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Phillott AD, Godfrey MH. Assessing the evidence of ‘infertile’ sea turtle eggs. ENDANGER SPECIES RES 2020. [DOI: 10.3354/esr01032] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
There is increasing concern about feminization of sea turtle populations resulting from female-biased production of hatchlings due to climate change and selective loss of males from other anthropogenic drivers. Extreme female-biased breeding populations would reduce the likelihood of successful mating and potentially result in high rates of infertile eggs. Infertile eggs are those in which none of the events between sperm penetration of the ovum and syngamy have occurred. Distinguishing between fertile and infertile eggs is challenging, especially in field conditions, and researchers often have relied on physical evidence gathered from unhatched eggs at the end of the incubation period, which likely have experienced tissue decomposition. We argue that infertility in sea turtle eggs can be demonstrated only by the absence of holes caused by sperm penetration of the inner perivitelline membrane; sperm bound between the inner and outer perivitelline membranes; nuclei in the blastodisc; embryonic tissue or membranes in egg contents; and/or the characteristic white spot on the egg exterior. Unhatched eggs can be examined at the end of the incubation period, but we recommend that studies specifically investigating infertility examine at least 20 oviposited eggs each from clutches laid by at least 20 different turtles at the peak of the nesting season.
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Affiliation(s)
- AD Phillott
- FLAME University, Pune, Maharashtra 412115, India
| | - MH Godfrey
- North Carolina Wildlife Resources Commission, Beaufort, NC 28516, USA
- Duke Marine Laboratory, Nicholas School of Environment, Duke University, Beaufort, NC 28516, USA
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27695, USA
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2
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Usategui-Martín A, Liria-Loza A, Miller JD, Medina-Suárez M, Jiménez-Bordón S, Pérez-Mellado V, Montero D. Effects of incubation temperature on hatchling performance and phenotype in loggerhead sea turtle Caretta caretta. ENDANGER SPECIES RES 2019. [DOI: 10.3354/esr00935] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Liles MJ, Peterson TR, Seminoff JA, Gaos AR, Altamirano E, Henríquez AV, Gadea V, Chavarría S, Urteaga J, Wallace BP, Peterson MJ. Potential limitations of behavioral plasticity and the role of egg relocation in climate change mitigation for a thermally sensitive endangered species. Ecol Evol 2019; 9:1603-1622. [PMID: 30847059 PMCID: PMC6392375 DOI: 10.1002/ece3.4774] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 10/12/2018] [Accepted: 11/05/2018] [Indexed: 01/18/2023] Open
Abstract
Anthropogenic climate change is widely considered a major threat to global biodiversity, such that the ability of a species to adapt will determine its likelihood of survival. Egg-burying reptiles that exhibit temperature-dependent sex determination, such as critically endangered hawksbill turtles (Eretmochelys imbricata), are particularly vulnerable to changes in thermal regimes because nest temperatures affect offspring sex, fitness, and survival. It is unclear whether hawksbills possess sufficient behavioral plasticity of nesting traits (i.e., redistribution of nesting range, shift in nesting phenology, changes in nest-site selection, and adjustment of nest depth) to persist within their climatic niche or whether accelerated changes in thermal conditions of nesting beaches will outpace phenotypic adaption and require human intervention. For these reasons, we estimated sex ratios and physical condition of hatchling hawksbills under natural and manipulated conditions and generated and analyzed thermal profiles of hawksbill nest environments within highly threatened mangrove ecosystems at Bahía de Jiquilisco, El Salvador, and Estero Padre Ramos, Nicaragua. Hawksbill clutches protected in situ at both sites incubated at higher temperatures, yielded lower hatching success, produced a higher percentage of female hatchlings, and produced less fit offspring than clutches relocated to hatcheries. We detected cooler sand temperatures in woody vegetation (i.e., coastal forest and small-scale plantations of fruit trees) and hatcheries than in other monitored nest environments, with higher temperatures at the deeper depth. Our findings indicate that mangrove ecosystems present a number of biophysical (e.g., insular nesting beaches and shallow water table) and human-induced (e.g., physical barriers and deforestation) constraints that, when coupled with the unique life history of hawksbills in this region, may limit behavioral compensatory responses by the species to projected temperature increases at nesting beaches. We contend that egg relocation can contribute significantly to recovery efforts in a changing climate under appropriate circumstances.
