botrylloides s p (Figure 2 2 ). These pre y species were considered primary diet constituents of green turtles based on stomach contents. I was unable to apply m ixing models to this study due to the inability to locate Pyrosoma s p during searches in fall 2011 and winter 2012 (see discussion). Body size did not have a significant effect on the proportion of seagr asses or tunicates in the diet (P seagrasses = 0.3127 P tunicates = 0.2215 ) although large turtles had a tendency toward higher tunicate consumption (see Appendix C) Body size had a significant positive relationship with 13 C (R 2 = 0.66, df = 38, p = < 0.001 ; Figure 2 3 ), but no relationship with 15 N (p = 0.054; Appendix D). Individuals in the population exhibited inconsistency in diet during the months before stomach samples were collected (Figure 2 2 ) T he stable isotope value of the epidermis tissue was not associated with the stable isotope value of the major diet item from the stomach contents

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27 Discussion The diet of juvenile green turtles in St. Joseph Bay in winters of 2008 and 2011 was considered to be predominantly omnivorous. These results are similar to other studies conducted in northwest Africa, Australia and San Diego Bay ( Cardona et al. 2009 Burkholder et al. 2011 Lemons et al. 2011 ) Seagrass ( Thalassia testudinum ) and tunicates ( Pyrosoma s p. and Botrylloides s p. ) presented high IRI values in both years of this study The high degree of invertebrate consumption in this study highlights the impor tance of quantifying the availability of animal prey and their nutritional contribution to green turtle s Previous research ( Da venport & Balazs 1991 ) examined the nutritional content of Pyrosoma atlanticum in Leatherback ( Dermochelys coriacea ) diet and found Pyrosoma bodies to be composed of 27% protein, 3% lipid, and 70% carbohydrate. It is suggested that these tunicates may be contain digestible organic material, while the tunica passes through the gut relatively undigested ( Davenport & Balazs 1991 ) The digestibility of tunicates such as Salpa and Pyrosoma spp. is not well known considering their high protein concentration relative to other gelatinous animals ( Dubischar et al. 2012 ) It is possible that although tunicates provide a high concentration of protein the protein may be bound in compounds not available to the turtle. Studies are needed that measure the digestibility and nutrient availability of the many animal species ingested by green turtles to better understand their role as a dietary component. St omach content analysis suggests a degree of individual variation but isotope data indicate no consistency over a few months. The wide distribution of 13 C values

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28 may result from (1) rapid tissue turnover (2) the contribution of pelagic diet items and/ or (3) long term individual inconsistency in feeding patterns The former explanation can be considered unlikely, as turtles are ectotherms inhabiting cool waters Isotopic studies that measure tissue turnover and incorporation rates in juvenile green turtles are needed in order to confidently reconstruct the diet. The second possible explanation for the wide distribution of 13 C values in some turtles is that the Pyrosoma sp. that the turtles consume may have low 13 C values. Low 13 C values would be expected in pelagic organisms blown in from deeper waters of the GoM. Our inability to sample these tunicates precludes our te sting this idea. Figure 2 1 presents a conceptual model of the isotope values through time if individual turtles are feeding in consistently (2 1a) or consistently (2 1b) If turtles were feeding inconsistently over time (i.e., a mixed diet of tunicate/sea grass) there would be no clustering around prey items as individuals would vary in their resource use. If individuals were feeding consistently over a long period, it would be expected that clustering would appear around each prey item (e.g. algae, seagra ss and tunicate ). Stable isotope results indicate low consistency, which may be attributed to inconsistent availability of seagrass and tunicates. Seasonal variation in seagrass biomass, algae biomass and tunicate occurrence may lead to alternative feeding strategies. Although seagrass species are present in SJB year round, there is a significant dieback of Thalassia, Halodule, and Syringodium spp in shallow areas of the bay. Additionally, it appears that red algae coverage increases in the fall months, th en decreases during winter (pers. obs.). Pyros oma are a pelagic species, known to form extensive, dense colonies that occur in irregular swarms ( Andersen & Sardou 1994 ) from temperate zone

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29 to temperate zone Mass dep osition events of pyrosomids have been recorded off the African coast ( Lebrato & Jones 2009 ) In the Gulf of Mexico, tunicates are reportedly patchily distributed in their environment ( Graham 2001 ) For example, d ense colonies of Pyrosoma atlanticum were reported in the California current region in 1955 and 1956, then became rare again ( Berner 1967 ) The oth er tunicate species found in this study ( Botrylloides sp. ) is a benthic tunicate that forms on blades of T. testudinum These tunicates appear when water temperatures decrease (Sheri Johnson, pers. comm.; pers. obs.). Green turtle digestive efficiency incr eases with an increase in water temperature ( Bjorndal 1980 ) so during winter green turtles may select animal diet items whi ch are of higher digestibility. I t appears that green turtles in St Joseph Bay exhibit plasticity feeding primarily as herbivores in some years ( Foley et al. 2007 ) and as omnivores in other years ( present study) Foley et al. (2007 ) analyzed green turtle stomach contents from the 2001 cold stunni ng event and found the primary diet item to be Thalassia testudinum Styela ; Molgula ; unknown) were present in small amounts ( Lessma n n 200 2 ) Differences in diet between years cannot be attributed to methodology, as stomach contents were thoroughly sorted and analyzed using the same methods. Finally, this study illustrates that care should be taken in setting a stomach sample size for rea sonable gut content conclusions, especially in gastric lavage where samples tend to be small (Nagaoka et al. 2012). Of the stomach samples in 2011 with volume < 9.0 mL (n = 18), two individuals had stomach contents composed of 100% seagrass, two were 10 0% tunicates, and the remaining samples were mixed diets of seagrass, tunicates and macroalgae. Although there were no significant differences between all

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30 samples and only large samples in 2011, the number of turtles with 100 % seagrass or tunicates was gre atly reduced after excluding small sample volumes. Small, homogenous sample volumes may represent one feeding event and give a different picture of diet based on volume. In the present study, green turtles revealed flexible foraging strategies as a specie s inhabiting the northern fringe of their range. Prior to the 2008 and 2011 SJB cold stunning events green turtles were feeding as omnivores ; however, prior to the cold stunning event in 2001 green turtles exhibited a herbivorous diet ( Foley et al. 2007 ) Questions of feeding consistency should be further examined by measuring seasonal and annual variation in prey availability and selection. Future studies should address the relationship between diet selection, digestive efficiency, and the nutritional value of animal matter in green turtle diet. Understanding the temporal a nd geographic variation in sea turtle foraging ecology in peripheral habitats is necessary f or implementing effective long term conservation and management plans. This information is essential to the conservation of endangered species such as the green turtle, as well as other species that reside in peripheral habitats and may be more susceptib le to environmental changes.

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31 Table 2 1. Diet composition of juvenile green turtles in St. Joseph Bay, Florida Percent vol ume, percent dry mass index of relative importance (IRI), and frequency of occurrence (% F) for green turtles from cold stunning events in St. Joseph Bay, Florida, in (> 9.0 mL ). refers to trace V alues are presented as mean (SD). UM: unidentified material; UPM: unidentified plant material. Prey item % Volume ( mL ) % Dry Mass (g) IRI % F 2008 n = 12 2011 n = 31 2011 ALL n = 49 2008 n = 12 2011 n = 31 2011 ALL n = 49 2008 n = 12 2011 n = 31 2011 ALL n =49 2008 n = 12 2011 n =31 2011 ALL n = 49 S eagrasses T. t. blades 22.8 (11.9) 12.2 (10.7) 7.8 (9.8) 2.30 (1.28) 1.14 (1.02) 0.7 (0.94) 74.4 70.1 70.3 100 100 88. 7 T. t. rhizome 0.4 (1.2) 0.1 (0.5) 0.1 (0.4) 0.03 (0.09) 0.02 (0.06) 0.01 (0.05) 0.21 0.13 0.11 16.67 16.13 11.3 H. wri ghtii 0.1 (0.4) 0.0 0.1 (0.3) 0.01 (0.03) 0.01 (0.01) 0.00 (0.02) 0. 03 0.02 0.05 8.33 12.9 9.4 S. filiforme 0.0 1.8 (9.0) 1.2 (6.9) 0.00 0.08 (0.37) 0.05 (0.28) 0.00 0.65 0.66 0.00 6.45 5.7 Macroalgae Gracilaria sp. 0.0 0.6 (3.1) 0.6 (2.5) 0.00 0.03 (0.12) 0.02 (0.10) 0.0 1 0.22 0.66 0.00 6.45 11.3 Enteromorpha sp 0.0 0.9 (3.3) 0.5 (2.6) 0.00 0.01 (0.07) 0.01 (0.05) 0.00 0.49 0.30 0.00 9.68 5. 7 Tunicates Pyrosoma sp. 3.5 (2.7) 5.1 (4.9) 3.2 (4.3) 0.23 (0.39) 0.19 (0.21) 0.13 (0.19) 11.4 26.7 26.7 100 90.3 79.3 Botrylloides sp. 5.7 (7.0) 0.6 (1.1) 0.3 0.9) 0.27 (0.35) 0.04 (0.07) 0.02 (0.05) 14.0 1.66 1.20 75 45. 2 30.2 Other materials feather 0.0 tr tr tr tr tr 0.00 tr tr 0.00 tr tr UM 0.0 tr t r 0.00 tr tr 0.00 tr tr 0.00 tr tr plastic 0.0 tr tr 0.00 tr tr 0.00 tr tr 0.00 3.2 1.9 shell 0.0 tr tr tr tr tr 0.00 tr tr 0.00 tr tr UPM 0.0 tr tr 0.00 tr tr 0.00 tr tr 0.00 tr tr

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32 Figure 2 1 Conceptual model of patterns of isotope values representing resource use through time. Closed symbols represent prey items; o pen symbols repr esent individual turtles. (a) inconsistent feeding and (b) consistent feeding over time. See text for discussion of model

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33 Figure 2 2. Plot of stable isotope ratios of nitrogen and carbon from epidermis samples and major prey items of juvenile green tur tles. Closed symbols represent prey items; open symbols represent individual turtles Prey items are shown as mean standard deviation 0 2 4 6 8 10 12 14 -18 -16 -14 -12 -10 -8 -6 -4 15 13 Tunicates Macroalgae Seagrasses > 50 % seagrasses > 50 % macroalgae > 50 % tunicates

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34 Figure 2 3. Chelonia mydas. Epidermis 13 C vs. curved carapace length in St. Joseph R = 0.662 -18 -16 -14 -12 -10 -8 -6 20 30 40 50 60 13 Curved carapace length (cm)

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35 APPENDIX A JANUARY 2008 DIET COMPOSITION Figure A 1. Diet composition ( proportion of volume; mL ) in 12 juven ile green turtles from the cold stunning event in St. Joseph Bay, Florida in January 2008 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Proportion of volume (ml) Individual turtles Seagrasses Macroalgae Tunicates Other materials

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36 Figure A 2. Diet composition (proportion of dry mass; mg) in 12 juvenile green turtles from the cold stunning event in St. Joseph Bay, Florida in January 2008 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Proportion of dry mass (mg) Individual turtles Seagrasses Macroalgae Tunicates Other materials

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37 APPENDIX B JANUARY 2011 DIET C OMPOSITION Figure B 1. Diet composition (proportion of volume; mL ) of 31 juvenile green turtles from the cold stunning event in St. Joseph Bay, Florida in January 2011. Each bar represents one turtle 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Proportion of volume (ml) Individual turtles Seagrasses Macroalgae Tunicates Other materials

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38 Figure B 2. Diet composition (proportion of dr y mass; mg) of 31 juvenile green turtles from the cold stunning event in St. Joseph Bay, Florida in January 2011. Each bar represents one turtle 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Proportion of dry mass (mg) Individual turtles Seagrasses Macroalgae Tunicates Other materials

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39 APPENDIX C 2011 DIET AND BODY S IZE Figure C 1. The relationship between green turtle body size (C CLmin) and seagrasses (P seagrasses = 0.3127 ) in St. Joseph Bay, Florida Figure is based on volume of stomach contents (n= 30)

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40 Figure C 2. The relationship between green turt le body size (CCLmin) and tunicates ( P tunicates = 0.2215 ) in St. Joseph Bay, Florida Figure is based on volume of stomach contents (n= 30)

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41 APPENDIX D 2011 15 N AND BODY SIZE Figure D 1. Chelonia mydas Epidermis 15 N vs. curved carapace length in St. Joseph Bay, Florida in 2011. Relationship is not significan 0 2 4 6 8 10 12 14 20 30 40 50 60 15 Curved carapace length (cm) 2011

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42 APPENDIX E DIET OF THE GREEN TURTLE, CHELONIA MYDAS Table E 1.Diet of the green turtle, Chelonia m ydas Item Location Life Stage Reference Atlantic Pacific & Indian Atlantic Pacific & Indian Plantae Angiosperms Seagrasses Cymodocea ovalis Yemen A Hirth et al. 1973 Cymodocea spp. Australia; Aldabra Atoll A, J Garnett et al. 1985; Fuentes et al. 2006; Frazier 1971 Diplanthera wrightii Mosquito Lagoon, Florida; Nicaragua J, U Mendonca 1983; Mortimer 1976 Halodule pinifolia Australia U Limpus & Reed 1985 Halodule spp. Australia J Fuentes et al 2006 Halodule uninervis Oman; Australia; Yemen U, J, A Ross 1985; Limpus et al. 1994; Brand Gardner et al. 1999; Hirth et al. 1973 Halodule wrightii Nicaragua; Mosquito Lagoon, Florida;GoM;SE Brazil;Texas A, J Mortimer 1981; Mendonca 1983; Foley e t al. 2007; Guebert Bartholo et al. 2011; Nagaoka et al. 2012; Coyne 1994; Santos et al. 2011 Halophila baillonis Nicaragua A, J Mortimer 1981 Halophila decipiens Hawaii J Arthur & Balazs 2008 Halophila engelmanni Mosquito Lagoon, Florida J Mendo nca 1983 Halophila hawaiiana Hawaii J Arthur & Balazs 2008 Halophila ovalis Oman;Australia; Yemen U, A, J Ross 1985; Limpus et al. 1994; Tucker & Read 2001; Brand Gardner et al. 1999; Hirth et al. 1973

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43 Table E 1. Continued Item Halophila ovat a Oman U Ross 1985 Halophila spinulosa Australia A, O, J, U Limpus et al. 1994; Garnett et al. 1985; Limpus & Reed 1985 Halophila spp. Australia J Fuentes et al. 2006 Phyllospadix torreyi Baja California U Lopez Mendilaharsu et al. 2005 Syringo dium filiforme Nicaragua;Mosquito Lagoon, Florida;GoM;Texas A, J, U Mortimer 1976, 1981; Mendonca 1983; Foley et al. 2007; Coyne 1994 Syringodium isoetifolium Yemen A Hirth et al. 1973 Syringodium spp. Australia J Fuentes et al. 2006 Thalassia s pp. Aldabra Atoll A Frazier 1971 Thalassia hemprichii Australia A, J Garnett et al. 1985; Tucker & Read 2001; Fuentes et al. 2006 Thalassia testudinum Nicaragua;Bahamas;GoM A, O, J, U Mortimer 1976, 1981; Bjorndal 1980; Foley et al. 2007 Thalassod endron ciliatum Yemen A Hirth et al. 1973 Zostera capricorni Australia A, O, J Limpus et al. 1994; Brand Gardner et al. 1999 Zostera marina New York Baja California J U Lopez Mendilaharsu et al. 2005; Burke et al. 1991 Angiosperms (terrestrial) Avicennia germinans Baja California U Lopez Mendilaharsu et al. 2005 Avicennia marina Australia J Read & Limpus 2002 Avicennia shaueriana SE Brazil J Guebert Bartholo et al. 2011; Nagaoka et al. 2012 Distichils spp. Peru A, J Hays Brown & Bro wn 1982 Ficus spp. leaves Colombia A, J Amorocho & Reina 2007

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44 Table E 1. Continued Item Hibiscus spp. leaves Colombia A, J Amorocho & Reina 2007 Ochroma spp. leaves Colombia A, J Amorocho & Reina 2007 Rhizophora mangle Galapagos Is. A, J Carrion Cortez et al. 2010 Spartina alterniflora SE Brazil J Nagaoka et al. 2012 Algae Phaeophyta Chnoospora implexa Australia A, J Garnett et al. 1985 Colpomenia spp. Australia J Fuentes et al. 2006 Cystoseira spp. Australia A, J Garnett et al. 1985 Dictoyota spp. Australia; Hawaii; Galapagos Is. A, J Garnett et al. 1985; Fuentes et al. 2006; Arthur & Balazs 2008; Carrion Cortez et al. 2010 Dictoyota dichotoma Brazil; Nicaragua A, J, U Ferreira 1968; Mortimer 1976 Dictyopte ris delicatula Nicaragua; Brazil A, J Mortimer 1981; Ferreira 1968 Dictyota flabellata Gulf of California A Seminoff et al. 2002 Fucus spp. New York, Brazil A, J Burke et al. 1991; Ferreira 1968 Hydroclathrus clathratus Australia A, J Garnett et al. 1985 Ishige sinicola Gulf of California A Seminoff et al. 2002 Lobophora variegata Nicaragua Hawaii U J Arthur & Balazs 2008; Mortimer 1976 Padina australis Australia A, J Garnett et al. 1985 Padina durvillaei Gulf of California A, J Seminof f et al. 2002 Padina pavonica Oman U Ross 1985

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45 Table E 1. Continued Item Padina spp. Australia;Hawaii J Fuentes et al. 2006; Arthur & Balazs 2008 Padina vickersiae Nicaragua U Mortimer 1976 Phaeophyta spp. Central, North Pacific O Parker et al. 2011 Pocockiella variegata Brazil A, J Ferreira 1968 Sargassum cymosum Brazil A, J Ferreira 1968 Sargassum filipendula Nicaragua A, J, U Mortimer 1976, 1981 Sargassum fluitans Nicaragua U Mortimer 1976 Sargassum horridum Baja Califo rnia U Lopez Mendilaharsu et al. 2005 Sargassum hystrix Nicaragua A, J, U Mortimer 1976, 1981 Sargassum illicifolium Oman U Ross 1985 Sargassum spp. SE Brazil; New York Australia;Gulf of California;Hawaii J A, J Garnett et al. 1985; Tucker & Read 2 001; Seminoff et al. 2002; Guebert Bartholo et al. 2011; Fuentes et al. 2006; Arthur & Balazs 2008; Burke et al. 1991 Sargassum vulgare Nicaragua; Brazil A, J Mortimer 1981; Ferreira 1968 Spatoplossum schroederi Brazil A, J Ferreira 1968 Sphacelaria spp. Australia A, J Garnett et al. 1985 Sporochnus bolleanus Gulf of California J Seminoff et al. 2002 Sporochnus pedunculatus Nicaragua A, J, U Mortimer 1976, 1981 Turbinaria ornata Australia;Hawaii A, J Tucker & Read 2001;Arthur & Balazs 2008

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46 Table E 1. Continued Item Turbinaria spp. Australia A, J Garnett et al. 1985;Fuentes et al. 2006 unidentified spp. Australia A Tucker & Read 2001 Zonaria spp. Hawaii J Arthur & Balazs 2008 Cyanophyta Lyngbya majuscula Hawaii J Ar thur & Balazs 2008 Lyngbya porphyrosiphonis Hawaii J Arthur & Balazs 2008 Lyngbya semiplena Hawaii J Arthur & Balazs 2008 Lyngbya spp. Australia A, J Garnett et al. 1985 Schizothrix spp. Hawaii J Arthur & Balazs 2008 Rhodophyta Acanthoph ora spicifera Brazil Hawaii;Australia A, J A, J Balazs et al. 1987;Garnett et al. 1985;Brand Gardner et al. 1999; Arthur & Balazs 2008; Ferreira 1968 Acanthophora spp. Australia A, J Garnett et al. 1985;Fuentes et al. 2006 Agardhiella tenera Brazil A J Ferreira 1968 Amansia glomerata Hawaii;Australia A, J Balazs et al. 1987;Garnett et al. 1985;Arthur & Balazs 2008 Amansia multifida Nicaragua; Brazil A, J, U Mortimer 1976, 1981; Ferreira 1968 Amphiroa spp. Hawaii J Arthur & Balazs 2008 Anh feltiopis spp. Galapagos Is. A, J Carrion Cortez et al. 2010 Bostrychia spp. SE Brazil Galapagos Is. J A, J Nagaoka et al. 2012; Carrion Cortez et al. 2010 Botryocladia spp. Australia A, J Garnett et al. 1985 Bryocladia spp. Texas J Coyne 1994 B ryothamnion triquetrum Brazil A, J Ferreira 1968 Bryothamnion seaforthii Brazil; Nicaragua A, J, U Ferreira 1968; Mortimer 1976

