Browsing by Author "Godfrey, MH"

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Open Access
A call for evaluation of the contribution made by rescue, resuscitation, rehabilitation, and release translocations to kemp’s ridley sea turtle (Lepidochelys kempii) population recovery
(Herpetological Conservation and Biology, 2016-01-01) Caillouet, CW; Putman, NF; Shaver, DJ; Valverde, RA; Seney, EE; Lohmann, KJ; Mansfield, KL; Gallaway, BJ; Flanagan, JP; Godfrey, MH
© 2016. Monica F. Blasi. All Rights Reserved. Kemp’s Ridley Sea Turtle (Lepidochelys kempii) conservation practices permitted by the National Marine Fisheries Service (NMFS) and U.S. Fish and Wildlife Service (USFWS), under authority of the U.S. Endangered Species Act of 1973, include translocations in which eggs or turtles are taken into captivity for various reasons and intervals, and turtles are later released into coastal waters of the Gulf of Mexico (GoM) or the Northwest Atlantic Ocean (NWAO). In 2013, the IUCN Species Survival Commission defined conservation translocation as the deliberate movement of organisms from one site for release in another, with the intention that it must yield a measurable conservation benefit at the levels of a population, species or ecosystem, and not only provide benefit to translocated individuals. Translocations of Kemp’s Ridley Sea Turtles that are found injured, ill, or otherwise debilitated, then rescued, resuscitated if necessary, rehabilitated, and released into the GoM or the NWAO have not been evaluated to determine whether they qualify as conservation translocations. We refer to them as rescue, resuscitation, rehabilitation, and release (i.e., RRRR) translocations. Captivity and human care, by altering behavioral and physiological fitness of RRRR translocated Kemp’s Ridley Sea Turtles, have the potential to influence post-release survival, growth, navigation, foraging, migration, maturation, natal beach homing, and reproduction. We recommend that NMFS and USFWS develop a plan for hypothesis-driven research and modeling aimed at determining if and how RRRR translocations contribute to Kemp’s Ridley Sea Turtle population recovery. Similar evaluations of RRRR translocations are also needed for other sea turtle species.
Open Access
Are we working towards global research priorities for management and conservation of sea turtles?
(Endangered Species Research, 2016-12-30) 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
© The authors 2016. In 2010, an international group of 35 sea turtle researchers refined an initial list of more than 200 research questions into 20 metaquestions that were considered key for management and conservation of sea turtles. These were classified under 5 categories: reproductive biology, biogeography, population ecology, threats and conservation strategies. To obtain a picture of how research is being focused towards these key questions, we undertook a systematic review of the peer-reviewed literature (2014 and 2015) attributing papers to the original 20 questions. In total, we reviewed 605 articles in full and from these 355 (59%) were judged to substantively address the 20 key questions, with others focusing on basic science and monitoring. Progress to answering the 20 questions was not uniform, and there were biases regarding focal turtle species, geographic scope and publication outlet. Whilst it offers some meaningful indications as to effort, quantifying peer-reviewed literature output is ob viously not the only, and possibly not the best, metric for understanding progress towards informing key conservation and management goals. Along with the literature review, an international group based on the original project consortium was assigned to critically summarise recent progress towards answering each of the 20 questions. We found that significant research is being expended towards global priorities for management and conservation of sea turtles. Although highly variable, there has been significant progress in all the key questions identified in 2010. Undertaking this critical review has highlighted that it may be timely to undertake one or more new prioritizing exercises. For this to have maximal benefit we make a range of recommendations for its execution. These include a far greater engagement with social sciences, widening the pool of contributors and focussing the questions, perhaps disaggregating ecology and conservation.
Open Access
Assessing the evidence of 'infertile' sea turtle eggs
(Endangered Species Research, 2020-01-01) Phillott, AD; Godfrey, MH
© 2020, Inter-Research. 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.
