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Stacy NI, Smith R, Sullivan KE, Nelson Jr SE, Nolan EC, De Voe RS, Witherington BE, Perrault JR. Health assessment of nesting loggerhead sea turtles ( Caretta caretta) in one of their largest rookeries (central eastern Florida coast, USA). CONSERVATION PHYSIOLOGY 2024; 12:coae064. [PMID: 39309467 PMCID: PMC11415931 DOI: 10.1093/conphys/coae064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/25/2024] [Revised: 08/15/2024] [Accepted: 08/27/2024] [Indexed: 09/25/2024]
Abstract
Reproduction is a physiologically demanding process for sea turtles. Health indicators, including morphometric indices and blood analytes, provide insight into overall health, physiology and organ function for breeding sea turtles as a way to assess population-level effects. The Archie Carr National Wildlife Refuge (ACNWR) on Florida's central eastern coast is critical nesting habitat for loggerhead sea turtles (Caretta caretta), but health variables from this location have not been documented. Objectives of the study were to (1) assess morphometrics and blood analyte data (including haematology, plasma biochemistry, protein electrophoresis, β-hydroxybutyrate, trace nutrients, vitamins and fatty acid profiles) from loggerheads nesting on or near the beaches of the ACNWR, (2) investigate correlations of body condition index (BCI) with blood analytes and (3) analyse temporal trends in morphometric and blood analyte data throughout the nesting season. Morphometric and/or blood analyte data are reported for 57 nesting loggerheads encountered between 2016 and 2019. Plasma copper and iron positively correlated with BCI. Mass tended to decline across nesting season, whereas BCI did not. Many blood analytes significantly increased or decreased across nesting season, reflecting the catabolic state and haemodynamic variations of nesting turtles. Twenty-three of 34 fatty acids declined across nesting season, which demonstrates the physiological demands of nesting turtles for vitellogenesis and reproductive activities, thus suggesting potential utility of fatty acids for the assessment of foraging status and phases of reproduction. The findings herein are relevant for future spatiotemporal and interspecies comparisons, investigating stressor effects and understanding the physiological demands in nesting sea turtles. This information provides comparative data for individual animals in rescue or managed care settings and for assessment of conservation strategies.
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Affiliation(s)
- Nicole I Stacy
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, 2015 SW 16TH AVE, Gainesville, FL 32610, USA
- Disney’s Animals, Science and Environment, 1200 N Savannah Circle, Disney's Animal Kingdom, Lake Buena Vista, FL 32830, USA
| | - Rachel Smith
- Disney’s Animals, Science and Environment, 1200 N Savannah Circle, Disney's Animal Kingdom, Lake Buena Vista, FL 32830, USA
| | - Kathleen E Sullivan
- Disney’s Animals, Science and Environment, 1200 N Savannah Circle, Disney's Animal Kingdom, Lake Buena Vista, FL 32830, USA
| | - Steven E Nelson Jr
- Disney’s Animals, Science and Environment, 1200 N Savannah Circle, Disney's Animal Kingdom, Lake Buena Vista, FL 32830, USA
| | - Elizabeth C Nolan
- Disney’s Animals, Science and Environment, 1200 N Savannah Circle, Disney's Animal Kingdom, Lake Buena Vista, FL 32830, USA
| | - Ryan S De Voe
- Disney’s Animals, Science and Environment, 1200 N Savannah Circle, Disney's Animal Kingdom, Lake Buena Vista, FL 32830, USA
| | - Blair E Witherington
- Disney’s Animals, Science and Environment, 1200 N Savannah Circle, Disney's Animal Kingdom, Lake Buena Vista, FL 32830, USA
- Inwater Research Group, Inc., 4160 NE Hyline Dr, Jensen Beach, FL 34957, USA
| | - Justin R Perrault
- Loggerhead Marinelife Center, 14200 US Highway 1, Juno Beach, FL 33408, USA
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2
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Silver-Gorges I, Ceriani SA, Fuentes MMPB. Fine-scale intraspecific niche partitioning in a highly mobile, marine megafauna species: implications for ecology and conservation. ROYAL SOCIETY OPEN SCIENCE 2023; 10:221529. [PMID: 37388320 PMCID: PMC10300683 DOI: 10.1098/rsos.221529] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 06/09/2023] [Indexed: 07/01/2023]
Abstract
A species may partition its realized ecological niche along bionomic and scenopoetic axes due to intraspecific competition for limited resources. How partitioning manifests depends on resource needs and availability by and for the partitioning groups. Here we demonstrate the utility of analysing short- and long-term stable carbon and nitrogen isotope ratios from imperiled marine megafauna to characterize realized niche partitioning in these species. We captured 113 loggerhead sea turtles (Caretta caretta) at a high-use area in the eastern Big Bend, Florida, between 2016 and 2022, comprising 53 subadults, 10 adult males and 50 adult females. We calculated trophic niche metrics using established and novel methods, and constructed Bayesian ellipses and hulls, to characterize loggerhead isotopic niches. These analyses indicated that loggerheads partition their realized ecological niche by lifestage, potentially along both bionomic (e.g. trophic) and/or scenopoetic (e.g. habitat, latitude or longitude) axes, and display different characteristics of resource use within their niches. Analysis of stable isotopes from tissues with different turnover rates enabled this first characterization of intraspecific niche partitioning between and within neritic lifestages in loggerhead turtles, which has direct implications for ongoing research and conservation efforts for this and other imperiled marine species.