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Affiliation(s)
- Michael J. Liles
- Asociación ProCostaSan SalvadorEl Salvador
- Eastern Pacific Hawksbill InitiativeSan DiegoCalifornia
| | - Tarla Rai Peterson
- Department of Communication, Environmental Science and Engineering ProgramUniversity of Texas at El PasoEl PasoTexas
| | - Jeffrey A. Seminoff
- National Oceanic and Atmospheric Administration – National Marine Fisheries ServiceSouthwest Fisheries Science CenterLa JollaCalifornia
- Eastern Pacific Hawksbill InitiativeSan DiegoCalifornia
| | - Alexander R. Gaos
- Department of BiologySan Diego State UniversitySan DiegoCalifornia
- Eastern Pacific Hawksbill InitiativeSan DiegoCalifornia
| | - Eduardo Altamirano
- Fauna and Flora InternationalManaguaNicaragua
- Eastern Pacific Hawksbill InitiativeSan DiegoCalifornia
| | - Ana V. Henríquez
- Asociación ProCostaSan SalvadorEl Salvador
- Eastern Pacific Hawksbill InitiativeSan DiegoCalifornia
| | - Velkiss Gadea
- Fauna and Flora InternationalManaguaNicaragua
- Eastern Pacific Hawksbill InitiativeSan DiegoCalifornia
| | - Sofía Chavarría
- Asociación ProCostaSan SalvadorEl Salvador
- Eastern Pacific Hawksbill InitiativeSan DiegoCalifornia
| | - José Urteaga
- School of Earth, Energy & Environmental SciencesStanford UniversityStanfordCalifornia
- Eastern Pacific Hawksbill InitiativeSan DiegoCalifornia
| | - Bryan P. Wallace
- Conservation Science Partners, Inc.Fort CollinsColorado
- Nicholas School of the EnvironmentDuke University Marine LabBeaufortNorth Carolina
- Eastern Pacific Hawksbill InitiativeSan DiegoCalifornia
| | - Markus J. Peterson
- Department of Biological SciencesUniversity of Texas at El PasoEl PasoTexas
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Ware M, Fuentes MM. Potential for Relocation to Alter the Incubation Environment and Productivity of Sea Turtle Nests in the Northern Gulf of Mexico. CHELONIAN CONSERVATION AND BIOLOGY 2018. [DOI: 10.2744/ccb-1306.1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Matthew Ware
- Department of Earth, Ocean, and Atmospheric Science, Florida State University, Tallahassee, Florida
| | - Mariana M.P.B. Fuentes
- Department of Earth, Ocean, and Atmospheric Science, Florida State University, Tallahassee, Florida
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5
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Marn N, Kooijman SALM, Jusup M, Legović T, Klanjšček T. Inferring physiological energetics of loggerhead turtle (Caretta caretta) from existing data using a general metabolic theory. MARINE ENVIRONMENTAL RESEARCH 2017; 126:14-25. [PMID: 28219019 DOI: 10.1016/j.marenvres.2017.01.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 01/18/2017] [Accepted: 01/19/2017] [Indexed: 05/14/2023]
Abstract
Loggerhead turtle is an endangered sea turtle species with a migratory lifestyle and worldwide distribution, experiencing markedly different habitats throughout its lifetime. Environmental conditions, especially food availability and temperature, constrain the acquisition and the use of available energy, thus affecting physiological processes such as growth, maturation, and reproduction. These physiological processes at the population level determine survival, fecundity, and ultimately the population growth rate-a key indicator of the success of conservation efforts. As a first step towards the comprehensive understanding of how environment shapes the physiology and the life cycle of a loggerhead turtle, we constructed a full life cycle model based on the principles of energy acquisition and utilization embedded in the Dynamic Energy Budget (DEB) theory. We adapted the standard DEB model using data from published and unpublished sources to obtain parameter estimates and model predictions that could be compared with data. The outcome was a successful mathematical description of ontogeny and life history traits of the loggerhead turtle. Some deviations between the model and the data existed (such as an earlier age at sexual maturity and faster growth of the post-hatchlings), yet probable causes for these deviations were found informative and discussed in great detail. Physiological traits such as the capacity to withstand starvation, trade-offs between reproduction and growth, and changes in the energy budget throughout the ontogeny were inferred from the model. The results offer new insights into physiology and ecology of loggerhead turtle with the potential to lead to novel approaches in conservation of this endangered species.
