Download or read book Using Biomarkers to Assess the Migratory Ecology and Reproduction of the Florida Green Turtle Chelonia Mydas written by Ryan Maddox Chabot and published by . This book was released on 2017 with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt: Migratory connectivity between breeding and foraging areas is a vital component of the ecology of a diverse collection of marine vertebrates. Habitat quality, composition, and resource availability at these locations have direct ramifications for individual fitness. The green turtle (Chelonia mydas) is a long-lived, highly migratory species of conservation concern. Important green turtle nesting habitat in Florida is protected, but more information is needed to identify foraging habitats and the influence these habitats have on reproduction. Here, I used stable isotope analysis of [delta]13C, [delta]15N, and [delta]34S and satellite telemetry validation to determine the number of putative foraging areas used by the breeding aggregation at the Archie Carr National Wildlife Refuge (ACNWR), and the relative contribution of each foraging area. I evaluated the influence of foraging area and other variables on egg size, clutch size, hatching success, and emerging success using model selection frameworks. Isotopic values of skin and eggs were used to build conversion equations between the two tissue types. Results suggest strong migratory connectivity between the ACNWR and the Florida Keys/Florida Bay complex. I found that the influences of foraging area are likely to be more detectable when evaluating female-centric fitness metrics like clutch size and egg size; these influences are more muted in hatching and emerging success, which are strongly influenced by nest incubation conditions. These are the first green turtle-specific tissue conversion equations for [delta]13C and [delta]15N, and the first [delta]34S equation for any marine turtle species. These will allow researchers to have a “common currency” between frequently collected samples to better compare results.

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 Recovery Plan for U S Population of Atlantic Green Turtle Chelonia Mydas written by and published by . This book was released on 1991 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Juvenile Green Turtle Chelonia Mydas Foraging Ecology written by Eliza Inez Gilbert and published by . This book was released on 2005 with total page 47 pages. Available in PDF, EPUB and Kindle. Book excerpt: For the endangered green turtle, Chelonia mydas, a fundamental component of recovery and conservation is an understanding of its foraging ecology. Foraging optimality models suggest animals will select resources of high quality over those of low quality. For green turtles, this behavior is important, as sufficient quantities of nutritionally adequate forage items are necessary for growth and reproduction. One intrinsic element in the understanding of green turtle foraging ecology is to identify and document the availability and quality of forage resources preferred by green turtles.

Download or read book The Ecology and Migrations of Sea Turtles written by Archie Fairly Carr and published by . This book was released on 1978 with total page 46 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 Long term Changes in Juvenile Green Turtle Abundance and Foraging Ecology in the Indian River Lagoon Florida written by Christopher Augustus Long and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Marine turtles are distributed in temperate, sub-tropical and tropical waters and beaches worldwide, often in areas heavily impacted by humans. Although there are many threats to marine turtle populations, the growing threats of nutrient pollution and harmful algal blooms are relatively understudied despite their widespread impacts on coastal marine ecosystems that marine turtles depend on. By studying juvenile green turtles (Chelonia mydas) in the Indian River Lagoon, Florida, where nutrient pollution and HABs are a widespread and longstanding issue, I aimed to conduct a case study of how these threats may affect this federally Threatened species. In Chapter 2, I used four concurrent, 18-year data sets to characterize and assess the interrelatedness of long-term trends in seagrass cover, macroalgae occurrence, juvenile green turtle abundance, and juvenile green turtle growth rates. From 2000 to 2018, IRL seagrass cover declined precipitously, macroalgae rose slowly through 2011 then declined during two severe HABs, juvenile green turtle abundance declined slowly, and growth rates declined through 2011 then rose through 2018. In Chapter 3, I conducted a 9-year study of juvenile green turtle foraging ecology using a comparative stable isotope approach. I found that carbon and nitrogen stable isotopic variance declined during and after two severe HABs in the IRL. In Chapter 4, I used two complementary methods to assess the diet of juvenile green turtles after two severe algal blooms in order to assess changes compared to previous diet studies. Visual identification of forage items showed that juvenile green turtle diet remained dominated by nutrient-tolerant red macroalgae with smaller components of seagrass and green algae; metabarcoding techniques largely failed to resolve their diet. My results highlight the web of complex effects and responses that factor in to determining the effects of nutrient pollution and HABs on juvenile green turtles. Future studies of habitat selection, foraging ecology, and the effects of these on juvenile green turtle growth and survival are needed to fully assess the threat of nutrient pollution.