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Affiliation(s)
- Ian Silver-Gorges
- Department of Earth, Ocean, and Atmospheric Science, Florida State University, Tallahassee, FL 32304, USA
| | - Simona A. Ceriani
- Fish and Wildlife Research Institute, Florida Fish and Wildlife Conservation Commission, St. Petersburg, FL 33701, USA
| | - Mariana M. P. B. Fuentes
- Department of Earth, Ocean, and Atmospheric Science, Florida State University, Tallahassee, FL 32304, USA
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3
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The secret life of baby turtles: A novel system to predict hatchling emergence, detect infertile nests, and remotely monitor sea turtle nest events. PLoS One 2022; 17:e0275088. [PMID: 36288397 PMCID: PMC9605334 DOI: 10.1371/journal.pone.0275088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 09/09/2022] [Indexed: 11/19/2022] Open
Abstract
Current understanding of sea turtle nesting, hatching, and emergence events has been largely limited to observable events on the surface of the sand, though recent approaches using audio or visual equipment have allowed scientists to better understand some underground nest phenomena. We used a technology-based approach to define motion-related Caretta caretta hatching and emergence nest events. We describe a novel low-cost, accelerometer-based system called TurtleSense that can detect movement and temperature within sea turtle nests remotely. TurtleSense is successfully able to specifically detect motion within sea turtle nests over the entire course of incubation. This system allows for the identification of infertile nests and the detection of four predictable sequential developmental activity patterns in viable nests, including a hatch and posthatch period, the timing of which can be used to tightly predict hatchling emergence events almost to the day. TurtleSense provides a much better understanding about what is happening in the nest before emergence and allows for the generation of a theory of the mechanism that triggers mass emergence. Our results suggest that motion plays a large role in hatchling communication and that the timing of emergence events may be related to the cessation of movement within the nest. Current management of sea turtle nesting events is primarily driven by counting the number of days since the nest was laid, with further safeguards placed at the nest upon subsequent visual observation of depression or emergence events. Use of TurtleSense technology can impact nest management and conservation efforts, allowing organizations to use this motion data to more tightly predict emergence dates for sea turtle hatchlings and to use viability data to inform nest management decisions.
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4
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Historical Records of Loggerhead Sea Turtle (Caretta caretta) Nesting at Tortuguero, Costa Rica. J HERPETOL 2022. [DOI: 10.1670/21-071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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5
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Maurer AS, Dawson C, Bjorkland R, Donaldson A, Stapleton SP, Richardson JI, Parker DM, Balazs GH, Schroeder BA. Satellite Telemetry Elucidates Migratory Pathways and Foraging Areas for Hawksbill Sea Turtles, Eretmochelys imbricata, in the Caribbean. CARIBB J SCI 2022. [DOI: 10.18475/cjos.v52i1.a10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Andrew S. Maurer
- NOAA, National Marine Fisheries Service, Southwest Fisheries Science Center, La Jolla, California, U.S.A.; ORCID ID: 0000-0002-7602-2295
| | - Clara Dawson
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, U.S.A
| | - Rhema Bjorkland
- Department of Environmental Science and Policy, George Mason University, Fairfax, Virginia, U.S.A
| | | | | | | | | | | | - Barbara A. Schroeder
- NOAA, National Marine Fisheries Service, Office of Protected Resources, Silver Spring, Maryland, U.S.A
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6
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Hatch JM, Haas HL, Sasso CR, Patel SH, Smolowitz RJ. Estimating the complex patterns of survey availability for loggerhead turtles. J Wildl Manage 2022. [DOI: 10.1002/jwmg.22208] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Joshua M. Hatch
- NOAA National Marine Fisheries Service, NEFSC Woods Hole 02543 MA USA
| | - Heather L. Haas
- NOAA National Marine Fisheries Service, NEFSC Woods Hole 02543 MA USA
| | | | - Samir H. Patel
- Coonamessett Farm Foundation, 277 Hatchville Road East Falmouth 02536 MA USA
| | - Ronald J. Smolowitz
- Coonamessett Farm Foundation, 277 Hatchville Road East Falmouth 02536 MA USA
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7
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Kot CY, Åkesson S, Alfaro‐Shigueto J, Amorocho Llanos DF, Antonopoulou M, Balazs GH, Baverstock WR, Blumenthal JM, Broderick AC, Bruno I, Canbolat AF, Casale P, Cejudo D, Coyne MS, Curtice C, DeLand S, DiMatteo A, Dodge K, Dunn DC, Esteban N, Formia A, Fuentes MMPB, Fujioka E, Garnier J, Godfrey MH, Godley BJ, González Carman V, Harrison A, Hart CE, Hawkes LA, Hays GC, Hill N, Hochscheid S, Kaska Y, Levy Y, Ley‐Quiñónez CP, Lockhart GG, López‐Mendilaharsu M, Luschi P, Mangel JC, Margaritoulis D, Maxwell SM, McClellan CM, Metcalfe K, Mingozzi A, Moncada FG, Nichols WJ, Parker DM, Patel SH, Pilcher NJ, Poulin S, Read AJ, Rees ALF, Robinson DP, Robinson NJ, Sandoval‐Lugo AG, Schofield G, Seminoff JA, Seney EE, Snape RTE, Sözbilen D, Tomás J, Varo‐Cruz N, Wallace BP, Wildermann NE, Witt MJ, Zavala‐Norzagaray AA, Halpin PN. Network analysis of sea turtle movements and connectivity: A tool for conservation prioritization. DIVERS DISTRIB 2022. [DOI: 10.1111/ddi.13485] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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8
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Martínez-Estévez L, Steller DL, Zilliacus KM, Cuevas Amador JP, Amador FC, Szuta D, Miller SD, Dayton GH, Tershy BR, Croll DA. Foraging ecology of critically endangered Eastern Pacific hawksbill sea turtles (Eretmochelys imbricata) in the Gulf of California, Mexico. MARINE ENVIRONMENTAL RESEARCH 2022; 174:105532. [PMID: 35032818 DOI: 10.1016/j.marenvres.2021.105532] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 11/14/2021] [Accepted: 11/21/2021] [Indexed: 06/14/2023]
Abstract
The Eastern Pacific hawksbill sea turtle population is one of the most endangered of all sea turtle species. Here, we examine the foraging ecology of 47 hawksbill turtles (40.5-90.3 cm CCL, mean = 54.1 ± 10.1 cm) around Isla San José, Gulf of California, Mexico by integrating information from passive acoustic telemetry, behavior recordings, fecal analysis, and habitat surveys. Tagged hawkbill turtles exhibited high site fidelity over months and years (tracking duration 1-1490 days, mean = 255 ± 373 days) to the location and benthic habitat where individuals were initially caught. Diet was dominated by benthic invertebrates and algae including sponges, algae, tunicates, and mangrove roots. The mean percent cover of these benthic food items was significantly greater in the mangrove estuary than in adjacent rocky and sandy reef habitats. The Isla San José foraging ground is a high-use area for hawksbills and should be granted national protection status.