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Affiliation(s)
- Nina Marn
- Ruđer Bošković Institute, Bijenička cesta 54, HR-10002 Zagreb, Croatia.
| | - S A L M Kooijman
- Vrije Universiteit Amsterdam, De Boelelaan 1105, 1081 HV Amsterdam, The Netherlands
| | - Marko Jusup
- Center of Mathematics for Social Creativity, Hokkaido University, 12-7 Kita Ward, 060-0812 Sapporo, Japan.
| | - Tarzan Legović
- Ruđer Bošković Institute, Bijenička cesta 54, HR-10002 Zagreb, Croatia
| | - Tin Klanjšček
- Ruđer Bošković Institute, Bijenička cesta 54, HR-10002 Zagreb, Croatia
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6
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Braun McNeill J, Avens L, Goodman Hall A, Goshe LR, Harms CA, Owens DW. Female-Bias in a Long-Term Study of a Species with Temperature-Dependent Sex Determination: Monitoring Sex Ratios for Climate Change Research. PLoS One 2016; 11:e0160911. [PMID: 27579608 PMCID: PMC5007042 DOI: 10.1371/journal.pone.0160911] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 07/27/2016] [Indexed: 11/18/2022] Open
Abstract
Alterations have occurred and continue to manifest in the Earth's biota as a result of climate change. Animals exhibiting temperature dependent sex determination (TSD), including sea turtles, are perhaps most vulnerable to a warming of the Earth as highly skewed sex ratios can result, potentially leading to population extinction resulting from decreased male recruitment. Recent studies have begun to quantify climate change impacts to sea turtle populations, especially in terms of predicting effects on hatchling sex ratios. However, given the inherent difficulty in studying sex ratios at this life stage, a more accurate assessment of changes in population sex ratios might be derived by evaluating the juvenile portion of foraging aggregations. We investigated the long-term trend in sex ratio of a juvenile loggerhead (Caretta caretta) sea turtle population inhabiting Pamlico and Core Sounds, North Carolina, USA. We used plasma testosterone reference ranges measured using radioimmunoassay (RIA) to assign sex for 959 turtles and confirmed sex assignment of a subset (N = 58) of the sampled turtles through laparoscopic examination of their gonads. Our results demonstrate that for this particular population of loggerheads, sex ratios (3Females:1Male) had not significantly changed over a 10 year period (1998-2007), nor showed any significant difference among 5-cm straight carapace length (SCL) size classes. Ultimately, these findings provide a basis for comparison with future sex ratios, and highlight the importance of establishing similar long-term studies monitoring secondary, rather than primary, sex ratios, so that needed mitigation measures to climate change impacts can be implemented.
