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1
Arthur, Karen E., Judith M. O'Neil, Colin J. Limpus, Kyler Abernathy und Greg Marshall. „Using Animal-Borne Imaging to Assess Green Turtle (Chelonia mydas) Foraging Ecology in Moreton Bay, Australia“. Marine Technology Society Journal 41, Nr. 4 (01.12.2007): 9–13. http://dx.doi.org/10.4031/002533207787441953.
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Traditional techniques for studying green turtle foraging ecology, such as the analysis of food availability and ingested dietary material, have concluded that green turtles are primarily herbivorous but selective foragers. However, green turtles that forage during Lyngbya majuscula blooms are exposed to toxins produced by the cyanobacterium overgrowing the seagrass. We used the Crittercam, an animal-borne imaging device, to observe green turtle foraging behavior in Moreton Bay, Australia, and to evaluate the system for assessing the impacts of Lyngbya blooms on green turtles. Eight large green turtles were captured while foraging on seagrass flats and each was fitted with a Crittercam. The deployments yielded over 28 hours of video and associated time-depth records. Turtles swam almost continuously and rarely stopped to feed on seagrass. Six turtles were observed feeding and all six consumed gelatinous animals from the water column. This prey source was previously undocumented in the Moreton Bay green turtle population but described in other green turtle populations using the Crittercam. Only one turtle was observed foraging on seagrass. The results of this study indicate that Crittercam technology can provide insight into turtle diet selection and that it will be a useful tool in identifying the impacts of Lyngbya blooms on green turtle feeding ecology. This study has also demonstrated that turtles in Moreton Bay may have a more flexible diet than previously described, indicating they could potentially supplement their diet with alternate prey items when seagrass quality or quantity is compromised. Longer deployment times, with an initial acclimation phase, are required to more fully understand questions pertaining to feeding ecology.
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Maldonado-Gasca,, A., und M. Zapata-Rosales. „PRIMEROS REGISTROS DE TORTUGAS BLANCAS Chelonia mydas CON FIBROPAPILOMAS, EN YUCATÁN, MÉXICO“. CICIMAR Oceánides 22, Nr. 1-2 (31.12.2007): 29. http://dx.doi.org/10.37543/oceanides.v22i1-2.35.
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First reports of green turtles Chelonia mydas with fibropapillomas, in Yucatán, México Fibropapillomas are cutaneous tumors that affect the health of marine turtles worldwide. In July 11th of 1998, a juvenile green turtle (Chelonia mydas) with tumors was captured by fishermen in the Sea Turtles Sanctuary of Rio Lagartos, Yucatán. The straight carapace length of this turtle was 44.6 cm, and we found 30 tumors with a size from 1 cm - 10 cm on the back flippers, neck, front flippers and in both eyes. On July 10th, 1999, another juvenile green turtle with fibropapillomatosis was captured by fishermen in the same area. This turtle was smaller (S.C.L. = 40.8 cm) with 5 small tumors (1 cm - 4 cm) on the back flippers and tail. The prevalence of fibro papillomatosis in Yucatan is low (2.4%). Considering the migratory route of this species and the high prevalence of green turtles with fibropapillomas in Florida, USA, we suggest an initial contagion between the populations of these peninsulas. Those are the first documented reports of green turtles with fibropapillomas in Yucatán, México.
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Maldonado-Gasca,, A., und M. Zapata-Rosales. „PRIMEROS REGISTROS DE TORTUGAS BLANCAS Chelonia mydas CON FIBROPAPILOMAS, EN YUCATÁN, MÉXICO“. CICIMAR Oceánides 22, Nr. 1-2 (31.12.2007): 29. http://dx.doi.org/10.37543/oceanides.v22i1-2.35.
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First reports of green turtles Chelonia mydas with fibropapillomas, in Yucatán, México Fibropapillomas are cutaneous tumors that affect the health of marine turtles worldwide. In July 11th of 1998, a juvenile green turtle (Chelonia mydas) with tumors was captured by fishermen in the Sea Turtles Sanctuary of Rio Lagartos, Yucatán. The straight carapace length of this turtle was 44.6 cm, and we found 30 tumors with a size from 1 cm - 10 cm on the back flippers, neck, front flippers and in both eyes. On July 10th, 1999, another juvenile green turtle with fibropapillomatosis was captured by fishermen in the same area. This turtle was smaller (S.C.L. = 40.8 cm) with 5 small tumors (1 cm - 4 cm) on the back flippers and tail. The prevalence of fibro papillomatosis in Yucatan is low (2.4%). Considering the migratory route of this species and the high prevalence of green turtles with fibropapillomas in Florida, USA, we suggest an initial contagion between the populations of these peninsulas. Those are the first documented reports of green turtles with fibropapillomas in Yucatán, México.
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Rodriguez, AR, und KL Heck Jr. „Green turtle herbivory and its effects on the warm, temperate seagrass meadows of St. Joseph Bay, Florida (USA)“. Marine Ecology Progress Series 639 (02.04.2020): 37–51. http://dx.doi.org/10.3354/meps13285.
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Green turtles Chelonia mydas occur sporadically in tropical and subtropical latitudes, but effective conservation efforts are leading to increasing abundances at higher latitudes. One consequence of increased green turtle abundance in some locations has been the overgrazing of seagrasses, their preferred food item. Recent, large increases in juvenile green turtle abundance in the warm temperate northern Gulf of Mexico, especially in the clear waters of St Joseph Bay, FL, make this a prime location to study effects of their feeding activities on the extensive turtlegrass Thalassia testudinum-dominated meadows. Using caging and simulated grazing to quantify green turtle effects, we found that excluding green turtles led to increased Thalassia shoot density, and that simulating turtle grazing resulted in narrowed leaves and decreased turtlegrass productivity. Naturally grazed areas protected from further turtle grazing did not recover after 14 wk of protection. Two years following relaxation of simulated grazing, turtlegrass continued to show residual stress symptoms, with narrower and fewer leaves per shoot than control areas. The future success of sea turtle conservation efforts is critically linked, and dependent on, the protection and sustainability of globally decreasing sea turtle feeding grounds. Thus, continued study of how increasing green turtle populations affect warm temperate turtlegrass meadows will provide important information on how best to manage both turtle and seagrass resources.
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Herrera, Candy, Evelyn Guerra, Andrea Rosas, Yingying Wei, Jack Pringle, Baltazar Espinoza und Baojun Song. „The Impact of Temperature-Dependent Sex Determination on the Population Dynamics of Green Sea Turtles (Chelonia mydas)“. Bionatura 5, Nr. 1 (15.02.2020): 1029–38. http://dx.doi.org/10.21931/rb/2020.05.01.4.
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The sex of the turtles is determined by the incubation temperature of the eggs during the mid-trimester of development. In green sea turtles (Chelonia mydas), recent studies show that sex ratios are changing, producing a female-biased sex ratio within the population. We developed a novel continuous model to analyze the dynamics of the green sea turtle population long-term. We determine the safe operating space for the proportion of eggs that become male at which the population of green sea turtle can exist without going to extinction. When the proportion of male eggs leaves this range the overall turtles’ population collapses. Additionally, we examined how temperature changes affect the sex ratios of the green sea turtle population.
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Hirth, Harold F., und Deborah L. H. Rohovit. „Marketing patterns of green and hawksbill turtles in Port Moresby, Papua New Guinea“. Oryx 26, Nr. 1 (Januar 1992): 39–42. http://dx.doi.org/10.1017/s0030605300023218.
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Of the six species of marine turtle in Papua New Guinea, the green turtle Chelonia mydas and the hawksbill turtle Eretmochelys imbricata are the most common and the most utilized in the Port Moresby region. This paper describes a study carried out in 1989, which monitored the trade in green turtles in the country's main market and the sale of tortoiseshell in a major shopping centre. The price of turtle meat was higher than that of some common reef fish, but cost less when fish was abundant. The commercial trade in tortoiseshell appeared to be negligible. As the urban population increases it is likely that demand for turtle meat will also increase. If this food resource is to be managed sustainably the size of the turtle population needs to be determined. The University of Papua New Guinea is supporting marine turtle field studies and a sea turtle education programme, but more needs to be done to ensure the survival of PNG's marine turtles.
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Corsini-Foka, Maria, Gerasimos Kondylatos und Elias Santorinios. „Increase of sea turtles stranding records in Rhodes Island (eastern Mediterranean Sea): update of a long-term survey“. Journal of the Marine Biological Association of the United Kingdom 93, Nr. 7 (29.05.2013): 1991–2002. http://dx.doi.org/10.1017/s0025315413000556.
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A total of 209 strandings of sea turtles (152 loggerhead turtles Caretta caretta, 42 green turtles Chelonia mydas, 15 unidentified) were recorded during the period 1984–2011 along the coasts of Rhodes (Aegean Sea, Greece). The proportion of dead to live individuals was different in the two species. Stranded Caretta caretta were larger than Chelonia mydas. The size range of stranded green turtles, usually juveniles, appeared to increase since 2000, including the largest specimens ever observed in Greek waters. For both species, a tendency to strand more frequently on the west coast of the island, along fishing ground areas, was noted. The higher incidence of loggerhead turtle strandings was observed in summer, while more green turtle strandings were documented in winter. Factors involved in the increased trend of stranding records of both species, along with the acceleration of this phenomenon in the last decade, are discussed. Data from Rhodes provide evidence that human activities detrimentally affect mainly larger-sized loggerhead turtles living in shallow waters.
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Mortimer, Jeanne A., Nicole Esteban, Antenor Nestor Guzman und Graeme C. Hays. „Estimates of marine turtle nesting populations in the south-west Indian Ocean indicate the importance of the Chagos Archipelago“. Oryx 54, Nr. 3 (10.02.2020): 332–43. http://dx.doi.org/10.1017/s0030605319001108.
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AbstractGlobal marine turtle population assessments highlight the importance of the south-west Indian Ocean region, despite data gaps for the Chagos Archipelago. The archipelago hosts nesting hawksbill Eretmochelys imbricata and green turtles Chelonia mydas, both heavily exploited for 2 centuries until protection in 1968–1970. We assessed available nesting habitat and spatial distribution of nesting activity during rapid surveys of 90% of the archipelago's coastline in 1996, 1999, 2006 and 2016. We quantified seasonality and mean annual egg clutch production from monthly track counts during 2006–2018 along a 2.8 km index beach on Diego Garcia island. An estimated 56% (132 km) of coastline provided suitable nesting habitat. Diego Garcia and Peros Banhos atolls accounted for 90.4% of hawksbill and 70.4% of green turtle nesting. Hawksbill turtles showed distinct nesting peaks during October–February, and green turtles nested year-round with elevated activity during June–October. Estimates of 6,300 hawksbill and 20,500 green turtle clutches laid annually during 2011–2018 indicate that nesting on the Chagos Archipelago has increased 2–5 times for hawksbill turtles and 4–9 times for green turtles since 1996. Regional estimates indicate green turtles produce 10 times more egg clutches than hawksbill turtles, and the Chagos Archipelago accounts for 39–51% of an estimated 12,500–16,000 hawksbill and 14–20% of an estimated 104,000–143,500 green turtle clutches laid in the south-west Indian Ocean. The improved status may reflect > 40 years without significant exploitation. Long-term monitoring is needed to captureinterannual variation in nesting numbers and minimize uncertainty in population estimates.
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Weir, Caroline R., Tamar Ron, Miguel Morais und Agostinho Domingos C. Duarte. „Nesting and at-sea distribution of marine turtles in Angola, West Africa, 2000–2006: occurrence, threats and conservation implications“. Oryx 41, Nr. 2 (April 2007): 224–31. http://dx.doi.org/10.1017/s003060530700186x.
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AbstractThe status of marine turtles in Angola, West Africa, is poorly known, and therefore during 2000–2006 a combination of both dedicated and opportunistic beach and at-sea turtle surveys were carried out, and interviews conducted with fishing communities and at markets. Green Chelonia mydas, olive ridley Lepidochelys olivacea, leatherback Dermochelys coriacea and loggerhead turtles Caretta caretta were recorded, and nesting of the first three species confirmed during September–March (peaking November–December). Green turtles nested mainly in the south, leatherback turtles in north and central Angola, and olive ridley turtle nesting was widespread. Olive ridley turtle nest density at Palmeirinhas averaged 32 nests km−1. At-sea surveys produced 298 turtle records, with peak occurrence during August. Significant anthropogenic-related mortality (including exploitation of meat and eggs and fishing bycatch) was recorded, in addition to natural predation and other threats. Maintenance of the long-term sustainability of these turtle populations should focus on the involvement of fishing communities and increasing awareness throughout Angola.
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Rakotonirina, Berthin, und Andrew Cooke. „Sea turtles of Madagascar – their status, exploitation and conservation“. Oryx 28, Nr. 1 (Januar 1994): 51–61. http://dx.doi.org/10.1017/s0030605300028295.
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Five species of sea turtles are known from Madagascar's coastal waters. Fishermen on the western and south-western coasts take green turtle Chelonia mydas, loggerhead turtle Caretta caretta and olive ridley Lepidochelys olivacea for their meat. The hawksbill turtle Eretmochelys imbricata is taken mainly for its shell and for making stuffed specimens while the leatherback Dermochelys coriacea is seldom caught. Anecdotal evidence of fishermen and dealers in turtle products, measurement of captured animals and personal observations of the authors all point to declines in numbers and average size for green and hawksbill turtles, coupled with marked declines in nesting rates for these and the olive ridley.
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Eguchi, T., J. Bredvik, S. Graham, R. LeRoux, B. Saunders und JA Seminoff. „Effects of a power plant closure on home ranges of green turtles in an urban foraging area“. Endangered Species Research 41 (27.02.2020): 265–77. http://dx.doi.org/10.3354/esr01027.
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A natural experiment was conducted to determine effects of a fossil-fueled power plant on home ranges of east Pacific green turtles Chelonia mydas in an urban foraging ground. The power plant, located in south San Diego Bay, California, USA, co-existed with a resident foraging aggregation of ~60 green turtles for ~50 yr. It was decommissioned during a long-term green turtle monitoring study, thus providing a rare opportunity to evaluate how the cessation of warm-water effluent affected turtle movements and habitat use in the area. During pre- and post-decommissioning of the power plant, 7 and 23 green turtles, respectively, were equipped with GPS-enabled satellite transmitters. Useful data were obtained from 17 turtles (4 for pre- and 13 for post-decommissioning). Core use areas (50% utilization distribution [UD]) increased from 0.71 to 1.37 km2 after the power plant decommissioning. Increase in post-power plant 50% UD was greater during nighttime (0.52 to 1.44 km2) than daytime (1.32 to 1.43 km2). Furthermore, UDs moved from the effluent channel to an area closer to seagrass pastures, a presumed foraging habitat of the turtles. The observed expansion of green turtle home ranges may increase turtle-human interactions, such as boat strikes, within the foraging ground; this underscores how seemingly innocuous human actions contribute to inadvertent consequences to wildlife. Possible management and conservation actions include increasing awareness of the public regarding turtle presence in the area through signage and education as well as legislating for a reduction in boat speeds in select areas of the bay.
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Afandy, Yusuf Arief, Fredinan Yulianda, Syamsul Bahri Agus und Lucy Peter Liew. „HABITAT SUITABILITY AND ZONING ANALYSIS FOR GREEN TURTLE Chelonia mydas IN THE MARINE CONSERVATION AREAS OF PANGUMBAHAN TURTLE PARK, SUKABUMI“. Jurnal Ilmu dan Teknologi Kelautan Tropis 8, Nr. 2 (06.04.2017): 539. http://dx.doi.org/10.28930/jitkt.v8i2.15820.
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<p>This study reviews the suitability of habitat for the green turtle in the Pangumbahan Turtle Park. The purpose of this study is to evaluate the existing zoning system and to provide recommendations of alternative zoning approach based on ecological suitability turtle habitat. Observations and fieldwork were undertaken throughout the coastal area of Pangumbahan from January to June 2015 by collecting data which include nesting site for turtles, sand temperature and moisture content, width of the beach, surface slope of the beach, vegetation cover, seagrass and secondary data. Methods of data analysis consists of suitability analysis with the spatial approach using Geographic Information System. The results of the analysis of overlay method were classified into three classes of suitability, which include very suitable covering 6,91 hectares, suitable covering 14,60 hectares and less suitable covering 37,21 hectares. The current existing zones needs to be revised using the recommended zoning system. As an implementation of the findings from this study as well as to effectively manage the conservation area based on the green turtle ecology, it is highly recommended to do a zoning system which is based on the principal of the green turtles habitat suitability to ensure the sustainability of the green turtle within the conservation area. This will ensure the zoning system suits the green turtles’ characteristics hence enabling each of the zones to effectively functioning.</p>
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Afandy, Yusuf Arief, Fredinan Yulianda, Syamsul Bahri Agus und Lucy Peter Liew. „HABITAT SUITABILITY AND ZONING ANALYSIS FOR GREEN TURTLE Chelonia mydas IN THE MARINE CONSERVATION AREAS OF PANGUMBAHAN TURTLE PARK, SUKABUMI“. Jurnal Ilmu dan Teknologi Kelautan Tropis 8, Nr. 2 (06.04.2017): 539–52. http://dx.doi.org/10.29244/jitkt.v8i2.15820.
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This study reviews the suitability of habitat for the green turtle in the Pangumbahan Turtle Park. The purpose of this study is to evaluate the existing zoning system and to provide recommendations of alternative zoning approach based on ecological suitability turtle habitat. Observations and fieldwork were undertaken throughout the coastal area of Pangumbahan from January to June 2015 by collecting data which include nesting site for turtles, sand temperature and moisture content, width of the beach, surface slope of the beach, vegetation cover, seagrass and secondary data. Methods of data analysis consists of suitability analysis with the spatial approach using Geographic Information System. The results of the analysis of overlay method were classified into three classes of suitability, which include very suitable covering 6,91 hectares, suitable covering 14,60 hectares and less suitable covering 37,21 hectares. The current existing zones needs to be revised using the recommended zoning system. As an implementation of the findings from this study as well as to effectively manage the conservation area based on the green turtle ecology, it is highly recommended to do a zoning system which is based on the principal of the green turtles habitat suitability to ensure the sustainability of the green turtle within the conservation area. This will ensure the zoning system suits the green turtles’ characteristics hence enabling each of the zones to effectively functioning.
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Chabot, Ryan, Ryan Welsh, Cody Mott, Jeffrey Guertin, Brian Shamblin und Blair Witherington. „A Sea Turtle Population Assessment for Florida's Big Bend, Northeastern Gulf of Mexico“. Gulf and Caribbean Research 32 (2021): 19–33. http://dx.doi.org/10.18785/gcr.3201.05.
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Coastal waters of Florida’s Big Bend, Gulf of Mexico (GOM) once supported one of the largest sea turtle fisheries in the United States. To fill an information gap in this region on abundance and distribution of sea turtles, we used vessel—based distance sampling and active capture methods to characterize current foraging aggregations near the St. Martins Marsh Aquatic Preserve. Over 10 sampling periods between 2012—2018, we completed 513 km of transects and recorded 819 turtles among 4 species—green turtle (Chelonia mydas, n = 624), Kemp’s ridley (Lepidochelys kempii, n = 147), loggerhead (Caretta caretta, n = 47), and a single hawksbill (Eretmochelys imbricata). Turtle densities in 4 study plots within the 200 km2 study site ranged from 57—221 immature green turtles/km2, 16—56 immature Kemp’s ridleys/km2, and 1—14 juvenile—to—adult loggerheads/km2. Of 200 green turtles captured, 67.5% showed skin tumors consistent with fibropapillomatosis, a frequency similar to that from urbanized estuaries of Florida’s east coast. The largest green turtles (> 60 cm straight standard carapace length), abundant in the southern portion of our study area, are of note because this size class is uncommonly recorded within US territorial waters. Analyses of green turtle mtDNA haplotypes found contributions from rookeries in the western GOM, Mexican Caribbean, and Costa Rica. Although Big Bend protected areas were principally designed to conserve marine and coastal habitats, these regulatory zones have also effectively encompassed a hotspot for foraging sea turtles.
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Coley, Stephanie J., und Andrew C. Smart. „The nesting success of green turtles on beaches at Kazanli, Turkey“. Oryx 26, Nr. 3 (Juli 1992): 165–71. http://dx.doi.org/10.1017/s0030605300023607.
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The green turtle Chelonia mydas is one of two marine turtle species to nest in Turkey. Its three main nesting beaches are in eastern Turkey, with possibly the densest congregation of nesting turtles in the Mediterranean being found at Kazanli. However, beach erosion, hatchling predation, agricultural encroachment and chemical pollution mean that the future of the Kazanli nest site is uncertain. The Turkish Society for the Protection of Nature (Dogal Hayati Koruma Dernegi) is making valiant efforts to protect all the turtle nesting beaches in Turkey but lacks detailed information on the numbers of nesting turtles on many beaches. This paper describes a short study of nesting turtles at Kazanli during 1990 and makes recommendations for the conservation of the nesting beach.
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Chuen-Im, Thanaporn, Korapan Sawetsuwannakun, Pimmnapar Neesanant und Nakarin Kitkumthorn. „Antibiotic-Resistant Bacteria in Green Turtle (Chelonia mydas) Rearing Seawater“. Animals 11, Nr. 6 (21.06.2021): 1841. http://dx.doi.org/10.3390/ani11061841.
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Antibiotic resistance of microorganisms is a serious health problem for both humans and animals. Infection of these bacteria may result in therapy failure, leading to high mortality rates. During an early intervention program process, the Sea Turtle Conservation Center of Thailand (STCCT) has faced high mortality rates due to bacterial infection. Previously, investigation of juvenile turtle carcasses found etiological agents in tissue lesions. Further determination of sea water in the turtle holding tanks revealed a prevalence of these causative agents in water samples, implying association of bacterial isolates in rearing water and infection in captive turtles. In this study, we examined the antibiotic resistance of bacteria in seawater from the turtle holding tank for a management plan of juvenile turtles with bacterial infection. The examination was carried out in three periods: 2015 to 2016, 2018, and 2019. The highest isolate numbers were resistant to beta-lactam, whilst low aminoglycoside resistance rates were observed. No gentamicin-resistant isolate was detected. Seventy-nine isolates (71.17%) were resistant to at least one antibiotic. Consideration of resistant bacterial and antibiotic numbers over three sampling periods indicated increased risk of antibiotic-resistant bacteria to sea turtle health. Essentially, this study emphasizes the importance of antibiotic-resistant bacterial assessment in rearing seawater for sea turtle husbandry.
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Camacho-Sánchez, Fátima Yedith, A. Alonso Aguirre, José Alberto Narváez-Zapata, Alan A. Zavala-Norzagaray, Cesar P. Ley-Quiñónez, H. Hugo Acosta-Sánchez, Hervey Rodriguez-González, Carlos Delgado-Trejo und Miguel Angel Reyes-López. „DNA barcode analysis of the endangered green turtle (Chelonia mydas) in Mexico1“. Genome 64, Nr. 9 (September 2021): 879–91. http://dx.doi.org/10.1139/gen-2019-0213.
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Technological and analytical advances to study evolutionary biology, ecology, and conservation of green turtles (Chelonia mydas) are realized through molecular approaches including DNA barcoding. We characterized the usefulness of COI DNA barcodes in green turtles in Mexico to better understand genetic divergence and other genetic parameters of this species. We analyzed 63 sequences, including 25 from green turtle field specimens collected from the Gulf of Mexico and from the Mexican Pacific and 38 already present in the Barcode of Life Data Systems (BOLD). A total of 13 haplotypes were identified with four novel haplotypes from the Pacific Ocean and three novel haplotypes from the Atlantic Ocean. Intraspecific distance values among COI gene sequences by two different models were 0.01, demonstrating that there is not a subdivision for green turtle species. Otherwise, the interspecific distance interval ranged from 0.07 to 0.13, supporting a clear subdivision among all sea turtle species. Haplotype and total nucleotide diversity values of the COI gene reflect a medium genetic diversity average. Green turtles of the Mexican Pacific showed common haplotypes to some Australian and Chinese turtles, but different from the haplotypes of the Mexican Atlantic. COI analysis revealed new haplotypes and confirmed that DNA barcodes were useful for evaluation of the population diversity of green turtles in Mexico.
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McNally, KL, CR Mott, JR Guertin und JL Bowen. „Microbial communities of wild-captured Kemp’s ridley (Lepidochelys kempii) and green sea turtles (Chelonia mydas)“. Endangered Species Research 45 (06.05.2021): 21–36. http://dx.doi.org/10.3354/esr01116.
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Conservation efforts for endangered sea turtle species, such as Kemp’s ridley turtles Lepidochelys kempii and green turtles Chelonia mydas, may benefit from information on the microbial communities that contribute to host health. Previous studies examining host-associated microbiomes of these species have been limited in geographic region, life stage, and/or health. Here, we characterized the microbiome of the oral cavity and cloaca from wild-captured Kemp’s ridley and green turtles off the west coast of Florida, USA, by using Illumina sequencing to analyze the 16S rRNA gene. Microbial communities were distinct between body sites as well as between turtle species, suggesting that the turtle species is more important than the local environment in determining the microbiome of sea turtles. We identified the core microbiome for each species at each body site and determined that there were very few bacteria shared among the oral samples of both species, and no taxa co-occurred in the cloaca samples among both species. The core microbiome of the green turtle cloaca was primarily from the order Clostridiales, which plays an important role in digestion for other herbivorous species. Due to high prevalence of fibropapillomatosis in the green turtles (90%), we also investigated the correlation between the microbiome and the severity of fibropapillomatosis, and we identified changes in beta diversity associated with the total number of tumors. This study provides the first glimpse of the microbiome in 2 sympatric species of sea turtle and sheds an important species-specific light on the microbiome of these endangered species.
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Sunardi, Sunardi, Azrul Mahfurdz und Shoffan Saifullah. „Green turtle and fish identification based on acoustic target strength“. International Journal of Advances in Intelligent Informatics 4, Nr. 1 (31.03.2018): 53. http://dx.doi.org/10.26555/ijain.v4i1.147.
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Fisherman accidentally caught sea turtles in their fishnet. It could be dangerous for its population. This study measures the turtle target strength (TS) using modified echosounder. The result could be used to improve the efficiency of turtle repellent device. The experiment conducted in a hatchery fiber tank contained saline water. The Green were 1, 3, 12 and 18 years old. The study used three species of fish to ensure there are no overlapped value between fish and sea turtle. TS of the animals were calculated incorporating reference targets (sphere). The echo power of the turtle was compared with the solid steel sphere which is confirmed good agreements with the theoretical values. The echo power reference by applying Fast Fourier Transform (FFT) analysis has been used in calculating TS of the animal. From the echo evaluation in time domain at different angles, it is obviously shown that echo signal structure is different between the parts of turtle body. This study reveals that high echo strength is acquired from the carapace and the plastron parts. The finding also showed that there are significant differences between 3, 12, 18 years old turtles and fish in every angle measurement.
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Godfrey, Matthew H., N. Mrosovsky und R. Barreto. „Estimating past and present sex ratios of sea turtles in Suriname“. Canadian Journal of Zoology 74, Nr. 2 (01.02.1996): 267–77. http://dx.doi.org/10.1139/z96-033.
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Leatherback (Dermochelys coriacea) and green (Chelonia mydas) sea turtles in Suriname lay eggs over several months of the year. During this nesting season, changes in rainfall produce changes in sand temperature, which in turn influence the sexual differentiation of incubating sea turtle embryos. The overall sex ratio of leatherback and green sea turtle hatchlings produced at Matapica beach in Suriname was investigated. Estimates of the sex ratios of these turtles in 1993 (green turtles 63.8% female, leatherbacks 69.4% female) were roughly 10% more female-biased than those from an earlier study in 1982. For both species, a significant negative relationship was found between monthly rainfall and monthly sex ratios. Using this relationship and data on rainfall in the past, it was possible to estimate overall sex ratios for an additional 12 years. These estimates varied considerably among different years, ranging from 20 to 90% female in the case of green turtles. Nevertheless, males tended to be produced primarily in April and May, while some females were produced in all months. Such seasonal patterns of production of turtles of different sexes have implications for sea turtle conservation programs that involve manipulating or harvesting eggs.
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McAlpine, Donald F., Stan A. Orchard, Kelly A. Sendall und Rod Palm. „Status of Marine Turtles in British Columbia Waters: A Reassessment“. Canadian Field-Naturalist 118, Nr. 1 (01.01.2004): 72. http://dx.doi.org/10.22621/cfn.v118i1.885.
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Marine turtles in British Columbia have previously been considered off course stragglers. Here we document 20 new reports for Green Turtles, Chelonia mydas, and Leatherback Turtles, Dermochelys coriacea, for the province. Until recently there had been no concerted effort to acquire data on marine turtle abundance or frequency off British Columbia. Observations presented here allow a reassessment of marine turtle status in British Columbia waters. We suggest Green Turtles and Leatherbacks should be considered rare vagrants and uncommon seasonal residents, respectively, off British Columbia and that they are a natural part of the British Columbia marine environment.
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Krismono, Adriani Sri Nastiti, Achmad Fitriyanto und Ngurah Nyoman Wiadnyana. „ASPEK MORFOLOGI, REPRODUKSI, DAN PERILAKU PENYU HIJAU (Chelonia mydas) Di PANTAI PANGUMBAHAN, KABUPATEN SUKABUMI, JAWA BARAT“. BAWAL Widya Riset Perikanan Tangkap 3, Nr. 2 (07.02.2017): 93. http://dx.doi.org/10.15578/bawal.3.2.2010.93-101.
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Penyu hijau (Chelonia mydas) termasuk dalam phylum Chordata dan famili Cheloniideae. Jumlah penyu hijau yang singgah ke Pantai Pangumbahan untuk bertelur semakin menurun karena tidak terkendalinya masyarakat melakukan penangkapan induk penyu dan pengambilan telurnya. Penelitian tentang morfologi, reproduksi, dan perilaku penyu hijau sebagai salah satu dasar pengelolaan telah dilakukan di Pantai Pangumbahan pada bulan Agustus 2008. Metode penelitian yang digunakan pengambilan contoh berstrata. Penelitian ini dilaksanakan pada bulan Agustus 2008 (pada saat puncak peneluran). Parameter yang diamati antara lain ukuran penyu dari 89 ekor jumlah penyu bersarang, jumlah telur dan tingkat penetasan, serta perilaku pada saat penyu bertelur. Hasil penelitian menunjukan yang diamati diperoleh panjang karapas berkisar antara 97-15 cm dan lebar karapas 83,5-108 cm, jumlah penyu naik ke pantai 89 ekor dan penyu yang bertelur 39 ekor. Jumlah telur penyu hijau berhasil dihitung 80-105 butir per induk penyu. Bulan Agustus 2008 merupakan puncak musim peneluran. Kegiatan peneluran penyu hijau dibagi menjadi enam tahap. Upaya konservasi yang sudah dilakukan adalah penetasan telur penyu semi alami, restocking tukik, dan menjaga keamanan sarang telur penyu. Green turtles (Chelonia mydas), including the phylum Chordata and families Cheloniideae. The number of green turtles come to lay eggs Pangumbahan beach to decline because of increasingly unmanageable public do making arrests turtles brood stock and their eggs. Research on the morphology, reproduction, and behavior of green turtles as one of the basic management has been conducted on the Pangumbahan Beach in August 2008. The method used stratified sampling. The experiment was conducted in August 2008 (at the peak of nesting). Other parameters were observed between the size of the 89 tail number of turtles nesting turtles, the number of eggs and hatching rate and behavior during turtle nesting. Results obtained showed that the observed length ranges from 97- 15 cm carapace and carapace width from 83.5-108 cm, the number went up to the beach 89 sea turtle and sea turtle nesting tail as much as 39 tails. The number of green turtle eggs had counted as many as 80-105 eggs per turtles brood stock. Month August 2008 is the peak nesting season of green turtle nesting activities are divided into six stages. Conservation efforts that have been done is semi natural turtle hatchery, restocking hatchlings, and nest of turtle eggs to maintain security.
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Kennett, Rod, N. Munungurritj und Djawa Yunupingu. „Migration patterns of marine turtles in the Gulf of Carpentaria, northern Australia: implications for Aboriginal management“. Wildlife Research 31, Nr. 3 (2004): 241. http://dx.doi.org/10.1071/wr03002.
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Marine turtles regularly migrate hundreds to thousands of kilometres between nesting beaches and home foraging grounds. Effective conservation of marine turtles requires understanding of migration patterns in order to facilitate regional cooperation across the turtles' migratory range. Indigenous Australians maintain traditional rights and responsibilities for marine turtle management across much of the northern Australian coast. To better understand turtle migrations and identify with whom the Aboriginal people of north-east Arnhem Land (Yolngu) share turtles, we used satellite telemetry to track the migration routes of 20 green turtles (Chelonia mydas) departing from a nesting beach ~45 km south of Nhulunbuy, north-east Arnhem Land, Northern Territory, Australia. All tracked turtles remained within the Gulf of Carpentaria. These results suggest that the foraging habitat for adults of this nesting population may be largely confined to the Gulf, offering an optimistic scenario for green turtle conservation. Given these results and the critical role indigenous people play in conserving and managing marine turtles, we recommend that a formal network of indigenous communities be established as the foundation of a community-based turtle-management strategy for the Gulf of Carpentaria region.
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Olendo, Mike I., Gladys M. Okemwa, Cosmas N. Munga, Lilian K. Mulupi, Lily D. Mwasi, Hassan B. Mohamed, Mxolisi Sibanda und Harrison O. Ong'anda. „The value of long-term, community-based monitoring of marine turtle nesting: a study in the Lamu archipelago, Kenya“. Oryx 53, Nr. 1 (01.08.2017): 71–80. http://dx.doi.org/10.1017/s0030605317000771.
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AbstractMonitoring of nesting beaches is often the only feasible and low-cost approach for assessing sea turtle populations. We investigated spatio-temporal patterns of sea turtle nesting activity monitored over 17 successive years in the Lamu archipelago, Kenya. Community-based patrols were conducted on 26 stretches of beach clustered in five major locations. A total of 2,021 nests were recorded: 1,971 (97.5%) green turtleChelonia mydasnests, 31 (1.5%) hawksbillEretmochelys imbricatanests, 8 (0.4%) olive ridleyLepidochelys olivaceanests and 11 (0.5%) unidentified nests. Nesting occurred year-round, increasing during March–July, when 74% of nests were recorded. A stable trend in mean annual nesting densities was observed in all locations. Mean clutch sizes were 117.7 ± SE 1 eggs (range 20–189) for green turtles, 103±SE 6 eggs (range 37–150) for hawksbill turtles, and 103±SE 6 eggs (range 80–133) for olive ridley turtles. Curved carapace length for green turtles was 65–125 cm, and mean annual incubation duration was 55.5±SE 0.05 days. The mean incubation duration for green turtle nests differed significantly between months and seasons but not locations. The hatching success (pooled data) was 81.3% (n = 1,841) and was higher for in situ nests (81.0±SE 1.5%) compared to relocated nests (77.8±SE 1.4%). The results highlight the important contribution of community-based monitoring in Kenya to sustaining the sea turtle populations of the Western Indian Ocean region.
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Adi Eti Harnino, Taurus Zeno, I. Nyoman Yoga Parawangsa, Luthfiana Aprilianita Sari und Sulastri Arsad. „Effectiveness of Sea Turtle Conservation Management at the Turtle Conservation and Education Center of Serangan, Denpasar Bali“. Journal of Marine and Coastal Science 10, Nr. 1 (22.02.2021): 18. http://dx.doi.org/10.20473/jmcs.v10i1.25604.