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Affiliation(s)
- Lourdes Martínez-Estévez
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, 95050, USA.
| | - Diana L Steller
- Moss Landing Marine Laboratories, Moss Landing, CA, 95039, USA
| | - Kelly M Zilliacus
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, 95050, USA
| | | | | | - Dorota Szuta
- Moss Landing Marine Laboratories, Moss Landing, CA, 95039, USA
| | - Scott D Miller
- Department of Biological Sciences, Florida State University, Tallahassee, FL, 32306, USA
| | - Gage H Dayton
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, 95050, USA
| | - Bernie R Tershy
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, 95050, USA
| | - Donald A Croll
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, 95050, USA
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9
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Martins S, Cardona L, Abella E, Silva E, Loureiro N, Roast M, Marco A. Effect of body size on the long-term reproductive output of East Atlantic loggerhead turtles Caretta caretta. ENDANGER SPECIES RES 2022. [DOI: 10.3354/esr01198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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10
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Ataman A, Gainsbury AM, Manire CA, Hoffmann SL, Page-Karjian A, Hirsch SE, Polyak MMR, Cassill DL, Aoki DM, Fraser KM, Klingshirn S, Stoll JA, Perrault JR. Evaluating prevalence of external injuries on nesting loggerhead sea turtles Caretta caretta in southeastern Florida, USA. ENDANGER SPECIES RES 2021. [DOI: 10.3354/esr01149] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Sea turtles face both anthropogenic and natural threats including boat strikes, fisheries, pollution, and predator attacks. Injuries from anthropogenic sources are more common than naturally caused injuries. The goal of this study was to determine prevalence and cause (e.g. boat strike, entanglement, hook, shark bite) of injuries on nesting loggerhead sea turtles Caretta caretta on Juno and Jupiter beaches, Florida, USA. During the 2019 and 2020 nesting seasons, 450 loggerhead females were examined for external injuries. Injuries were categorized by anatomic location, condition, and cause. We found that 24% of loggerheads had at least 1 injury. Of the 111 injuries found on 107 nesting females, 88% were healed, 9% were partially healed with some scarred tissue, and 3% were fresh injuries. Most injuries (55%) were lateral injuries on the carapace or appendages. We were able to attribute 60 injuries to a specific cause. Boat strikes accounted for 75% of the 60 injuries, shark bites accounted for 15%, fishing hooks accounted for 7%, and entanglements accounted for the remaining 3%. This study provides new insight into the prevalence of anthropogenic injuries relative to natural injuries in loggerhead sea turtles nesting in the most densely nested beach in the Western Hemisphere and can be used to improve conservation management plans through implementation of fishing and/or boating restrictions in the nesting and foraging areas most commonly frequented by sea turtles.
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Affiliation(s)
- A Ataman
- Department of Integrative Biology, University of South Florida St. Petersburg, St. Petersburg, Florida 33701, USA
| | - AM Gainsbury
- Department of Integrative Biology, University of South Florida St. Petersburg, St. Petersburg, Florida 33701, USA
| | - CA Manire
- Loggerhead Marinelife Center, Juno Beach, Florida 33408, USA
| | - SL Hoffmann
- Applied Biological Services, Biomark Inc., Boise, Idaho 83702, USA
| | - A Page-Karjian
- Florida Atlantic University, Harbor Branch Oceanographic Institute, Fort Pierce, Florida 34946, USA
| | - SE Hirsch
- Loggerhead Marinelife Center, Juno Beach, Florida 33408, USA
| | - MMR Polyak
- Loggerhead Marinelife Center, Juno Beach, Florida 33408, USA
| | - DL Cassill
- Department of Integrative Biology, University of South Florida St. Petersburg, St. Petersburg, Florida 33701, USA
| | - DM Aoki
- Loggerhead Marinelife Center, Juno Beach, Florida 33408, USA
- Florida Atlantic University, Harbor Branch Oceanographic Institute, Fort Pierce, Florida 34946, USA
| | - KM Fraser
- Loggerhead Marinelife Center, Juno Beach, Florida 33408, USA
| | - S Klingshirn
- Loggerhead Marinelife Center, Juno Beach, Florida 33408, USA
- Florida Atlantic University, Harbor Branch Oceanographic Institute, Fort Pierce, Florida 34946, USA
| | - JA Stoll
- Department of Environmental Conservation, University of Massachusetts, Amherst, Massachusetts 01003, USA
| | - JR Perrault
- Loggerhead Marinelife Center, Juno Beach, Florida 33408, USA
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11
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Silver-Gorges I, Ingels J, dos Santos GAP, Valdes Y, Pontes LP, Silva AC, Neres PF, Shantharam A, Perry D, Richterkessing A, Sanchez-Zarate S, Acevedo L, Gillis AJ, Ceriani SA, Fuentes MMPB. Epibionts Reflect Spatial and Foraging Ecology of Gulf of Mexico Loggerhead Turtles (Caretta caretta). Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.696412] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Sea turtles are exposed to numerous threats during migrations to their foraging grounds and at those locations. Therefore, information on sea turtle foraging and spatial ecology can guide conservation initiatives, yet it is difficult to directly observe migrating or foraging turtles. To gain insights into the foraging and spatial ecology of turtles, studies have increasingly analyzed epibionts of nesting turtles, as epibionts must overlap spatially and ecologically with their hosts to colonize successfully. Epibiont analysis may be integrated with stable isotope information to identify taxa that can serve as indicators of sea turtle foraging and spatial ecology, but few studies have pursued this. To determine if epibionts can serve as indicators of foraging and spatial ecology of loggerhead turtles nesting in the northern Gulf of Mexico we combined turtle stable isotope and taxonomic epibiont analysis. We sampled 22 individual turtles and identified over 120,000 epibiont individuals, belonging to 34 macrofauna taxa (>1 mm) and 22 meiofauna taxa (63 μm–1 mm), including 111 nematode genera. We quantified epidermis δ13C and δ15N, and used these to assign loggerhead turtles to broad foraging regions. The abundance and presence of macrofauna and nematodes did not differ between inferred foraging regions, but the presence of select meiofauna taxa differentiated between three inferred foraging regions. Further, dissimilarities in macrofauna, meiofauna, and nematode assemblages corresponded to dissimilarities in individual stable isotope values within inferred foraging regions. This suggests that certain epibiont taxa may be indicative of foraging regions used by loggerhead turtles in the Gulf of Mexico, and of individual turtle foraging and habitat use specialization within foraging regions. Continued sampling of epibionts at nesting beaches and foraging grounds in the Gulf of Mexico and globally, coupled with satellite telemetry and/or dietary studies, can expand upon our findings to develop epibionts as efficient indicators of sea turtle foraging and spatial ecology.
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12
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Edmunds PJ. Recruitment hotspots and bottlenecks mediate the distribution of corals on a Caribbean reef. Biol Lett 2021; 17:20210149. [PMID: 34256581 PMCID: PMC8278041 DOI: 10.1098/rsbl.2021.0149] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 06/21/2021] [Indexed: 12/21/2022] Open
Abstract
Recruitment hotspots are locations where organisms are added to populations at high rates. On tropical reefs where coral abundance has declined, recruitment hotspots are important because they have the potential to promote population recovery. Around St. John, US Virgin Islands, coral recruitment at five sites revealed a hotspot that has persistent for 14 years. Recruitment created a hotspot in density of juvenile corals that was 600 m southeast of the recruitment hotspot. Neither hotspot led to increased coral cover, thus revealing the stringency of the demographic bottleneck impeding progression of recruits to adult sizes and preventing population growth. Recruitment hotspots in low-density coral populations are valuable targets for conservation and sources of corals for restoration.
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Affiliation(s)
- Peter J. Edmunds
- Department of Biology, California State University, 18111 Nordhoff Street, Northridge, CA 91330-8303, USA
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13
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O'Connell D, Kehl CE, Taylor BK, Piacenza J, Piacenza S, Faller Ii KJ. A computational framework for studying energetics and resource management in sea turtle migration and autonomous systems. J Theor Biol 2021; 527:110815. [PMID: 34166710 DOI: 10.1016/j.jtbi.2021.110815] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 06/10/2021] [Accepted: 06/15/2021] [Indexed: 11/18/2022]
Abstract
Sea turtles complete migrations across vast distances, covering entire ocean basins. To track these migrations, satellite tracking tags are attached to their shells. The impact of these tags must be considered to ensure that turtles' natural behavior is not artificially and adversely impacted through tag-related drag, and that the data collected by a small sample of sea turtles accurately represents the larger population. Additionally, it can be difficult to study animal energetics in the field over large migration distances. In this work, we modify a computational behavior model to study how satellite tracking tags affect turtle migration behavior. Our agent based model contains synthetic magnetic field environments that are used for navigation cues, an ocean current, resource distributions that represent locations of food, and an agent that attempts to migrate to several different goals. The agent loses energy as it progresses, and searches for the resource distributions to replenish itself. Our novel simulation framework demonstrates the relationship between an agent's available energy capacity, its energy consumption based on mechanical power expended, and its ability to navigate to all migratory goal points. This study can be utilized to (1) probe the impacts of an animal's energy capacity and foraging behavior on its resulting navigation and ecology, (2) guide future satellite tag designs, and (3) develop usage recommendations for a suitable tracking tag based on the type of experiment being conducted. Our model can be expanded beyond sea turtles to study other marine species (e.g., sharks, whales). Additionally, this model could be expanded to other domains within the marine environment. For example, it could be modified to examine design trade-offs in remotely operated vehicles (ROVs), which share many of the same operational constraints as sea turtles and other migratory species.