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Affiliation(s)
- Joanne Braun McNeill
- Southeast Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Beaufort, North Carolina, United States of America
- * E-mail:
| | - Larisa Avens
- Southeast Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Beaufort, North Carolina, United States of America
| | - April Goodman Hall
- Southeast Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Beaufort, North Carolina, United States of America
| | - Lisa R. Goshe
- Southeast Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Beaufort, North Carolina, United States of America
| | - Craig A. Harms
- Center for Marine Sciences and Technology, College of Veterinary Medicine, North Carolina State University, Morehead City, North Carolina, United States of America
| | - David W. Owens
- University of Charleston, South Carolina at the College of Charleston, Charleston, South Carolina, United States of America
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7
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Candan O, Kolankaya D. Sex Ratio of Green Turtle (Chelonia mydas) Hatchlings at Sugözü, Turkey: Higher Accuracy with Pivotal Incubation Duration. CHELONIAN CONSERVATION AND BIOLOGY 2016. [DOI: 10.2744/ccb-1132.1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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8
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Escobedo-Galván AH, López-Luna MA, Cupul-Magaña FG. Thermal fluctuation within nests and predicted sex ratio of Morelet's Crocodile. J Therm Biol 2016; 58:23-8. [PMID: 27157330 DOI: 10.1016/j.jtherbio.2016.03.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Revised: 03/12/2016] [Accepted: 03/13/2016] [Indexed: 10/22/2022]
Abstract
Understanding the interplay between thermal variations and sex ratio in reptiles with temperature-dependent sex determination is the first step for developing long-term conservation strategies. In case of crocodilians, the information is fragmentary and insufficient for establishing a general framework to consider how thermal fluctuation influence sex determination under natural conditions. The main goal of this study was to analyze thermal variation in nests of Crocodylus moreletii and to discuss the potential implications for predicting offspring sex ratio. The study was carried out at the Centro de Estudios Tecnológicos del Mar N° 2 and at the Sistemas Productivos Cocodrilo, Campeche, Mexico. Data was collected in the nesting season of Morelet's Crocodiles during three consecutive seasons (2007-2009). Thermal fluctuations for multiple areas of the nest chamber were registered by data loggers. We calculate the constant temperature equivalent based on thermal profiles among nests to assess whether there are differences between the nest temperature and its equivalent to constant temperature. We observed that mean nest temperature was only different among nests, while daily thermal fluctuations vary depending on the depth position within the nest chamber, years and nests. The constant temperature equivalent was different among and within nests, but not among survey years. We observed differences between constant temperature equivalent and mean nest temperature both at the top and in the middle of the nest cavities, but were not significantly different at the bottom of nest cavities. Our results enable examine and discuss the relevance of daily thermal fluctuations to predict sex ratio of the Morelet's Crocodile.
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Affiliation(s)
- Armando H Escobedo-Galván
- Centro Universitario de la Costa, Universidad de Guadalajara, Av. Universidad 203, 48280 Puerto Vallarta, Jalisco, México.
| | - Marco A López-Luna
- División Académica de Ciencias Biológicas, Universidad Juárez Autónoma de Tabasco, Carr. Villahermosa-Cárdenas km.0.5 s/n, Entrq. Bosques de Saloya, 86039 Villahermosa, Tabasco, México
| | - Fabio G Cupul-Magaña
- Centro Universitario de la Costa, Universidad de Guadalajara, Av. Universidad 203, 48280 Puerto Vallarta, Jalisco, México
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9
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Wyneken J, Lolavar A. Loggerhead sea turtle environmental sex determination: Implications of moisture and temperature for climate change based predictions for species survival. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2015; 324:295-314. [DOI: 10.1002/jez.b.22620] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 03/02/2015] [Indexed: 11/09/2022]
Affiliation(s)
- Jeanette Wyneken
- Department of Biological Sciences; Florida Atlantic University; Boca Raton Florida
| | - Alexandra Lolavar
- Department of Biological Sciences; Florida Atlantic University; Boca Raton Florida
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10
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Sex ratio estimations of loggerhead sea turtle hatchlings at Kuriat islands, Tunisia: can minor nesting sites contribute to compensate globally female-biased sex ratio? ScientificWorldJournal 2014; 2014:419410. [PMID: 25379528 PMCID: PMC4212550 DOI: 10.1155/2014/419410] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2014] [Accepted: 09/08/2014] [Indexed: 12/03/2022] Open
Abstract
Hatchling sex ratios in the loggerhead turtle Caretta caretta were estimated by placing electronic temperature recorders in seven nests at Kuriat islands (Tunisia) during the 2013 nesting season. Based on the mean temperatures during the middle third of the incubation period, and on incubation duration, the sex ratio of hatchlings at Kuriat islands was highly male-biased. Presently, the majority of hatchling sex ratio studies are focused on major nesting areas, whereby the sex ratios are universally believed to be heavily female-biased. Here we present findings from a minor nesting site in the Mediterranean, where the hatchling sex ratio was found to be male-biased, suggesting a potential difference between major and minor nesting sites.