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47 Table E 1. Continued Item Caloglossa spp. SE Brazil Galapagos Is. J A, J Nagaoka et al. 2012; Carrion Cortez et al 2010 Callophylis spp. Galapagos Is. A, J Carrion Cortez et al. 2010 Catenella opuntia Galapagos Is. A, J Carrion Cortez et al. 2010 Caulacanthus spp. Australia A, J Garnett et al. 1985 Centroceras clavulatum Hawaii J Arthur & Balazs 2008 Cen troceras spp. Galapagos Is. A, J Carrion Cortez et al. 2010 Ceramium spp. Australia A, J Garnett et al. 1985 Cerium spp. Hawaii J Arthur & Balazs 2008 Champia spp. Australia A, J Garnett et al. 1985 Chondracanthus canaliculatus Baja California U Lopez Mendilaharsu et al. 2005 Chondracanthus elegans SE Brazil J Santos et al. 2011 Chondria spp. Australia;Hawaii A, J Garnett et al. 1985; Arthur & Balazs 2008 Coelothrix spp. Australia A, J Garnett et al. 1985 Compsopogon spp. SE Brazil J Nagaoka et al. 2012 Corallina cubensis Nicaragua A, J Mortimer 1981 Coralina spp. Galapagos Is. A, J Carrion Cortez et al. 2010 Cryptonemia crennulata Nicaragua; Brazil A, J Mortimer 1981; Ferreira 1968 Cryptonemia luxurians Brazil; Nicaragua A, J, U Ferreira 1968; Mortimer 1976 Dasya spp. Australia A, J Garnett et al. 1985; Fuentes et al. 2006 Enantiocladia duperryi Nicaragua; Brazil A, J Mortimer 1981; Ferreira 1968 Euchema uncinatum Gulf of California A Seminoff et al. 2002

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48 Table E 1. Continued Item Eucheuma muricatum Australia A, J Garnett et al. 1985 Eucheuma spp. Brazil Australia A, J A, J Garnett et al. 1985; Ferreira 1968 Galaxaura obtusata Brazil A, J Ferreira 1968 Galaxaura spp. Australia A, J Garnett et a l. 1985; Fuentes et al. 2006 Gelidiella acerosa Brazil Australia A, J A, J Garnett et al. 1985; Ferreira 1968 Gelidiella spp. Australia; Hawaii; Galapagos Is. A, J Fuentes et al. 2006; Arthur & Balazs 2008; Carrion Cortez et al. 2010 Gelidiella trini tatensis Brazil A, J Ferreira 1968 Gelidiopsis acrocarpa Australia A, J Garnett et al. 1985 Gelidiopsis gracilis Brazil A, J Ferreira 1968 Gelidiopsis variabilis Australia A, J Garnett et al. 1985 Gelidium corneum Brazil A, J Ferreira 1968 Gelidium floridanum SE Brazil J Santos et al. 2011 Gelidium johnstonii Gulf of California A Seminoff et al. 2002 Gelidium robustum Baja California U Lopez Mendilaharsu et al. 2005 Gelidium spp. Oman; Colombia; Hawaii; Aldabra Atoll; Galapagos I s. A J, U Ross 1985; Amorocho & Reina 2007; Arthur & Balazs 2008; Frazier 1971; Galapagos Is. Gigartina spp. SE Brazil Gulf of California; Peru J A, J Seminoff et al. 2002;Guebert Bartholo et al. 2011; Hays Brown & Brown 1982

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49 Table E 1. Continued It em Gracilaria cervicornus Brazil A, J Ferreira 1968 Gracilaria crassa Australia A, J Garnett et al. 1985 Gracilaria cuneata Brazil A, J Ferreira 1968 Gracilaria cylindrica Nicaragua A, J Mortimer 1981 Gracilaria debilis Nicaragua U Mo rtimer 1976 Gracilaria domingensis Brazil A, J Ferreira 1968 Gracilaria foliifera Brazil A, J Ferreira 1968 Gracilaria ferox Brazil A, J Ferreira 1968 Gracilaria mammillaris Nicaragua; SE Brazil A, J Mortimer 1981; Santos et al. 2011 Gracil aria ornata Brazil A, J Ferreira 1968 Gracilaria pacifica Baja California U Lopez Mendilaharsu et al. 2005 Gracilaria spinigera Gulf of California A, J Seminoff et al. 2002 Gracilaria spp. Nicaragua;SE Brazil Australia; Hawaii; Galapagos Is. A, J A, J Mortimer 1981;Garnett et al. 1985;Brand Gardner et al. 1999;Guebert Bartholo et al. 2011;Fuentes et al. 2006;Arthur & Balazs 2008; Carrion Cortez et al. 2010 Gracilaria textorii Baja California U Lopez Mendilaharsu et al. 2005 Gracilaria verrucos a Nicaragua A, J Mortimer 1981 Gracilariopsis lemaneiformis Baja California U Lopez Mendilaharsu et al. 2005 Gracilariopsis sjoestedtii Brazil A, J Ferreira 1968 Gracilariopsis tenuifrons SE Brazil J Santos et al. 2011 Griffithsia spp. Austra lia A, J Garnett et al. 1985

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50 Table E 1. Continued Item Gymnogrongus griffithsiae SE Brazil J Santos et al. 2011 Gymnogrongus spp. Galapagos Is. A, J Carrion Cortez et al. 2010 Haloplegma duperreyi Brazil A, J Ferreira 1968 Halymenia flor esii Nicaragua; Brazil A, J Mortimer 1981; Santos et al. 2011; Ferreira 1968 Halymenia refugiensis Gulf of California A, J Seminoff et al. 2002 Halymenia spp. Australia; Galapagos Is. A, J Garnett et al. 1985; Carrion Cortez et al. 2010 Heterosiph onia spp. Australia A, J Garnett et al. 1985 Hypnea cervicornis Brazil Australia A, J A, O, J Limpus et al. 1994; Ferreira Hypnea johnstonii Baja California U Lopez Mendilaharsu et al. 2005 Hypnea musciformis Nicaragua;Texas; Brazil A, J Mortime r 1981;Coyne 1994 ; Santos et al. 2011; Ferreira 1968 Hypnea spp. SE Brazil Oman; Australia; Hawaii; Galapagos Is. J J, U, A Ross 1985; Garnett et al. 1985; Tucker & Read 2001; Brand Gardner et al. 1999; Guebert Bartholo et al. 2011; Fuentes et al. 2006; Arthur & Balazs 2008; Carrion Cortez et al. 2010 Hypoglossum spp. Australia A, J Garnett et al. 1985 Jania spp. Australia J Fuentes et al. 2006 Laurencia brongniartii Australia A, J Garnett et al. 1985 Laurencia johnstonii Gulf of California A, J Seminoff et al. 2002 Laurencia mariannensis Hawaii J Balazs et al. 1987

