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 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 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 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 132 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Biology of Sea Turtles Volume I written by Peter L. Lutz and published by CRC Press. This book was released on 2017-12-06 with total page 446 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sea turtles have existed for millions of years, making them fascinating subjects of study. In the last 20 years, the science of sea turtle biology has expanded at an exponential rate, leading to major advances in many areas. This book synthesizes the results of these advances and focuses on how these endangered marine reptiles operate in, adapt to, and are dependent upon particular features of their marine environment. New technology in data gathering, such as DNA analyses, remote sensing, and physiological monitoring techniques, has led to a much greater understanding of the biology of the sea turtle at all stages of their life history.
Download or read book Proceedings of the International Symposium on Sea Turtle Conservation Genetics 12 14 September 1995 Miami Florida written by Brian W. Bowen and published by . This book was released on 1996 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Significance of the South Atlantic Equatorial Countercurrent to the Ecology of the Green Turtle Breeding Population of Ascension Island written by C. W. Brown and published by . This book was released on 1990 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synopsis of Biological Data on the Hawksbill Turtle Eretmochelys Imbricata Linnaeus 1766 written by W. N. Witzell and published by Food & Agriculture Org.. This book was released on 1983 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Proceedings of the Fifteenth Annual Symposium on Sea Turtle Biology and Conservation 20 25 February 1995 Hilton Head South Carolina written by John A. Keinath and published by . This book was released on 1996 with total page 408 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Reproductive Biology of the Chelonia written by Gerald Kuchling and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 229 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents a comparative view of chelonian reproduction and discusses ecophysiological implications for their captive breeding. Chelonians, with their protective rigid armour, are a phylogenetically antique group of reptiles which radiated to occupy niches from the open waters of the oceans, to rivers, creeks, swamps, forests, savannahs, and deserts. A few North American turtle species have been well studied, but until recently reproductive data on other chelonian species have been scarce. The way in which chelonians adjust their conservative mode of reproduction to the various requirements of their habitats and life styles is the theme of this book; the physiology of reproduction and its interplay with ecological conditions are its central subjects.
Download or read book Proceedings of the Eighth Annual Workshop on Sea Turtle Conservation and Biology written by and published by . This book was released on 1988 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Biological Report written by and published by . This book was released on 1984 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Man Who Saved Sea Turtles written by Frederick R. Davis and published by Oxford University Press. This book was released on 2007-07-02 with total page 331 pages. Available in PDF, EPUB and Kindle. Book excerpt: Archie Carr, one of the greatest biologists of the twentieth century, played a leading part in finding a new and critical role for natural history and systematics in a post-1950s world dominated by the glamorous science of molecular biology. With the rise of molecular biology came a growing popular awareness of species extinction. Carr championed endangered sea turtles, and his work reflects major shifts in the study of ecology and evolution. A gifted nature writer, his books on the natural history of sea turtles and their habitats in Florida, the Caribbean, and Africa entertained and educated a wide audience. Carr's conservation ethic grew from his field work as well as his friendships with the fishermen who supplied him with many of the stories he retold so engagingly. With Archie Carr as the focus, The Man Who Saved Sea Turtles explores the evolution of the naturalist tradition, biology, and conservation during the twentieth century.
Download or read book Insights Into the Mating Systems of Green Turtle Populations from Molecular Parentage Analyses written by Lucy Isabel Wright and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Gaining a good understanding of marine turtle mating systems is fundamental for their effective conservation, yet there are distinct gaps in our knowledge of their breeding ecology and life history, owing largely to the difficulty in observing these highly mobile animals at sea. Whilst multiple mating by females, or polyandry, has been documented in all marine turtle species, the fitness consequences of this behaviour have not been fully investigated. Furthermore, male mating patterns, operational sex ratios and the number of males contributing to breeding populations are poorly understood, impeding accurate assessments of population viability. In this thesis, I use molecular-based parentage analysis to study, in detail, the genetic mating system of two green turtle (Chelonia mydas) populations. In the focal population in northern Cyprus, I show that, despite exhibiting a strongly female-biased hatchling sex ratio and contrary to our expectations, there are at least 1.3 breeding males to every nesting female. I go on to assess the breeding frequency of male turtles in the population and determine that males do not breed annually at this site, demonstrating that the observed relatively equal sex ratio of breeders is not the result of a few males mating every year, but that the number of breeding males in the population is greater than expected. I show that 24% of nesting females in the population produce clutches with multiple paternity, but do not detect any fitness benefits to polyandrous females, and discuss the potential role of sexual conflict in influencing female mating decisions. Finally, I reveal a high frequency of multiple paternity in green turtle clutches on Ascension Island, one of the largest green turtle rookeries in the world, and discuss possible causes of variation in the level of polyandry among marine turtle populations. The results presented here shed new light on aspects of marine turtle mating systems that are challenging to study, and illustrate the value of molecular data, not only in describing mating patterns, but in elucidating aspects of life history and behaviour that would otherwise be very difficult to ascertain.
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 Turtles of the United States and Canada written by Carl H. Ernst and published by JHU Press. This book was released on 2009-06-15 with total page 840 pages. Available in PDF, EPUB and Kindle. Book excerpt: Winner, 2011 Book Award, The Wildlife Society2009 Outstanding Academic Title, Choice Ernst and Lovich’s thoroughly revised edition of this classic reference provides the most updated information ever assembled on the natural histories of North American turtles. From diminutive mud turtles to giant alligator snappers, two of North America’s most prominent experts describe the turtles that live in the fresh, brackish, and marine waters north of Mexico. Incorporating the explosion of new scientific information published on turtles over the past fifteen years—including the identification of four new species—Ernst and Lovich supply comprehensive coverage of all fifty-eight species, with discussions of conservation status and recovery efforts. Each species account contains information on identification, genetics, fossil record, distribution, geographic variation, habitat, behavior, reproduction, biology, growth and longevity, food habits, populations, predators, and conservation status. The book includes range maps for freshwater and terrestrial species, a glossary of scientific names, an extensive bibliography for further research, and an index to scientific and common names. Logically organized and richly illustrated—with more than two hundred color photographs and fifty-two maps—Turtles of the United States and Canada remains the standard for libraries, museums, nature centers, field biologists, and professional and amateur herpetologists alike.
Download or read book Copeia written by and published by . This book was released on 1989 with total page 1210 pages. Available in PDF, EPUB and Kindle. Book excerpt:
