1
|
Lima FD, Parra H, Alves RB, Santos MAR, Bjorndal KA, Bolten AB, Vandeperre F. Effects of gear modifications in a North Atlantic pelagic longline fishery: A multiyear study. PLoS One 2023; 18:e0292727. [PMID: 37856523 PMCID: PMC10586631 DOI: 10.1371/journal.pone.0292727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 09/27/2023] [Indexed: 10/21/2023] Open
Abstract
The threat of population declines caused by pelagic longline fisheries in the Atlantic has increased the concern to find strategies that minimize the bycatch and mortality of non-target marine animals. Gear modification, such as the use of circle hooks instead of conventional J-hooks, has been identified as an effective bycatch reduction strategy in different pelagic longline fisheries around the world. This study aimed to verify the effectiveness of the use of circle hooks by quantifying catch rates, relative size selectivity, and anatomical hooking position for the most common target species (swordfish, Xiphias gladius, and blue shark, Prionace glauca), and some bycatch species (loggerhead sea turtles, Caretta caretta, and shortfin mako, Isurus oxyrinchus) caught by the Azorean longline fishing fleet. The trial was conducted for five consecutive years (2000-2004) using eight different types of hooks. In general, the blue shark catches using circle hooks were significantly higher compared to J (Mustad 9/0). The circle hooks also showed high probabilities of catching juvenile blue sharks. Conversely, the circle hooks were efficient in reducing the loggerhead sea turtle bycatch and were related to fewer catches of small sea turtle individuals. The use of circle hooks was also associated with reduced swordfish catches compared to J (Mustad 9/0), and the effect of hook types on length at capture was only significant for Circle (L. & P. 18/0-CLP18) and Ringed Tuna (RT). No significant differences were observed comparing hook type to either catch rates or size selectivity for shortfin mako. Additionally, circle hooks were more likely to lodge in the mouth than in deeper anatomical positions, when compared to J (Mustad 9/0), for the four species analysed. The present study demonstrated that the use of circle hooks could mitigate the impact of the pelagic longline fisheries in the Azores by decreasing the bycatch of sea turtles and reducing animal injuries caused by deep hooking.
Collapse
Affiliation(s)
- Françoise D. Lima
- IMAR–Institute of Marine Research, Departamento de Oceanografia e Pescas, Universidade dos Açores, Horta, Portugal
- Institute of Marine Sciences—Okeanos,–Departamento de Oceanografia e Pescas, Universidade dos Açores, Horta, Portugal
| | - Hugo Parra
- IMAR–Institute of Marine Research, Departamento de Oceanografia e Pescas, Universidade dos Açores, Horta, Portugal
- Institute of Marine Sciences—Okeanos,–Departamento de Oceanografia e Pescas, Universidade dos Açores, Horta, Portugal
| | - Rita B. Alves
- ISPA—Instituto Universitário de Ciências Psicológicas, Sociais e da Vida, Lisboa, Portugal
| | - Marco A. R. Santos
- DROTRH–Direção Regional do Ordenamento do Território e dos Recursos Hídricos, Governo dos Açores, Horta, Portugal
| | - Karen A. Bjorndal
- ACCSTR–Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, Gainesville, FL, United States of America
| | - Alan B. Bolten
- ACCSTR–Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, Gainesville, FL, United States of America
| | - Frederic Vandeperre
- IMAR–Institute of Marine Research, Departamento de Oceanografia e Pescas, Universidade dos Açores, Horta, Portugal
- Institute of Marine Sciences—Okeanos,–Departamento de Oceanografia e Pescas, Universidade dos Açores, Horta, Portugal
| |
Collapse
|
2
|
Gulick AG, Constant N, Bolten AB, Bjorndal KA. Holopelagic Sargassum aggregations provide warmer microhabitats for associated fauna. Sci Rep 2023; 13:15129. [PMID: 37704665 PMCID: PMC10499784 DOI: 10.1038/s41598-023-41982-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 09/04/2023] [Indexed: 09/15/2023] Open
Abstract
Drifting aggregations of Sargassum algae provide critical habitat for endemic, endangered, and commercially important species. They may also provide favorable microclimates for associated fauna. To quantify thermal characteristics of holopelagic Sargassum aggregations, we evaluated thermal profiles of 50 aggregations in situ in the Sargasso Sea. Sea surface temperature (SST) in the center of aggregations was significantly higher than in nearby open water, and SST differential was independent of aggregation volume, area, and thickness. SST differential between aggregation edge and open water was smaller than those between aggregation center and aggregation edge and between aggregation center and open water. Water temperature was significantly higher inside and below aggregations compared to open water but did not vary inside aggregations with depth. Holopelagic Sargassum aggregations provide warmer microhabitats for associated fauna, which may benefit marine ectotherms, though temperature differentials were narrow (up to 0.7 °C) over the range of aggregation sizes we encountered (area 0.01-15 m2). We propose a hypothetical curve describing variation in SST differential with Sargassum aggregation size as a prediction for future studies to evaluate across temporal and geographic ranges. Our study provides a foundation for investigating the importance of thermal microhabitats in holopelagic Sargassum ecosystems.
Collapse
Affiliation(s)
- Alexandra G Gulick
- Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, Gainesville, FL, USA.
- Glacier Bay National Park and Preserve, National Park Service, Bartlett Cove, AK, USA.
| | - Nerine Constant
- Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, Gainesville, FL, USA.
| | - Alan B Bolten
- Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, Gainesville, FL, USA
| | - Karen A Bjorndal
- Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, Gainesville, FL, USA
| |
Collapse
|
3
|
Gulick AG, Johnson RA, Palma LA, Kusel AM, Pollock CG, Hillis‐Starr Z, Bolten AB, Bjorndal KA. An underwater Serengeti: Seagrass‐mediated effects on intake and cultivation grazing behavior of a marine megaherbivore. Ecosphere 2022. [DOI: 10.1002/ecs2.4259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- Alexandra G. Gulick
- Archie Carr Center for Sea Turtle Research and Department of Biology University of Florida Gainesville Florida USA
| | - Robert A. Johnson
- Archie Carr Center for Sea Turtle Research and Department of Biology University of Florida Gainesville Florida USA
| | - Laura A. Palma
- Archie Carr Center for Sea Turtle Research and Department of Biology University of Florida Gainesville Florida USA
| | - Ashley M. Kusel
- Archie Carr Center for Sea Turtle Research and Department of Biology University of Florida Gainesville Florida USA
| | - Clayton G. Pollock
- Division of Resource Management and Research, Buck Island Reef National Monument National Park Service Christiansted St. Croix US Virgin Islands
| | - Zandy Hillis‐Starr
- Division of Resource Management and Research, Buck Island Reef National Monument National Park Service Christiansted St. Croix US Virgin Islands
| | - Alan B. Bolten
- Archie Carr Center for Sea Turtle Research and Department of Biology University of Florida Gainesville Florida USA
| | - Karen A. Bjorndal
- Archie Carr Center for Sea Turtle Research and Department of Biology University of Florida Gainesville Florida USA
| |
Collapse
|
4
|
Vilaça ST, Piccinno R, Rota‐Stabelli O, Gabrielli M, Benazzo A, Matschiner M, Soares LS, Bolten AB, Bjorndal KA, Bertorelle G. Divergence and hybridization in sea turtles: Inferences from genome data show evidence of ancient gene flow between species. Mol Ecol 2021; 30:6178-6192. [PMID: 34390061 PMCID: PMC9292604 DOI: 10.1111/mec.16113] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 07/26/2021] [Indexed: 11/30/2022]
Abstract
Reconstructing past events of hybridization and population size changes are required to understand speciation mechanisms and current patterns of genetic diversity, and ultimately contribute to species' conservation. Sea turtles are ancient species currently facing anthropogenic threats including climate change, fisheries, and illegal hunting. Five of the seven extant sea turtle species are known to currently hybridize, especially along the Brazilian coast where some populations can have ~32%-42% of hybrids. Although frequently observed today, it is not clear what role hybridization plays in the evolutionary diversification of this group of reptiles. In this study, we generated whole genome resequencing data of the five globally distributed sea turtle species to estimate a calibrated phylogeny and the population size dynamics, and to understand the role of hybridization in shaping the genomes of these ancient species. Our results reveal discordant species divergence dates between mitochondrial and nuclear genomes, with a high frequency of conflicting trees throughout the nuclear genome suggesting that some sea turtle species frequently hybridized in the past. The reconstruction of the species' demography showed a general decline in effective population sizes with no signs of recovery, except for the leatherback sea turtle. Furthermore, we discuss the influence of reference bias in our estimates. We show long-lasting ancestral gene flow events within Chelonioidea that continued for millions of years after initial divergence. Speciation with gene flow is a common pattern in marine species, and it raises questions whether current hybridization events should be considered as a part of these species' evolutionary history or a conservation issue.
Collapse
Affiliation(s)
| | - Riccardo Piccinno
- Department of Sustainable Agro‐ecosystems and BioresourcesFondazione Edmund MachTrentoItaly
| | - Omar Rota‐Stabelli
- Department of Sustainable Agro‐ecosystems and BioresourcesFondazione Edmund MachTrentoItaly
| | - Maëva Gabrielli
- Department of Life Sciences and BiotechnologyUniversity of FerraraFerraraItaly
| | - Andrea Benazzo
- Department of Life Sciences and BiotechnologyUniversity of FerraraFerraraItaly
| | | | - Luciano S. Soares
- Archie Carr Center for Sea Turtle Research and Department of BiologyUniversity of FloridaGainesvilleFLUSA
| | - Alan B. Bolten
- Archie Carr Center for Sea Turtle Research and Department of BiologyUniversity of FloridaGainesvilleFLUSA
| | - Karen A. Bjorndal
- Archie Carr Center for Sea Turtle Research and Department of BiologyUniversity of FloridaGainesvilleFLUSA
| | - Giorgio Bertorelle
- Department of Life Sciences and BiotechnologyUniversity of FerraraFerraraItaly
| |
Collapse
|
5
|
Pagès Barceló L, Seminoff JA, Vander Zanden HB, Jones TT, Bjorndal KA, Bolten AB, Mustin W, Busquets-Vass G, Newsome SD. Hydrogen isotope assimilation and discrimination in green turtles. J Exp Biol 2021; 224:238723. [PMID: 33653718 DOI: 10.1242/jeb.231431] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 02/22/2021] [Indexed: 11/20/2022]
Abstract
Although hydrogen isotopes (δ2H) are commonly used as tracers of animal movement, minimal research has investigated the use of δ2H as a proxy to quantify resource and habitat use. While carbon and nitrogen are ultimately derived from a single source (food), the proportion of hydrogen in consumer tissues originates from two distinct sources: body water and food. Before hydrogen isotopes can be effectively used as a resource and habitat tracer, we need estimates of (net) discrimination factors (Δ2HNet) that account for the physiologically mediated differences in the δ2H values of animal tissues relative to that of the food and water sources they use to synthesize tissues. Here, we estimated Δ2HNet in captive green turtles (Chelonia mydas) by measuring the δ2H values of tissues (epidermis and blood components) and dietary macromolecules collected in two controlled feeding experiments. Tissue δ2H and Δ2HNet values varied systematically among tissues, with epidermis having higher δ2H and Δ2HNet values than blood components, which mirrors patterns between keratinaceous tissues (feathers, hair) and blood in birds and mammals. Serum/plasma of adult female green turtles had significantly lower δ2H values compared with juveniles, likely due to increased lipid mobilization associated with reproduction. This is the first study to quantify Δ2HNet values in a marine ectotherm, and we anticipate that our results will further refine the use of δ2H analysis to better understand animal resource and habitat use in marine ecosystems, especially coastal areas fueled by a combination of marine (e.g. micro/macroalgae and seagrass) and terrestrial (e.g. mangroves) primary production.
Collapse
Affiliation(s)
| | - Jeffrey A Seminoff
- National Oceanic and Atmospheric Administration-National Marine Fisheries Service, Southwest Fisheries Science Center, La Jolla, CA 92037, USA
| | | | - T Todd Jones
- NOAA Fisheries, Pacific Islands Fisheries Science Center, Honolulu, HI 96818, USA
| | - Karen A Bjorndal
- Department of Biology, University of Florida, Gainesville, FL 32611, USA
| | - Alan B Bolten
- Department of Biology, University of Florida, Gainesville, FL 32611, USA
| | - Walter Mustin
- Cayman Turtle Conservation and Education Center, Grand Cayman KY1-1301, Cayman Islands
| | - Geraldine Busquets-Vass
- Department of Biology, University of New Mexico, Albuquerque, NM 87131, USA.,Centro de Investigación Científica y Educación Superior de Ensenada, Unidad La Paz, Laboratorio de Macroecología Marina, Baja California Sur 23050, Mexico
| | - Seth D Newsome
- Department of Biology, University of New Mexico, Albuquerque, NM 87131, USA
| |
Collapse
|
6
|
Soares LS, Bjorndal KA, Bolten AB, Wayne ML, Castilhos JC, Weber MI, López-Mendilaharsu M, Marcovaldi MA, Vilaça ST, Naro-Maciel E. Reproductive output, foraging destinations, and isotopic niche of olive ridley and loggerhead sea turtles, and their hybrids, in Brazil. ENDANGER SPECIES RES 2021. [DOI: 10.3354/esr01095] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Hybridization is a fundamental evolutionary and ecological process with significant conservation ramifications. Sea turtle hybridization occurs at unusually high frequencies along the northeastern coast of Brazil. To better understand the process, we studied the reproductive output, migration patterns (through satellite telemetry), and isotopic niches of loggerhead turtles Caretta caretta and olive ridley turtles Lepidochelys olivacea and their hybrids. We classified 154 nesting females as loggerhead (n = 91), olive ridley (n = 38), or hybrid (n = 25) based on mitochondrial and nuclear DNA. Further, we compared nesting female morphological data and reproductive parameters (clutch size, emergence success, hatchling production, incubation period) of 405 nests among hybrids and parental species. We found no significant differences among the 3 groups when hatchling production was corrected for female body size, indicating that hybrids and parental species produce similar numbers of hatchlings per clutch. Satellite tracking of 8 post-nesting hybrid females revealed shared foraging grounds with both parental species, as well as neritic migrations between foraging and nesting areas similar to those previously reported for loggerheads and olive ridleys. Analyses of 13C and 15N isotope values (n = 69) further confirmed this pattern, as hybrid isotopic niches overlapped extensively with both parental species. Thus, given the similarities presented between hybrids and their parental species in reproductive, ecological, and behavioral characteristics, we conclude that these hybrids may persist along with other sea turtle nesting populations in the area, with research and conservation implications.
Collapse
Affiliation(s)
- LS Soares
- Archie Carr Center for Sea Turtle Research, University of Florida, Gainesville, FL 32611, USA
- Department of Biology, University of Florida, Gainesville, FL 32611, USA
| | - KA Bjorndal
- Archie Carr Center for Sea Turtle Research, University of Florida, Gainesville, FL 32611, USA
- Department of Biology, University of Florida, Gainesville, FL 32611, USA
| | - AB Bolten
- Archie Carr Center for Sea Turtle Research, University of Florida, Gainesville, FL 32611, USA
- Department of Biology, University of Florida, Gainesville, FL 32611, USA
| | - ML Wayne
- Department of Biology, University of Florida, Gainesville, FL 32611, USA
- University of Florida Genetics Institute, University of Florida, Gainesville, FL 32611, USA
| | - JC Castilhos
- Projeto TAMAR/Fundação Pró-TAMAR, Aracaju, SE 49035-730, Brazil
| | - MI Weber
- Projeto TAMAR/Fundação Pró-TAMAR, Aracaju, SE 49035-730, Brazil
| | | | - MA Marcovaldi
- Projeto TAMAR/Fundação Pró-TAMAR, Salvador, BA 41510-045, Brazil
| | - ST Vilaça
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara 44121, Italy
| | - E Naro-Maciel
- Liberal Studies, New York University, New York, NY 10003, USA
| |
Collapse
|
7
|
Gulick AG, Johnson RA, Pollock CG, Hillis-Starr Z, Bolten AB, Bjorndal KA. Recovery of a large herbivore changes regulation of seagrass productivity in a naturally grazed Caribbean ecosystem. Ecology 2020; 101:e03180. [PMID: 32882749 DOI: 10.1002/ecy.3180] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 05/19/2020] [Accepted: 07/14/2020] [Indexed: 11/05/2022]
Abstract
What happens in meadows after populations of natural grazers rebound following centuries of low abundance? Many seagrass ecosystems are now experiencing this phenomenon with the recovery of green turtles (Chelonia mydas), large-bodied marine herbivores that feed on seagrasses. These seagrass ecosystems provide a rare opportunity to study ecosystem-wide shifts that result from a recovery of herbivores. We evaluate changes in regulation of seagrass productivity in a naturally grazed tropical ecosystem by (1) comparing Thalassia testudinum productivity in grazed and ungrazed areas and (2) evaluating potential regulating mechanisms of T. testudinum productivity. We established 129 green turtle exclusion cages in grazed and ungrazed areas to quantify T. testudinum growth (linear, area, mass, productivity : biomass [P:B]). In each exclosure, we recorded temperature, irradiance, water depth, nitrogen : phosphorus ratio (N:P) of blade tissue, grazing intensity before cage placement, and T. testudinum structural and nutrient characteristics. Thalassia testudinum exhibited compensatory growth in grazed areas via stimulated blade linear growth, blade area growth, and P:B across seasonal high and low growth periods and in shallow (3-4 m) and deep (9-10 m) seagrass meadows. Irradiance, depth, and N:P ratios had significant roles in regulating mass growth and P:B of T. testudinum in ungrazed areas. Depth was a significant regulating factor of mass growth and P:B in grazed areas; rates were higher and more variable in shallow meadows than in deep meadows. Grazing intensity was also a significant regulating factor for P:B, stimulating tissue turnover with increasing grazing pressure. This study provides important insights into how recovery of a large marine herbivore can result in dramatic, sustainable changes in the regulation of seagrass productivity. We also highlight the need for a historical perspective and use of appropriate indicators, including P:B and grazing intensity, when evaluating seagrass response to green turtle grazing as meadows are returned to a natural grazed state. In an age of green turtle recovery and global seagrass decline due to anthropogenic threats, a thorough understanding of green turtle-seagrass interactions at the ecosystem level is critical to ensure the restoration of seagrass ecosystems and continued recovery of green turtle populations.
Collapse
Affiliation(s)
- Alexandra G Gulick
- Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, Gainesville, Florida, 32611, USA
| | - Robert A Johnson
- Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, Gainesville, Florida, 32611, USA
| | - Clayton G Pollock
- Division of Resource Management and Research, Buck Island Reef National Monument, National Park Service, Christiansted, U.S. Virgin Islands, 00820, USA
| | - Zandy Hillis-Starr
- Division of Resource Management and Research, Buck Island Reef National Monument, National Park Service, Christiansted, U.S. Virgin Islands, 00820, USA
| | - Alan B Bolten
- Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, Gainesville, Florida, 32611, USA
| | - Karen A Bjorndal
- Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, Gainesville, Florida, 32611, USA
| |
Collapse
|
8
|
López-Mendilaharsu M, Giffoni B, Monteiro D, Prosdocimi L, Vélez-Rubio GM, Fallabrino A, Estrades A, Santos AS, Lara PH, Pires T, Tiwari M, Bolten AB, Marcovaldi MÂ. Multiple-threats analysis for loggerhead sea turtles in the southwest Atlantic Ocean. ENDANGER SPECIES RES 2020. [DOI: 10.3354/esr01025] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Priority-setting approaches for widely distributed and long-lived species can be challenging. This is especially true for sea turtles, which are species of conservation concern. The aim of this study was to conduct a detailed analysis of threats to identify, quantify and prioritize the main impacts to the loggerhead Caretta caretta population in the southwest Atlantic (SWA) region. A matrix of relative threats was constructed. Threats were identified and classified for 8 different life stages (nesting females, eggs, hatchlings, swim-frenzy transitional stage, juveniles-neritic, juveniles-oceanic, adults-neritic, adults-oceanic) and for 3 ecosystems inhabited by sea turtles (terrestrial, neritic and oceanic). Results indicated that fisheries bycatch represents a major threat for loggerheads in the SWA. The trawl fishery was identified as the main source of mortality for neritic juvenile and adult turtles, whereas juveniles in oceanic areas are mostly impacted by surface longlines. In terrestrial environments, eggs and hatchlings are mainly affected by habitat alteration and by native and exotic predators. Loggerheads have shown a positive nesting trend at their main nesting beaches in the SWA, probably due to long-term conservation efforts to reduce mortality of the different life stages within the terrestrial zone. However, the high mortality rates of juveniles and sub-adults documented at some known foraging grounds represent a reason for concern, as this may affect the overall population trend in the future. This threat analysis provides a tool to review the goals of national action plans, prioritize actions and optimize the allocation of management resources.
Collapse
Affiliation(s)
- M López-Mendilaharsu
- Fundação Pró-Tamar, Rua Rubens Guelli 134/ 307, Itaigara - Salvador, CEP: 41815-135 Bahia, Brazil
| | - B Giffoni
- Fundação Pró-Tamar, Rua Rubens Guelli 134/ 307, Itaigara - Salvador, CEP: 41815-135 Bahia, Brazil
| | - D Monteiro
- Núcleo de Educação e Monitoramento Ambiental - NEMA, Rua Maria Araújo 450, 96207-480 Rio Grande, RS, Brazil
- Laboratório de Ecologia e Conservação da Megafauna Marinha, EcoMega, Universidade Federal do Rio Grande, FURG, 96203-900 Rio Grande, RS, Brazil
| | - L Prosdocimi
- Programa Regional de Investigación y Conservación de Tortugas Marinas de la Argentina (PRICTMA), 1609 Buenos Aires, Argentina
| | - GM Vélez-Rubio
- Karumbé NGO, Zoo Villa Dolores, 11600 Montevideo, Uruguay
- Centro Universitario Regional del Este (CURE), Universidad de la República, 27000 Rocha, Uruguay
| | - A Fallabrino
- Karumbé NGO, Zoo Villa Dolores, 11600 Montevideo, Uruguay
| | - A Estrades
- Karumbé NGO, Zoo Villa Dolores, 11600 Montevideo, Uruguay
| | - AS Santos
- Fundação Pró-Tamar, Rua Rubens Guelli 134/ 307, Itaigara - Salvador, CEP: 41815-135 Bahia, Brazil
| | - PH Lara
- Fundação Pró-Tamar, Rua Rubens Guelli 134/ 307, Itaigara - Salvador, CEP: 41815-135 Bahia, Brazil
| | - T Pires
- Fundação Pró-Tamar, Rua Rubens Guelli 134/ 307, Itaigara - Salvador, CEP: 41815-135 Bahia, Brazil
| | - M Tiwari
- NOAA-National Marine Fisheries Service, Marine Turtle Ecology & Assessment Program, Southwest Fisheries Science Center, La Jolla, California 92034, USA
| | - AB Bolten
- Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, Gainesville, Florida 32611, USA
| | - MÂ Marcovaldi
- Fundação Pró-Tamar, Rua Rubens Guelli 134/ 307, Itaigara - Salvador, CEP: 41815-135 Bahia, Brazil
| |
Collapse
|
9
|
van der Zee JP, Christianen MJA, Nava M, Velez-Zuazo X, Hao W, Bérubé M, van Lavieren H, Hiwat M, Berzins R, Chevalier J, Chevallier D, Lankester MC, Bjorndal KA, Bolten AB, Becking LE, Palsbøll PJ. Population recovery changes population composition at a major southern Caribbean juvenile developmental habitat for the green turtle, Chelonia mydas. Sci Rep 2019; 9:14392. [PMID: 31591419 PMCID: PMC6779738 DOI: 10.1038/s41598-019-50753-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 09/18/2019] [Indexed: 11/09/2022] Open
Abstract
Understanding the population composition and dynamics of migratory megafauna at key developmental habitats is critical for conservation and management. The present study investigated whether differential recovery of Caribbean green turtle (Chelonia mydas) rookeries influenced population composition at a major juvenile feeding ground in the southern Caribbean (Lac Bay, Bonaire, Caribbean Netherlands) using genetic and demographic analyses. Genetic divergence indicated a strong temporal shift in population composition between 2006-2007 and 2015-2016 (ϕST = 0.101, P < 0.001). Juvenile recruitment (<75.0 cm straight carapace length; SCL) from the north-western Caribbean increased from 12% to 38% while recruitment from the eastern Caribbean region decreased from 46% to 20% between 2006-2007 and 2015-2016. Furthermore, the product of the population growth rate and adult female abundance was a significant predictor for population composition in 2015-2016. Our results may reflect early warning signals of declining reproductive output at eastern Caribbean rookeries, potential displacement effects of smaller rookeries by larger rookeries, and advocate for genetic monitoring as a useful method for monitoring trends in juvenile megafauna. Furthermore, these findings underline the need for adequate conservation of juvenile developmental habitats and a deeper understanding of the interactions between megafaunal population dynamics in different habitats.