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51 Table E 1. Continued Item Laurencia spp. GoM; Brazil Australia;Hawaii; Aldabra Atoll A, J A Garnett et al. 1985;Foley et al. 2007;Fuentes et al. 2006;Arthur & Balazs 200 8;Santos et al. 2011; Ferreira 1968; Frazier 1971 Lenormandiopsis lorentzii Australia A, J Garnett et al. 1985 Lenormandiopsis spp. Australia A, J Garnett et al. 1985 Leveillea jungermannioides Australia A, J Garnett et al. 1985 Leveillea spp. A ustralia J Fuentes et al. 2006 Lithophyllum spp. Gulf of California A, J Seminoff et al. 2002 Mazzaela flaccida Baja California U Lopez Mendilaharsu et al. 2005 Peyssonnelia simulans Nicaragua U Mortimer 1976 Platysiphonia spp. Australia A, J Garnett et al. 1985 Polysiphonia spp. SE Brazil Australia; Hawaii; Galapagos Is. J A, J Garnett et al. 1985;Nagaoka et al. 2012;Arthur & Balazs 2008; Carrion Cortez et al. 2010 Prionites obtusa Australia A, J Garnett et al. 1985 Prionites spp. Galap agos Is. A, J Carrion Cortez et al. 2010 Protokuetzingia schottii Brazil A, J Ferreira 1968 Pterocladia capillacea SE Brazil Hawaii;Baja California J J, U Balazs et al. 1987; Lopez Mendilaharsu et al. 2005; Santos et al. 2011 Pterocladia spp. Galap agos Is. A, J Carrion Cortez et al. 2010 Pterocladiella spp. Hawaii J Arthur & Balazs 2008 Rhodymenia pseudopalmata Texas; SE Brazil J Coyne 1994 ;Santos et al. 2011 Rhodymenia spp. Peru A, J Hays Brown & Brown 1982

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52 Table E 1. Continued Item Schizymenia epiphytica Baja California U Lopez Mendilaharsu et al. 2005 Scinaia spp. Australia A, J Garnett et al. 1985 Spyridia filamentosa Nicaragua Australia A, J, U A, J Mortimer 1976, 1981;Garnett et al. 1985 Tolypiocladia glomerulata Aus tralia A, J Garnett et al. 1985 unidentified Rhodomelaceae SE Brazil J Nagaoka et al. 2012 unidentified Rhodophyta Mosquito Lagoon, Florida Central, North Pacific J O Parker et al. 2011; Mendonca 1983 Vidalia obtusiloba Nicaragua; Brazil A, J, U Mo rtimer 1976, 1981; Ferreira 1968 Vidalia spp. Australia A, J Garnett et al. 1985 Chlorophyta Acetabularia crenulata Nicaragua U Mortimer 1976 Anadyomene spp. Australia A, J Garnett et al. 1985 Avrainvillea spp. Brazil A, J Ferreira 1968 Bryopsis spp. Hawaii J Arthur & Balazs 2008 Caulerpa ashmeadii Nicaragua U Mortimer 1976 Caulerpa brachypus Australia A, J Garnett et al. 1985 Caulerpa cupressoides Brazil; Nicaragua Australia U A, J Garnett et al. 1985; Ferreira 1968; Mortimer 19 76 Caulerpa farlowii Nicaragua U Mortimer 1976 Caulerpa lentillifera Australia A, J Garnett et al. 1985 Caulerpa longiseta Nicaragua U Mortimer 1976 Caulerpa mexicana Brazil A, J Santos et al. 2011; Ferreira 1968

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53 Table E 1. Continued Item Caulerpa opuntia Nicaragua U Mortimer 1976 Caulerpa paspaloides Nicaragua U Mortimer 1976 Caulerpa prolifera Nicaragua; Brazil A, J, U Mortimer 1976, 1981; Ferreira 1968 Caulerpa racemosa Australia; Galapagos Is. A, J Garnett et al. 1985; Car rion Cortez et al. 2010 Caulerpa sertularioides Nicaragua; Brazil Australia A, J, U A, J Mortimer 1976, 1981; Garnett et al. 1985; Ferreira 1968 Caulerpa spp. Nicaragua Australia; Aldabra Atoll U A Tucker & Read 2001; Frazier 1971; Mortimer 1976 Caulerp a spp. rhizoids Australia A, J Garnett et al. 1985 Caulerpa urvilliana Australia A, J Garnett et al. 1985 Chaetomorpha aerea SE Brazil Oman J U Ross 1985;Santos et al. 2011 Chaetomorpha antennina Gulf of California A, J Seminoff et al. 2002 Chaet omorpha spp. Australia A, J Garnett et al. 1985;Fuentes et al. 2006 Cladophora spp. Colombia;Hawaii A, J Amorocho & Reina 2007;Arthur & Balazs 2008 Cladophora vagabunda SE Brazil J Santos et al. 2011 Codium amplivesiculatum Baja California U Lop ez Mendilaharsu et al. 2005 Codium edule Hawaii J Balazs et al. 1987 Codium isthmocladum Nicaragua; Brazil A, J Mortimer 1981; Ferreira 1968 Codium simulans Baja California U Lopez Mendilaharsu et al. 2005

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54 Table E 1. Continued Item Codi um spp. New York; Nicaragua Australia; Gulf of California; Hawaii; Aldabra Atoll; Galapagos Is. J, U A, J Garnett et al. 1985;Tucker & Read 2001;Seminoff et al. 2002;Arthur & Balazs 2008; Frazier 1971; Burke et al. 1991; Mortimer 1976 Dictyosphaeria spp. Hawaii J Arthur & Balazs 2008 Enteromorpha acanthophora Gulf of California A, J Seminoff et al. 2002 Enteromorpha spp. GoM; New York Hawaii J J Foley et al. 2007;Arthur & Balazs 2008; Burke et al. 1991 Gayralia spp. SE Brazil J Nagaoka et al. 2012 Halimeda incrassata Nicaragua U Mortimer 1976 Halimeda opuntia Nicaragua Hawaii U J Arthur & Balazs 2008; Mortimer 1976 Halimeda simulans Nicaragua U Mortimer 1976 Halimeda spp. Nicaragua Australia A, J, U A, J Mortimer 1976, 1981;Tucker & Read 20 01;Fuentes et al. 2006 Monostroma oxyspermum Brazil A, J Ferreira 1968 Neomeris spp. Nicaragua U Mortimer 1976 Penicillus capitatus Nicaragua A, J, U Mortimer 1976, 1981 Penicillus spp. Nicaragua U Mortimer 1976 Rhipocephalus phoenix Nicaragua U Mortimer 1976 Rhipocephalus spp. Nicaragua U Mortimer 1976

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55 Table E 1. Continued Item Rhizoclonium grande Hawaii J Arthur & Balazs 2008 Rhizoclonium spp. SE Brazil Australia J A, J Garnett et al. 1985;Nagaoka et al. 2012 Udotea conglut inata Nicaragua U Mortimer 1976 Udotea flabellum Nicaragua A, J, U Mortimer 1976, 1981 Udotea spinulosa Nicaragua U Mortimer 1976 Udotea spp. Nicaragua Australia U A, J Garnett et al. 1985; Mortimer 1976 Ulva fasciata Texas; Brazil A, J Coyne 1 994; Ferreira 1968 Ulva lactuca Gulf of California; Galapagos Is. A, J Seminoff et al. 2002; Carrion Cortez et al. 2010 Ulva reticulata Hawaii J Balazs et al. 1987 Ulva spp. S. Brazil;SE Brazil; New York Hawaii J J Guebert Bartholo et al. 2011;Nagao ka et al. 2012;Arthur & Balazs 2008; Burke et al. 1991 unidentified spp. SE Brazil J Mendonca 1983;Guebert Bartholo et al. 2011 Chrysophyta Vaucheria spp. SE Brazil J Nagaoka et al. 2012 Animalia Pisces Hirundichthys speculi ger Central, North Pacific O Parker et al. 2011 Ostraciidae: Lactoria diaphana Central, North Pacific O Parker et al. 2011 Scombridae: Scomber japonicus Central, North Pacific O Parker et al. 2011

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56 Table E 1. Continued Item unidentified spp Central, North Pacific; Peru O, A, J Parker et al. 2011; Hays Brown & Brown 1982 Mollusca Bivalvia Mytilus spp. Peru A, J Hays Brown & Brown 1982 Semele spp. Peru A, J Hays Brown & Brown 1982 Gastropoda Aplysia vaccaria Gulf o f California A, J Seminoff et al. 2002 Aplysua spp. eggs SE Brazil J Nagaoka et al. 2012 Cavoliniidae southwest Pacific O Boyle & Limpus 2008 Columbela fuscata Gulf of California A, J Seminoff et al. 2002 Dentalium neohexagonum Gulf of Californ ia A, J Seminoff et al. 2002 Dosidicus gigas Gulf of California A, J Seminoff et al. 2002 gastropod eggs Nicaragua Gulf of California U A, J Seminoff et al. 2002; Mortimer 1976 Mytella guyanensis Gulf of California A, J Seminoff et al. 2002 Nassar ius spp. Peru A, J Hays Brown & Brown 1982 Olivella dama Gulf of California A, J Seminoff et al. 2002 Ptenoglossa: Janthina spp. Central, North Pacific O Parker et al. 2011 Pterioda southwest Pacific O Boyle & Limpus 2008

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57 Table E 1. Continu ed Item Pteropoda: Cavolinia spp. including C. globulosa and C. tridentate Central, North Pacific O Parker et al. 2011 Pterotrachids including Carinaria spp. Central, North Pacific O Parker et al. 2011 Rissoina spp. Colombia A, J Amorocho & R eina 2007 Stylochilus spp. Hawaii J Arthur & Balazs 2008 Tonnidae southwest Pacific O Boyle & Limpus 2008 Triphora spp. Colombia A, J Amorocho & Reina 2007 Trypsica trypsica Gulf of California A, J Seminoff et al. 2002 Turridae Gulf of Califo rnia A, J Seminoff et al. 2002 unidentified spp. New York Australia; Galapagos Is. J A, J Garnett et al. 1985; Burke et al. 1991; Carrion Cortez et al. 2010 Decopoda Cephalopoda Central, North Pacific O Parker et al. 2011 Ommastrephes bartrami Central, North Pacific O Parker et al. 2011 Arthropoda Amphipoda Central, North Pacific; Peru O, A, J Parker et al. 2011; Hays Brown & Brown 1982 Class Insecta southwest Pacific O Boyle & Limpus 2008 Class Pycnogonida Nicaragua U Mortimer 1976

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58 Table E 1. Continued Item Crustacea Cirripedia southwest Pacific P Boyle & Limpus 2008 Cl. Malacostraca southwest Pacific P Boyle & Limpus 2008 Cl. Maxillopod southwest Pacific P Boyle & Limpus 2008 Copepod Central, North Pacif ic O Parker et al. 2011 Lepas spp. Central, North Pacific O Parker et al. 2011 Natantia spp. Gulf of California A, J Seminoff et al. 2002 Penneus spp. Colombia A, J Amorocho & Reina 2007 Pleuroncodes planipes Baja California U Lopez Mendilahar su et al. 2005 unidentified spp. New York Central, North Pacific;Australia; Hawaii; Peru J A, O, J Parker et al. 2011;Garnett et al. 1985;Arthur & Balazs 2008; Burke et al. 1991; Hays Brown & Brown 1982 Echinodermata Brittle star Australia J Brand Gardner et al. 1999 Clypeaster testudinarus Gulf of California A, J Seminoff et al. 2002 unidentified spp. Australia A, J Garnett et al. 1985 Porifera Acarnus erithacus Gulf of California A, J Seminoff et al. 2002 Chondrilla nucula Bahamas U Bjorndal 1990 Chondrosia chuchalla Hawaii J Balazs et al. 1987 Haliclona rubens Nicaragua A, J Mortimer 1981 Haliclona spp. Gulf of California A, J Seminoff et al. 2002 Haliclona viridis Nicaragua U Mortimer 1976

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59 Table E 1. Continued I tem Halisarca spp. Gulf of California A, J Seminoff et al. 2002 Hippiospongia gossipina Nicaragua U Mortimer 1976 Hymeniacidon rugosus Gulf of California A, J Seminoff et al. 2002 Hymeniacidon sinapium Gulf of California A, J Seminoff et a l. 2002 Labrisomidae vertebra Gulf of California A, J Seminoff et al. 2002 unidentified spp. Nicaragua Australia;Gulf of California;Baja California U A, J, U Garnett et al. 1985;Seminoff et al. 2002;Lopez Mendilaharsu et al. 2005; Mortimer 1976 Cnidar ia Central, North Pacific O Parker et al. 2011 Antipathes galapagensis Gulf of California A, J Seminoff et al. 2002 Catostylus mosaicus Australia A, J, O Limpus et al. 1994 Lytocarpus nuttingi Gulf of California A, J Seminoff et al. 2002 Murice a spp. Gulf of California A, J Seminoff et al. 2002 Pseudopterogorgia spp. Nicaragua U Mortimer 1976 Physalia spp. Australia O Booth & Peters 1972 Pocillopora spp. Colombia A, J Amorocho & Reina 2007 Porpita spp. southwest Pacific; Australia O Boyle & Limpus 2008; Booth & Peters 1972 Ptilosarcus undulatus Gulf of California A, J Seminoff et al. 2002 unidentified anemone Nicaragua Australia U J Brand Gardner et al. 1999; Mortimer 1976

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60 Table E 1. Continued Item unidentified Anthozoa Australia A Tucker & Read 2001 unidentified Medusozoa spp. Peru A, J Hays Brown & Brown 1982 unidentified Scyphozoa southwest Pacific;Australia O, A Boyle & Limpus 2008;Tucker & Read 2001 unidentified spp. southwest Pacific; Australia; Galapagos Is. A, O, J Boyle & Limpus 2008; Brand Gardner et al.1999; Carrion Cortez et al. 2010 Hydrozoa Sertularia inflata Nicaragua A, J, U Mortimer 1976, 1981 unidentified spp. SE Brazil; Nicaragua Australia; Galapagos Is. J, U A, J Nagaoka et al. 201 2;Tucker & Read 2001; Mortimer 1976; Carrion Cortez et al. 2010 Siphonophora Galapagos Is. A, J Carrion Cortez et al. 2010 Velella spp. Australia O Booth & Peters 1972 Bryozoa Hyppothoa spp. Gulf of California A, J Seminoff et al. 2002 unid entified spp. SE Brazil; Nicaragua Australia J, U A Garnett et al. 1985; Nagaoka et al. 2012; Mortimer 1976 Scyphozoa unidentified spp. Galapagos Is. A, J Carrion Cortez et al. 2010 Ctenophora unidentified spp. Central, North Pacific; Aus tralia O Parker et al. 2011; Booth & Peters 1972 Tunicata Ascidia interrupta Gulf of California A, J Seminoff et al. 2002 Doliolidae Colombia A, J Amorocho & Reina 2007 Pyrosoma atlanticum Central, North Pacific O Parker et al. 2011

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61 Table E 1. Continued Item Salpidae Central, North Pacific;Colombia A, J, O Parker et al. 2011;Amorocho & Reina 2007 unidentified ascidian Australia A, J Tucker & Read 2001;Brand Gardner et al. 1999;Fuentes et al. 2006 unidentified spp. Nicaragua Aus tralia U A, J Garnett et al. 1985; Mortimer 1976 Annelida Sabellidae Gulf of California A, J Seminoff et al. 2002 Spunalidae Galapagos Is. A, J Carrion Cortez et al. 2010 unidentified polychaete spp. Peru A, J Hays Brown & Brown 1982 Nemato da unidentified spp. Galapagos Is. A, J Carrion Cortez et al. 2010 Eukaryota unidentified spp. Australia A Tucker & Read 2001

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62 LIST OF REFERENCES Amorocho DF, Reina RD (2007) Feeding ecology of the East Pacific gree n sea turtle, Chelonia mydas agassizii at Gorgona National Park, Colombia. Endangered Species Research 3:43 51 Andersen V, Sardou J (1994) Pyrosoma atlanticum (Tunicata, Thaliacea) Diel migration and vertical distribution as a function of colony size. J Plankton Res 16:337 349 Arthur KE, McMahon KM, Limpus CJ, Dennison WC (2009) Feeding ecology of green turtles ( Chelonia mydas ) from Shoalwater Bay, Australia. Marine Turtle Newsletter 123:6 12 Avens L, Goshe LR, Harms C, Anderson E, Goodman A, Cluse W, Godfrey M, Braun McNeill J, Stacy B, Bailey R, Lamont MM (2012) Population characteristics, age structure, and growth dynamics of neritic juvenile green turtles ( Chelonia mydas ) in the northeastern Gulf of Mexico. Marine Ecology Progress Series 458:213 22 9 Balazs GH (1980) Synopsis of biological data on the green turtle in the Hawaiian Islands. In. NOAA Tech. Memo NOAA NMFS SWFC 7, Honolulu, Hawaii Balazs GH, Forsyth RG, Kam AKH (1987) Preliminary assessment of habitat utilization by Hawaiian green tur tles in their resident foraging pastures. In. National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Honolulu Berner LDJ (1967) Distribution atlas of Thaliacea in the California current region. In: Calcofi Atlas, Book 8 Bjorn dal KA (1980) Nutrition and grazing behavior of the green turtle, Chelonia mydas Marine Biology 56:147 154 Bjorndal KA (1982) The consequences of herbivory for the life history pattern of the Caribbean green turtle. In: Bjorndal KA (ed) Biology and Conse rvation of Sea Turtles. Smithsonian Institution Press, Washington, DC Bjorndal KA (1985) Nutritional ecology of sea turtles. Copeia 1985:736 751 Bjorndal KA (1997) Foraging ecology and nutrition of sea turtles. In: Lutz PL, Musick JA (eds) The biology of sea turtles. CRC Press, London p. 199 231 Bjorndal KA, Bolten AB, Lagueux CJ, Jackson DR (1997) Dietary overlap in three sympatric congeneric freshwater turtles (Pseudemys) in Florida. Chelonian Conservation and Biology 2:430 433

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63 Bolten AB (1999) Tech niques for Measuring Sea Turtles. In: Eckert KL, K. A. Bjorndal, F. A. Abreu Grobois, and M. Donnelly (ed) Research and Management Techniques for the Conservation of Sea Turtles. IUCN/SSC Marine Turtle Specialist Group Publication No. 4 p. 110 114 Bolten AB (2003) Variation in sea turtle life history patterns: neritic vs. oceanic developmental stages. In: Lutz P, Musick J, Wyneken J (eds) The biology of sea turtles, volume II. CRC Press, Boca Raton, FL p. 243 257 Booth J, Peters JA (1972) Behavioural st udies on the green turtle ( Chelonia mydas ) in the sea. Animal Behaviour 20:808 812 Burke V, Morreale S, Logan P, Standora E Diet of green turtles ( Chelonia mydas ) in the waters of Long Island, N.Y. In: Salmon M, Wyneken J (eds). Proc Proceedings 11th Annu al Workshop on Sea Turtle Biology and Conservation. NOAA Tech. Memo. NMFS SEFS 302 Burke VJ, Standora EA, Morreale SJ (1993) Diet of juvenile Kemp's r idley and loggerhead sea turtles from Long Island, New York. Copeia 1993:1176 1180 Burkholder DA, Heitha us MR, Thomson JA, Fourqurean JW (2011) Diversity in trophic interactions of green sea turtles Chelonia mydas on a relatively pristine coastal foraging ground. Marine Ecology Progress Series 439:277 293 Cardona L, Aguilar A, Pazos L (2009) Delayed ontogen ic dietary shift and high levels of omnivory in green turtles ( Chelonia mydas ) from the NW coast of Africa. Marine Biology 156:1487 1495 Carr A (1952) Handbook of Turtles. The Turtles of the United States, Canada and Baja California, Vol. Comstock Publish ing Associates, Ithaca, N.Y. Carrin Cortez JA, Zrate P, Seminoff JA (2010) Feeding ecology of the green sea turtle ( Chelonia mydas ) in the Galapagos Islands. Journal of the Marine Biological Association of the United Kingdom 90:1005 1013 Coyne MS (199 4) Feeding ecology of subadult green sea turtles in south Texas waters. MS thesis, Texas A&M University, College Station, Texas Dalerum F, Angerbjrn A (2005) Resolving temporal variation in vertebrate diets using naturally occurring stable isotopes. Oeco logia 144:647 658 Davenport J, Balazs G (1991) 'Fiery bodies' are pyrosomas an important component of the diet of leatherback turtles? British Herpetological Society Bulletin 37:33 38

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64 DEP F (2008) St. Joseph Bay Aquatic Preserve Management Plan Septemb er, 2008 August, 2018. Accessed 19 June. http://www.dep.state.fl.us/coastal/sites/stjoseph/publications.htm Dubischar CD, Pakhomov EA, von Harbou L, Hunt BPV, Bathmann UV (2012) Salps in the Lazarev Sea, Southern Ocean: II. Biochemical composition and potential prey value. Marine Biology 159:15 24 Ferreira MM (1968) On the feeding habits of the green turtle Chelonia mydas along the coast of the state of Ceara. Arquivos da Estacao de Biologia Marinha da Universidade do Ceara 8:83 86 Foley AM, Singel KE, Dutton PH, Summers TM, Redlow AE, Lessma n n J (2007) Characteristics of a green turtle ( Chelonia mydas ) assemblage in northwestern Florida determined during a hypothermic stu nning event. Gulf of Mexico Science 25:131 143 Frazier J (1971) Observations on sea turtles at Aldabra Atoll. Philosophical Transactions of the Royal Society of London Series B Biological Sciences 260:373 410 Fritts TH (1981) Pelagic feeding habits of tu rtles in the eastern Pacific. Marine Turtle Newsletter:4 5 Fuentes MMPB, Lawler IR, Gyuris E (2006) Dietary preferences of juvenile green turtles ( Chelonia mydas ) on a tropical reef flat. Wildlife Research 33:671 678 Garnett S, Price I, Scott F (1985) Th e diet of the green turtle, Chelonia mydas (L.), i n Torres Strait. Wildlife Research 12:103 112 Gilbert EI (2005) Juvenile green turtle ( Chelonia mydas ) foraging ecology: feeding selectivity and forage nutrient analysis. MS thesis, University of Central F lorida, Orlando, FL Graham WM (2001) Numerical increases and distributional shifts of Chrysaora quinquecirrha (Desor) and Aurelia aurita (Linne) (Cnidaria : Scyphozoa) in the northern Gulf of Mexico. Hydrobiologia 451:97 111 Guebert Bartholo FM, Barletta M, Costa MF, Monteiro Filho ELA (2011) Using gut contents to assess foraging patterns of juvenile green turtles Chelonia mydas in the Paranagu Estuary, Brazil. Endangered Species Research 13:131 143 Hatase H, Sato K, Yamaguchi M, Takahashi K, Tsukamoto K (2006) Individual variation in feeding habitat use by adult female green sea turtles ( Chelonia mydas ): are they obligately neritic herbivores? Oecologia 149:52 64