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Affiliation(s)
- Delaney O'Connell
- Department of Biology, The University of North Carolina, Chapel Hill, United States.
| | - Catherine E Kehl
- Department of Biology, The University of North Carolina, Chapel Hill, United States.
| | - Brian K Taylor
- Department of Biology, The University of North Carolina, Chapel Hill, United States
| | - Joseph Piacenza
- Department of Mechanical Engineering, The University of West Florida, United States.
| | - Susan Piacenza
- Department of Biology, The University of West Florida, United States.
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14
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Patel SH, Winton MV, Hatch JM, Haas HL, Saba VS, Fay G, Smolowitz RJ. Projected shifts in loggerhead sea turtle thermal habitat in the Northwest Atlantic Ocean due to climate change. Sci Rep 2021; 11:8850. [PMID: 33893380 PMCID: PMC8065110 DOI: 10.1038/s41598-021-88290-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Accepted: 03/31/2021] [Indexed: 11/24/2022] Open
Abstract
It is well established that sea turtles are vulnerable to atmospheric and oceanographic shifts associated with climate change. However, few studies have formally projected how their seasonal marine habitat may shift in response to warming ocean temperatures. Here we used a high-resolution global climate model and a large satellite tagging dataset to project changes in the future distribution of suitable thermal habitat for loggerheads along the northeastern continental shelf of the United States. Between 2009 and 2018, we deployed 196 satellite tags on loggerheads within the Middle Atlantic Bight (MAB) of the Northwest Atlantic continental shelf region, a seasonal foraging area. Tag location data combined with depth and remotely sensed sea surface temperature (SST) were used to characterize the species’ current thermal range in the MAB. The best-fitting model indicated that the habitat envelope for tagged loggerheads consisted of SST ranging from 11.0° to 29.7 °C and depths between 0 and 105.0 m. The calculated core bathythermal range consisted of SSTs between 15.0° and 28.0 °C and depths between 8.0 and 92.0 m, with the highest probability of presence occurred in regions with SST between 17.7° and 25.3 °C and at depths between 26.1 and 74.2 m. This model was then forced by a high-resolution global climate model under a doubling of atmospheric CO2 to project loggerhead probability of presence over the next 80 years. Our results suggest that loggerhead thermal habitat and seasonal duration will likely increase in northern regions of the NW Atlantic shelf. This change in spatiotemporal range for sea turtles in a region of high anthropogenic use may prompt adjustments to the localized protected species conservation measures.
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Affiliation(s)
- Samir H Patel
- Coonamessett Farm Foundation, 277 Hatchville Road, East Falmouth, MA, 02536, USA.
| | - Megan V Winton
- School for Marine Science and Technology, University of Massachusetts Dartmouth, 836 S Rodney French Blvd, New Bedford, MA, 02744, USA.,Atlantic White Shark Conservancy, 235 Orleans Road, North Chatham, MA, 02650, USA
| | - Joshua M Hatch
- Northeast Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 166 Water Street, Woods Hole, MA, 02543, USA
| | - Heather L Haas
- Northeast Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 166 Water Street, Woods Hole, MA, 02543, USA
| | - Vincent S Saba
- Geophysical Fluid Dynamics Laboratory, Northeast Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Princeton University Forrestal Campus, 201 Forrestal Road, Princeton, NJ, 08544, USA
| | - Gavin Fay
- School for Marine Science and Technology, University of Massachusetts Dartmouth, 836 S Rodney French Blvd, New Bedford, MA, 02744, USA
| | - Ronald J Smolowitz
- Coonamessett Farm Foundation, 277 Hatchville Road, East Falmouth, MA, 02536, USA
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15
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Meiofauna Life on Loggerhead Sea Turtles-Diversely Structured Abundance and Biodiversity Hotspots That Challenge the Meiofauna Paradox. DIVERSITY 2020. [DOI: 10.3390/d12050203] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Sea turtles migrate thousands of miles annually between foraging and breeding areas, carrying dozens of epibiont species with them on their journeys. Most sea turtle epibiont studies have focused on large-sized organisms, those visible to the naked eye. Here, we report previously undocumented levels of epibiont abundance and biodiversity for loggerhead sea turtles (Caretta caretta), by focusing on the microscopic meiofauna. During the peak of the 2018 loggerhead nesting season at St. George Island, Florida, USA, we sampled all epibionts from 24 carapaces. From the subsamples, we identified 38,874 meiofauna individuals belonging to 20 higher taxa. This means 810,753 individuals were recovered in our survey, with an average of 33,781 individuals per carapace. Of 6992 identified nematodes, 111 different genera were observed. To our knowledge, such levels of sea turtle epibiont abundance and diversity have never been recorded. Loggerhead carapaces are without doubt hotspots of meiofaunal and nematode diversity, especially compared to other non-sedimentary substrates. The posterior carapace sections harbored higher diversity and evenness compared to the anterior and middle sections, suggesting increased colonization and potentially facilitation favoring posterior carapace epibiosis, or increased disturbance on the anterior and middle carapace sections. Our findings also shed new light on the meiofauna paradox: “How do small, benthic meiofauna organisms become cosmopolitan over large geographic ranges?” Considering high loggerhead epibiont colonization, the large distances loggerheads migrate for reproduction and feeding, and the evolutionary age and sheer numbers of sea turtles worldwide, potentially large-scale exchange and dispersal for meiofauna through phoresis is implied. We distinguished different groups of loggerhead carapaces based on divergent epibiont communities, suggesting distinct epibiont colonization processes. These epibiont observations hold potential for investigating loggerhead movements and, hence, their conservation.