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Turtles are one of the reptile animals that can migrate long distances along the Indian Ocean, Pacific Ocean and Southeast Asia. The purpose of turtle migration is to mate, find spawning locations and to find food. Sea turtles have an important role in maintaining the balance of the marine ecosystem. However, the high utilization of sea turtles by humans causes the turtle population to decline. One of the conservation sites that help the government program is in Serangan, Denpasar Bali, namely the TCEC (Turtle Conservation and Education Center), where there are several types of turtles such as the lekang turtle, hawksbill and green turtle. Data collection techniques in this study used observation methods including beach monitoring, relocation of turtle eggs to semi-natural hatchery hatching, hatchling and turtle nesting as well as measurement of turtle length and width carapase curve (CCL/CCW), sand temperature, nest depth, nest diameter, nest distance and nest calculation of the number of eggs to see the success of hatching. The results are turtle conservation activities, ranging from turtle maintenance, hatching of turtle eggs, relocation of eggs, and maintenance of hatchlings to release turtles. The effectiveness given by TCEC to manage and preserve the existence of sea turtles in Indonesia, especially in the Bali region is to provide awareness to the community by not consuming eggs and turtle meat.
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Piovano, S., GE Lemons, A. Ciriyawa, A. Batibasaga und JA Seminoff. „Diet and recruitment of green turtles in Fiji, South Pacific, inferred from in-water capture and stable isotope analysis“. Marine Ecology Progress Series 640 (23.04.2020): 201–13. http://dx.doi.org/10.3354/meps13287.
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Green turtles Chelonia mydas are listed as Endangered on the IUCN Red List, yet in the South Pacific few conservation-relevant data are available for the species, especially relating to foraging and habitat use. Here, in situ observations and stable isotope analysis (δ13C and δ15N) were used to evaluate green turtle diet and recruitment patterns at Yadua Island and Makogai Island, Fiji. Juvenile green turtles (N = 110) were hand-captured, measured, and sampled. Stable isotope analysis was performed on skin samples and on putative prey items. ‘Resident’ turtles versus ‘recent recruits’ were classified based on their bulk skin tissue isotope values, which were compared with stable isotope values of local prey items and analyzed via cluster analysis. Green turtle diet composition was estimated using MixSIAR, a Bayesian mixing model. Recent recruits were characterized by ‘low δ13C/high δ15N’ values and ranged in curved carapace length (CCL) from 25.5 to 60.0 cm (mean ± SD = 48.5 ± 5.7 cm). Recruitment mostly occurred in summer. Green turtles identified as ‘residents’ had CCLs ranging from 43.5 to 89.0 cm (mean ± SD = 57.4 ± 9.0 cm) and were characterized by ‘high δ13C/low δ15N’ values; mixing model results indicate they fed primarily on invertebrates (40%), fishes (31%), and marine plants (29%). This study confirms the value of seagrass pastures as both an essential habitat and a primary food source for green turtles, and can serve as a baseline for evaluations of natural and anthropogenic changes in local green turtle aggregations.
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Limpus, CJ, D. Zeller, D. Kwan und W. Macfarlane. „Sea-Turtle Rookeries in North-Western Torres Strait“. Wildlife Research 16, Nr. 5 (1989): 517. http://dx.doi.org/10.1071/wr9890517.
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Deliverance Island, Kerr Islet and Turu Cay in north-western Torres Strait support a major nesting population and the most northerly recorded rookery of the flatback turtle, Natator depressa. Nesting occurs there year round, with a peak in the early months of the year. The islands are insignificant nesting sites for the green turtle, Chelonia mydas, and the hawksbill turtle, Eretmochelys imbricata. The N. depressa turtles that nest in western Torres Strait-north-eastern Gulf of Carpentaria are smaller and lay smaller eggs on average than the N. depressa turtles that breed in the southern Great Barrier Reef. On Deliverance Island, the inhabitants of nearby Queensland islands and Papua New Guinea coastal villages infrequently harvest N. depressa eggs as well as the green turtles that feed over the surrounding reef flats.
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Mortimer, Jeanne A. „Recovery of green turtles on Aldabra“. Oryx 19, Nr. 3 (Juli 1985): 146–50. http://dx.doi.org/10.1017/s0030605300025308.
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The numbers of green turtles that nest on Aldabra's beaches have increased significantly in the past 20 years. The author, who studied the turtles between 1981 and 1984, suggests explanations for the recovery. It is likely that the Aldabra population is still well below that which thrived there before exploitation began, and with sustained conservation efforts turtle numbers could continue to increase.
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Carrión-Cortez, Javier A., Patricia Zárate und Jeffrey A. Seminoff. „Feeding ecology of the green sea turtle (Chelonia mydas) in the Galapagos Islands“. Journal of the Marine Biological Association of the United Kingdom 90, Nr. 5 (16.04.2010): 1005–13. http://dx.doi.org/10.1017/s0025315410000226.
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The Galapagos Islands are among the most important nesting areas for the green sea turtle, Chelonia mydas, in the eastern Pacific Ocean. In addition, the coastal waters of this oceanic archipelago host many important feeding areas for this species, although little is known about green turtle feeding ecology at these sites. The goal of this study was to identify and quantify the most important items in the diet of the green turtle at the foraging grounds of Bahia Elizabeth, Caleta Derek and Punta Nuñez. Our analysis was based on 65 oesophageal samples from turtles captured in 2006 and 2007. We compared spatial and seasonal composition of diet using non-metric multidimensional scaling analysis (MDS) and analysis of similarity (ANOSIM). Green turtle diet was composed mainly of the algae species Ulva lactuca, Polysiphonia sp., Hypnea sp. and Dictyota sp., and the red mangrove Rhizophora mangle. Turtles also consumed animal matter, mainly cnidarians, albeit to a lesser extent. Content of turtle diets was different among feeding grounds and seasons. The ANOSIM showed that diet composition can differ between foraging grounds using presence/absence of diet items. Even though U. lactuca was the most abundant algae consumed in both seasons, changes in species richness of algae were found between both sampling events, with diet during the warm season more varied than the cold season (χ2 = 16.84, df = 6; P < 0.05).
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Werneck, M. R., und R. J. Da Silva. „Checklist of sea turtles endohelminth in Neotropical region“. Helminthologia 53, Nr. 3 (01.09.2016): 211–23. http://dx.doi.org/10.1515/helmin-2016-0045.
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SummaryThis paper presents a list of parasites described in sea turtles from the Neotropical region. Through the review of literature the occurrence of 79 taxa of helminthes parasites were observed, mostly consisting of the Phylum Platyhelminthes with 76 species distributed in 14 families and 2 families of the Phylum Nematoda within 3 species. Regarding the parasite records, the most studied host was the green turtle (Chelonia mydas) followed by the hawksbill turtle (Eretmochelys imbricata), olive ridley turtle (Lepidochelys olivacea), loggerhead turtle (Caretta caretta) and leatherback turtle (Dermochelys coriacea). Overall helminths were reported in 12 countries and in the Caribbean Sea region. This checklist is the largest compilation of data on helminths found in sea turtles in the Neotropical region.
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Werneck, M. R., R. Velloso, P. B. Costa Das Chagas, H. Jerdy Leandro und R. Martins De Amorim. „First report of Pyelosomum cochlear (Digenea: Pronocephalidae) in a Hawksbill Turtle – Eretmochelys imbricata L. found in Brazilian Coast“. Helminthologia 56, Nr. 4 (06.11.2019): 334–37. http://dx.doi.org/10.2478/helm-2019-0024.
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SummaryPyelosomum cochlearLooss 1899 (Digenea: Pronocephalidae) is a parasite exclusive to sea turtles, having been described in the green turtle (Chelonia mydas) in Egypt, the USA, Panama, Costa Rica and Brazil as well as the olive ridley turtle (Lepidochelys olivacea) in Brazil. The present note describes the first occurrence of P. cochlear in a hawksbill turtle (Eretmochelys imbricata) found on the coast of Brazil.
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Grazette, S., J. A. Horrocks, Paul E. Phillip und Crafton J. Isaac. „An assessment of the marine turtle fishery in Grenada, West Indies“. Oryx 41, Nr. 3 (Juli 2007): 330–36. http://dx.doi.org/10.1017/s0030605307000613.