Open Access
Crude Oil and Dispersant Cause Acute Clinicopathological Abnormalities in Hatchling Loggerhead Sea Turtles (Caretta caretta)
(Frontiers in Veterinary Science, 2019-10-15) Harms, CA; McClellan-Green, P; Godfrey, MH; Christiansen, EF; Broadhurst, HJ; Godard-Codding, CAJ
Following the explosion of the Deepwater Horizon MC252 oil rig in 2010, 319 live sea turtles exposed to crude oil and oil-dispersant (Corexit) combinations were admitted to rehabilitation centers for decontamination and treatment. Treatment of oiled sea turtles was guided by expected physiological and pathological effects of crude oil exposure extrapolated from studies in other species and from a single loggerhead sea turtle (Caretta caretta) study. While invaluable starting points, inherent limitations to extrapolation, and small sample size of the experimental exposure study, reduce their utility for clinical guidance and for assessing oil spill impacts. Effects of dispersants were not included in the previous experimental exposure study, and cannot be effectively isolated in the analysis of field data from actual spills. A terminal study of pivotal temperature of sex determination using eggs salvaged from doomed loggerhead nests provided an opportunity for an ancillary exposure study to investigate the acute effects of crude oil, dispersant, and a crude oil/dispersant combination in sea turtle hatchlings. Eggs were incubated at 27.2–30.8°C, and hatchlings were randomly assigned to control, oil, dispersant, and combined oil/dispersant exposures for 1 or 4 days. Contaminant exposures were started after a 3 day post-hatching period simulating nest emergence. Turtles were placed in individual glass bowls containing aged seawater and exposed to oil (Gulf Coast—Mixed Crude Oil Sweet, CAS #8002-05-9, 0.833 mL/L) and/or dispersant (Corexit 9500A, 0.083 mL/L), replicating concentrations encountered during oil spills and subsequent response. Statistically significant differences between treatments and non-exposed controls were detected for PCV, AST, uric acid, glucose, calcium, phosphorus, total protein, albumin, globulin, potassium, and sodium. The principal dyscrasias reflected acute osmolar, electrolyte and hydration challenges that were more numerous and greater in combined oil/dispersant exposures at 4 days. Clinicopathological findings were supported by a failure to gain weight (associated with normal hatchling hydration in seawater) in dispersant and combination exposed hatchlings. These findings can help guide clinical response for sea turtles exposed to crude oil and crude oil/dispersant combinations, and indicate potential impacts on wildlife to consider when deploying dispersants in an oil spill response.
Open Access
Exposure of marine turtle nesting grounds to named storms along the continental USA
(Remote Sensing, 2019-12-01) Fuentes, MMPB; Godfrey, MH; Shaver, D; Ceriani, S; Gredzens, C; Boettcher, R; Ingram, D; Ware, M; Wildermann, N
© 2019 by the authors. Named storms can cause substantial impacts on the habitat and reproductive output of threatened species, such as marine turtles. To determine the impacts of named storms on marine turtles and inform management, it is necessary to determine the exposure of marine turtle nesting grounds to recent storm activities. To address this, remote sensing information of named storm tracks coupled with nesting ground data were used to investigate the temporal and spatial overlap between nesting grounds for four species of marine turtles in the continental United States of America. All species of marine turtles were exposed to named storms, with variation in exposure driven by the spatial distribution of each population's nesting ground, the temporal overlap between the storms and reproductive events, and nest placement on the beach. Loggerhead turtles were the most exposed species to named storms, with the northern management unit having significantly higher exposure levels than all other loggerhead management units. Kemp's ridley turtles, in contrast, were found to be the least exposed species to named storms. This study establishes a valuable current baseline against which to measure and compare future impacts that result as climate change progresses and storms become more frequent and intense. Importantly, cumulative and synergetic effects from other climatic processes and anthropogenic stressors should be considered in future analysis.
