Download or read book Conservation Implications of the Genetic Structure and Habitat Use of Green Turtles Chelonia Mydas in the South China Region and Baseline Contaminant Levels in Green Turtles and Burmese Pythons Python Bivittatus written by Ka Yan Ng and published by . This book was released on 2015 with total page 720 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synopsis of the Biological Data on the Green Turtle Chelonia Mydas Linnaeus 1758 written by Harold F. Hirth and published by . This book was released on 1997 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Population and Genetic Structure of the Green Turtle Chelonia Mydas in West and Central Africa written by Angela Formia and published by . This book was released on 2002 with total page 540 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Spatial and Temporal Patterns of Habitat Use by East Pacific Green Turtles Chelonia Mydas in a Highly Urbanized Foraging Ground written by and published by . This book was released on 2012 with total page 43 pages. Available in PDF, EPUB and Kindle. Book excerpt: Green sea turtles, Chelonia mydas, utilize coastal areas as foraging grounds for the majority of their lives. Human development of coastlines is increasing, but the effects of the urbanization of foraging grounds on green turtles are poorly understood. I used both manual and automated acoustic telemetry to determine the home ranges, movement behavior, and temporal patterns of site visitation of green turtles during 2009-2011 in San Diego Bay, California, a highly urbanized temperate foraging area. The home ranges of all tracked turtles were restricted to the southern portion of San Diego Bay, where eelgrass (Zostera marina) is abundant and where human activity is the lowest within the bay. Core activity areas coincided with eelgrass distribution or occurred adjacent to the warm water-effluent outfall of a waterfront power plant. Automated monitoring of sites throughout south San Diego Bay confirmed this finding, showing that green turtles most frequently visited the outfall of the power plant and areas known to contain eelgrass. This method also elucidated that turtle presence at the power plant was strongest during the winter and at night, whereas visitation to eelgrass areas was strongest during the spring and in the daytime. Turtle visitation to a high boat traffic shipping terminal was rare but occurred almost exclusively during the daytime, the period during which human activities in the area are also the highest. Manual tracking of green turtles similarly demonstrated that individuals ranged across larger portions of south San Diego Bay during the day, during which they exhibited high swimming speeds but highly non-linear movement. Turtle activity at night was primarily restricted to the power plant's effluent outfall channel and adjacent jetty. Nighttime movement was characterized by long periods of inactivity sporadically interrupted by brief, linear movements to new resting locations. Collectively, the results of this study paint a robust picture of the spatial, diel, and seasonal patterns of habitat use by green turtles in San Diego Bay. All data support the hypothesis that south San Diego Bay serves as important turtle habitat within the bay. Further, a combination of manual and automated acoustic telemetry enables a more complete understanding of turtle spatial ecology that would not have been possible with exclusive use of one technique. Future monitoring and modeling is required to document the potential effects of changing environmental conditions, including power plant closure, on green turtles resident to San Diego Bay. This study helps to assess the data gap of how turtles use urbanized foraging areas and changing coastal ecosystems, a currently novel scenario that will likely become commonplace in the face of increasing coastal development worldwide.