Collapse
Affiliation(s)
- Jurjan P van der Zee
- Marine Evolution and Conservation, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborg 7, 9747 AG, Groningen, The Netherlands. .,Wageningen Marine Research, Ankerpark 27, 1781 AG, Den Helder, The Netherlands.
| | - Marjolijn J A Christianen
- Marine Evolution and Conservation, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborg 7, 9747 AG, Groningen, The Netherlands.,Aquatic Ecology and Water Quality Management Group, Wageningen University & Research, P.O. Box 47, 6700 AA, Wageningen, The Netherlands
| | - Mabel Nava
- Sea Turtle Conservation Bonaire, P.O. Box 492, Kaya Korona 53, Kralendijk, Bonaire, The Netherlands
| | - Ximena Velez-Zuazo
- Sea Turtle Conservation Bonaire, P.O. Box 492, Kaya Korona 53, Kralendijk, Bonaire, The Netherlands.,Smithsonian Conservation Biology Institute, National Zoological Park, Washington, DC, USA
| | - Wensi Hao
- Marine Evolution and Conservation, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborg 7, 9747 AG, Groningen, The Netherlands
| | - Martine Bérubé
- Marine Evolution and Conservation, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborg 7, 9747 AG, Groningen, The Netherlands.,Center for Coastal Studies, 5 Holway Avenue, Provincetown, MA, 02657, USA
| | | | - Michael Hiwat
- WWF Guianas, Henck Arronstraat 63, Paramaribo, Suriname
| | - Rachel Berzins
- ONCFS Guyane, Campus Agronomique, BP316, 97379, Kourou, French Guiana
| | - Johan Chevalier
- RNN Amana, Réserve Naturelle de l'Amana, Maison de la Réserve, 270 Avenue 31 Décembre, 97319, Awala-Yalimapo, French Guiana
| | - Damien Chevallier
- Université de Strasbourg, CNRS, IPHC, 23 Rue Becquerel, UMR, 7178, Strasbourg, France
| | - Marie-Clélia Lankester
- RNN Amana, Réserve Naturelle de l'Amana, Maison de la Réserve, 270 Avenue 31 Décembre, 97319, Awala-Yalimapo, French Guiana
| | - Karen A Bjorndal
- Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, P.O. Box 118525, Gainesville, FL, 32611, USA
| | - Alan B Bolten
- Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, P.O. Box 118525, Gainesville, FL, 32611, USA
| | - Leontine E Becking
- Wageningen Marine Research, Ankerpark 27, 1781 AG, Den Helder, The Netherlands.,Marine Animal Ecology Group, Wageningen University & Research, P.O. Box 338, 6700 AH, Wageningen, The Netherlands
| | - Per J Palsbøll
- Marine Evolution and Conservation, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborg 7, 9747 AG, Groningen, The Netherlands.,Center for Coastal Studies, 5 Holway Avenue, Provincetown, MA, 02657, USA
| |
Collapse
|
10
|
Johnson RA, Gulick AG, Bolten AB, Bjorndal KA. Rates of Sediment Resuspension and Erosion Following Green Turtle Grazing in a Shallow Caribbean Thalassia testudinum Meadow. Ecosystems 2019. [DOI: 10.1007/s10021-019-00372-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
11
|
Pfaller JB, Payton AC, Bjorndal KA, Bolten AB, McDaniel SF. Hitchhiking the high seas: Global genomics of rafting crabs. Ecol Evol 2019; 9:957-974. [PMID: 30805133 PMCID: PMC6374717 DOI: 10.1002/ece3.4694] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2018] [Revised: 10/04/2018] [Accepted: 10/05/2018] [Indexed: 12/04/2022] Open
Abstract
Population differentiation and diversification depend in large part on the ability and propensity of organisms to successfully disperse. However, our understanding of these processes in organisms with high dispersal ability is biased by the limited genetic resolution offered by traditional genotypic markers. Many neustonic animals disperse not only as pelagic larvae, but also as juveniles and adults while drifting or rafting at the surface of the open ocean. In theory, the heightened dispersal ability of these animals should limit opportunities for species diversification and population differentiation. To test these predictions, we used next-generation sequencing of genomewide restriction-site-associated DNA tags (RADseq) and traditional mitochondrial DNA sequencing, to investigate the species-level relationships and global population structure of Planes crabs collected from oceanic flotsam and sea turtles. Our results indicate that species diversity in this clade is low-likely three closely related species-with no evidence of cryptic or undescribed species. Moreover, our results indicate weak population differentiation among widely separated aggregations with genetic indices showing only subtle genetic discontinuities across all oceans of the world (RADseq F ST = 0.08-0.16). The results of this study provide unprecedented resolution of the systematics and global biogeography of this group and contribute valuable information to our understanding of how theoretical dispersal potential relates to actual population differentiation and diversification among marine organisms. Moreover, these results demonstrate the limitations of single gene analyses and the value of genomic-level resolution for estimating contemporary population structure in organisms with large, highly connected populations.
Collapse
Affiliation(s)
- Joseph B. Pfaller
- Department of Biology, Archie Carr Center for Sea Turtle ResearchUniversity of FloridaGainesvilleFlorida
- Caretta Research ProjectSavannahGeorgia
| | - Adam C. Payton
- Department of BiologyUniversity of FloridaGainesvilleFlorida
| | - Karen A. Bjorndal
- Department of Biology, Archie Carr Center for Sea Turtle ResearchUniversity of FloridaGainesvilleFlorida
| | - Alan B. Bolten
- Department of Biology, Archie Carr Center for Sea Turtle ResearchUniversity of FloridaGainesvilleFlorida
| | | |
Collapse
|
12
|
Wildermann NE, Gredzens C, Avens L, Barrios-Garrido HA, Bell I, Blumenthal J, Bolten AB, Braun McNeill J, Casale P, Di Domenico M, Domit C, Epperly SP, Godfrey MH, Godley BJ, González-Carman V, Hamann M, Hart KM, Ishihara T, Mansfield KL, Metz TL, Miller JD, Pilcher NJ, Read MA, Sasso C, Seminoff JA, Seney EE, Willard AS, Tomás J, Vélez-Rubio GM, Ware M, Williams JL, Wyneken J, Fuentes MMPB. Informing research priorities for immature sea turtles through expert elicitation. ENDANGER SPECIES RES 2018. [DOI: 10.3354/esr00916] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
|
13
|
Stacy NI, Bjorndal KA, Perrault JR, Martins HR, Bolten AB. Blood analytes of oceanic-juvenile loggerhead sea turtles ( Caretta caretta) from Azorean waters: reference intervals, size-relevant correlations and comparisons to neritic loggerheads from western Atlantic coastal waters. Conserv Physiol 2018; 6:coy006. [PMID: 29479433 PMCID: PMC5814815 DOI: 10.1093/conphys/coy006] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2017] [Revised: 01/05/2018] [Accepted: 01/24/2018] [Indexed: 05/06/2023]
Abstract
Blood analyte reference intervals are scarce for immature life stages of the loggerhead sea turtle (Caretta caretta). The objectives of this study were to (1) document reference intervals of packed cell volume (PCV) and 20 plasma chemistry analytes from wild oceanic-juvenile stage loggerhead turtles from Azorean waters, (2) investigate correlations with body size (minimum straight carapace length: SCLmin) and (3) compare plasma chemistry data to those from older, larger neritic juveniles (<80 cm SCLmin) and adult loggerheads (≥80 cm SCLmin) that have recruited to the West Atlantic in waters around Cape Canaveral, Florida. Twenty-eight Azorean loggerhead turtles with SCLmin of 17.6-60.0 cm (mean 34.9 ± 12.1 cm) were captured, sampled and immediately released. Reference intervals are reported. There were several biologically relevant correlations of blood analytes with SCLmin: positive correlations of PCV, proteins and triglycerides with SCLmin indicated somatic growth, increasing diving activity and/or diet; negative correlations of tissue enzymes with SCLmin suggested faster growth at smaller turtle size, while negative correlations of electrolytes with SCLmin indicated differences in diet, environmental conditions and/or osmoregulation unique to the geographic location. Comparisons of loggerhead turtles from the Azores (i.e. oceanic) and Cape Canaveral (i.e. neritic) identified significant differences regarding diet, somatic growth, and/or environment: in Azorean turtles, albumin, triglycerides and bilirubin increased with SCLmin, while alkaline phosphatase, lactate dehydrogenase and sodium decreased. In larger neritic Cape Canaveral turtles, aspartate aminotransferase increased with SCLmin, while the albumin:globulin ratio, phosphorus and cholesterol decreased. These differences suggest unique physiological disparities between life stage development and migration, reflecting biological and habitat differences between the two populations. This information presents biologically important data that is applicable to stranded individual turtles and to the population level, a tool for the development of conservation strategies, and a baseline for future temporal and spatial investigations of the Azorean loggerhead sea turtle population.
Collapse
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
- Corresponding author: Department of Large Animal Clinical Sciences, Aquatic Animal Health, College of Veterinary Medicine, University of Florida, 2015 SW 16th Ave, Gainesville, FL 32610, USA.
| | - Karen A Bjorndal
- Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, PO Box 118525, Gainesville, FL 32611, USA
| | - Justin R Perrault
- Loggerhead Marinelife Center, 14200 U.S. Hwy 1, Juno Beach, FL 33408, USA
| | - Helen R Martins
- University of the Azores, Department of Oceanography and Fisheries, PT-9901-862 Horta, Azores, Portugal
| | - Alan B Bolten
- Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, PO Box 118525, Gainesville, FL 32611, USA
| |
Collapse
|
14
|
Bjorndal KA, Bolten AB, Chaloupka M, Saba VS, Bellini C, Marcovaldi MAG, Santos AJB, Bortolon LFW, Meylan AB, Meylan PA, Gray J, Hardy R, Brost B, Bresette M, Gorham JC, Connett S, Crouchley BVS, Dawson M, Hayes D, Diez CE, van Dam RP, Willis S, Nava M, Hart KM, Cherkiss MS, Crowder AG, Pollock C, Hillis-Starr Z, Muñoz Tenería FA, Herrera-Pavón R, Labrada-Martagón V, Lorences A, Negrete-Philippe A, Lamont MM, Foley AM, Bailey R, Carthy RR, Scarpino R, McMichael E, Provancha JA, Brooks A, Jardim A, López-Mendilaharsu M, González-Paredes D, Estrades A, Fallabrino A, Martínez-Souza G, Vélez-Rubio GM, Boulon RH, Collazo JA, Wershoven R, Guzmán Hernández V, Stringell TB, Sanghera A, Richardson PB, Broderick AC, Phillips Q, Calosso M, Claydon JAB, Metz TL, Gordon AL, Landry AM, Shaver DJ, Blumenthal J, Collyer L, Godley BJ, McGowan A, Witt MJ, Campbell CL, Lagueux CJ, Bethel TL, Kenyon L. Ecological regime shift drives declining growth rates of sea turtles throughout the West Atlantic. Glob Chang Biol 2017; 23:4556-4568. [PMID: 28378354 DOI: 10.1111/gcb.13712] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Revised: 03/20/2017] [Accepted: 03/21/2017] [Indexed: 05/24/2023]
Abstract
Somatic growth is an integrated, individual-based response to environmental conditions, especially in ectotherms. Growth dynamics of large, mobile animals are particularly useful as bio-indicators of environmental change at regional scales. We assembled growth rate data from throughout the West Atlantic for green turtles, Chelonia mydas, which are long-lived, highly migratory, primarily herbivorous mega-consumers that may migrate over hundreds to thousands of kilometers. Our dataset, the largest ever compiled for sea turtles, has 9690 growth increments from 30 sites from Bermuda to Uruguay from 1973 to 2015. Using generalized additive mixed models, we evaluated covariates that could affect growth rates; body size, diet, and year have significant effects on growth. Growth increases in early years until 1999, then declines by 26% to 2015. The temporal (year) effect is of particular interest because two carnivorous species of sea turtles-hawksbills, Eretmochelys imbricata, and loggerheads, Caretta caretta-exhibited similar significant declines in growth rates starting in 1997 in the West Atlantic, based on previous studies. These synchronous declines in productivity among three sea turtle species across a trophic spectrum provide strong evidence that an ecological regime shift (ERS) in the Atlantic is driving growth dynamics. The ERS resulted from a synergy of the 1997/1998 El Niño Southern Oscillation (ENSO)-the strongest on record-combined with an unprecedented warming rate over the last two to three decades. Further support is provided by the strong correlations between annualized mean growth rates of green turtles and both sea surface temperatures (SST) in the West Atlantic for years of declining growth rates (r = -.94) and the Multivariate ENSO Index (MEI) for all years (r = .74). Granger-causality analysis also supports the latter finding. We discuss multiple stressors that could reinforce and prolong the effect of the ERS. This study demonstrates the importance of region-wide collaborations.