Open Access
Global research priorities for sea turtles: informing management and conservation in the 21st century
(Endangered Species Research, 2010-05-26) 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; I Jiunn, C; Kaska, Y; Lewison, R; Mortimer, JA; Nichols, WJ; Reina, RD; Shanker, K; Spotila, JR; Tomás, J; Wallace, BP; Work, TM; Zbinden, J; Godley, BJ
Over the past 3 decades, the status of sea turtles and the need for their protection to aid population recovery have increasingly captured the interest of government agencies, non-governmental organisations (NGOs) and the general public worldwide. This interest has been matched by increased research attention, focusing on a wide variety of topics relating to sea turtle biology and ecology, together with the interrelations of sea turtles with the physical and natural environments. Although sea turtles have been better studied than most other marine fauna, management actions and their evaluation are often hindered by the lack of data on turtle biology, human-turtle interactions, turtle population status and threats. In an effort to inform effective sea turtle conservation a list of priority research questions was assembled based on the opinions of 35 sea turtle researchers from 13 nations working in fields related to turtle biology and/or conservation. The combined experience of the contributing researchers spanned the globe as well as many relevant disciplines involved in conservation research. An initial list of more than 200 questions gathered from respondents was condensed into 20 metaquestions and classified under 5 categories: reproductive biology, biogeography, population ecology, threats and conservation strategies. © Inter-Research 2010.
Open Access
Hawksbill sea turtle life-stage durations, somatic growth patterns, and age at maturation
(Endangered Species Research, 2021-01-01) Avens, L; Ramirez, MD; Goshe, LR; Clark, JM; Meylan, AB; Teas, W; Shaver, DJ; Godfrey, MH; Howell, L
Sea turtles exhibit complex life histories, encompassing intermittent use of multiple spatially separated habitats throughout long lifespans. This broad scope presents challenges for collecting comprehensive biological and ecological data, yet absence of such information complicates evaluation of management strategies for populations at risk of extinction. Hawksbill sea turtles Eretmochelys imbricata are endangered worldwide, primarily due to long-term, directed harvest. However, available information regarding life stage durations, somatic growth patterns, and maturation attributes to enhance understanding of anthropogenic impacts and recovery potential remains constrained. To address these data gaps in the western North Atlantic, we conducted skeletochronological analysis for hawksbills stranded along US coastlines to generate straightline carapace length (SCL)-at-age and somatic growth data. Generalized additive mixed models and bootstrapped von Bertalanffy growth curves were used to characterize age at maturation and covariate influence on somatic growth. For a subset of turtles, annual bone growth incrementspecific stable isotope and trace element analyses were incorporated to evaluate habitat use relative to age. Integration of these data sources indicated that juveniles transitioned from oceanic to neritic habitat at 1-3 yr old and mean SCLs of 23-24 cm (range 15.7-35.0 cm). Initial ages at maturation for this population at minimum nesting female SCLs were estimated at 15-25 yr. Somatic growth varied significantly relative to size, age, and stranding location, while no association with sex or calendar year was observed. Our results demonstrate the utility of these complementary analytical approaches for generating baseline data fundamental to characterizing hawksbill sea turtle population attributes.
Open Access
Incidental capture and mortality of sea turtles in the industrial double-rig-bottom trawl fishery in south-eastern Brazil
(Aquatic Conservation: Marine and Freshwater Ecosystems, 2019-01-01) Tagliolatto, AB; Giffoni, B; Guimarães, S; Godfrey, MH; Monteiro-Neto, C
© 2019 John Wiley & Sons, Ltd. Incidental capture by fisheries is one of the principal threats to sea turtles. This study analysed spatial and temporal patterns of sea turtle bycatch, and estimated the direct initial mortality rate of these animals, in the industrial double-rig-bottom trawl fishery in south-eastern Brazil. This is also the first attempt to relate bycatch/at-sea mortality in bottom trawling to stranded turtles found along the adjacent coast. The fishery was monitored from October 2015 to April 2018 through data collected voluntarily by the captains of eight industrial double-rig trawlers. Two hundred and one sea turtles were captured during 9362 tows (43,657.52 trawling hours), resulting in a catch per unit effort (CPUE) of 0.0025 ± 0.0032 turtles h−1 with a standard net of 30.5 m headrope, with no significant difference between the estimated CPUEs for licensed shrimp and demersal fish trawlers. Caretta caretta (52.24%) and Lepidochelys olivacea (38.81%) were the most frequently captured species. According to Generalized Linear Models, C. caretta bycatch was significantly higher during winter, at lower latitudes (−24° to −23°) and higher longitudes (−42° to −40°), while the L. olivacea bycatch was significantly higher at higher latitudes (−23° to −21°). The direct initial mortality rate of sea turtles in the shrimp trawlers was 7.65 ± 3.85%. However, none of the dead individuals subsequently released with plastic tags (n = 10) were found stranded on the coast. Mortality was not significantly related to the depth or duration of the trawling. The results of this study suggest the need for improvements to the current management of the bottom trawl fishery in Brazil, moving from a species-based to a spatial and seasonal-based approach. There is also a need to develop turtle excluder devices adapted to local fishing conditions.