Download or read book Recovery Plan for U S Pacific Populations of the Green Turtle Chelonia Mydas written by Pacific Sea Turtle Recovery Team (U.S.) and published by . This book was released on 1998 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Physiological Consequences of Basking Disease and Captivity in the Green Turtle Chelonia Mydas written by Jana Yonat Beth Swimmer and published by . This book was released on 1997 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synopsis of Biological Data on the Green Turtle Chelonia Mydas Linnaeus 1758 written by Harold F. Hirth and published by . This book was released on 1971 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Recovery Plan for U S Pacific Populations of the East Pacific Green Turtle Chelonia Mydas written by Pacific Sea Turtle Recovery Team (U.S.) and published by . This book was released on 1998 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Genetic Structure of Green Sea Turtle Chelonia Mydas Foraging Aggregations on the East Coast of Florida written by Monica R. Reusche and published by . This book was released on 2020 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: The genetic structure of juvenile green turtles (Chelonia mydas) foraging on the east coast of central Florida is not well understood, nor has it been examined over time. In the last three decades, the dramatic increase in the number of green sea turtle nests in Florida, in association with other population parameters, has led to this species being down-listed under the Endangered Species Act from “endangered” to “threatened” in the northwest Atlantic. However, it was unclear if the exponential growth in Florida nest numbers had any influence on the genetic structure of juveniles in nearby foraging aggregations. To understand this potential impact mixed-stock analysis was conducted using mitochondrial DNA fragments that were over 800 base pairs long on samples taken from juveniles captured from 2002-2005 and 2016-2018 in the central Indian River Lagoon and Trident Submarine Basin in Port Canaveral. Results indicate the sampled foraging sites are genetically distinct habitats. In both sites, recruitment from Florida nesting beaches remained low despite increases in nesting while contributions from rookeries in Costa Rica and Mexico dominated both foraging aggregations across time. Haplotype diversity and nucleotide diversity decreased at both foraging sites over time. The foraging sites shared the two most frequently occurring haplotypes, but also had haplotypes that were unique to the site or sample period. Our results highlight the need for broader sampling of rookeries and foraging aggregations to understand the impacts of nesting increases in one rookery on juvenile diversity. Future studies should include all life stages of green turtles to enhance understanding of both the census population and effective population to better inform conservation policies necessary for a continued recovery.

Download or read book Influence of Temperature on Habitat Use by East Pacific Green Turtles chelonian Mynas in an Urbanized Environment written by Sheila Veronica Madrak and published by . This book was released on 2016 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt: Project Overview. Thermal characteristics of marine environments are changing rapidly on both global and local scales. Worldwide, ocean temperatures are increasing -- a trend expected to continue (Meehl et al. 2005; Bindoff et al. 2007; IPCC 2007). However, at the local level water temperature is more variable, demonstrating both warming and cooling through space and time (Hoegh-Guldberg and Bruno 2010; Kosaka and Xie 2013). Many marine organisms are adapted to specific, often highly constrained, thermal ranges. Global climate change and anthropogenic influences have already had dramatic effects on marine species (Harley et al. 2006; IPCC 2007; Hoegh-Guldberg and Bruno 2010). While large-scale changes in temperature can be attributed to shifts in the global climate regime, there are other human-mediated factors that influence local thermal conditions. One major anthropogenic influence on local marine environments is thermal effluent from power plants and industry that utilize once-through cooling (OTC) systems. The stations that use OTC systems generate waste heat, a by-product of the cooling process, which must be released into the environment (either via cooling towers or natural water source). Thus, OTC system stations alter the thermal environment proximate to their locations. Although local and global scale changes may be driven by different factors, changes to the thermal environment at the local level can provide a model system to study the effects of largescale climate change. Characterizing the responses of coastal fauna to rapid shifts in thermal conditions addresses a key gap in ecological knowledge -- understanding how populations of longlived marine vertebrates will be affected by a thermally dynamic environment that is changing at rapid rate. The fossil fuel-based South Bay Power Plant (SBPP) in San Diego, California was in operation from 1960 to 2010 and discharged warm-water effluent into southern San Diego Bay (SDB) and utilized an OTC system. East Pacific green sea turtles (Chelonia mydas), resident in SDB since at least the 1890's (Parsons 1962), have been routinely observed in the power plant outfall area since the 1960s (Stinson 1984; McDonald and Dutton 1990). Previous research suggests that these turtles used the outfall area to reduce metabolic costs and exhibit higher growth rates than other populations of green turtles (Eguchi et al. 2010, Eguchi et al. 2012). On December 31, 2009, two of the plant's four generators were permanently shut down; complete decommissioning of the plant occurred on December 31, 2010. This power plant closure provided a rare experimental opportunity to assess how rapid changes in the thermal environment will affect a resident marine turtle population in a coastal foraging area. The first chapter of my dissertation represents a review of the scientific studies that demonstrated physiological and behavioral changes across mobile aquatic reptiles utilizing these areas with heated effluent. I identify key responses to thermal effluent in reptiles in both marine and freshwater environments and present a case study from green turtles in SDB. The second chapter of my dissertation reflects my research using acoustic telemetry to monitor the changes in distribution and behavior of green turtles in response to the closure of the SBPP. The third and final chapter of my dissertation summarizes the changes of dive behavior by green turtles before and after the closure of the SBPP.