Collapse
Affiliation(s)
- Karen A Bjorndal
- Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, Gainesville, FL, USA
| | - Alan B Bolten
- Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, Gainesville, FL, USA
| | - Milani Chaloupka
- Ecological Modelling Services Pty Ltd, University of Queensland, St Lucia, QLD, Australia
| | - Vincent S Saba
- NOAA National Marine Fisheries Service, Northeast Fisheries Science Center, Geophysical Fluid Dynamics Laboratory, Princeton, NJ, USA
| | - Cláudio Bellini
- Centro TAMAR-ICMBio, CLBI - Parnamirim, Rio Grande do Norte, Brazil
| | | | | | | | - Anne B Meylan
- Florida Fish and Wildlife Conservation Commission, Fish and Wildlife Research Institute, St. Petersburg, FL, USA
- Smithsonian Tropical Research Institute, Washington, DC, USA
| | - Peter A Meylan
- Smithsonian Tropical Research Institute, Washington, DC, USA
- Natural Sciences Collegium, Eckerd College, St. Petersburg, FL, USA
| | | | - Robert Hardy
- Florida Fish and Wildlife Conservation Commission, Fish and Wildlife Research Institute, St. Petersburg, FL, USA
| | - Beth Brost
- Florida Fish and Wildlife Conservation Commission, Fish and Wildlife Research Institute, St. Petersburg, FL, USA
| | | | | | | | | | - Mike Dawson
- Geronimo Program, St. George's School, Newport, RI, USA
| | - Deborah Hayes
- Geronimo Program, St. George's School, Newport, RI, USA
| | | | | | - Sue Willis
- Sea Turtle Conservation Bonaire, Kralendijk, Bonaire, Dutch Caribbean
| | - Mabel Nava
- Sea Turtle Conservation Bonaire, Kralendijk, Bonaire, Dutch Caribbean
| | - Kristen M Hart
- U.S. Geological Survey, Wetland and Aquatic Research Center, Davie, FL, USA
| | - Michael S Cherkiss
- U.S. Geological Survey, Wetland and Aquatic Research Center, Davie, FL, USA
| | - Andrew G Crowder
- Cherokee Nation Technologies, NSU Center for Collaborative Research, Davie, FL, USA
| | - Clayton Pollock
- National Park Service, Christiansted, St. Croix, Virgin Islands
| | | | - Fernando A Muñoz Tenería
- Facultad de Agronomía y Veterinaria, Universidad Autónoma de San Luis Potosí, San Luis Potosí, México
| | | | | | - Armando Lorences
- Dirección de Ecología Municipio de Solidaridad, Quintana Roo, México
| | | | - Margaret M Lamont
- US Geological Survey, Wetland and Aquatic Research Center, Gainesville, FL, USA
| | - Allen M Foley
- Florida Fish and Wildlife Conservation Commission, Fish and Wildlife Research Institute, Jacksonville Field Laboratory, Jacksonville, FL, USA
| | - Rhonda Bailey
- Florida Fish and Wildlife Conservation Commission, Fish and Wildlife Research Institute, St. Petersburg, FL, USA
| | - Raymond R Carthy
- US Geological Survey, Florida Cooperative Fish and Wildlife Research Unit, Gainesville, FL, USA
| | - Russell Scarpino
- Florida Cooperative Fish and Wildlife Research Unit, Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, FL, USA
| | - Erin McMichael
- Florida Cooperative Fish and Wildlife Research Unit, Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, FL, USA
| | - Jane A Provancha
- Environmental Services, Integrated Mission Support Services, Kennedy Space Center, Florida, USA
| | | | | | | | | | | | | | | | | | | | - Jaime A Collazo
- U.S. Geological Survey, North Carolina Cooperative Fish and Wildlife Research Unit, Department of Applied Ecology, North Carolina State University, Raleigh, NC, USA
| | | | | | - Thomas B Stringell
- Centre for Ecology and Conservation, University of Exeter, Penryn, Cornwall, UK
| | | | | | - Annette C Broderick
- Centre for Ecology and Conservation, University of Exeter, Penryn, Cornwall, UK
| | - Quinton Phillips
- Department of Environment and Coastal Resources, National Environment Centre, Providenciales, Turks and Caicos Islands
| | - Marta Calosso
- The School for Field Studies, Center for Marine Resource Studies, South Caicos, Turks and Caicos Islands
| | - John A B Claydon
- Department of Environment and Coastal Resources, National Environment Centre, Providenciales, Turks and Caicos Islands
| | - Tasha L Metz
- Texas A&M University at Galveston, Galveston, TX, USA
| | - Amanda L Gordon
- Environmental Institute of Houston, University of Houston - Clear Lake, Houston, TX, USA
| | | | | | | | - Lucy Collyer
- Department of Environment, Grand Cayman, Cayman Islands
| | - Brendan J Godley
- Centre for Ecology and Conservation, University of Exeter, Penryn, Cornwall, UK
| | - Andrew McGowan
- Centre for Ecology and Conservation, University of Exeter, Penryn, Cornwall, UK
| | - Matthew J Witt
- Environment and Sustainability Institute, University of Exeter, Penryn, Cornwall, UK
| | - Cathi L Campbell
- Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, Gainesville, FL, USA
| | - Cynthia J Lagueux
- Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, Gainesville, FL, USA
| | | | - Lory Kenyon
- Elbow Reef Lighthouse Society, Abaco, The Bahamas
| |
Collapse
|
15
|
Johnson RA, Gulick AG, Bolten AB, Bjorndal KA. Blue carbon stores in tropical seagrass meadows maintained under green turtle grazing. Sci Rep 2017; 7:13545. [PMID: 29051581 PMCID: PMC5648853 DOI: 10.1038/s41598-017-13142-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Accepted: 09/18/2017] [Indexed: 11/17/2022] Open
Abstract
Seagrass meadows are important sites for carbon storage. Green turtles (Chelonia mydas) are marine megaherbivores that consume seagrass throughout much of their global range. With successful conservation efforts, turtle abundance will increase, leading to more meadows being returned to their natural grazed state. There is concern this may lead to a loss of carbon stored in these systems, but the effects of green turtle grazing on seagrass ecosystem carbon dynamics have not been investigated. Here we experimentally show that despite 79% lower net ecosystem production (NEP) following grazing (24.7 vs. 119.5 mmol C m−2 d−1) in a Caribbean Thalassia testudinum seagrass meadow, grazed areas maintained net positive metabolic carbon uptake. Additionally, grazing did not change the meadow production to respiration ratio, indicating it did not stimulate remineralization of sediment carbon stores. Compared to other published estimates of seagrass NEP (median: 20.6 mmol C m−2 d−1), NEP in grazed Caribbean T. testudinum meadows is similar to that in many other ungrazed systems. Our results demonstrate that while grazing does decrease potential future carbon sequestration as a result of lower NEP, it does not promote a metabolic release of current carbon stocks.
Collapse
Affiliation(s)
- Robert A Johnson
- Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, Gainesville, FL, 32611, USA.
| | - Alexandra G Gulick
- Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, Gainesville, FL, 32611, USA
| | - Alan B Bolten
- Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, Gainesville, FL, 32611, USA
| | - Karen A Bjorndal
- Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, Gainesville, FL, 32611, USA
| |
Collapse
|
16
|
Stacy BA, Chapman PA, Foley AM, Greiner EC, Herbst LH, Bolten AB, Klein PA, Manire CA, Jacobson ER. Evidence of Diversity, Site, and Host Specificity of Sea Turtle Blood Flukes (Digenea: Schistosomatoidea: "Spirorchiidae"): A Molecular Prospecting Study. J Parasitol 2017; 103:756-767. [PMID: 28816609 DOI: 10.1645/16-31] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Neospirorchis (Digenea: "Spirorchiidae") are blood flukes of sea turtles. Trematodes tentatively identified as Neospirorchis sp. infect various sites within sea turtles inhabiting waters of the southeastern United States, but efforts to obtain specimens adequate for morphologic study has proven difficult. Two genetic targets, the internal transcribed spacer region of the ribosomal RNA gene and the partial mitochondrial cytochrome c oxidase subunit I gene, were used to investigate potential diversity among parasite specimens collected from stranded sea turtles. Sequence data were obtained from 215 trematode and egg specimens collected from 92 individual free-ranging cheloniid sea turtles comprising 4 host species. Molecular analysis yielded more than 20 different genotypes. We were able to assign 1 genotype to 1 of the 2 recognized species, Neospirorchis pricei Manter and Larson, 1950 . In many examples, genotypes exhibited host and site specificity. Our findings indicate considerable diversity of parasites resembling Neospirorchis with evidence of a number of uncharacterized blood flukes that require additional study.
Collapse
Affiliation(s)
- Brian A Stacy
- National Marine Fisheries Service, National Oceanic and Atmospheric Administration, University of Florida (duty station), P.O. Box 110885, 2187 Mowry Rd., Building 471, Gainesville, Florida 32641
| | - Phoebe A Chapman
- National Marine Fisheries Service, National Oceanic and Atmospheric Administration, University of Florida (duty station), P.O. Box 110885, 2187 Mowry Rd., Building 471, Gainesville, Florida 32641
| | - Allen M Foley
- National Marine Fisheries Service, National Oceanic and Atmospheric Administration, University of Florida (duty station), P.O. Box 110885, 2187 Mowry Rd., Building 471, Gainesville, Florida 32641
| | - Ellis C Greiner
- National Marine Fisheries Service, National Oceanic and Atmospheric Administration, University of Florida (duty station), P.O. Box 110885, 2187 Mowry Rd., Building 471, Gainesville, Florida 32641
| | - Lawrence H Herbst
- National Marine Fisheries Service, National Oceanic and Atmospheric Administration, University of Florida (duty station), P.O. Box 110885, 2187 Mowry Rd., Building 471, Gainesville, Florida 32641
| | - Alan B Bolten
- National Marine Fisheries Service, National Oceanic and Atmospheric Administration, University of Florida (duty station), P.O. Box 110885, 2187 Mowry Rd., Building 471, Gainesville, Florida 32641
| | - Paul A Klein
- National Marine Fisheries Service, National Oceanic and Atmospheric Administration, University of Florida (duty station), P.O. Box 110885, 2187 Mowry Rd., Building 471, Gainesville, Florida 32641
| | - Charles A Manire
- National Marine Fisheries Service, National Oceanic and Atmospheric Administration, University of Florida (duty station), P.O. Box 110885, 2187 Mowry Rd., Building 471, Gainesville, Florida 32641
| | - Elliott R Jacobson
- National Marine Fisheries Service, National Oceanic and Atmospheric Administration, University of Florida (duty station), P.O. Box 110885, 2187 Mowry Rd., Building 471, Gainesville, Florida 32641
| |
Collapse
|
17
|
Pham CK, Rodríguez Y, Dauphin A, Carriço R, Frias JPGL, Vandeperre F, Otero V, Santos MR, Martins HR, Bolten AB, Bjorndal KA. Plastic ingestion in oceanic-stage loggerhead sea turtles (Caretta caretta) off the North Atlantic subtropical gyre. Mar Pollut Bull 2017; 121:222-229. [PMID: 28606614 DOI: 10.1016/j.marpolbul.2017.06.008] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2017] [Revised: 06/02/2017] [Accepted: 06/03/2017] [Indexed: 05/25/2023]
Abstract
Juvenile oceanic-stage sea turtles are particularly vulnerable to the increasing quantity of plastic coming into the oceans. In this study, we analysed the gastrointestinal tracts of 24 juvenile oceanic-stage loggerheads (Caretta caretta) collected off the North Atlantic subtropical gyre, in the Azores region, a key feeding ground for juvenile loggerheads. Twenty individuals were found to have ingested marine debris (83%), composed exclusively of plastic items (primarily polyethylene and polypropylene) identified by μ-Fourier Transform Infrared Spectroscopy. Large microplastics (1-5mm) represented 25% of the total number of debris and were found in 58% of the individuals sampled. Average number of items was 15.83±6.09 (±SE) per individual, corresponding to a mean dry mass of 1.07±0.41g. The results of this study demonstrate that plastic pollution acts as another stressor for this critical life stage of loggerhead turtles in the North Atlantic.