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11
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Horne CR, Fuller WJ, Godley BJ, Rhodes KA, Snape R, Stokes KL, Broderick AC. The effect of thermal variance on the phenotype of marine turtle offspring. Physiol Biochem Zool 2014; 87:796-804. [PMID: 25461644 DOI: 10.1086/678238] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Temperature can have a profound effect on the phenotype of reptilian offspring, yet the bulk of current research considers the effects of constant incubation temperatures on offspring morphology, with few studies examining the natural thermal variance that occurs in the wild. Over two consecutive nesting seasons, we placed temperature data loggers in 57 naturally incubating clutches of loggerhead sea turtles Caretta caretta and found that greater diel thermal variance during incubation significantly reduced offspring mass, potentially reducing survival of hatchlings during their journey from the nest to offshore waters and beyond. With predicted scenarios of climate change, behavioral plasticity in nest site selection may be key for the survival of ectothermic species, particularly those with temperature-dependent sex determination.
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Affiliation(s)
- C R Horne
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Cornwall TR10 9FE, United Kingdom; 2Faculty of Veterinary Medicine, Near East University, Nicosia, North Cyprus, Mersin 10, Turkey; 3North Cyprus Society for Protection of Turtles, PK65, Kyrenia, North Cyprus, Mersin 10, Turkey
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12
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dei Marcovaldi MA, Santos AJ, Santos AS, Soares LS, Lopez GG, Godfrey MH, López-Mendilaharsu M, Fuentes MM. Spatio-temporal variation in the incubation duration and sex ratio of hawksbill hatchlings: Implication for future management. J Therm Biol 2014; 44:70-7. [PMID: 25086976 DOI: 10.1016/j.jtherbio.2014.06.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2014] [Revised: 06/27/2014] [Accepted: 06/30/2014] [Indexed: 11/25/2022]
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13
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Kamel SJ. Vegetation cover predicts temperature in nests of the hawksbill sea turtle: implications for beach management and offspring sex ratios. ENDANGER SPECIES RES 2013. [DOI: 10.3354/esr00489] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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14
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LeBlanc AM, Wibbels T, Shaver D, Walker JS. Temperature-dependent sex determination in the Kemp’s ridley sea turtle: effects of incubation temperatures on sex ratios. ENDANGER SPECIES RES 2012. [DOI: 10.3354/esr00465] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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15
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Sieg AE, Binckley CA, Wallace BP, Tomillo PS, Reina RD, Paladino FV, Spotila JR. Sex ratios of leatherback turtles: hatchery translocation decreases metabolic heating and female bias. ENDANGER SPECIES RES 2011. [DOI: 10.3354/esr00372] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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16
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Gomes AS, Ferreira Júnior PD. Management and relocation of nests of Podocnemis expansa (Schweigger, 1812) (Testudines, Podocnemididae) on the Crixás-Açu river, Brazil. BRAZ J BIOL 2011. [DOI: 10.1590/s1519-69842011000500017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Podocnemis expansa nests in the sandbanks of the Crixás-Açu River in central Brazil during the dry season. With the return of the rainy season, the river banks are once again inundated, flooding nests and eggs and drowning hatchlings. This study evaluated relocation as an alternative to manage nests at risk of flooding. Forty P. expansa nests from four beaches of the Crixás-Açu were relocated to nurseries constructed in tanks filled with sand from the same river. Nine nests were covered with palm fronds to simulate shading conditions and to lower the incubation temperature. The base of the egg chamber was at a depth of 60 cm in all the nests. The duration of incubation varied for sunlit (49.1 ± 2.35 days) and shaded nests (51.7 ± 1.75 days), but did not change with nest position (center or edge of nurseries). Hatching success was 47.3 ± 13.6%, and did not vary significantly with sunlight/shade or nest position. The mean incubation temperature during the thermosensitivity period varied from 33 ± 1.56 °C to 34.1 ± 1.40 °C. The lowest mean temperature during the thermosensitivity period (31.9 ± 0.95 °C) and the highest proportion of males (up to 45% of hatchlings) were observed in a shaded nest. Most sunlit nests produced only females. The results suggest that relocation is a viable alternative in managing nests at risk of flooding during the rainy season in the Crixás-Açu. Moreover, artificial shading was shown to be an option to increase the proportion of males.