Open Access
Informing research priorities for immature sea turtles through expert elicitation
(Endangered Species Research, 2018-01-01) Wildermann, NE; Gredzens, C; Avens, L; BarriosGarrido, HA; Bell, I; Blumenthal, J; Bolten, AB; McNeill, JB; 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; Williard, AS; Tomás, J; Vélez-Rubio, GM; Ware, M; Williams, JL; Wyneken, J; Fuentes, MMPB
© The authors 2018. Although sea turtles have received substantial focus worldwide, research on the immature life stages is still relatively limited. The latter is of particular importance, given that a large proportion of sea turtle populations comprises immature individuals. We set out to identify knowledge gaps and identify the main barriers hindering research in this field. We analyzed the perceptions of sea turtle experts through an online survey which gathered their opinions on the current state of affairs on immature sea turtle research, including species and regions in need of further study, priority research questions, and barriers that have interfered with the advancement of research. Our gap analysis indicates that studies on immature leatherback Dermochelys coriacea and hawksbill Eretmochelys imbricata turtles are lacking, as are studies on all species based in the Indian, South Pacific, and South Atlantic Oceans. Experts also perceived that studies in population ecology, namely on survivorship and demography, and habitat use/behavior, are needed to advance the state of knowledge on immature sea turtles. Our survey findings indicate the need for more interdisciplinary research, collaborative efforts (e.g. data-sharing, joint field activities), and improved communication among researchers, funding bodies, stakeholders, and decision-makers.
Open Access
Maturity of a giant: age and size reaction norm for sexual maturity for Atlantic leatherback turtles
(Marine Ecology, 2021-01-01) Girondot, M; Mourrain, B; Chevallier, D; Godfrey, MH
Leatherback marine turtles are the largest extant turtles with some individuals measuring up to 2 m in carapace length. In addition, this species remains in oceanic habitat during much its life, making it difficult to investigate its ontogeny from hatchling to adult stage. Furthermore, distinct chondro-osseous (cartilage and bone) tissue morphology has led to speculation that sexual maturity may be reached as early as 3 years while others have estimated a minimum of 25 years to reach adulthood. Using a combination of reanalysis of the growth trajectories of juveniles maintained in captivity, and the age–size relationship of individuals in the field, we demonstrate and quantify the indeterminate growth of this species. Using comparisons of female size distribution on nesting beaches and stranded or captured-at-sea size distributions adjusted with a new asymmetric sigmoid function, we were able to model the size reaction norm for female sexual maturity. Combining these two models, we show that some females may reach maturity at 14 years in natural conditions, while others will take 50 years or more. Sexual maturity may even be reached at 5 years when individuals experience exceptionally good environmental conditions. This extreme plasticity in the age of sexual maturity has been demonstrated in loggerhead turtles in natural conditions and in green turtles in captivity. It may be a general life-history feature of marine turtles.