Collapse
Affiliation(s)
- Christopher K Pham
- IMAR-Institute of Marine Research and MARE-Marine and Environmental Sciences Centre, University of the Azores, Horta, Portugal.
| | - Yasmina Rodríguez
- IMAR-Institute of Marine Research and MARE-Marine and Environmental Sciences Centre, University of the Azores, Horta, Portugal
| | - Axelle Dauphin
- ENVT - École Nationale Vétérinaire de Toulouse, 23 Chemin des Capelles, 31300 Toulouse, France
| | - Rita Carriço
- IMAR-Institute of Marine Research and MARE-Marine and Environmental Sciences Centre, University of the Azores, Horta, Portugal
| | - João P G L Frias
- IMAR-Institute of Marine Research and MARE-Marine and Environmental Sciences Centre, University of the Azores, Horta, Portugal
| | - Frederic Vandeperre
- IMAR-Institute of Marine Research and MARE-Marine and Environmental Sciences Centre, University of the Azores, Horta, Portugal
| | - Vanessa Otero
- Department of Conservation and Restoration and LAQV-REQUIMTE, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, 2829-516 Monte da Caparica, Portugal
| | - Marco R Santos
- DRAM - Direção Regional dos Assuntos do Mar/Regional Directorate for Sea Affairs, Secretaria Regional do Mar, Ciência e Tecnologia, Colónia Alemã - Apartado 9, 9900-014 Horta, Faial, Portugal
| | - Helen R Martins
- IMAR-Institute of Marine Research and MARE-Marine and Environmental Sciences Centre, University of the Azores, Horta, Portugal
| | - Alan B Bolten
- ACCSTR - Archie Carr Center for Sea Turtle Research, Department of Biology, PO Box 118525, University of Florida, Gainesville, FL, USA
| | - Karen A Bjorndal
- ACCSTR - Archie Carr Center for Sea Turtle Research, Department of Biology, PO Box 118525, University of Florida, Gainesville, FL, USA
| |
Collapse
|
18
|
Rees AF, Alfaro-Shigueto J, Barata PCR, Bjorndal KA, Bolten AB, Bourjea J, Broderick AC, Campbell LM, Cardona L, Carreras C, Casale P, Ceriani SA, Dutton PH, Eguchi T, Formia A, Fuentes MMPB, Fuller WJ, Girondot M, Godfrey MH, Hamann M, Hart KM, Hays GC, Hochscheid S, Kaska Y, Jensen MP, Mangel JC, Mortimer JA, Naro-Maciel E, Ng CKY, Nichols WJ, Phillott AD, Reina RD, Revuelta O, Schofield G, Seminoff JA, Shanker K, Tomás J, van de Merwe JP, Van Houtan KS, Vander Zanden HB, Wallace BP, Wedemeyer-Strombel KR, Work TM, Godley BJ. Are we working towards global research priorities for management and conservation of sea turtles? ENDANGER SPECIES RES 2016. [DOI: 10.3354/esr00801] [Citation(s) in RCA: 175] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
|
19
|
Vander Zanden HB, Bolten AB, Tucker AD, Hart KM, Lamont MM, Fujisaki I, Reich KJ, Addison DS, Mansfield KL, Phillips KF, Pajuelo M, Bjorndal KA. Biomarkers reveal sea turtles remained in oiled areas following the Deepwater Horizon oil spill. Ecol Appl 2016; 26:2145-2155. [PMID: 27755731 DOI: 10.1002/eap.1366] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Revised: 01/19/2016] [Accepted: 03/08/2016] [Indexed: 06/06/2023]
Abstract
Assessments of large-scale disasters, such as the Deepwater Horizon oil spill, are problematic because while measurements of post-disturbance conditions are common, measurements of pre-disturbance baselines are only rarely available. Without adequate observations of pre-disaster organismal and environmental conditions, it is impossible to assess the impact of such catastrophes on animal populations and ecological communities. Here, we use long-term biological tissue records to provide pre-disaster data for a vulnerable marine organism. Keratin samples from the carapace of loggerhead sea turtles record the foraging history for up to 18 years, allowing us to evaluate the effect of the oil spill on sea turtle foraging patterns. Samples were collected from 76 satellite-tracked adult loggerheads in 2011 and 2012, approximately one to two years after the spill. Of the 10 individuals that foraged in areas exposed to surface oil, none demonstrated significant changes in foraging patterns post spill. The observed long-term fidelity to foraging sites indicates that loggerheads in the northern Gulf of Mexico likely remained in established foraging sites, regardless of the introduction of oil and chemical dispersants. More research is needed to address potential long-term health consequences to turtles in this region. Mobile marine organisms present challenges for researchers to monitor effects of environmental disasters, both spatially and temporally. We demonstrate that biological tissues can reveal long-term histories of animal behavior and provide critical pre-disaster baselines following an anthropogenic disturbance or natural disaster.
Collapse
Affiliation(s)
- Hannah B Vander Zanden
- Department of Geology and Geophysics, University of Utah, 115 S 1460 E Salt Lake City, Utah, 84112, USA.
- Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, PO Box 118525 Gainesville, Florida, 32611, USA.
| | - Alan B Bolten
- Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, PO Box 118525 Gainesville, Florida, 32611, USA
| | - Anton D Tucker
- Mote Marine Laboratory, 1600 Ken Thompson Pkwy, Sarasota, Florida, 34236, USA
| | - Kristen M Hart
- Wetland and Aquatic Research Center, U.S. Geological Survey, 3321 College Ave, Davie, Florida, 33314, USA
| | - Margaret M Lamont
- Wetland and Aquatic Research Center, U.S. Geological Survey, 7920 NW 71St St, Gainesville, Florida, 32653, USA
| | - Ikuko Fujisaki
- Ft. Lauderdale Research and Education Center, University of Florida, 3205 College Ave, Davie, Florida, 33314, USA
| | - Kimberly J Reich
- Texas A & M Galveston, P.O. Box 1675, Galveston, Texas, 77553, USA
| | - David S Addison
- Conservancy of Southwest Florida, 1495 Smith Preserve Way, Naples, Florida, 34102, USA
| | - Katherine L Mansfield
- Department of Biology, University of Central Florida, 4110 Libra Dr, Orlando, Florida, 32816, USA
| | - Katrina F Phillips
- Department of Biology, University of Central Florida, 4110 Libra Dr, Orlando, Florida, 32816, USA
| | - Mariela Pajuelo
- Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, PO Box 118525 Gainesville, Florida, 32611, USA
| | - Karen A Bjorndal
- Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, PO Box 118525 Gainesville, Florida, 32611, USA
| |
Collapse
|
20
|
Bjorndal KA, Chaloupka M, Saba VS, Diez CE, van Dam RP, Krueger BH, Horrocks JA, Santos AJB, Bellini C, Marcovaldi MAG, Nava M, Willis S, Godley BJ, Gore S, Hawkes LA, McGowan A, Witt MJ, Stringell TB, Sanghera A, Richardson PB, Broderick AC, Phillips Q, Calosso MC, Claydon JAB, Blumenthal J, Moncada F, Nodarse G, Medina Y, Dunbar SG, Wood LD, Lagueux CJ, Campbell CL, Meylan AB, Meylan PA, Burns Perez VR, Coleman RA, Strindberg S, Guzmán‐H. V, Hart KM, Cherkiss MS, Hillis‐Starr Z, Lundgren IF, Boulon RH, Connett S, Outerbridge ME, Bolten AB. Somatic growth dynamics of West Atlantic hawksbill sea turtles: a spatio‐temporal perspective. Ecosphere 2016. [DOI: 10.1002/ecs2.1279] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
|
21
|
Shamblin BM, Dutton PH, Bjorndal KA, Bolten AB, Naro-Maciel E, Santos AJB, Bellini C, Baptistotte C, Marcovaldi MÂ, Nairn CJ. Deeper Mitochondrial Sequencing Reveals Cryptic Diversity and Structure in Brazilian Green Turtle Rookeries. Chelonian Conservation and Biology 2015. [DOI: 10.2744/ccb-1152.1] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Brian M. Shamblin
- Daniel B. Warnell School of Forestry and Natural Resources, University of Georgia, Athens, Georgia 30602 USA [ ; ]
| | - Peter H. Dutton
- Marine Mammal and Turtle Division, Southwest Fisheries Science Center, National Marine Fisheries Service, National Oceanographic and Atmospheric Administration, 8901 La Jolla Shores Drive, La Jolla, California 92037 USA [ ]
| | - Karen A. Bjorndal
- Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, Gainesville, Florida 32611 USA [ ; ]
| | - Alan B. Bolten
- Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, Gainesville, Florida 32611 USA [ ; ]
| | - Eugenia Naro-Maciel
- College of Staten Island, City University of New York, 2800 Victory Boulevard, Staten Island, New York 10314 USA [ ]
| | | | - Claudio Bellini
- Centro Nacional de Conservação e Manejo de Tartarugas Marinhas, TAMAR-ICMBio, Caixa Postal 2219 Rio Vermelho, CEP 41950-970, Salvador, BA, Brazil [ ; ]
| | - Cecilia Baptistotte
- Centro Nacional de Conservação e Manejo de Tartarugas Marinhas, TAMAR-ICMBio, Caixa Postal 2219 Rio Vermelho, CEP 41950-970, Salvador, BA, Brazil [ ; ]
| | | | - Campbell J. Nairn
- Daniel B. Warnell School of Forestry and Natural Resources, University of Georgia, Athens, Georgia 30602 USA [ ; ]
| |
Collapse
|
22
|
Zanden HBV, Tucker AD, Hart KM, Lamont MM, Fuisaki I, Addison D, Mansfield KL, Phillips KF, Wunder MB, Bowen GJ, Pajuelo M, Bolten AB, Bjorndal KA. Determining origin in a migratory marine vertebrate: a novel method to integrate stable isotopes and satellite tracking. Ecol Appl 2015; 25:320-335. [PMID: 26263657 DOI: 10.1890/14-0581.1] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Stable isotope analysis is a useful tool to track animal movements in both terrestrial and marine environments. These intrinsic markers are assimilated through the diet and may exhibit spatial gradients as a result of biogeochemical processes at the base of the food web. In the marine environment, maps to predict the spatial distribution of stable isotopes are limited, and thus determining geographic origin has been reliant upon integrating satellite telemetry and stable isotope data. Migratory sea turtles regularly move between foraging and reproductive areas. Whereas most nesting populations can be easily accessed and regularly monitored, little is known about the demographic trends in foraging populations. The purpose of the present study was to examine migration patterns of loggerhead nesting aggregations in the Gulf of Mexico (GoM), where sea turtles have been historically understudied. Two methods of geographic assignment using stable isotope values in known-origin samples from satellite telemetry were compared: (1) a nominal approach through discriminant analysis and (2) a novel continuous-surface approach using bivariate carbon and nitrogen isoscapes (isotopic landscapes) developed for this study. Tissue samples for stable isotope analysis were obtained from 60 satellite-tracked individuals at five nesting beaches within the GoM. Both methodological approaches for assignment resulted in high accuracy of foraging area determination, though each has advantages and disadvantages. The nominal approach is more appropriate when defined boundaries are necessary, but up to 42% of the individuals could not be considered in this approach. All individuals can be included in the continuous-surface approach, and individual results can be aggregated to identify geographic hotspots of foraging area use, though the accuracy rate was lower than nominal assignment. The methodological validation provides a foundation for future sea turtle studies in the region to inexpensively determine geographic origin for large numbers of untracked individuals. Regular monitoring of sea turtle nesting aggregations with stable isotope sampling can be used to fill critical data gaps regarding habitat use and migration patterns. Probabilistic assignment to origin with isoscapes has not been previously used in the marine environment, but the methods presented here could also be applied to other migratory marine species.