Download or read book Identifying foraging and space use patterns of juvenile green sea turtles Chelonia mydas in Brewers Bay St Thomas using a fine scale positioning acoustic array written by Taylor Brunson and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: As green sea turtle (Chelonia mydas) populations in the Caribbean recover from historical overexploitation, growing environmental obstacles pose threats to the recovery of this species. The invasion of Halophila stipulacea seagrass in previously Syringodiumfiliforme and Halodule wrightii -dominated beds drastically alters the composition of green turtle foraging habitat. This change in forage supply for juvenile and adult green turtles in the Caribbean could impact their future habitat use and resource partitioning, information that conservation and management agencies use to implement protective guidelines for this species. We conducted a fine-scale tracking study of green turtles’ space use and movement patterns in Brewers Bay, St. Thomas to investigate their foraging selectivity in the mixed-species seagrass beds. The fine-scale positioning system(FPS) acoustic receiver array was deployed across ~1.5 km2 of the bay, which includes seagrass, coral reef, and sand/rock benthic habitat. Seventeen individual juvenile green sea turtles were tracked with acoustic transmitters with an estimated precision of ± 2meters. The native and invasive seagrass composition was mapped in the highest trafficked daytime area to pair with the turtles’ foraging locations. Turtles displayed typical diel patterns of movement with higher activity levels in shallow mixed-seagrass habitats during the day and lower activity levels in shallow reefs and rocky habitats at night. These movement results were linked to seagrass composition within the sampling grid using resource selection functions (RSF) to estimate turtle selection towards each seagrass species in Brewers Bay. Turtles were actively selecting the two native species, with no selection towards the invasive seagrass despite its high abundance. Interestingly, three individuals utilized foraging areas outside the sampling grid and in deeper water with monotypic invasive seagrass. This pattern of space use has not been observed in past tracking and observational studies in Brewers Bay, implying that part of this population has started modifying its foraging patterns to incorporate H. stipulacea.

Download or read book Assessing the Composition of Green Turtle Chelonia Mydas Foraging Grounds in Australasia Using Mixed Stock Analyses written by Michael Paul Jensen and published by . This book was released on 2010 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding the population dynamics in both breeding and foraging habitats is a vital part of assessing the long-term viability of any species, especially those that are highly migratory. This is particularly true for green turtles, Chelonia mydas, which are long-lived marine turtles that undergo migrations for several years as post hatchlings until they select foraging grounds, and as adults, migrate between their foraging grounds and nesting beaches. Monitoring of populations at the foraging grounds may help detect early signs of population trends that would otherwise take decades to be observed at the nesting beach. In order to gain such insights the connectivity between nesting and foraging habitats must be established. Genetic analysis of rookeries to define discrete populations (stocks), in combination with Mixed Stock Analysis (MSA) based on data from molecular markers, provides an effective approach for estimating the origin of turtles sampled away from their nesting beach. In this thesis, new investigations into the genetic structure of green turtle populations in Australasia were conducted using longer (~780 bp) mitochondrial (mt) DNA sequences, larger sample sizes and new locations. This information provided the baseline data used in Mixed Stock Analyses of the composition of foraging grounds in three regions of Australasia including Western Australia, the Great Barrier Reef (GBR) and Malaysia. In chapter 2, I review what has been learned since the first MSA studies in marine turtles more than a decade ago. Since the early 1990s, numerous studies used this method to elucidate the rookery origins of young pelagic stage turtles and of older turtles in benthic foraging grounds, in fisheries by-catch and in strandings. These studies have all shown how Mixed Stock Analysis has provided valuable new insights into the distribution of marine turtles, although in most cases the estimates are affected by large uncertainty. Several issues in the effective use of MSA need to be addressed concerning study design, sample sizes and the resolution provided by the genetic marker. Nonetheless, Mixed Stock Analysis holds great potential for monitoring population trends at oceanic and coastal foraging grounds for all size classes. Comparisons of adults and juveniles provide an opportunity to pick