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Identifying patterns in foraging-area origins in breeding aggregations of migratory species: Loggerhead turtles in the Northwest Atlantic. PLoS One 2020; 15:e0231325. [PMID: 32282844 PMCID: PMC7153900 DOI: 10.1371/journal.pone.0231325] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 03/20/2020] [Indexed: 11/20/2022] Open
Abstract
Population assessments conducted at reproductive sites of migratory species necessitate understanding the foraging-area origins of breeding individuals. Without this information, efforts to contextualize changes in breeding populations and develop effective management strategies are compromised. We used stable isotope analysis of tissue samples collected from loggerhead sea turtles (Caretta caretta) nesting at seven sites in the Northern Recovery Unit (NRU) of the eastern United States (North Carolina, South Carolina and Georgia) to assign females to three separate foraging areas in the Northwest Atlantic Ocean (NWA). We found that the majority of the females at NRU nesting sites (84.4%) use more northern foraging areas in the Mid-Atlantic Bight, while fewer females use more proximate foraging areas in the South Atlantic Bight (13.4%) and more southerly foraging areas in the Subtropical Northwest Atlantic (2.2%). We did not find significant latitudinal or temporal trends in the proportions of NRU females originating from different foraging areas. Combining these findings with previous data from stable isotope and satellite tracking studies across NWA nesting sites showed that variation in the proportion of adult loggerheads originating from different foraging areas is primarily related differences between recovery units: individuals in the NRU primarily use the Mid-Atlantic Bight foraging area, while individuals from the three Florida recovery units primarily use the Subtropical Northwest Atlantic and Eastern Gulf of Mexico foraging areas. Because each foraging area is associated with its own distinct ecological characteristics, environmental fluctuations and anthropogenic threats that affect the abundance and productivity of individuals at nesting sites, this information is critical for accurately evaluating population trends and developing effective region-specific management strategies.
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Casale P, Ceriani SA. Sea turtle populations are overestimated worldwide from remigration intervals: correction for bias. ENDANGER SPECIES RES 2020. [DOI: 10.3354/esr01019] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Haywood JC, Fuller WJ, Godley BJ, Margaritoulis D, Shutler JD, Snape RTE, Widdicombe S, Zbinden JA, Broderick AC. Spatial ecology of loggerhead turtles: Insights from stable isotope markers and satellite telemetry. DIVERS DISTRIB 2020. [DOI: 10.1111/ddi.13023] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Affiliation(s)
- Julia C. Haywood
- Marine Turtle Research Group Centre for Ecology and Conservation University of Exeter Cornwall UK
- Plymouth Marine Laboratory Plymouth UK
| | - Wayne J. Fuller
- Faculty of Veterinary Medicine Near East University North Cyprus
| | - Brendan J. Godley
- Marine Turtle Research Group Centre for Ecology and Conservation University of Exeter Cornwall UK
- Environment and Sustainability Institute University of Exeter Cornwall UK
| | | | - Jamie D. Shutler
- Centre for Geography and Environmental Science University of Exeter Cornwall UK
| | - Robin TE. Snape
- Marine Turtle Research Group Centre for Ecology and Conservation University of Exeter Cornwall UK
- Society for the Protection of Turtles North Cyprus
| | | | | | - Annette C. Broderick
- Marine Turtle Research Group Centre for Ecology and Conservation University of Exeter Cornwall UK
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Fleming KA, Perrault JR, Stacy NI, Coppenrath CM, Gainsbury AM. Heat, health and hatchlings: associations of in situ nest temperatures with morphological and physiological characteristics of loggerhead sea turtle hatchlings from Florida. CONSERVATION PHYSIOLOGY 2020; 8:coaa046. [PMID: 32523697 PMCID: PMC7269062 DOI: 10.1093/conphys/coaa046] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 03/05/2020] [Accepted: 05/06/2020] [Indexed: 05/20/2023]
Abstract
Incubation temperatures, in addition to an embryo's genetic makeup, are critical in many aspects of adequate sea turtle embryonic development. The effects of high and low incubation temperatures on hatchling quality have been previously examined; however, many of these studies were conducted on relocated or laboratory-reared nests, which do not accurately reflect natural nest temperature fluctuations. To observe the impacts of varying in situ incubation temperatures on loggerhead sea turtle (Caretta caretta) hatchling morphology, various health variables and locomotor performance, temperature data loggers were deployed in 15 loggerhead nests on Juno Beach, Florida, between May and July 2018. Over the course of the study period, 10 morphological traits were measured, blood analytes and heart rate were assessed for the establishment of reference intervals and the self-righting response in seawater was evaluated. Warmer months were associated with smaller body size and higher body condition index, larger umbilical scar size, slower righting time, lower heart rates and higher packed cell volume, hemoglobin, total solids, total white blood cell count, absolute heterophils and absolute basophils. These findings provide evidence that higher in situ incubation temperatures have the potential to adversely affect hatchlings from warmer nests due to increased risk of predation from smaller body sizes, decreased physical responses and overall fitness, altered hemodynamic balance (e.g. dehydration) and potential inflammation and/or stress. With rising temperatures, we predict sea turtle hatchlings may have increasing risks of developing suboptimal physiological features affecting overall fitness and ultimately survival. These results demonstrate that rising environmental temperatures can negatively impact sea turtle hatchlings, thus representing additional stress on sea turtle populations and contributing to our understanding of potential pathophysiological effects of climate change on the delicate life-stage class of the sea turtle hatchling. This information will be useful for formulating effective future sea turtle management plans.