Collapse
|
23
|
Kaufman TJ, Pajuelo M, Bjorndal KA, Bolten AB, Pfaller JB, Williams KL, Vander Zanden HB. Mother-egg stable isotope conversions and effects of lipid extraction and ethanol preservation on loggerhead eggs. Conserv Physiol 2014; 2:cou049. [PMID: 27293670 PMCID: PMC4806724 DOI: 10.1093/conphys/cou049] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Revised: 09/22/2014] [Accepted: 09/23/2014] [Indexed: 06/06/2023]
Abstract
Carbon and nitrogen stable isotope (δ(13)C and δ(15)N) analysis has been used to elucidate foraging and migration behaviours of endangered sea turtle populations. Isotopic analysis of tissue samples from nesting females can provide information about their foraging locations before reproduction. To determine whether loggerhead (Caretta caretta) eggs provide a good proxy for maternal isotope values, we addressed the following three objectives: (i) we evaluated isotopic effects of ethanol preservation and lipid extraction on yolk; (ii) we examined the isotopic offset between maternal epidermis and corresponding egg yolk and albumen tissue δ(13)C and δ(15)N values; and (iii) we assessed the accuracy of foraging ground assignment using egg yolk and albumen stable isotope values as a proxy for maternal epidermis. Epidermis (n = 61), albumen (n = 61) and yolk samples (n = 24) were collected in 2011 from nesting females at Wassaw Island, GA, USA. Subsamples from frozen and ethanol-preserved yolk samples were lipid extracted. Both lipid extraction and ethanol preservation significantly affected yolk δ(13)C, while δ(15)N values were not altered at a biologically relevant level. The mathematical corrections provided here allow for normalization of yolk δ(13)C values with these treatments. Significant tissue conversion equations were found between δ(13)C and δ(15)N values of maternal epidermis and corresponding yolk and albumen. Finally, the consistency in assignment to a foraging area was high (up to 84%), indicating that these conversion equations can be used in future studies where stable isotopes are measured to determine female foraging behaviour and trophic relationships by assessing egg components. Loggerhead eggs can thus provide reliable isotopic information when samples from nesting females cannot be obtained.
Collapse
Affiliation(s)
- Temma J. Kaufman
- Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, PO Box 118525, Gainesville, FL 32611, USA
| | - Mariela Pajuelo
- Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, PO Box 118525, Gainesville, FL 32611, USA
| | - Karen A. Bjorndal
- Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, PO Box 118525, Gainesville, FL 32611, USA
| | - Alan B. Bolten
- Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, PO Box 118525, Gainesville, FL 32611, USA
| | - Joseph B. Pfaller
- Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, PO Box 118525, Gainesville, FL 32611, USA
- Caretta Research Project, PO Box 9841, Savannah, GA 31412, USA
| | | | - Hannah B. Vander Zanden
- Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, PO Box 118525, Gainesville, FL 32611, USA
| |
Collapse
|
24
|
Vander Zanden HB, Tucker AD, Bolten AB, Reich KJ, Bjorndal KA. Stable isotopic comparison between loggerhead sea turtle tissues. Rapid Commun Mass Spectrom 2014; 28:2059-2064. [PMID: 25156595 DOI: 10.1002/rcm.6995] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Revised: 07/21/2014] [Accepted: 07/22/2014] [Indexed: 06/03/2023]
Abstract
RATIONALE Stable isotope analysis has been used extensively to provide ecological information about diet and foraging location of many species. The difference in isotopic composition between animal tissue and its diet, or the diet-tissue discrimination factor, varies with tissue type. Therefore, direct comparisons between isotopic values of tissues are inaccurate without an appropriate conversion factor. We focus on the loggerhead sea turtle (Caretta caretta), for which a variety of tissues have been used to examine diet, habitat use, and migratory origin through stable isotope analysis. We calculated tissue-to-tissue conversions between two commonly sampled tissues. METHODS Epidermis and scute (the keratin covering on the carapace) were sampled from 33 adult loggerheads nesting at two beaches in Florida (Casey Key and Canaveral National Seashore). Carbon and nitrogen stable isotope ratios were measured in the epidermis and the youngest portion of the scute tissue, which reflect the isotopic composition of the diet and habitat over similar time periods of the order of several months. RESULTS Significant linear relationships were observed between the δ(13)C and δ(15)N values of these two tissues, indicating they can be converted reliably. CONCLUSIONS Whereas both epidermis and scute samples are commonly sampled from nesting sea turtles to study trophic ecology and habitat use, the data from these studies have not been comparable without reliable tissue-to-tissue conversions. The equations provided here allow isotopic datasets using the two tissues to be combined in previously published and subsequent studies of sea turtle foraging ecology and migratory movement. In addition, we recommend that future isotopic comparisons between tissues of any organism utilize linear regressions to calculate tissue-to-tissue conversions.
Collapse
Affiliation(s)
- Hannah B Vander Zanden
- Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, Gainesville, FL, 32611, USA; Department of Geology and Geophysics, University of Utah, Salt Lake City, UT, 84112, USA
| | | | | | | | | |
Collapse
|
25
|
Bjorndal KA, Parsons J, Mustin W, Bolten AB. Variation in age and size at sexual maturity in Kemp’s ridley sea turtles. ENDANGER SPECIES RES 2014. [DOI: 10.3354/esr00608] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
|
26
|
López-Castro MC, Bjorndal KA, Bolten AB. Evaluation of scute thickness to infer life history records in the carapace of green and loggerhead turtles. ENDANGER SPECIES RES 2014. [DOI: 10.3354/esr00593] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
|
27
|
Shamblin BM, Bolten AB, Abreu-Grobois FA, Bjorndal KA, Cardona L, Carreras C, Clusa M, Monzón-Argüello C, Nairn CJ, Nielsen JT, Nel R, Soares LS, Stewart KR, Vilaça ST, Türkozan O, Yilmaz C, Dutton PH. Geographic patterns of genetic variation in a broadly distributed marine vertebrate: new insights into loggerhead turtle stock structure from expanded mitochondrial DNA sequences. PLoS One 2014; 9:e85956. [PMID: 24465810 PMCID: PMC3900438 DOI: 10.1371/journal.pone.0085956] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 12/04/2013] [Indexed: 11/24/2022] Open
Abstract
Previous genetic studies have demonstrated that natal homing shapes the stock structure of marine turtle nesting populations. However, widespread sharing of common haplotypes based on short segments of the mitochondrial control region often limits resolution of the demographic connectivity of populations. Recent studies employing longer control region sequences to resolve haplotype sharing have focused on regional assessments of genetic structure and phylogeography. Here we synthesize available control region sequences for loggerhead turtles from the Mediterranean Sea, Atlantic, and western Indian Ocean basins. These data represent six of the nine globally significant regional management units (RMUs) for the species and include novel sequence data from Brazil, Cape Verde, South Africa and Oman. Genetic tests of differentiation among 42 rookeries represented by short sequences (380 bp haplotypes from 3,486 samples) and 40 rookeries represented by long sequences (∼800 bp haplotypes from 3,434 samples) supported the distinction of the six RMUs analyzed as well as recognition of at least 18 demographically independent management units (MUs) with respect to female natal homing. A total of 59 haplotypes were resolved. These haplotypes belonged to two highly divergent global lineages, with haplogroup I represented primarily by CC-A1, CC-A4, and CC-A11 variants and haplogroup II represented by CC-A2 and derived variants. Geographic distribution patterns of haplogroup II haplotypes and the nested position of CC-A11.6 from Oman among the Atlantic haplotypes invoke recent colonization of the Indian Ocean from the Atlantic for both global lineages. The haplotypes we confirmed for western Indian Ocean RMUs allow reinterpretation of previous mixed stock analysis and further suggest that contemporary migratory connectivity between the Indian and Atlantic Oceans occurs on a broader scale than previously hypothesized. This study represents a valuable model for conducting comprehensive international cooperative data management and research in marine ecology.
Collapse
Affiliation(s)
- Brian M. Shamblin
- National Research Council Research Associateship Program, Washington, D.C., United States of America
- Marine Mammal and Turtle Division, Southwest Fisheries Science Center, National Atmospheric and Oceanic Administration Fisheries, La Jolla, California, United States of America
| | - Alan B. Bolten
- Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, Gainesville, Florida, United States of America
| | - F. Alberto Abreu-Grobois
- Unidad Académica Mazatlán, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Mazatlán, Sinaloa, México
| | - Karen A. Bjorndal
- Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, Gainesville, Florida, United States of America
| | - Luis Cardona
- Department of Animal Biology and IRBio, Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - Carlos Carreras
- Department of Animal Biology and IRBio, Faculty of Biology, University of Barcelona, Barcelona, Spain
- Marine Turtle Research Group, College of Life and Environmental Sciences, University of Exeter, Cornwall Campus, Peryn, Cornwall, United Kingdom
| | - Marcel Clusa
- Department of Animal Biology and IRBio, Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - Catalina Monzón-Argüello
- Departamento de Biología, Universidad de Las Palmas de Gran Canaria, Campus de Tafira, Las Palmas de Gran Canaria, Spain
| | - Campbell J. Nairn
- Daniel B. Warnell School of Forestry and Natural Resources, University of Georgia, Athens, Georgia, United States of America
| | - Janne T. Nielsen
- Department of Biology, University of Miami, Coral Gables, Florida, United States of America
| | - Ronel Nel
- Zoology Department, Nelson Mandela Metropolitan University, Summerstrand Campus South, University Way, Summerstrand, Port Elizabeth, South Africa
| | - Luciano S. Soares
- Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, Gainesville, Florida, United States of America
- Projeto TAMAR-ICMBio, Salvador, BA, Brazil
| | - Kelly R. Stewart
- Marine Mammal and Turtle Division, Southwest Fisheries Science Center, National Atmospheric and Oceanic Administration Fisheries, La Jolla, California, United States of America
- The Ocean Foundation, Washington, D.C., United States of America
| | - Sibelle T. Vilaça
- Laboratório de Biodiversidade e Evolução Molecular, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Oguz Türkozan
- Adnan Menderes University, Faculty of Science and Arts, Department of Biology, Aydin, Turkey
| | - Can Yilmaz
- Adnan Menderes University, Faculty of Science and Arts, Department of Biology, Aydin, Turkey
| | - Peter H. Dutton
- Marine Mammal and Turtle Division, Southwest Fisheries Science Center, National Atmospheric and Oceanic Administration Fisheries, La Jolla, California, United States of America
- * E-mail:
| |
Collapse
|
28
|
Pajuelo M, Bjorndal KA, Reich KJ, Vander Zanden HB, Hawkes LA, Bolten AB. Assignment of nesting loggerhead turtles to their foraging areas in the Northwest Atlantic using stable isotopes. Ecosphere 2012. [DOI: 10.1890/es12-00220.1] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
|
29
|
Vander Zanden HB, Bjorndal KA, Mustin W, Ponciano JM, Bolten AB. Inherent variation in stable isotope values and discrimination factors in two life stages of green turtles. Physiol Biochem Zool 2012; 85:431-41. [PMID: 22902371 DOI: 10.1086/666902] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
We examine inherent variation in carbon and nitrogen stable isotope values of multiple soft tissues from a population of captive green turtles Chelonia mydas to determine the extent of isotopic variation due to individual differences in physiology. We compare the measured inherent variation in the captive population with the isotopic variation observed in a wild population of juvenile green turtles. Additionally, we measure diet-tissue discrimination factors to determine the offset that occurs between isotope values of the food source and four green turtle tissues. Tissue samples (epidermis, dermis, serum, and red blood cells) were collected from captive green turtles in two life stages (40 large juveniles and 30 adults) at the Cayman Turtle Farm, Grand Cayman, and analyzed for carbon and nitrogen stable isotopes. Multivariate normal models were fit to the isotope data, and the Bayesian Information Criterion was used for model selection. Inherent variation and discrimination factors differed among tissues and life stages. Inherent variation was found to make up a small portion of the isotopic variation measured in a wild population. Discrimination factors not only are tissue and life stage dependent but also appear to vary with diet and sea turtle species, thus highlighting the need for appropriate discrimination factors in dietary reconstructions and trophic-level estimations. Our measures of inherent variation will also be informative in field studies employing stable isotope analysis so that differences in diet or habitat are more accurately identified.