Download or read book Reproductive Ecology of the Green Turtle Chelonia Mydas at Ascension Island written by Jeanne A. Mortimer and published by . This book was released on 1981 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt: The reproductive ecology and behavior of the green turtle, Chelonia mydas, were studied at Ascension Island, an isolated peak in the Central Equatorial Atlantic Ocean. Physical characteristics of the 32 cove-head beaches of the island were measured, and their influence on beach-choice by gravid females, on the behavior of females during nest construction, and on viability of the eggs and hatchlings was examined. Characteristics of the offshore approaches exert more influence on beach selection by nesting females than do features above the high tide line. Nesting is most dense on beaches with approaches unobstructed by submerged rocks. The turtles avoid beaches with foreshores cluttered by rocks, or where there is artificial lighting nearby. Females have difficulty digging egg chambers in the coarse, dry Ascension sand. Typically, they emerge repeatedly, on two or three successive nights, and dig multiple trial nest holes before depositing eggs. Successive egg clutches are laid at intervals of about 14 days. Although females may lay as many as seven clutches in a season, the average number recorded was between two and three. The numbers of eggs laid by individual females during a season decreases with successive nestings; the average clutch size measured was 120.9 eggs. Four years, followed by three years, are the predominant remigratory intervals recorded in Ascension turtles. During renesting emergences, the females usually land at the same beach, often to within a few meters of their previous nesting place, or at an adjacent beach. Stronger site tenacity was evident in renestings separated by less than seven days (assumed to be repeated attempts to lay the same clutch of eggs), than in those separated by longer time intervals. These differences correlate with predictable patterns of behavior observed in females, the movements of which were visually tracked during their internesting intervals. After successful oviposition, tracked females travelled to a shallow area off the northwest coast of the island. The frustrated nesters remained in the vicinity of the nesting beach that they had just abandoned. Both rarely entered water more than 18 m deep. Nesting occurs on all the beaches, although on some, hatching success approaches zero. No correlation between nesting density and percent hatchling emergence on the beaches was found. Reproductive success is influenced by characteristics of the beach sand, especially particle size distribution. Sand that is too fine, or too poorly sorted inhibits gas diffusion. Coarse sand causes cave-ins. A positive correlation between hatching success and depth of the nest was observed, probably because higher moisture levels occur at great depths. Elevated levels of salinity in the sand, most frequently seen in poorly sorted sand, may induce desiccation through osmotic stress. The positive correlation between hatching success and distance from the sea may be related to inundation by rollers. There is a relative dearth of both terrestrial and offshore predation upon the eggs and hatchlings. Heavy mortality is caused by edaphic and density-dependent f actors--beach erosion, inundation, and females digging up previously laid clutches. An estimated 2,600 females nested at Ascension during the 1976-77 season, and 1,800 during the 1977-78 season.

Download or read book Movements and Feeding Ecology of Immature Green Turtles Chelonia Mydas written by Mary T. Mendonca and published by . This book was released on 1981 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Ecology and Migrations of Sea Turtles written by Archie Carr and published by . This book was released on 1962 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Ecology of Juvenile Green Turtles Chelonia Mydas at a Temperate Foraging Area in the Northeastern Gulf of Mexico written by Erin McMichael and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT: In recent years, scientists have recognized the need to conduct in-water studies to better understand the biology of juvenile sea turtles. Little is known regarding the seasonal abundance of juvenile populations in temperate developmental areas such as those in the Gulf of Mexico. It is likely that the Gulf of Mexico supports a year-round population of juvenile sea turtles.

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 Proceedings of the Twenty ninth Annual Symposium on Sea Turtle Biology and Conservation written by and published by . This book was released on 2012 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Trophic Ecology of Green Turtles Chelonia Mydas From Dry Tortugas National Park Florida written by David C. Roche and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Diet Characterization in Immature Neritic Green Turtles Chelonia Mydas Using Gut Contents and Stable Isotope Analyses written by Natalie Christine Williams and published by . This book was released on 2012 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent developments in open water research have refined our understanding of green turtle, Chelonia mydas, foraging ecology, but diet characterization among populations remains understudied. Previous hypotheses state that once young green turtles recruit to shallow water habitat they shift rapidly from an omnivorous to herbivorous diet. Supporting evidence has primarily been derived from traditional gut content analysis that only provides a small window in time to perceive the diet of an animal. In contrast, stable isotope analysis explore show a consumer uses its resources over a broad temporal scale. We tested the dietary shift hypothesis using gut content and stable isotope analyses to assess the nutritional ecology of a juvenile green turtle aggregation in the northern Gulf of Mexico. We examined the gut contents of 65 green turtles collected from 2008 and 2011 hypothermic stunning events in St. Joseph Bay, Florida. Gut contents were evaluated using volume, dry mass, percent frequency of occurrence, and index of relative importance (IRI). Juvenile green turtles showed omnivorous feeding behavior, feeding on a variety of animal and vegetal items with a bias towards seagrass and tunicates. In addition, we evaluated feeding consistency by stable isotope patterns from epidermis tissue. We measured the stable carbon (delta13C)and nitrogen (delta15N)isotope values in epidermis of 43 green turtles, ranging from 22.5 to 72.7cm in curved carapace length (CCLmin), and eight known prey items (e.g., algae, seagrasses, invertebrates) collected in 2011. Our study provides a foundation for characterizing the foraging ecology of green turtles in St. Joseph Bay and highlights the value of utilizing isotopic ecology for further foraging studies.

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 Biology of Sea Turtles Volume II written by Peter L. Lutz and published by CRC Press. This book was released on 2002-12-17 with total page 510 pages. Available in PDF, EPUB and Kindle. Book excerpt: The success of the first volume of The Biology of Sea Turtles revealed a need for broad but comprehensive reviews of major recent advances in sea turtle biology. Biology of Sea Turtles, Volume II emphasizes practical aspects of biology that relate to sea turtle management and to changes in marine and coastal ecosystems. These topics i