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65 Hays Brown C, Brown WM (1982) Status of sea turtles in the southeastern Pacific: emphasis on Peru. In: Bjorndal KA (ed) Biology and conservation of sea turtles. Smithsonian Institution Press, Washington, DC Hobson KA, Clark RG (1992) Assessing avian diets using stable isotopes .1. Turnover of C13 in tissues. Condor 94:181 188 Hyslop EJ (1980) Stomach contents analysis a review of methods and their application. Journal of Fish Biology 17:411 429 JMP (1989 2010) In. SAS Institute Inc., Cary, NC Lebrato M, Jones DOB (2009) Mass deposition event of P yrosoma atlanticum carcasses off Ivory Coast (West Africa). Limnology and Oceanography 54:1197 1209 Lemons G, Lewison R, Komoroske L, Gaos A, Lai C T, Dutton P, Eguchi T, LeRoux R, Seminoff JA (2011) Trophic ecology of green sea turtles in a highly urbanized bay: Insights from stable isotopes and m ixing models. Journal of Experimental Marine Biology and Ecology 405:25 32 Leonard CL, McClintock JB (1999) The population dynamics of the brittlestar Ophioderma brevispinum in near and farshore seagrass habitats of Port Saint Joseph Bay, Florida. Gulf o f Mexico Science 17:87 94 Lessman n JM (2002) Analysis of Chelonia mydas gut conten t from Florida's Panhandle. Eckerd College St. Petersburg, Florida Lpez Mendilaharsu M, Gardner SC, Riosmena Rodriguez R, Seminoff JA (2008) Diet selection by immature gr een turtles ( Chelonia mydas ) at Baha Magdalena foraging ground in the Pacific Coast of the Baja California Peninsula, Mxico. Journal of the Marine Biological Association of the UK 88 Mansfield KL New insights to the in water behavior and movements of oc eanic stage neonate sea turtles. In. Proc International Sea Turtle Symposium McMichael E (2005) Ecology of juvenile green turtles, Chelonia mydas at a temperate foraging area in the northeastern Gulf of Mexico. MS thesis, University of Florida, Gainesvil le, Florida Mendona MT (1983) Movements and feeding ecology of immature green turtles ( Chelonia mydas ) in a Florida Lagoon. Copeia 1983:1013 1023 Mendonca MT, Ehrhart LM (1982) Activity, population size and structure of immature Chelonia mydas and Caretta caretta in Mosquito Lagoon, Florida. Copeia 1982 :161 167

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66 Meylan AB (1995) Sea turtle migration: Evidence from tag returns. In: Bjorndal KA (ed) Biology and conservation of sea turtles. Smithsonian Institution Press, Washington, DC Morreale SJ, Mey lan AB, Sadove SS, Standora EA (1992) Annual occurrence and winter mortality of marine turtles in New York waters. Journal of Herpetology 26:301 308 Mortimer JA (1976) Observations on the feeding ecology of the green turtle, Chelonia mydas in the western Caribbean. MS thesis, University of Florida, Gainesville, FL Mortimer JA (1981) The feeding ecology of the west Caribbean green turtle ( Chelonia mydas ) in Nicaragua. Biotropica 13:49 58 Mortimer JA (1982) Feeding ecology of sea turtles. In: Bjorndal KA (ed) Biology and conservation of sea turtles. Smithsonian Institution Press, Washington, DC Nagaoka SM, Martins AS, Santos RG, Tognella MMP, Oliveira Filho EC, Seminoff JA (2012) Diet of juvenile green turtles ( Chelonia mydas ) associating with artisanal f ishing traps in a subtropical estuary in Brazil. Marine Biology 159:573 581 Parker DM, Dutton PH, Balazs GH (2011) Oceanic diet and distribution of haplotypes for the green turtle, Chelonia mydas in the central north Pacific. Pacific Science 65:419 431 P hillips DL, Gregg JW (2003) Source partitioning using stable isotopes: coping with too many sources. Oecologia 136:261 269 Read MA, Limpus CJ (2002) The green turtle, Chelonia mydas in Queensland: Feeding ecology of immature turtles in Moreton Bay, south eastern Queensland. Memoirs of the Queensland Museum 48:207 214 Reich KJ, Bjorndal KA, Bolten AB (2007) The 'lost years' of green turtles: using stable isotopes to study cryptic lifestages. Biology letters 3:712 714 Ross JP (1985) Biology of the green tu rtle, Chelonia mydas on an Arabian feeding ground. Journal of Herpetology 19:459 468 Schwartz FJ (1978) Behavioral and tolerance responses to cold water temperatures by three species of sea turtles (Reptilia, Cheloniidae) in North Carolina. Florida Marin e Research Publications 33:16 18 Seminoff JA, Resendiz A, Nichols WJ (2002) Diet of East Pacific green turtles ( Chelonia mydas ) in the central Gulf of California, Mxico. Journal of Herpetology 36:447 453

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67 Stewart RA, Gorsline DS (1962) Recent sedimentary history of St. Joseph Bay, Florida. Sedimentology 1:256 286 Ultsch GR (2006) The ecology of overwintering among turtles: where turtles overwinter and its consequences. Biological Reviews 81:339 367 Witherington BE, Ehrhart LM (1989) Hypothermic stunning and mortality of marine turtles in the Indian River Lagoon system, Florida. Copeia 1989:696 703

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68 BIOGRAPHICAL SKETCH Natalie Christine Willi ams was born in 1985 in Milan, Tennessee and lived with her parents, James and Lynn Williams, in Jackson, Tennes see until entering college. She Jackson for high school. At the age of seven, her mother and godmother introduced her to their love of sea turtles by sending her on he r first nesting turtle patrol in Charleston, South Carolina. After that, she knew she would study sea turtles and go to school in Charleston. Upon grad uating high school she studied b iology and Spanish at the College of Charleston in Charleston, South Caro lina. She received her Bachelor of Science degree in 2007 with honors. During 2008 she moved to Gainesville, Florida to work with Dr. Jane Brockmann studying mating behavior in horseshoe crabs. In 2009 she entered the University of Florida Department of W ildlife Ecology and Conservation ecology in green sea turtles. Upon completion she will spend a year working in the field and traveling to gain experience with new species an d habitats. She will then continue her studies in habitat selection and foraging ecology in a PhD program. She hopes to continue her work in wildlife ecology and conservation and enjoy each day of life.