up early signs of shifts in the contributions of populations that may indicate population decline (or increase) (e.g., Chapter 5). Recent increases in industrial development of coastal island and offshore habitats in Western Australia (WA) have highlighted the need to better understand the dynamics of marine turtle populations in these areas. An analysis of previously sampled populations (Management Units; MUs) and four new rookeries identified two possible new Management Units in this region at Cobourg Peninsula and Cocos (Keeling) Island and grouped Browse Island with the existing MU at Scott Reef and Barrow Island to the large North West Shelf MU. These analyses used a 780 bp sequence of the mtDNA control region that encompassed the 386 bp sequence used in a previous study. The longer sequence, larger sample sizes and new locations revealed more than doubled the number of haplotypes (n = 39) than previously observed. However, this made little difference to the population genetic structure as common haplotypes were still shared among population. MSA showed that the majority (>90%) of turtles foraging at Shark Bay were from neighbouring North West Shelf rookeries, while the Cocos (Keeling) foraging ground was composed of turtles mainly from Cocos (~70%), but with some contributions from North West Shelf and possibly Scott Reef MUs. In an investigation of foraging populations in Malaysia, mtDNA sequence data were analysed from 81 immature green turtles at two foraging grounds at Mantanani Island and Layang Layang Island located northwest of Sabah, Malaysia. Previously published data from 17 Australasian green turtle populations were used as the baseline data for tracing back the origin of turtles at the two foraging grounds. The majority of these turtles originated from major rookeries in the Malaysia and Philippine Turtle Islands (~30%), and Sarawak (~60%) in north-western Borneo. These same rookeries have a long tradition of using unshaded beach hatcheries that has resulted in the production of mostly female hatchlings. This may have contributed to the 1:4 female biases seen at the two foraging grounds. The implications of hatchery practises at nesting beaches are discussed and the importance of continued monitoring and research at these foraging areas is highly recommended to improve the management of marine turtles in the region. Detailed MSA of green turtle aggregations at six major foraging grounds along the east coast of Australian were combined with data from more than 30 years of mark–recapture efforts along the Great Barrier Reef. Overall, the MSA in combination with the mark-recapture data supports a model in which the foraging aggregations are composed of individuals from the two Great Barrier Reef stocks (nGBR, sGBR) with small contributions from other stocks. The north/south transect of foraging grounds analysed spanned ~2300 km. Along this transect the main contributor shifted from being predominantly the nGBR stock at foraging grounds in Torres Strait, Clack Reef and the Howicks Group to predominantly the sGBR stock at Edgecombe Bay, Shoalwater Bay and Moreton Bay. At the most northern foraging ground in the Torres Strait, significant shifts in haplotype frequencies between juveniles and adults resulted in major shifts in the estimated stock contributions for these groups. Fewer juveniles originated from the nGBR stock and higher proportion originated from the sGBR and „other‟ stocks in comparison to adults. This trend was apparent in the four most northern foraging grounds, even in Edgecombe Bay, which had a predominance of turtles from the sGBR stock. Point estimates of contributions from the nGBR stock dropped from 0.89 in adults to 0.53 in juveniles in Torres, Strait, from 0.69 to 0.49 at Clack Reef, from 0.66 to 0.49 in the Howicks Group and from 0.10 in adults to 0.01 in juveniles at Edgecombe Bay. In contrast, at the Shoalwater Bay foraging ground the opposite was observed, with a drop in contribution from the sGBR stock from 0.98 in adults to 0.84 and 0.85 in juveniles and sub-adults, respectively, and an increase in contributions from „other‟ stocks in juveniles and sub-adults. The observed patterns at the various foraging grounds likely resulted from several causes and four possible explanations are explored, the mostly likely of which were that (i) juveniles have shifted foraging grounds as they mature, or that (ii) reduced hatching success from the main nGBR rookery at Raine Island for more than a decade has resulted in reduced recruitment into the nGBR foraging ground. The later possibility suggests a need to take action to conserve the nGBR population The combined strength of data derived from mark-recapture studies, demographic studies to determine sex, maturity and breeding status of the turtles, genetic studies to determine stock composition and satellite telemetry, are needed to provide informed assessments of foraging populations necessary for guiding sustainable management of marine turtles.