Open Access
Network analysis of sea turtle movements and connectivity: A tool for conservation prioritization
(Diversity and Distributions, 2022-04-01) Kot, CY; Åkesson, S; Alfaro-Shigueto, J; Amorocho Llanos, DF; Antonopoulou, M; Balazs, GH; Baverstock, WR; Blumenthal, JM; Broderick, AC; Bruno, I; Canbolat, AF; Casale, P; Cejudo, D; Coyne, MS; Curtice, C; DeLand, S; DiMatteo, A; Dodge, K; Dunn, DC; Esteban, N; Formia, A; Fuentes, MMPB; Fujioka, E; Garnier, J; Godfrey, MH; Godley, BJ; González Carman, V; Harrison, AL; Hart, CE; Hawkes, LA; Hays, GC; Hill, N; Hochscheid, S; Kaska, Y; Levy, Y; Ley-Quiñónez, CP; Lockhart, GG; López-Mendilaharsu, M; Luschi, P; Mangel, JC; Margaritoulis, D; Maxwell, SM; McClellan, CM; Metcalfe, K; Mingozzi, A; Moncada, FG; Nichols, WJ; Parker, DM; Patel, SH; Pilcher, NJ; Poulin, S; Read, AJ; Rees, AF; Robinson, DP; Robinson, NJ; Sandoval-Lugo, AG; Schofield, G; Seminoff, JA; Seney, EE; Snape, RTE; Sözbilen, D; Tomás, J; Varo-Cruz, N; Wallace, BP; Wildermann, NE; Witt, MJ; Zavala-Norzagaray, AA; Halpin, PN
Aim: Understanding the spatial ecology of animal movements is a critical element in conserving long-lived, highly mobile marine species. Analyzing networks developed from movements of six sea turtle species reveals marine connectivity and can help prioritize conservation efforts. Location: Global. Methods: We collated telemetry data from 1235 individuals and reviewed the literature to determine our dataset's representativeness. We used the telemetry data to develop spatial networks at different scales to examine areas, connections, and their geographic arrangement. We used graph theory metrics to compare networks across regions and species and to identify the role of important areas and connections. Results: Relevant literature and citations for data used in this study had very little overlap. Network analysis showed that sampling effort influenced network structure, and the arrangement of areas and connections for most networks was complex. However, important areas and connections identified by graph theory metrics can be different than areas of high data density. For the global network, marine regions in the Mediterranean had high closeness, while links with high betweenness among marine regions in the South Atlantic were critical for maintaining connectivity. Comparisons among species-specific networks showed that functional connectivity was related to movement ecology, resulting in networks composed of different areas and links. Main conclusions: Network analysis identified the structure and functional connectivity of the sea turtles in our sample at multiple scales. These network characteristics could help guide the coordination of management strategies for wide-ranging animals throughout their geographic extent. Most networks had complex structures that can contribute to greater robustness but may be more difficult to manage changes when compared to simpler forms. Area-based conservation measures would benefit sea turtle populations when directed toward areas with high closeness dominating network function. Promoting seascape connectivity of links with high betweenness would decrease network vulnerability.
Open Access
NMR metabolomic analysis of skeletal muscle, heart, and liver of hatchling loggerhead sea turtles (caretta caretta) experimentally exposed to crude oil and/or corexit
(Metabolites, 2019-02-01) Bembenek-Bailey, SA; Niemuth, JN; McClellan-Green, PD; Godfrey, MH; Harms, CA; Gracz, H; Stoskopf, MK
© 2019 by the authors. Licensee MDPI, Basel, Switzerland. We used nuclear magnetic spectroscopy (NMR) to evaluate the metabolic impacts of crude oil, Corexit 5900A, a dispersant, and a crude oil Corexit 5900A mixture exposure on skeletal muscle, heart, and liver physiology of hatchling loggerhead sea turtles (Caretta caretta). Tissue samples were obtained from 22 seven-day-old hatchlings after a four day cutaneous exposure to environmentally relevant concentrations of crude oil, Corexit 5900A, a combination of crude oil and Corexit 9500A, or a seawater control. We identified 38 metabolites in the aqueous extracts of the liver, and 30 metabolites in both the skeletal and heart muscle aqueous extracts, including organic acids/osmolytes, energy compounds, amino acids, ketone bodies, nucleosides, and nucleotides. Skeletal muscle lactate, creatines, and taurine concentrations were significantly lower in hatchlings exposed to crude oil than in control hatchlings. Lactate, taurine, and cholines appeared to be the basis of some variation in hatchling heart samples, and liver inosine, uracil, and uridine appeared to be influenced by Corexit and crude oil exposure. Observed decreases in concentrations of lactate and creatines may reflect energy depletion in skeletal muscle of oil-exposed animals, while decreased taurine concentrations in these animals may reflect higher oxidative stress.