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Affiliation(s)
- Kelsey A Fleming
- Department of Biological Sciences, University of South Florida St. Petersburg, St. Petersburg, FL 33701, USA
| | | | - Nicole I Stacy
- Aquatic, Amphibian, and Reptile Pathology Program, Department of Comparative, Diagnostic, and Population Medicine, College of Veterinary Medicine, University of Florida, Gainesville, FL 32608, USA
| | | | - Alison M Gainsbury
- Department of Biological Sciences, University of South Florida St. Petersburg, St. Petersburg, FL 33701, USA
- Corresponding author: Department of Biological Sciences, University of South Florida St. Petersburg, St. Petersburg, FL 33701, USA.
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Figgener C, Bernardo J, Plotkin PT. Beyond trophic morphology: stable isotopes reveal ubiquitous versatility in marine turtle trophic ecology. Biol Rev Camb Philos Soc 2019; 94:1947-1973. [PMID: 31338959 PMCID: PMC6899600 DOI: 10.1111/brv.12543] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 06/07/2019] [Accepted: 06/13/2019] [Indexed: 11/30/2022]
Abstract
The idea that interspecific variation in trophic morphology among closely related species effectively permits resource partitioning has driven research on ecological radiation since Darwin first described variation in beak morphology among Geospiza. Marine turtles comprise an ecological radiation in which interspecific differences in trophic morphology have similarly been implicated as a pathway to ecopartition the marine realm, in both extant and extinct species. Because marine turtles are charismatic flagship species of conservation concern, their trophic ecology has been studied intensively using stable isotope analyses to gain insights into habitat use and diet, principally to inform conservation management. This legion of studies provides an unparalleled opportunity to examine ecological partitioning across numerous hierarchical levels that heretofore has not been applied to any other ecological radiation. Our contribution aims to provide a quantitative analysis of interspecific variation and a comprehensive review of intraspecific variation in trophic ecology across different hierarchical levels marshalling insights about realised trophic ecology derived from stable isotopes. We reviewed 113 stable isotope studies, mostly involving single species, and conducted a meta-analysis of data from adults to elucidate differences in trophic ecology among species. Our study reveals a more intricate hierarchy of ecopartitioning by marine turtles than previously recognised based on trophic morphology and dietary analyses. We found strong statistical support for interspecific partitioning, as well as a continuum of intraspecific trophic sub-specialisation in most species across several hierarchical levels. This ubiquity of trophic specialisation across many hierarchical levels exposes a far more complex view of trophic ecology and resource-axis exploitation than suggested by species diversity alone. Not only do species segregate along many widely understood axes such as body size, macrohabitat, and trophic morphology but the general pattern revealed by isotopic studies is one of microhabitat segregation and variation in foraging behaviour within species, within populations, and among individuals. These findings are highly relevant to conservation management because they imply ecological non-exchangeability, which introduces a new dimension beyond that of genetic stocks which drives current conservation planning. Perhaps the most remarkable finding from our data synthesis is that four of six marine turtle species forage across several trophic levels. This pattern is unlike that seen in other large marine predators, which forage at a single trophic level according to stable isotopes. This finding affirms suggestions that marine turtles are robust sentinels of ocean health and likely stabilise marine food webs. This insight has broader significance for studies of marine food webs and trophic ecology of large marine predators. Beyond insights concerning marine turtle ecology and conservation, our findings also have broader implications for the study of ecological radiations. Particularly, the unrecognised complexity of ecopartitioning beyond that predicted by trophic morphology suggests that this dominant approach in adaptive radiation research likely underestimates the degree of resource overlap and that interspecific disparities in trophic morphology may often over-predict the degree of realised ecopartitioning. Hence, our findings suggest that stable isotopes can profitably be applied to study other ecological radiations and may reveal trophic variation beyond that reflected by trophic morphology.
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Affiliation(s)
- Christine Figgener
- Marine Biology Interdisciplinary ProgramTexas A&M University3258 TAMU, College StationTX77843U.S.A.
- Department of BiologyTexas A&M University3258 TAMU, College StationTX77843U.S.A.
- Department of OceanographyTexas A&M University3146 TAMU, College StationTX77843U.S.A.
| | - Joseph Bernardo
- Marine Biology Interdisciplinary ProgramTexas A&M University3258 TAMU, College StationTX77843U.S.A.
- Department of BiologyTexas A&M University3258 TAMU, College StationTX77843U.S.A.
- Program in Ecology and Evolutionary BiologyTexas A&M University2475 TAMU, College StationTX77843U.S.A.
| | - Pamela T. Plotkin
- Marine Biology Interdisciplinary ProgramTexas A&M University3258 TAMU, College StationTX77843U.S.A.
- Department of OceanographyTexas A&M University3146 TAMU, College StationTX77843U.S.A.