Download or read book The Green Turtle and Hawksbill Reptilia Cheloniidae written by Brian Groombridge and published by . This book was released on 1989 with total page 612 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Genetic Composition Population Structure and Natal Origins of Foraging Green Turtles Chelonia Mydas in Puerto Rico written by Yabriel Pagán Benítez and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The green turtles (Chelonia mydas), by nature, migrate between nesting populations and feeding grounds. This movement influenced the mixing and separation of different genetic groups across the North and South Atlantic Ocean. Our study used genetic markers derived from mitochondrial DNA to investigate the genetic composition, population structure, and natal origins of the green turtles found in Puerto Rico feeding grounds. Through an analysis of 491 base pair of the mitochondrial DNA (mtDNA) control region sequences from 38 individuals, we identified five haplotypes of these: CM-A1 (42.1%), followed by CM-A3 (36.8%), CM-A5 (13.2%), CM-A2 (5.3%) and CM-26 (2.6%) were identified. Haplotype (h) and nucleotide (TT) diversities were 0.684 ± 0.044 and 0.006 ± 0.003, respectively, showing a high genetic variability between them. In our spatial analysis of differentiation consisting of 19 Atlantic feeding aggregations, we found a significant differentiation in most populations, except for North Atlantic populations (p > 0.05). To address the possible natal origings of foraging green turtles found in Puerto Rico, we use a Mix Stock Analysis (MSA) incorporating 14 Atlantic nesting populations as possible natal origins, indicating four leading contributing stocks to the Puerto Rico feeding population: East Central Florida, USA (72%); Aves Island, Venezuela (6%); South Florida, USA (5%) and Costa Rica (5%). This study provides valuable information about green turtles' movement and genetic diversity in Puerto Rico's feeding areas by incorporating new data from isolated groups or as solitary individuals across the island, offering vital knowledge for their effective conservation and management.

Download or read book Synopsis of the Biological Data on the Green Turtle Chelonia Mydas Linnaeus 1758 written by Hirth and published by CreateSpace. This book was released on 2015-02-14 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: The main purposes of this synopsis are to bring together the current and salient information on the biology of the green turtle and to draw attention to some of the major gaps in our knowledge of the species. Because of the nature of a synopsis, that of providing an entry into the literature, researchers should persue the original papers for details of methodologies and conclusions.

Download or read book The Conservation Genetics of Green Turtles Chelonia Mydas written by Tigerin Peare and published by . This book was released on 1997 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Evaluation of Seagrass Community Structure and Its Role in Green Sea Turtle Chelonia Mydas Forgaging Dynamics in the Lower Laguna Madre written by Tracy Fisher Weatherall and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Satellite tracking data of juvenile and subadult green turtles captured and released by Texas A & M University at Galveston's Sea Turtle and Fisheries Ecology Research Lab (STFERL) from the lower Laguna Madre indicate green sea turtles (Chelonia mydas) exhibit high fidelity to seagrass communities where they can be found year-round. Population growth is prerequisite to eventual down listing of this endangered species to a threatened status and its subsequent recovery. The role Texas' green turtle population will play in this recovery will depend, in part, on the ability of seagrass communities in the lower Laguna Madre to sustain continued growth of this population. Seagrass community structure was characterized during 7-8 March 2009 to determine if foraging grounds in the lower Laguna Madre can sustain green turtle population growth. Differences in seagrass community structure influencing foraging potential between high fidelity sites (Region 1) were compared to adjacent areas in which green turtles have not been captured and tracked by the STFERL (Region 2). Seagrass samples were taken from six seagrass communities to characterize seagrass and invertebrate community parameters. In addition, three standardized and randomized bag seine collections of nekton, invertebrates and plant debris were conducted within the six seagrass communities. Family richness and abundance of fishes and invertebrate fauna were assessed from the standardized bag seine collections. Seagrass species including Thalassia testudinum (turtle grass), Syringodium filiforme (manatee grass), and Halodule wrightii (shoal grass) were found in Region 1 whereas T. testudinum and H. wrightii were found in Region 2. Total seagrass biomass from Region 1 was significantly greater than that from Region 2 implying a healthier seagrass community. Seagrass beds in Region 2 were highly patchy and sparse. Family richness and faunal density collected with the bag seine in Region 1 were significantly higher than those in Region 2 suggesting seagrass habitat complexity was higher in Region 1. These data suggest a trend toward increased seagrass habitat quality and community complexity in Region 1 which, in turn, may contribute to a healthier seagrass environment that serves as an optimal foraging area for green turtles in the lower Laguna Madre.