Open Access
Plastic and marine turtles: A review and call for research
(ICES Journal of Marine Science, 2016-01-01) Nelms, SE; Duncan, EM; Broderick, AC; Galloway, TS; Godfrey, MH; Hamann, M; Lindeque, PK; Godley, BJ
© International Council for the Exploration of the Sea 2015. Plastic debris is now ubiquitous in the marine environment affecting a wide range of taxa, from microscopic zooplankton to large vertebrates. Its persistence and dispersal throughout marine ecosystems has meant that sensitivity toward the scale of threat is growing, particularly for species of conservation concern, such as marine turtles. Their use of a variety of habitats, migratory behaviour, and complex life histories leave them subject to a host of anthropogenic stressors, including exposure to marine plastic pollution. Here, we review the evidence for the effects of plastic debris on turtles and their habitats, highlight knowledge gaps, and make recommendations for future research. We found that, of the seven species, all are known to ingest or become entangled in marine debris. Ingestion can cause intestinal blockage and internal injury, dietary dilution, malnutrition, and increased buoyancy which in turn can result in poor health, reduced growth rates and reproductive output, or death. Entanglement in plastic debris (including ghost fishing gear) is known to cause lacerations, increased drag - which reduces the ability to forage effectively or escape threats - and may lead to drowning or death by starvation. In addition, plastic pollution may impact key turtle habitats. In particular, its presence on nesting beaches may alter nest properties by affecting temperature and sediment permeability. This could influence hatchling sex ratios and reproductive success, resulting in population level implications. Additionally, beach litter may entangle nesting females or emerging hatchlings. Lastly, as an omnipresent and widespread pollutant, plastic debris may cause wider ecosystem effects which result in loss of productivity and implications for trophic interactions. By compiling and presenting this evidence, we demonstrate that urgent action is required to better understand this issue and its effects on marine turtles, so that appropriate and effective mitigation policies can be developed.
Open Access
Reflections on sea turtle conservation
(Oryx, 2020-05) Godley, BJ; Broderick, AC; Colman, LP; Formia, A; Godfrey, MH; Hamann, M; Nuno, A; Omeyer, LCM; Patrício, AR; Phillott, AD; Rees, AF; Shanker, K
Open Access
Spatio-temporal distribution of sea turtle strandings and factors contributing to their mortality in south-eastern Brazil
(Aquatic Conservation: Marine and Freshwater Ecosystems, 2019-01-01) Tagliolatto, AB; Goldberg, DW; Godfrey, MH; Monteiro-Neto, C
© 2019 John Wiley & Sons, Ltd. Data on stranded sea turtles were examined between 2010 and 2016 along the northern region of Rio de Janeiro state and between 2016 and 2017 in the southern region, looking for spatio-temporal patterns and determining which factors contributed to their mortality. A total of 12,162 strandings of all five species that occur in Brazil were recorded, with Chelonia mydas being the most common (89.9%). Sea turtles use the Rio de Janeiro coast as a feeding and/or migration area. The intense upwelling (October to April) may be an important factor for the sea turtles feeding in this region, mainly for Eretmochelys imbricata and Dermochelys coriacea, which had a higher number of strandings during this period. Areas further north of the study area include an important nesting site for Caretta caretta in Brazil, which explains the higher concentration of strandings of subadults/adults of this species in this region and during its nesting season. Many anthropogenic threats to sea turtles were documented, mainly incidental capture in fisheries and marine debris, indicating possible hotspots for these threats in the regions of Sepetiba and Guanabara Bays, Cabo Frio, and São Francisco de Itabapoana. Among the natural causes of strandings, the primary factors were chronic illness, endoparasites, and fibropapillomatosis. However, pollution may also be an indirect threat, which negatively affects these animals through reduced health and immunosuppression, leaving them more susceptible to opportunistic diseases. These data are valuable for directing and implementing specific and local mitigation measures along the Rio de Janeiro state coast, such as avoiding bycatch hotspots through fleet communication programmes and/or area and seasonal closures, enforceable legislation, effective penalties and proper waste management.