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Warm water and cool nests are best. How global warming might influence hatchling green turtle swimming performance. PLoS One 2011; 6:e23162. [PMID: 21826236 PMCID: PMC3149641 DOI: 10.1371/journal.pone.0023162] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Accepted: 07/07/2011] [Indexed: 11/19/2022] Open
Abstract
For sea turtles nesting on beaches surrounded by coral reefs, the most important element of hatchling recruitment is escaping predation by fish as they swim across the fringing reef, and as a consequence hatchlings that minimize their exposure to fish predation by minimizing the time spent crossing the fringing reef have a greater chance of surviving the reef crossing. One way to decrease the time required to cross the fringing reef is to maximize swimming speed. We found that both water temperature and nest temperature influence swimming performance of hatchling green turtles, but in opposite directions. Warm water increases swimming ability, with hatchling turtles swimming in warm water having a faster stroke rate, while an increase in nest temperature decreases swimming ability with hatchlings from warm nests producing less thrust per stroke.
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Stewart KR, Dutton PH. Paternal genotype reconstruction reveals multiple paternity and sex ratios in a breeding population of leatherback turtles (Dermochelys coriacea). CONSERV GENET 2011. [DOI: 10.1007/s10592-011-0212-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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19
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Ferreira-Júnior PD, Treichel RL, Scaramussa TL, Scalfoni JT. Morphometric pattern in Caretta caretta (Linnaeus, 1758)(Cheloniidae) hatchlings from nests with different embryo development rates. BRAZ J BIOL 2011; 71:151-6. [PMID: 21437412 DOI: 10.1590/s1519-69842011000100022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2010] [Accepted: 06/29/2010] [Indexed: 11/21/2022] Open
Abstract
The geometric morphometric analysis of the shell of Caretta caretta hatchlings revealed that morphological variations may be related to incubation duration. Based on the overlapping of anatomical landmarks of the carapace and the plastron, it was possible to discriminate hatchlings from slow and fast developing clutches. Carapace and plastron of hatchlings from nests where incubation lasted less than 55 days are rounder as compared to the hatchlings from nests where incubation took 67 days. The differences observed in shell shape in terms of incubation duration were statistically significant, though carapace and plastron shape overlapping was observed in several individuals. Our results indicate that the incubation duration explains only a small part of the total variation in the shell shape as a whole. Yet, in spite of the low discriminant function coefficient, cross-validation tests indicated that 84.7% and 77.8% of the hatchlings were correctly categorised concerning the carapace and plastron, when the descriptive variable is incubation duration.
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Affiliation(s)
- P D Ferreira-Júnior
- Programa de Pós-Graduação em Ecologia de Ecossistemas, Centro Universitário Vila Velha, Vila Velha, ES, Brazil.
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Witt MJ, Hawkes LA, Godfrey MH, Godley BJ, Broderick AC. Predicting the impacts of climate change on a globally distributed species: the case of the loggerhead turtle. ACTA ACUST UNITED AC 2010; 213:901-11. [PMID: 20190115 DOI: 10.1242/jeb.038133] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Marine turtles utilise terrestrial and marine habitats and several aspects of their life history are tied to environmental features that are altering due to rapid climate change. We overview the likely impacts of climate change on the biology of these species, which are likely centred upon the thermal ecology of this taxonomic group. Then, focusing in detail on three decades of research on the loggerhead turtle (Caretta caretta L.), we describe how much progress has been made to date and how future experimental and ecological focus should be directed. Key questions include: what are the current hatchling sex ratios from which to measure future climate-induced changes? What are wild adult sex ratios and how many males are necessary to maintain a fertile and productive population? How will climate change affect turtles in terms of their distribution?
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Affiliation(s)
- M J Witt
- University of Exeter, Centre for Ecology and Conservation, School of Biosciences, Tremough Campus, Penryn, Cornwall TR10 9EZ, UK
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