- Texas Sea Grant, Texas A&M University4115 TAMU, College StationTX77843U.S.A.
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Chabot RM, Ceriani SA, Seminoff JA, Mills KA, Mansfield KL. Characterizing stable isotope relationships between green turtle (Chelonia mydas) skin and unhatched eggs. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2019; 33:1277-1285. [PMID: 31034695 DOI: 10.1002/rcm.8467] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 02/28/2019] [Accepted: 04/15/2019] [Indexed: 06/09/2023]
Abstract
RATIONALE Stable isotope analysis is used to understand the foraging habits and movements of a diverse set of organisms. Variability in stable isotope ratios among tissues derived from the same animal makes it difficult to compare data among study results in which different tissue types are evaluated. Isotopic relationships between two green turtle (Chelonia mydas) tissue types, skin and unhatched egg contents are unknown. Similarly, few data exist to evaluate the influence of time elapsed after oviposition (as a proxy for decomposition) on isotopic variability among unhatched eggs within the same nest. METHODS Skin and unhatched egg contents were collected from 69 adult female green turtles and associated nests at the Archie Carr National Wildlife Refuge in Florida, USA. Values of δ13 C, δ15 N, and δ34 S were measured for both tissue types using a continuous flow isotope ratio mass spectrometer. Standardized major-axis (SMA) regression was used to generate conversion equations of carbon, nitrogen, and sulfur isotope ratios between the two tissue types. Model selection frameworks consisting of single-factor linear models were employed per isotope ratio to assess how egg time-in-nest affected intraclutch isotopic variability. RESULTS Conversion equations for all three isotope ratios indicated significant relationships between skin and unhatched egg values, although model fits were lower than found in some studies examining similar patterns in other marine turtle species. The probability of increased intraclutch variability was significantly higher among eggs collected at longer intervals after deposition. CONCLUSIONS This study reports the first-ever δ13 C and δ15 N conversion equations between skin and unhatched eggs for green turtles, and the first δ34 S conversion equation for any marine turtle species. SMA regression was used to directly convert tissue values bidirectionally, unlike equations generated using ordinary least-squares regression. Issues with increased intraclutch variability at later excavation dates highlight the importance of collecting unhatched eggs as soon as possible after hatchling emergence.
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Affiliation(s)
- Ryan M Chabot
- Marine Turtle Research Group, Department of Biological Sciences, University of Central Florida, Orlando, FL, USA
- Inwater Research Group, Inc., Jensen Beach, FL, USA
| | - Simona A Ceriani
- Marine Turtle Research Group, Department of Biological Sciences, University of Central Florida, Orlando, FL, USA
- Florida Fish and Wildlife Conservation Commission - Fish and Wildlife Research Institute, St. Petersburg, FL, USA
| | - Jeffrey A Seminoff
- National Oceanic and Atmospheric Administration - National Marine Fisheries Service, Southwest Fisheries Science Center, La Jolla, CA, USA
| | - Kali A Mills
- Marine Turtle Research Group, Department of Biological Sciences, University of Central Florida, Orlando, FL, USA
| | - Katherine L Mansfield
- Marine Turtle Research Group, Department of Biological Sciences, University of Central Florida, Orlando, FL, USA
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Pearson RM, van de Merwe JP, Gagan MK, Limpus CJ, Connolly RM. Distinguishing between sea turtle foraging areas using stable isotopes from commensal barnacle shells. Sci Rep 2019; 9:6565. [PMID: 31024029 PMCID: PMC6483986 DOI: 10.1038/s41598-019-42983-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 04/11/2019] [Indexed: 11/18/2022] Open
Abstract
Understanding the movement behaviour of marine megafauna within and between habitats is valuable for informing conservation management, particularly for threatened species. Stable isotope analyses of soft-tissues have been used to understand these parameters in sea turtles, usually relying on concurrent satellite telemetry at high cost. Barnacles that grow on sea turtles have been shown to offer a source of isotopic history that reflects the temperature and salinity of the water in which the host animal has been. We used a novel method that combines barnacle growth rates and stable isotope analysis of barnacle shells (δ18O and δ13C) as predictors of home area for foraging sea turtles. We showed high success rates in assigning turtles to foraging areas in Queensland, Australia, based on isotope ratios from the shells of the barnacles that were attached to them (86–94% when areas were separated by >400 km). This method could be used to understand foraging distribution, migration distances and the habitat use of nesting turtles throughout the world, benefiting conservation and management of these threatened species and may be applied to other taxa that carry hitchhiking barnacles through oceans or estuaries.
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Affiliation(s)
- Ryan M Pearson
- Australian Rivers Institute - Coasts & Estuaries, and School of Environment & Science, Griffith University, Gold Coast, Queensland, 4222, Australia.
| | - Jason P van de Merwe
- Australian Rivers Institute - Coasts & Estuaries, and School of Environment & Science, Griffith University, Gold Coast, Queensland, 4222, Australia
| | - Michael K Gagan
- Research School of Earth Sciences, Australian National University, Canberra, Australian Capital Territory, 2600, Australia.,School of Earth and Environmental Sciences, The University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Colin J Limpus
- Threatened Species Unit, Department of Environment and Science, Brisbane, Queensland, 4102, Australia
| | - Rod M Connolly
- Australian Rivers Institute - Coasts & Estuaries, and School of Environment & Science, Griffith University, Gold Coast, Queensland, 4222, Australia
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