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AbstractThe marine turtle fishery of Grenada was assessed using interviews with marine turtle fishermen and by examination of turtle catch data from a major landing site. An estimated 782 turtles, mainly Endangered green turtles Chelonia mydas and Critically Endangered hawksbill turtles Eretmochelys imbricata, were caught around Grenada and its sister island Carriacou each year between 1996 and 2001 during an annual 8-month open season, with only a small percentage being officially recorded at a landing site. Turtles were primarily caught with nets and spearguns, with more green turtles caught by net fishermen and more hawksbill turtles by spear fishermen. Catch per unit effort data suggested that relative abundance had declined since the previous estimate was made in 1969. Few adult green or loggerhead turtles Caretta caretta were caught, indicating the relative scarcity of this size class of these two species around Grenada. Adult-sized hawksbill turtles were caught regularly, with larger adults being caught in the non-breeding months of the open season than in the breeding months. A higher percentage of adult hawksbill turtles present during the breeding season are likely to be animals that nest in Grenada, and their smaller size may result from historically heavy fishing pressure. The larger sized adults caught during the non-breeding season are likely to be animals that forage around Grenada but breed elsewhere in the Caribbean where they are protected.
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Detjen, M., E. Sterling und A. Gómez. „Stable isotopes in barnacles as a tool to understand green sea turtle (<i>Chelonia mydas</i>) regional movement patterns“. Biogeosciences 12, Nr. 23 (08.12.2015): 7081–86. http://dx.doi.org/10.5194/bg-12-7081-2015.
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Abstract. Sea turtles are migratory animals that travel long distances between their feeding and breeding grounds. Traditional methods for researching sea turtle migratory behavior have important disadvantages, and the development of alternatives would enhance our ability to monitor and manage these globally endangered species. Here we report on the isotope signatures in green sea-turtle (Chelonia mydas) barnacles (Platylepas sp.) and discuss their potential relevance as tools with which to study green sea turtle migration and habitat use patterns. We analyzed oxygen (δ18O) and carbon (δ13C) isotope ratios in barnacle calcite layers from specimens collected from green turtles captured at the Palmyra Atoll National Wildlife Refuge (PANWR) in the central Pacific. Carbon isotopes were not informative in this study. However, the oxygen isotope results suggest likely regional movement patterns when mapped onto a predictive oxygen isotope map of the Pacific. Barnacle proxies could therefore complement other methods in understanding regional movement patterns, informing more effective conservation policy that takes into account connectivity between populations.
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Detjen, M., E. Sterling und A. Gómez. „Stable isotopes in barnacles as a tool to understand green sea turtle (<i>Chelonia mydas</i>) regional movement patterns“. Biogeosciences Discussions 12, Nr. 6 (23.03.2015): 4655–69. http://dx.doi.org/10.5194/bgd-12-4655-2015.
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Abstract. Sea turtles are migratory animals that travel long distances between their feeding and breeding grounds. Traditional methods for researching sea turtle migratory behavior have important disadvantages, and the development of alternatives would enhance our ability to monitor and manage these globally endangered species. Here we report on the isotope signatures in green sea turtle (Chelonia mydas) barnacles (Platylepas sp.) and discuss their potential relevance as tools with which to study green sea turtle migration and habitat use patterns. We analyzed oxygen (δ18O) and carbon (δ13C) isotope ratios in barnacle calcite layers from specimens collected from green turtles captured at the Palmyra Atoll National Wildlife Refuge (PANWR) in the Central Pacific. Carbon isotopes were not informative in this study. However, the oxygen isotope results suggest likely regional movement patterns when mapped onto a predictive oxygen isotope map of the Pacific. Barnacle proxies could therefore complement other methods in understanding regional movement patterns, informing more effective conservation policy that takes into account connectivity between populations.
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Limpus, CJ, und N. Nicholls. „The Southern Oscillation Regulates the Annual Numbers of Green Turtles (Chelonia-Mydas) Breeding Around Northern Australia“. Wildlife Research 15, Nr. 2 (1988): 157. http://dx.doi.org/10.1071/wr9880157.
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The green turtle (Chelonia mydas) is one of six turtle species which breeds around northern Australia and Indonesia. The number of green turtles observed nesting varies substantially from year to year. The interannual fluctuations in the number of nesting turtles are in phase at widely separated rookeries. They are also correlated with an index of the Southern Oscillation, a coherent pattern of atmospheric pressure, temperature and rainfall fluctuations which dominates the interannual variability of the climate of the tropical Pacific. Major fluctuations in the numbers of turtles breeding occur two years after major fluctuations in the Southern Oscillation. The relationship is strong enough to be useful in predicting, two years in advance, the numbers of green turtles breeding in Great Barrier Reef rookeries. This is the first study to report a biological impact of the Southern Oscillation that allows such a long-range prediction of the impact.
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Fuller, W. J., A. C. Broderick, S. K. Hooker, M. J. Witt und B. J. Godley. „Insights into Habitat Utilization by Green Turtles (Chelonia mydas) During the Inter-Nesting Period Using Animal-Borne Digital Cameras“. Marine Technology Society Journal 43, Nr. 3 (01.08.2009): 51–59. http://dx.doi.org/10.4031/mtsj.43.3.4.
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AbstractMany marine turtle habitat utilization studies have historically relied on inferences from logged data or direct visual observation. Here we remotely investigate aspects of the habitat utilization of inter-nesting female green turtles (Chelonia mydas) nesting on the Mediterranean island of Cyprus. Using an animal-borne digital video camera set to take only still images, with an integrated time-depth recorder, we recorded a total of 2,375 images and 2,899 dives for two nesting female green turtles. Both turtles spent over 80% of their time at depths of 5 m or less. Photographic evidence allowed us to categorize sub-surface behaviors from 66 of the deeper dives (turtle A with 40 dives and turtle B with 26 dives) containing more than 900 images into three categories: swimming, probable foraging and resting. Methodologically, our study highlights future utility in using camera technologies to clarify at-sea behavior of marine organisms, with a view to generating reliable time budgets.
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Guimarães, Suzana Machado, Davi Castro Tavares und Cassiano Monteiro-Neto. „Incidental capture of sea turtles by industrial bottom trawl fishery in the Tropical South-western Atlantic“. Journal of the Marine Biological Association of the United Kingdom 98, Nr. 6 (27.03.2017): 1525–31. http://dx.doi.org/10.1017/s0025315417000352.
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The five sea turtle species occurring in Brazilian waters are susceptible to threats, including incidental catches by fisheries. Studies on incidental captures in fishing gears are the main focus of several conservation actions due to high sea turtle fishery mortality worldwide. This study provides the first evaluation of incidental sea turtle catches by industrial bottom trawl fisheries operating in Brazilian waters. Four twin-trawler vessels were monitored between July 2010 and December 2011 by captains who voluntarily completed logbooks. Forty-four turtles were captured during the 1996 tows (8313 fishing hours), resulting in a catch of 5.3 ± 0.8 turtles per 1000 h per unit effort. Captured species included the loggerhead turtle (Caretta caretta, 22 individuals), olive ridley turtles (Lepidochelys olivacea, 21 individuals) and one green turtle (Chelonia mydas). Water depth was the only variable that significantly affected sea turtle captures according to Generalized Linear Models. The capture rates reported in this study ranked sixth in relation to other published studies of similar fisheries occurring worldwide. Considering the importance of this region for sea turtles, the increasing evidence of sea turtle mortality and the goals of the National Action Plan for Conservation of Sea Turtles in Brazil, it is essential to identify the main threats towards these animals and propose mitigating solutions to reduce sea turtle mortality induced by fishing activities. This study provides results that may guide future research and goals in meeting sea turtle conservation strategies.
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Sunardi, Sunardi, Anton Yudhana, Azrul Mahfurdz und Sharipah Salwa Mohamed. „Echo voltage reflected by turtle on various angles“. International Journal of Advances in Intelligent Informatics 1, Nr. 1 (31.03.2015): 48. http://dx.doi.org/10.26555/ijain.v1i1.9.
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This research proposes the acoustic measurement by using echo sounder for green turtle detection of 1 year, 12 and 18 years. Various positions or angles of turtles are head, tail, shell, lung, left and right side. MATLAB software and echo sounder are used to analyse the frequency and the response of the turtle as echo voltage and target strength parameter. Based on the experiment and analysis have been conducted, the bigger size of the turtle, the higher echo voltage and target strength. The target strength of turtle for lung and shell for all ages are -26.52 dB and –26.17 dB respectively. The target strength of turtles in this research is different with target strength of fish in our previous research. Therefore, for future research, the repellant system based on differences of target strength the turtle and fish for avoided the turtle trapping in the net can be implemented to protect the population of turtle from extinction
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Barnett, Linda K., Craig Emms, Alpha Jallow, Anna Mbenga Cham und Jeanne A. Mortimer. „The distribution and conservation status of marine turtles in The Gambia, West Africa: a first assessment“. Oryx 38, Nr. 2 (April 2004): 203–8. http://dx.doi.org/10.1017/s0030605304000353.
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This paper reports the first systematic survey of the marine turtles of the 80 km of Gambian coastline, and brings together new data and all past records and reports of marine turtles in The Gambia. Green turtles Chelonia mydas are the most abundant turtles and this is the only species so far observed nesting in The Gambia, with peak nesting between August and October. Although 75% (60 km) of The Gambian coastline appears to be suitable for turtle nesting, most nesting activity is confined to the southern coastline. Offshore foraging habitat is apparently extensive. Strandings of green turtles, olive ridley turtles Lepidochelys olivacea, leatherback turtles Dermochelys coriacea and hawksbill turtles Eretmochelys imbricata have been recorded, but we were unable to find evidence for loggerhead turtles Caretta caretta. Threats are mainly of human origin, and include illegal harvesting of eggs, juveniles and adults, as well as mortality as fisheries bycatch, including trawling. One stranded green turtle apparently had fibropapilloma disease. The major threat to nesting habitats is erosion and unregulated development of the coast for tourism. Marine turtles are fully protected under Gambian law. Other national efforts to conserve turtles in The Gambia are described and assessed.