Open Access
¹H-nmr metabolomic study of whole blood from hatchling loggerhead sea turtles (Caretta caretta) exposed to crude oil and/or corexit
(Royal Society Open Science, 2017-11-22) Bembenek Bailey, SA; Niemuth, JN; McClellan-Green, PD; Godfrey, MH; Harms, CA; Stoskopf, MK
© 2017 The Authors. We used proton nuclear magnetic resonance spectroscopy (1H-NMR) to evaluate metabolic impacts of environmentally relevant crude oil and Corexit exposures on the physiology of hatchling loggerhead sea turtles (Caretta caretta). Sample extraction and data acquisition methods for very small volume whole blood samples and sources of variation between individual hatchlings were assessed. Sixteen unclotted, whole blood samples were obtained from 7-day-old hatchlings after a 4-day cutaneous exposure to either control seawater, crude oil, Corexit 9500A or a combination of crude oil and Corexit 9500A. After extraction, one- and two-dimensional 1 H-NMR spectra of the samples were obtained, and 17 metabolites were identified and confirmed in the whole blood spectra. Variation among samples due to the concentrations of metabolites 3-hydroxybutyrate, lactate, trimethylamine oxide and propylene glycol did not statistically correlate with treatment group. However, the characterization of the hatchling loggerhead whole blood metabolome provides a foundation for future metabolomic research with sea turtles and a basis for the study of tissues from exposed hatchling sea turtles.
Open Access
Thermal conditions of green turtle (Chelonia mydas) nests in the largest rookery in the eastern Mediterranean
(Endangered Species Research, 2023-01-01) Türkozan, O; Yılmaz, C; Almpanidou, V; Godfrey, MH; Mazaris, AD
Climate change impacts on vertebrates have many implications. The thermal conditions of vertebrates during incubation are known to influence morphological, physiological, and behavioral traits. Thus, incubation temperatures have consequences for ecological and evolutionary processes, and for certain reptiles can determine sex. For oviparous reptiles, information on the thermal environment of nests is often used to estimate sex ratio, metabolic heat, and their effects on hatching success. This critical baseline information is not always available for all species in all regions, hampering our ability to design analyses that could direct future management and conservation actions. Such is the case for green turtles in the Mediterranean, which nest at many different sites but few of which have had their thermal environment documented in detail. We recorded temperature in 225 green turtle nests (between 2009 and 2013) and 12 control sites in the sand (15, 30, and 45 m distance from high tide line between 2010 and 2013) at 75 cm depth at Akyatan beach, Turkey. The mean temperature of the nests ranged from 28.4 to 33.5°C, and those experiencing high temperatures exhibited low hatching success. The observed thermal environment within the nests exhibited a narrow range relative to the control sites, with daily temperature fluctuations in nests ranging from 0.1°C up to 4.5°C. The nest temperature was strongly negatively correlated with incubation duration, while metabolic heating was highest in the last third of the incubation duration, and was significantly correlated to clutch size
Open Access
Tissue and temperature-specific RNA-seq analysis reveals genomic versatility and adaptive potential in wild sea turtle hatchlings (Caretta caretta)
(Animals, 2021-11-01) Chow, JC; Kyritsis, N; Mills, M; Godfrey, MH; Harms, CA; Anderson, PE; Shedlock, AM