Collapse
Affiliation(s)
- Hannah B Vander Zanden
- Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, P.O. Box 118525, Gainesville, FL 32611, USA.
| | | | | | | | | |
Collapse
|
30
|
Shamblin BM, Bjorndal KA, Bolten AB, Hillis-Starr ZM, Lundgren I, Naro-Maciel E, Nairn CJ. Mitogenomic sequences better resolve stock structure of southern Greater Caribbean green turtle rookeries. Mol Ecol 2012; 21:2330-40. [PMID: 22432442 DOI: 10.1111/j.1365-294x.2012.05530.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Analyses of mitochondrial control region polymorphisms have supported the presence of several demographically independent green turtle (Chelonia mydas) rookeries in the Greater Caribbean region. However, extensive sharing of common haplotypes based on 490-bp control region sequences confounds assessment of the scale of natal homing and population structure among regional rookeries. We screened the majority of the mitochondrial genomes of 20 green turtles carrying the common haplotype CM-A5 and representing the rookeries of Buck Island, St. Croix, United States Virgin Islands (USVI); Aves Island, Venezuela; Galibi, Suriname; and Tortuguero, Costa Rica. Five single-nucleotide polymorphisms (SNPs) were identified that subdivided CM-A5 among regions. Mitogenomic pairwise φ(ST) values of eastern Caribbean rookery comparisons were markedly lower than the respective pairwise F(ST) values. This discrepancy results from the presence of haplotypes representing two divergent lineages in each rookery, highlighting the importance of choosing the appropriate test statistic for addressing the study question. Haplotype frequency differentiation supports demographic independence of Aves Island and Suriname, emphasizing the need to recognize the smaller Aves rookery as a distinct management unit. Aves Island and Buck Island rookeries shared mitogenomic haplotypes; however, frequency divergence suggests that the Buck Island rookery is sufficiently demographically isolated to warrant management unit status for the USVI rookeries. Given that haplotype sharing among rookeries is common in marine turtles with cosmopolitan distributions, mitogenomic sequencing may enhance inferences of population structure and phylogeography, as well as improve the resolution of mixed stock analyses aimed at estimating natal origins of foraging turtles.
Collapse
Affiliation(s)
- Brian M Shamblin
- Daniel B. Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA 30605, USA.
| | | | | | | | | | | | | |
Collapse
|
31
|
Affiliation(s)
- Hannah B. Vander Zanden
- Department of Biology and Archie Carr Center for Sea Turtle Research; University of Florida; PO Box 118525; Gainesville; Florida; 32611-8525; USA
| | - Karen A. Bjorndal
- Department of Biology and Archie Carr Center for Sea Turtle Research; University of Florida; PO Box 118525; Gainesville; Florida; 32611-8525; USA
| | - Patrick W. Inglett
- Department of Soil and Water Science; University of Florida; PO Box 110510; Gainesville; Florida; 32611-0510; USA
| | - Alan B. Bolten
- Department of Biology and Archie Carr Center for Sea Turtle Research; University of Florida; PO Box 118525; Gainesville; Florida; 32611-8525; USA
| |
Collapse
|
32
|
Almeida AP, Moreira LMP, Bruno SC, Thomé JCA, Martins AS, Bolten AB, Bjorndal KA. Green turtle nesting on Trindade Island, Brazil: abundance, trends, and biometrics. ENDANGER SPECIES RES 2011. [DOI: 10.3354/esr00357] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
|
33
|
Wallace BP, DiMatteo AD, Hurley BJ, Finkbeiner EM, Bolten AB, Chaloupka MY, Hutchinson BJ, Abreu-Grobois FA, Amorocho D, Bjorndal KA, Bourjea J, Bowen BW, Dueñas RB, Casale P, Choudhury BC, Costa A, Dutton PH, Fallabrino A, Girard A, Girondot M, Godfrey MH, Hamann M, López-Mendilaharsu M, Marcovaldi MA, Mortimer JA, Musick JA, Nel R, Pilcher NJ, Seminoff JA, Troëng S, Witherington B, Mast RB. Regional management units for marine turtles: a novel framework for prioritizing conservation and research across multiple scales. PLoS One 2010; 5:e15465. [PMID: 21253007 PMCID: PMC3003737 DOI: 10.1371/journal.pone.0015465] [Citation(s) in RCA: 226] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2010] [Accepted: 10/01/2010] [Indexed: 11/18/2022] Open
Abstract
Background Resolving threats to widely distributed marine megafauna requires definition of the geographic distributions of both the threats as well as the population unit(s) of interest. In turn, because individual threats can operate on varying spatial scales, their impacts can affect different segments of a population of the same species. Therefore, integration of multiple tools and techniques — including site-based monitoring, genetic analyses, mark-recapture studies and telemetry — can facilitate robust definitions of population segments at multiple biological and spatial scales to address different management and research challenges. Methodology/Principal Findings To address these issues for marine turtles, we collated all available studies on marine turtle biogeography, including nesting sites, population abundances and trends, population genetics, and satellite telemetry. We georeferenced this information to generate separate layers for nesting sites, genetic stocks, and core distributions of population segments of all marine turtle species. We then spatially integrated this information from fine- to coarse-spatial scales to develop nested envelope models, or Regional Management Units (RMUs), for marine turtles globally. Conclusions/Significance The RMU framework is a solution to the challenge of how to organize marine turtles into units of protection above the level of nesting populations, but below the level of species, within regional entities that might be on independent evolutionary trajectories. Among many potential applications, RMUs provide a framework for identifying data gaps, assessing high diversity areas for multiple species and genetic stocks, and evaluating conservation status of marine turtles. Furthermore, RMUs allow for identification of geographic barriers to gene flow, and can provide valuable guidance to marine spatial planning initiatives that integrate spatial distributions of protected species and human activities. In addition, the RMU framework — including maps and supporting metadata — will be an iterative, user-driven tool made publicly available in an online application for comments, improvements, download and analysis.
Collapse
Affiliation(s)
- Bryan P Wallace
- International Union for Conservation of Nature (IUCN)/SSC Marine Turtle Specialist Group-Burning Issues Working Group, Arlington, Virginia, United States of America.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
34
|
Osborne AG, Jacobson ER, Bresette MJ, Singewald DA, Scarpino RA, Bolten AB. Reference intervals and relationships between health status, carapace length, body mass, and water temperature and concentrations of plasma total protein and protein electrophoretogram fractions in Atlantic loggerhead sea turtles and green turtles. J Am Vet Med Assoc 2010; 237:561-7. [DOI: 10.2460/javma.237.5.561] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
35
|
Hamann M, Godfrey MH, Seminoff JA, Arthur K, Barata PCR, Bjorndal KA, Bolten AB, Broderick AC, Campbell LM, Carreras C, Casale P, Chaloupka M, Chan SKF, Coyne MS, Crowder LB, Diez CE, Dutton PH, Epperly SP, FitzSimmons NN, Formia A, Girondot M, Hays GC, Cheng IS, Kaska Y, Lewison R, Mortimer JA, Nichols WJ, Reina RD, Shanker K, Spotila JR, Tomás J, Wallace BP, Work TM, Zbinden J, Godley BJ. Global research priorities for sea turtles: informing management and conservation in the 21st century. ENDANGER SPECIES RES 2010. [DOI: 10.3354/esr00279] [Citation(s) in RCA: 409] [Impact Index Per Article: 29.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
|
36
|
Vander Zanden HB, Bjorndal KA, Reich KJ, Bolten AB. Individual specialists in a generalist population: results from a long-term stable isotope series. Biol Lett 2010; 6:711-4. [PMID: 20335202 DOI: 10.1098/rsbl.2010.0124] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Individual variation in resource use has often been ignored in ecological studies, but closer examination of individual patterns through time may reveal significant intrapopulation differences. Adult loggerhead sea turtles (Caretta caretta) are generalist carnivores with a wide geographical range, resulting in a broad isotopic niche. We microsampled scute, a persistent and continuously growing tissue, to examine long-term variation in resource use (up to 12 years) in 15 nesting loggerhead turtles. Using stable isotopes of nitrogen and carbon, we examined the resource use patterns (integration of diet, habitat and geographical location) and demonstrate that individual loggerheads are long-term specialists within a generalist population. We present our results in the context of a conceptual model comparing isotopic niches in specialist and generalist populations. Individual consistency may have important ecological, evolutionary and conservation consequences, such as the reduction of intraspecific competition.
Collapse
Affiliation(s)
- Hannah B Vander Zanden
- Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, PO Box 118525, Gainesville, FL 32611, USA.
| | | | | | | |
Collapse
|
37
|
Moncada F, Abreu-Grobois FA, Bagley D, Bjorndal KA, Bolten AB, Camiñas JA, Ehrhart L, Muhlia-Melo A, Nodarse G, Schroeder BA, Zurita J, Hawkes LA. Movement patterns of loggerhead turtles Caretta caretta in Cuban waters inferred from flipper tag recaptures. ENDANGER SPECIES RES 2010. [DOI: 10.3354/esr00248] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
|
38
|
Bjorndal KA, Reich KJ, Bolten AB. Effect of repeated tissue sampling on growth rates of juvenile loggerhead turtles Caretta caretta. Dis Aquat Organ 2010; 88:271-273. [PMID: 20377016 DOI: 10.3354/dao02175] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
We evaluated the effect of repeated tissue sampling on growth rates of juvenile loggerhead sea turtles Caretta caretta. Samples of blood, skin, and scute (keratinized epidermal layer covering the bony shell) were collected at 3 intervals over a 120 d period from 37 loggerheads; 8 control turtles were not sampled. No infections or scarring occurred at the sampling sites, and growth in mass of experimental and control turtles was not significantly different. The sampling regime did not affect the health or physiological status of the turtles.
Collapse
Affiliation(s)
- Karen A Bjorndal
- Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, PO Box 118525, Gainesville, Florida 32611, USA.
| | | | | |
Collapse
|
39
|
Frick MG, Williams KL, Bolten AB, Bjorndal KA, Martins HR. Foraging ecology of oceanic-stage loggerhead turtles Caretta caretta. ENDANGER SPECIES RES 2009. [DOI: 10.3354/esr00227] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
|
40
|
Abstract
The purpose of this study was to assess the compensatory responses to food restriction and subsequent increased food availability in juvenile green turtles (Chelonia mydas). Turtles were fed an ad libitum ration for 12 weeks (AL), a restricted ration for 12 weeks (R), or a restricted ration for 5 weeks and an ad libitum ration for 7 weeks (R-AL). Analysis of covariance was used to test the relationships between (1) growth and body size, (2) intake and body size, and (3) growth and intake for each of the three treatment groups. Body composition of turtles in each group was also evaluated at the beginning of the study and after weeks 5 and 12. After the switch to ad libitum feeding, R-AL turtles consumed comparable amounts of food and grew faster than AL turtles on a size-adjusted basis, but mean body sizes did not converge, although the overlap in their size ranges increased with time. The R-AL turtles also converted food to growth more efficiently and allocated proportionally more nutrients to protein accretion, thereby restoring body composition (except mineral content) to AL levels by the end of the study. Thus, accelerated size-specific growth without hyperphagia restored body condition but not size. These results indicate that (1) intake in juvenile green turtles is maximal when food is readily available and cannot be increased to compensate for a previous period of food limitation, (2) growth rates of ad libitum-fed turtles are only mildly plastic in response to past nutritional history, and (3) priority rules for nutrient allocation favor the attainment of an optimal condition rather than an optimal size. Nutritional setbacks experienced during the vulnerable juvenile stage could therefore have long-lasting consequences for wild turtles in terms of size-specific mortality risk, but these risks may be mitigated by the potential benefits of maintaining sufficient body stores.