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LOHMANN, KENNETH J., und CATHERINE M. FITTINGHOFF LOHMANN. „Orientation to Oceanic Waves by Green Turtle Hatchlings“. Journal of Experimental Biology 171, Nr. 1 (01.10.1992): 1–13. http://dx.doi.org/10.1242/jeb.171.1.1.
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Minutes after emerging from underground nests, hatchling green turtles (Chelonia mydas L.) enter the sea and begin a migration towards the open ocean. To test the hypothesis that migrating hatchlings use wave cues to maintain their seaward headings, we released turtles offshore during unusual weather conditions when waves moved in atypical directions. Hatchlings swam into approaching waves in all experiments, even when doing so resulted in orientation back towards land. These data suggest that green turtle hatchlings normally maintain seaward headings early in the offshore migration by using wave propagation direction as an orientation cue. Because waves and swells reliably move towards shore in shallow coastal areas, swimming into waves usually results in movement towards the open sea. The physiological mechanisms that underlie wave detection by sea turtle hatchlings are not known. Calculations indicate that, at the depth at which hatchlings swim, accelerations produced beneath typical waves and swells along the Florida coast are sufficient to be detected by the vertebrate inner ear. We therefore hypothesize that hatchlings determine wave direction while under water by monitoring the sequence of horizontal and vertical accelerations that occur as waves pass above.
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Homer, B. L., E. R. Jacobson, J. Schumacher und G. Scherba. „Chlamydiosis in Mariculture-reared Green Sea Turtles (Chelonia mydas)“. Veterinary Pathology 31, Nr. 1 (Januar 1994): 1–7. http://dx.doi.org/10.1177/030098589403100101.
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From August 1990 to June 1991, a moderate die-off of 4- to 5-year-old green sea turtles ( Chelonia mydas) occurred at Cayman Turtle Farm, Grand Cayman, British West Indies. Clinical signs included lethargy, anorexia, and inability to dive. Many of the ill turtles floated on the surface of their tanks. There was no apparent sex predilection. Complete necropsies, including histopathologic examination of tissues, were performed on eight turtles. Necropsies revealed multiple irregular discrete to patchy 1–10-mm pale gray foci throughout the hearts of four turtles. By light microscopic examination, the most severe and consistent lesions were necrotizing myocarditis, histiocytic to fibrinous splenitis, and hepatic lipidosis and necrosis. A mixed leukocytic infiltrate of acidophils, macrophages, and lymphocytes was present in affected areas of the heart. Other lesions included lymphocytic/plasmacytic interstitial nephritis, subacute interstitial pneumonia, subacute mesenteric vasculitis, chronic/active enteritis of the small intestine, and occasional granulomas associated with spirorchid trematode ova. Chlamydiae could be demonstrated in macrophages in sections of paraffin-embedded heart, liver, and spleen and in myocardial fibers and hepatocytes using a modified Macchiavello's stain. Chlamydial antigen was detected by light microscopic examination in the cytoplasm of myocardial fibers and in occasional hepatocytes using a commercially available genus-specific antichlamydial monoclonal antibody and the avidin biotin peroxidase complex staining method. Electron microscopic examination of the heart of the most severely affected turtle revealed developmental stages of chlamydial organisms. A suspension of heart from this turtle was inoculated into the yolk sacs of chicken embryos. Chlamydial elementary bodies could be demonstrated in infected yolk-sac membranes approximately 7 days after inoculation.
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Nada, Mohamed, und Paolo Casale. „Sea turtle bycatch and consumption in Egypt threatens Mediterranean turtle populations“. Oryx 45, Nr. 1 (Januar 2011): 143–49. http://dx.doi.org/10.1017/s0030605310001286.
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AbstractTurtle trade in the fish markets of Alexandria was reported up to the late 1990s, motivating conservation initiatives and enforcement of legal protection. To assess the current trade and bycatch levels in Alexandria and other ports we carried out an interview survey of 445 people in 2007, mostly fishermen and fishmongers, in 15 coastal cities and fishing ports along the Mediterranean coast of Egypt. The declared catch rates and official fishing fleet statistics suggest that captures of loggerhead Caretta caretta and green turtles Chelonia mydas are in the order of several thousands per year, possibly > 7,000 per year, mainly from trawling, longlining and set nets. Probably several hundred turtles die each year as a consequence of the high mortality rates typical of these fishing gears. In addition, most fishermen from Alexandria and some fishermen from other regions declared that they kill turtles for meat. Regulations and enforcement appear to be ineffective, as turtles are usually killed and consumed on board or only their meat is landed. Some turtles are still traded on the black market in some Alexandria fish markets. The overall mortality probably represents an unsustainable toll on the Mediterranean loggerhead and green turtle populations, and the perception of fishermen is that turtle numbers are declining. Mitigating the identified threats is thus urgent. In particular, intentional killing should be tackled through its cultural drivers, and measures to reduce bycatch mortality need to be tested and implemented.
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Pendoley, K. L., P. A. Whittock, A. Vitenbergs und C. Bell. „Twenty years of turtle tracks: marine turtle nesting activity at remote locations in the Pilbara, Western Australia“. Australian Journal of Zoology 64, Nr. 3 (2016): 217. http://dx.doi.org/10.1071/zo16021.
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Little is known about the biology and ecology of marine turtles in the Pilbara region of Western Australia and most potential habitat is unconfirmed and, therefore, undescribed. Understanding basic biological parameters at a regional level is critically important for effective long-term management. We used the ‘track census’ methodology to identify reproductive habitat and assess species-specific abundance of adult flatback (Natator depressus), green (Chelonia mydas) and hawksbill (Eretmochelys imbricata) turtles at 154 locations in the Pilbara region of Western Australia. Between 1992 and 2012, potential nesting habitat was assessed via either ground or aerial ‘snapshot’ (single visit) or ‘census’ (more than one night) surveys and additional information obtained using the Expert Elicitation Method. Species-specific abundance (tracks night–1 ± s.d.) was varied; green turtles were most abundant, nesting at fewer locations (n = 47) but in greater numbers (1200.5 ± 62.0) than flatback or hawksbill turtles and primarily (93%) at island locations. Flatback turtle nests were more widely distributed (n = 77) than those of green or hawksbill turtles, yet abundance (877.4 ± 29.5) was lower than that of green and greater than that of hawksbill turtles. Activity was primarily (76%) island-based and activity on the mainland coastline was concentrated close to Mundabullangana and Cemetery Beach. Hawksbill turtle abundance (314.1 ± 17.1) was lowest and the least widespread (n = 43), concentrated primarily in the Onslow and Dampier subregions with no activity recorded in the Port Hedland subregion or on the mainland coastline. The findings provide information with which the Federal government can meaningfully assess the status and distribution of EPBC Act–listed species where habitat overlaps with areas zoned for development. We highlight the urgent need for the Federal Government to regulate the process by which we accumulate data to support data quality and provide meaningful information to enhance efficacy in state and Federal management of species of concern.
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Perrault, Justin R., Milton Levin, Cody R. Mott, Caitlin M. Bovery, Michael J. Bresette, Ryan M. Chabot, Christopher R. Gregory et al. „Insights on Immune Function in Free-Ranging Green Sea Turtles (Chelonia mydas) with and without Fibropapillomatosis“. Animals 11, Nr. 3 (18.03.2021): 861. http://dx.doi.org/10.3390/ani11030861.
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Chelonid alphaherpesviruses 5 and 6 (ChHV5 and ChHV6) are viruses that affect wild sea turtle populations. ChHV5 is associated with the neoplastic disease fibropapillomatosis (FP), which affects green turtles (Chelonia mydas) in panzootic proportions. ChHV6 infection is associated with lung-eye-trachea disease (LETD), which has only been observed in maricultured sea turtles, although antibodies to ChHV6 have been detected in free-ranging turtles. To better understand herpesvirus prevalence and host immunity in various green turtle foraging aggregations in Florida, USA, our objectives were to compare measures of innate and adaptive immune function in relation to (1) FP tumor presence and severity, and (2) ChHV5 and ChHV6 infection status. Free-ranging, juvenile green turtles (N = 45) were captured and examined for external FP tumors in Florida’s Big Bend, Indian River Lagoon, and Lake Worth Lagoon. Blood samples were collected upon capture and analyzed for ChHV5 and ChHV6 DNA, antibodies to ChHV5 and ChHV6, in vitro lymphocyte proliferation using a T-cell mitogen (concanavalin A), and natural killer cell activity. Despite an overall high FP prevalence (56%), ChHV5 DNA was only observed in one individual, whereas 20% of turtles tested positive for antibodies to ChHV5. ChHV6 DNA was not observed in any animals and only one turtle tested positive for ChHV6 antibodies. T-cell proliferation was not significantly related to FP presence, tumor burden, or ChHV5 seroprevalence; however, lymphocyte proliferation in response to concanavalin A was decreased in turtles with severe FP (N = 3). Lastly, green turtles with FP (N = 9) had significantly lower natural killer cell activity compared to FP-free turtles (N = 5). These results increase our understanding of immune system effects related to FP and provide evidence that immunosuppression occurs after the onset of FP disease.