Background: Digital transcriptomics is rapidly emerging as a powerful new technology for modelling the environmental dynamics of the adaptive landscape in diverse lineages. This is particularly valuable in taxa such as turtles and tortoises (order Testudines) which contain a large fraction of endangered species at risk due to anthropogenic impacts on the environment, including pollution, overharvest, habitat degradation, and climate change. Sea turtles (family Cheloniidae) in particular invite a genomics-enabled approach to investigating their remarkable portfolio of adaptive evolution. The sex of the endangered loggerhead sea turtle (Caretta caretta) is subject to temperature-dependent sex determination (TSD), a mechanism by which exposure to temperatures during embryonic development irreversibly determines sex. Higher temperatures produce mainly female turtles and lower temperatures produce mainly male turtles. Incubation temperature can have long term effects on the immunity, migratory ability, and ultimately longevity of hatchlings. We perform RNA-seq differential expression analysis to investigate tissue-and temperature-specific gene expression within brain (n = 7) and gonadal (n = 4) tissue of male and female loggerhead hatchlings. Results: We assemble tissue-and temperature-specific transcriptomes and identify differentially expressed genes relevant to sexual development and life history traits of broad adaptive interest to turtles and other amniotic species. We summarize interactions among differentially expressed genes by producing network visualizations, and highlight shared biological pathways related to migration, immunity, and longevity reported in the avian and reptile literature. Conclusions: The measurement of tissue-and temperature-specific global gene expression of an endangered, flagship species such as the loggerhead sea turtle (Caretta caretta) reveals the genomic basis for potential resiliency and is crucial to future management and conservation strategies with attention to changing climates. Brain and gonadal tissue collected from experimentally reared loggerhead male and female hatchlings comprise an exceedingly rare dataset that permits the identification of genes enriched in functions related to sexual development, immunity, longevity, and migratory behavior and will serve as a large, new genomic resource for the investigation of genotype–phenotype relationships in amniotes.
Open Access
Using random forest algorithm to model cold-stunning events in sea turtles in North Carolina
(Journal of Fish and Wildlife Management, 2020-12-01) Niemuth, JN; Ransom, CC; Finn, SA; Godfrey, MH; Nelson, SAC; Stoskopf, MK
© 2020 U.S. Fish and Wildlife Service. All rights reserved. Sea turtle strandings due to cold-stunning are seen when turtles are exposed to ocean temperatures that acutely and persistently drop below approximately 128C. In North Carolina, this syndrome affects imperiled loggerhead Caretta caretta, green Chelonia mydas, and Kemp’s ridley Lepidochelys kempii sea turtle species. Based on oceanic and meteorological patterns of cold-stunning in sea turtles, we hypothesized that we could predict the daily size of cold-stunning events in North Carolina using random forest models. We used cold-stunning data from the North Carolina Sea Turtle Stranding and Salvage Network from 2010 to 2015 and oceanic and meteorological data from the National Data Buoy Center from 2009 to 2015 to create a random forest model that explained 99% of the variance. We explored additional models using the 10 and 20 most important variables or only oceanic and meteorological variables. These models explained similar percentages of variance. The variables most frequently found to be important were related to air temperature, atmospheric pressure, wind direction, and wind speed. Surprisingly, variables associated with water temperature, which is critical from a biological perspective, were not among the most important variables identified. We also included variables for the mean change in these metrics daily from 4 d before the day of stranding. These variables were among the most important in several of our models, especially the change in mean air temperature from 4 d before stranding to the day of stranding. The importance of specific variables from our random forest models can be used to guide the selection of future model predictors to estimate daily size of cold-stunning events. We plan to apply the results of this study to a predictive model that can serve as a warning system and to a downscaled climate projection to determine the potential impact of climate change on cold-stunning event size in the future.

Browsing by Author "Godfrey, MH"

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