Collapse
Affiliation(s)
- Alison M Roark
- Archie Carr Center for Sea Turtle Research, Department of Zoology, University of Florida, Box 118525, Gainesville, Florida 32611-8525, USA.
| | | | | |
Collapse
|
41
|
Roark AM, Bjorndal KA, Bolten AB, Leeuwenburgh C. Biochemical indices as correlates of recent growth in juvenile green turtles (Chelonia mydas). J Exp Mar Biol Ecol 2009; 376:59-67. [PMID: 20161581 PMCID: PMC2808034 DOI: 10.1016/j.jembe.2009.06.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Nucleic acid and protein concentrations and their ratios are increasingly used as correlates of nutritional condition and growth in marine species. However, their application in studies of reptile growth has not yet been validated. The green turtle (Chelonia mydas) is an endangered marine reptile for which assessing population health requires knowledge of demographic parameters such as individual growth rates. The purpose of this study was to evaluate a number of biochemical indices ([DNA], [RNA], RNA:DNA ratio, [protein], protein:DNA ratio, and RNA:protein ratio) in liver, heart, and blood as potential predictors of recent growth rate in juvenile green turtles under controlled feeding conditions. Intake of juvenile green turtles was manipulated over twelve weeks to obtain a range of growth rates. With the exception of [RNA](blood), [DNA](heart), and [protein]:[DNA](liver), all biochemical indices demonstrated significant linear relationships with growth rate during the last 1.5 weeks of the study. The best single predictors of recent growth were hepatic [RNA] and [RNA]:[protein], which explained 66% and 49%, respectively, of the variance in growth. Contrary to expectations, these two indices were negatively correlated with growth rate. To investigate the possibility that hepatic [RNA] was higher in slow-growing turtles because of elevated expression of antioxidant genes, we quantified glutathione peroxidase activity and total antioxidant potential. Both measures of antioxidant function were affected by intake and growth histories, but these effects did not explain our results for hepatic RNA and protein concentrations. We developed a model that predicted 68% of the variance in specific growth rate (SGR) with the equation SGR = -0.913(ln[RNA](liver)) + 17.689(Condition Index) + 4.316. In addition, our findings that [DNA] and [RNA]:[DNA] for blood were significantly correlated with SGR demonstrate the potential utility of minimally invasive tissue sampling that could facilitate instantaneous population monitoring.
Collapse
Affiliation(s)
- Alison M. Roark
- Archie Carr Center for Sea Turtle Research, Department of Zoology, University of Florida, Box, 118525, Gainesville, FL 32611, USA
| | - Karen A. Bjorndal
- Archie Carr Center for Sea Turtle Research, Department of Zoology, University of Florida, Box, 118525, Gainesville, FL 32611, USA
| | - Alan B. Bolten
- Archie Carr Center for Sea Turtle Research, Department of Zoology, University of Florida, Box, 118525, Gainesville, FL 32611, USA
| | - Christiaan Leeuwenburgh
- Department of Aging and Geriatrics, College of Medicine, University of Florida Institute on, Aging Genomics and Biomarkers Core, Biochemistry of Aging Laboratory, Gainesville, FL 32611, USA
| |
Collapse
|
42
|
Abstract
Ignorance of the location or inaccessible locations of lifestages can impede the study and management of species. We used stable isotopes of carbon and nitrogen to identify the habitats and diets and to estimate the duration of a 'missing' lifestage: the early juvenile stage of the green turtle, Chelonia mydas. Stable isotopes in scute from young herbivorous green turtles in shallow-water habitats revealed that they spend 3-5 years as carnivores in oceanic habitats before making a rapid ontogenetic shift in diet and habitat. Stable isotopes in persistent and continuously growing tissues, such as some fish scales, bird bills and claws and mammal hair and claws, can be used to evaluate the ecology of inaccessible lifestages.
Collapse
Affiliation(s)
- Kimberly J Reich
- Archie Carr Center for Sea Turtle Research, Department of Zoology, PO Box 118525, University of Florida, Gainesville, FL 32611, USA.
| | | | | |
Collapse
|
43
|
Seminoff JA, Bjorndal KA, Bolten AB. Stable Carbon and Nitrogen Isotope Discrimination and Turnover in Pond Sliders Trachemys Scripta: Insights for Trophic Study of Freshwater Turtles. COPEIA 2007. [DOI: 10.1643/0045-8511(2007)2007[534:scanid]2.0.co;2] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
44
|
Abstract
Traditional mixed stock analyses use morphological, chemical, or genetic markers measured in several source populations and in a single mixed population to estimate the proportional contribution of each source to the mixed population. In many systems, however, different individuals from a particular source population may go to a variety of mixed populations. Now that data are becoming available from (meta)populations with multiple mixed stocks, the need arises to estimate contributions in this 'many-to-many' scenario. We suggest a Bayesian hierarchical approach, an extension of previous Bayesian mixed stock analysis algorithms, that can estimate contributions in this case. Applying the method to mitochondrial DNA data from green turtles (Chelonia mydas) in the Atlantic gives results that are largely consistent with previous results but makes some novel points, e.g. that the Florida, Bahamas and Corisco Bay foraging grounds have greater contributions than previously thought from distant foraging grounds. More generally, the 'many-to-many' approach gives a more complete understanding of the spatial ecology of organisms, which is especially important in species such as the green turtle that exhibit weak migratory connectivity (several distinct subpopulations at one end of the migration that mix in unknown ways at the other end).
Collapse
Affiliation(s)
- Benjamin M Bolker
- Department of Zoology & Archie Carr Center for Sea Turtle Research, University of Florida, PO Box 118525, Gainesville, FL 32611-8525, USA.
| | | | | | | |
Collapse
|
45
|
Bjorndal KA, Bolten AB, Moreira L, Bellini C, Marcovaldi MÂ. Population Structure and Diversity of Brazilian Green Turtle Rookeries Based on Mitochondrial DNA Sequences. Chelonian Conservation and Biology 2006. [DOI: 10.2744/1071-8443(2006)5[262:psadob]2.0.co;2] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
46
|
Bowen BW, Grant WS, Hillis-Starr Z, Shaver DJ, Bjorndal KA, Bolten AB, Bass AL. Mixed-stock analysis reveals the migrations of juvenile hawksbill turtles (Eretmochelys imbricata) in the Caribbean Sea. Mol Ecol 2006; 16:49-60. [PMID: 17181720 DOI: 10.1111/j.1365-294x.2006.03096.x] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Hawksbill turtles (Eretmochelys imbricata) migrate between nesting beaches and feeding habitats that are often associated with tropical reefs, but it is uncertain which nesting colonies supply which feeding habitats. To address this gap in hawksbill biology, we compile previously published and new mitochondrial DNA (mtDNA) haplotype data for 10 nesting colonies (N = 347) in the western Atlantic and compare these profiles to four feeding populations and four previously published feeding samples (N = 626). Nesting colonies differ significantly in mtDNA haplotype frequencies (Phi(ST) = 0.588, P < 0.001), corroborating earlier conclusions of nesting site fidelity and setting the stage for mixed-stock analysis. Feeding aggregations show lower but significant structure (Phi(ST) = 0.089, P < 0.001), indicating that foraging populations are not homogenous across the Caribbean Sea. Bayesian mixed-stock estimates of the origins of juveniles in foraging areas show a highly significant, but shallow, correlation with nesting population size (r = 0.378, P = 0.004), supporting the premise that larger rookeries contribute more juveniles to feeding areas. A significant correlation between the estimated contribution and geographical distance from nesting areas (r = -0.394, P = 0.003) demonstrates the influence of proximity on recruitment to feeding areas. The influence of oceanic currents is illustrated by pelagic stage juveniles stranded in Texas, which are assigned primarily (93%) to the upstream rookery in Yucatan. One juvenile had a haplotype previously identified only in the eastern Atlantic, invoking rare trans-oceanic migrations. The mixed-stock analysis demonstrates that harvests in feeding habitats will impact nesting colonies throughout the region, with the greatest detriment to nearby nesting populations.
Collapse
Affiliation(s)
- B W Bowen
- Hawaii Institute of Marine Biology, University of Hawaii, PO Box 1346, Kaneohe, Hawaii 96744, USA.
| | | | | | | | | | | | | |
Collapse
|
47
|
Tiwari M, Bjorndal KA, Bolten AB, Bolker BM. Intraspecific application of the mid‐domain effect model: spatial and temporal nest distributions of green turtles,
Chelonia mydas
, at Tortuguero, Costa Rica. Ecol Lett 2005; 8:918-924. [DOI: 10.1111/j.1461-0248.2005.00793.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Manjula Tiwari
- Archie Carr Center for Sea Turtle Research and Department of Zoology, University of Florida, PO Box 118525, Gainesville, FL 32611, USA
| | | | - Alan B. Bolten
- Archie Carr Center for Sea Turtle Research and Department of Zoology, University of Florida, PO Box 118525, Gainesville, FL 32611, USA
| | - Benjamin M. Bolker
- Archie Carr Center for Sea Turtle Research and Department of Zoology, University of Florida, PO Box 118525, Gainesville, FL 32611, USA
| |
Collapse
|
48
|
Bowen BW, Bass AL, Chow SM, Bostrom M, Bjorndal KA, Bolten AB, Okuyama T, Bolker BM, Epperly S, Lacasella E, Shaver D, Dodd M, Hopkins-Murphy SR, Musick JA, Swingle M, Rankin-Baransky K, Teas W, Witzell WN, Dutton PH. Natal homing in juvenile loggerhead turtles (Caretta caretta). Mol Ecol 2005; 13:3797-808. [PMID: 15548292 DOI: 10.1111/j.1365-294x.2004.02356.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Juvenile loggerhead turtles (Caretta caretta) from West Atlantic nesting beaches occupy oceanic (pelagic) habitats in the eastern Atlantic and Mediterranean, whereas larger juvenile turtles occupy shallow (neritic) habitats along the continental coastline of North America. Hence the switch from oceanic to neritic stage can involve a trans-oceanic migration. Several researchers have suggested that at the end of the oceanic phase, juveniles are homing to feeding habitats in the vicinity of their natal rookery. To test the hypothesis of juvenile homing behaviour, we surveyed 10 juvenile feeding zones across the eastern USA with mitochondrial DNA control region sequences (N = 1437) and compared these samples to potential source (nesting) populations in the Atlantic Ocean and Mediterranean Sea (N = 465). The results indicated a shallow, but significant, population structure of neritic juveniles (PhiST = 0.0088, P = 0.016), and haplotype frequency differences were significantly correlated between coastal feeding populations and adjacent nesting populations (Mantel test R2 = 0.52, P = 0.001). Mixed stock analyses (using a Bayesian algorithm) indicated that juveniles occurred at elevated frequency in the vicinity of their natal rookery. Hence, all lines of evidence supported the hypothesis of juvenile homing in loggerhead turtles. While not as precise as the homing of breeding adults, this behaviour nonetheless places juvenile turtles in the vicinity of their natal nesting colonies. Some of the coastal hazards that affect declining nesting populations may also affect the next generation of turtles feeding in nearby habitats.
Collapse
Affiliation(s)
- Brian W Bowen
- Hawaii Institute of Marine Biology, University of Hawaii, PO Box 1346, Kaneohe, HI 96744, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
49
|
|
50
|
Schmid JR, Bolten AB, Bjorndal KA, Lindberg WJ, Percival HF, Zwick PD. Home Range and Habitat Use by Kemp's Ridley Turtles in West-Central Florida. J Wildl Manage 2003. [DOI: 10.2307/3803075] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|