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Broderick, Annette C., Fiona Glen, Brendan J. Godley und Graeme C. Hays. „Estimating the number of green and loggerhead turtles nesting annually in the Mediterranean“. Oryx 36, Nr. 3 (Juli 2002): 227–35. http://dx.doi.org/10.1017/s0030605302000431.
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Most species of marine turtle breed every two or more years and it is the norm for females to lay more than one clutch of eggs within a nesting season. Knowing the interval between breeding seasons and the clutch frequency (number of clutches laid by an individual in a breeding season) of females allows us to assess the status of a nesting population. At Alagadi Beach, Northern Cyprus, over a period of 6 years (1995–2000), we attributed 96% of green Chelonia mydas and 80% of loggerhead Caretta caretta turtle clutches to known individual females. This intensive level of monitoring enabled us to estimate the clutch frequency for both species. Using four different methods we estimated clutch frequency to be 2.9–3.1 clutches per female for green turtles and 1.8–2.2 clutches per female for loggerhead turtles. The median interval between nesting seasons for green turtles was 3 years, and for loggerhead turtles it was 2 years. Utilizing these parameters and available data from other beaches that are monitored regularly, we estimate that there are 2,280–2,787 logger-head and 339–360 green turtles nesting annually at these sites in the Mediterranean. This highlights the Critically Endangered status of this population of green turtles. Furthermore, as conventional beach patrols underestimate clutch frequency, these population estimates are likely to be optimistic.
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Booth, DT, A. Dunstan, I. Bell, R. Reina und J. Tedeschi. „Low male production at the world’s largest green turtle rookery“. Marine Ecology Progress Series 653 (29.10.2020): 181–90. http://dx.doi.org/10.3354/meps13500.
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Because the sex of all sea turtle hatchlings is determined by incubation temperature, with low temperatures producing mainly males and high temperatures producing mainly females, sea turtle populations worldwide are threatened by feminization of hatchlings due to increases in global temperature. Data obtained by laparoscopic sexing of immature individuals captured from a major feeding ground indicates that over several decades there has been little recruitment of males into the northern Great Barrier Reef (nGBR) green turtle Chelonia mydas population, one of the largest sea turtle populations in the world. Over 2 nesting seasons, we measured nest temperatures at Raine Island, the most important nesting site for this nGBR population, and predicted that almost all nests would have produced all female hatchlings. The few nests that produced some male hatchlings were constructed at the very end of the nesting season, and these nests had the lowest hatching success. Taking into account monthly variations in nest construction, hatching success, and hatchling sex ratio, we estimate that over an entire nesting season only 0.7% of hatchlings produced are male. Hence, we conclude that the nGBR population of green turtles has likely recruited very few males in recent years.
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Bell, Catherine D. L., Joe Parsons, Timothy J. Austin, Annette C. Broderick, Gina Ebanks-Petrie und Brendan J. Godley. „Some of them came home: the Cayman Turtle Farm headstarting project for the green turtle Chelonia mydas“. Oryx 39, Nr. 2 (April 2005): 137–48. http://dx.doi.org/10.1017/s0030605305000372.
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Headstarting is a management technique employed to enhance recruitment of turtles into diminished or extirpated marine turtle populations. Although there have been numerous projects worldwide, there has been a paucity of detailed investigations into its efficacy. Between 1980 and 2001, 16,422 captive-raised hatchlings and 14,347 yearling green marine turtles Chelonia mydas were released from the Cayman Turtle Farm. Approximately 80% of all turtles released were subject to some form of tagging, including living tags. A total of 392 tagged animals have been recaptured at intervals of up to 19 years. Of this total, 160 individuals were captured in the Cayman Islands and 232 were recorded from other locations within the wider Caribbean and southeastern USA. There was significant variation in the release-recapture intervals at the three countries with most returns (Cayman, Cuba and Nicaragua). A positive relationship exists between time at large and size at recapture and data suggest growth rates comparable to those of wild green turtles in the region. There have been at least six living tag returns, four involving turtles released as yearlings and two involving turtles released as hatchlings. This demonstrates an age at maturity that may be as short as 15–19 years, depending on stage of release. Results show that some headstarted turtles are moving around the Caribbean, surviving for long periods of time, contributing to the local breeding population, and are possibly displaying shifts in habitat utilization with age similar to those recorded by wild individuals.
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Robinson, Nathan J., Eric A. Lazo-Wasem, Frank V. Paladino, John D. Zardus und Theodora Pinou. „Assortative epibiosis of leatherback, olive ridley and green sea turtles in the Eastern Tropical Pacific“. Journal of the Marine Biological Association of the United Kingdom 97, Nr. 6 (19.05.2016): 1233–40. http://dx.doi.org/10.1017/s0025315416000734.
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Sea turtles host a diverse array of epibionts, yet it is not well understood what factors influence epibiont community composition. To test whether epibiont communities of sea turtles are influenced by the hosts’ nesting or foraging habitats, we characterized the epibiota of leatherback, olive ridley and green turtles nesting at a single location on the Pacific coast of Costa Rica. We also compared the epibiota of these turtles to conspecific populations nesting elsewhere in the East Pacific. If epibiont communities are influenced by nesting habitats, we predicted that sympatrically nesting turtles would have comparable epibiont taxa. Alternatively, if epibiont communities are influenced by foraging habitats, we predicted the diversity of epibiont taxa should reflect the type and diversity of the hosts’ foraging habitats. We identified 18 epibiont taxa from 18 leatherback, 19 olive ridley and six green turtles. Epibiont diversity was low on leatherbacks (four taxa), but higher for olive ridley and green turtles (12 and nine epibiont taxa respectively). The epibiont communities of olive ridley and green turtles were not statistically different, but both were different from leatherbacks. In addition, conspecific sea turtles from other nesting locations hosted more similar epibiont communities than sympatrically nesting, non-conspecifics. We conclude that epibiont diversity of nesting sea turtles is partially linked to the diversity of their foraging habitats. We also conclude that the surface properties of the skin and carapace of these turtles may contribute to the uniqueness of leatherback turtle epibiont communities and the similarities between olive ridley and green turtle epibiont communities.
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Nastiti, Adriani Sri, Masayu Rahmia Anwar Putri, Joni Haryadi, Arif Wibowo und Ngurah N. Wiadnyana. „ANALYSIS 16S RDNA OF THE TURTLES IN FORECLOSURE CAGES AT PADEI LAUT, CENTRAL SULAWESI, INDONESIA“. Indonesian Fisheries Research Journal 23, Nr. 1 (17.10.2017): 39. http://dx.doi.org/10.15578/ifrj.23.1.2017.39-44.
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Marine turtle is one of the protected aquatic animals as listed in CITES Appendix and IUCN red list. However, illegal fishing of marine turtle is still occurred Padei Laut Village, in Morowali Regency, Central Sulawesi Province, Indonesia. The research aims to study the population of marine turtle based on the carapace length and the genetic relationships. Data of carapace length was measured in-situ and genetic analysis was used mitochondrial DNA. The results showed that the carapace (ten samples which was green turtles/Chelonia mydas) was ranges between 42-102 cm; 91% of samples was immature and 9% was mature. Moreover, it also revealed that those turtles resembled by 99.98% of genetic similarity.
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Lu, Yuanan, Vivek R. Nerurkar, Tina M. Weatherby und Richard Yanagihara. „Identification of Papilloma-Like Virus Particles in Cell Lines Derived from Green Sea Turtle (Chelonia Mydas) With Fibropapilloma“. Microscopy and Microanalysis 4, S2 (Juli 1998): 1158–59. http://dx.doi.org/10.1017/s1431927600025915.
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The near epidemic occurrence of fibropapilloma in green sea turtle (Chelonia my das) (Figure 1) significantly threatens the survival of this species which is protected under the U.S. Endangered Species Act. Although collective evidence suggests a viral etiology, the causative virus of green sea turtle fibropapilloma has not been isolated. To facilitate the isolation and characterization of the causative virus(es), we established 13 cell lines from multiple organs/tissues (tumor, kidney, lung, heart, gall bladder, testis, and skin) of green sea turtles with fibropapilloma. Serial subcultivation of cell lines derived from lungs, testis, eye soft tissues and tumors resulted in the formation of tumor-like aggregates, which attained sizes of 1-2 mm in diameter within two weeks (Figure 2). Media from such cultures, when inoculated onto cells derived from healthy turtle embryos, produced similar tumor-like aggregates, suggesting the presence of a transmissible agent.