Download or read book Development of Methods for Estimating Hatchling Sea Turtle Sex Ratios written by Joanne Nicole Hanson and published by . This book was released on 1997 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Sex Ratios of Sea Turtle Hatchlings Direct and Indirect Estimates written by Matthew Howland Godfrey and published by . This book was released on 1997 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: To generate more data on sex ratios of sea turtle hatchlings, I developed a simple method of collecting daily mean sand temperatures on nesting beaches. Sand temperature can be used as an index of sex ratio. I then measured sand temperatures and sampled gonads of hatchlings of two sea turtle species on a nesting beach in Suriname during 1993. From histological analysis of the gonads, combined with information on the relative numbers of turtles nesting during the season, I generated overall estimates of sex ratio for green sea turtles (63.8% female) and for leatherback turtles (69.4% female). Relative numbers of male and female hatchlings varied throughout the season, and this corresponded to changes in sand temperatures and rainfall. From historical rainfall records and from past records of nesting frequency, I estimated overall sex ratios for another 13 seasons. Seasonal sex ratios fluctuated yearly. A revised estimate of the pivotal temperature (that constant incubation temperature which produces equal numbers of each sex) of green turtles in Suriname was 29.4$\sp\circ$C; this was slightly higher than past estimates. The transitional range of temperature (TRT), which is the range of incubation temperatures over which both sexes are produced, spanned several degrees. Metabolic warming was monitored in leatherback nests. It was found that eggs were about 0.8$\sp\circ$C warmer on average than the surrounding sand during the thermosensitive period of sexual differentiation. Because the leatherback has a narrow TRT, the influence of metabolic warming on sex ratio probably is restricted to a narrow range of incubation temperatures. Lastly, a new method of estimating sex ratios was devised, based on the rate of development of eggs and prevailing incubation temperatures. In general, nests with shorter incubation times produce mostly females and nests with longer incubation times produce mostly males. This relationship could be useful for generating predictions of sex ratio from natural nests for which only the incubation duration is known. In addition, by comparing this relationship from laboratory and field studies, it was possible to quantify the time it takes loggerhead hatchlings to dig up from the nest once they have hatched.
Download or read book Research and Management Techniques for the Conservation of Sea Turtles written by and published by . This book was released on 1999 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Sex Ratios of Sea Turtle Hatchlings Direct and Indirect Estimates written by and published by . This book was released on 1997 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Temperature Dependent Sex Determination in Vertebrates written by Nicole Valenzuela and published by Smithsonian Institution Scholarly Press. This book was released on 2004 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt: Edited by the world's foremost authorities on the subject, with essays by leading scholars in the field, this work shows how the sex of reptiles and many fish is determined not by the chromosomes they inherit but by the temperature at which incubation takes place.
Download or read book The Leatherback Turtle written by James R. Spotila and published by JHU Press. This book was released on 2015-10-30 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: The most comprehensive book ever written on leatherback sea turtles. Weighing as much as 2,000 pounds and reaching lengths of over seven feet, leatherback turtles are the world’s largest reptile. These unusual sea turtles have a thick, pliable shell that helps them to withstand great depths—they can swim more than one thousand meters below the surface in search of food. And what food source sustains these goliaths? Their diet consists almost exclusively of jellyfish, a meal they crisscross the oceans to find. Leatherbacks have been declining in recent decades, and some predict they will be gone by the end of this century. Why? Because of two primary factors: human redevelopment of nesting beaches and commercial fishing. There are only twenty-nine index beaches in the world where these turtles nest, and there is immense pressure to develop most of them into homes or resorts. At the same time, longline and gill net fisheries continue to overwhelm waters frequented by leatherbacks. In The Leatherback Turtle, James R. Spotila and Pilar Santidrián Tomillo bring together the world’s leading experts to produce a volume that reveals the biology of the leatherback while putting a spotlight on the conservation problems and solutions related to the species. The book leaves us with options: embark on the conservation strategy laid out within its pages and save one of nature’s most splendid creations, or watch yet another magnificent species disappear.
Download or read book Predicting Leatherback Sea Turtles Sex Ratios Using Spatial Interpolation of Nesting Beach Temperatures written by Emily G. Weston and published by . This book was released on 2013 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sex determination in leatherback sea turtles is directed primarily by the temperatures a clutch experiences during the middle third of development. Warmer temperatures tend to produce females while cooler temperatures yield males. Nest temperatures can vary spatially and temporally. During the 2010 and 2011 nesting seasons, this study estimated the hatchling sex ratio of leatherback sea turtles on Sandy Point National Wildlife Refuge (SPNWR), St. Croix, U.S. Virgin Islands. I measured sand temperatures from May - August and across the spatial range of leatherback nesting habitat. I spatially interpolated those temperatures to create maps that predicted temperatures for all nests incubating on SPWNR. Nest temperatures were also directly measured and compared with predicted nest temperatures to validate the prediction model. Sexes of dead-in-nest hatchlings and full term embryos were used to confirm the sex-temperature response. The model showed that microclimatic variation likely impacts the production of both sexes on SPNWR.
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
Download or read book Climate Change in Australia written by Commonwealth Scientific and Industrial Research Organization (Australia) and published by . This book was released on 2007 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt: An assessment of climate change in Australia, including projections of Australia's future climate.
Download or read book Estimating Past and Present Sex Ratios of Loggerhead Sea Turtle Caretta Caretta Hatchlings on Edisto Island South Carolina written by Cassandra Marshburn Bell and published by . This book was released on 2003 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Proceedings of the Nineteenth Annual Symposium on Sea Turtle Conservation and Biology 2 6 March 1999 South Padre Island Texas U S A written by and published by . This book was released on 1998 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Reptilian Incubation written by Denis Charles Deeming and published by . This book was released on 2004-01-01 with total page 349 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reptiles have been a topic for scientific study for many decades and remain widely studied around the world. In particular, their reproductive patterns and strategies have been extensively studied, proving useful in analysis of life-history strategies. A pivotal aspect of reptilian reproduction is incubation of eggs. Oviparity is found in all turtles, crocodilians and the tuatara and is prevalent in many lizards and snakes. Many aspects of the eggs, embryos and incubation conditions have been the subject of numerous scientific reports. This volume is dedicated to systematic analysis of reptilian incubation. The concept for the book is to look at reptilian eggs, development and incubation conditions in a functional way with particular emphasis on the natural incubation environment and, rather than concentrating on Family accounts, (e.g. incubation in crocodilians) the chapters review the topics in all reptile types allowing for the first time a systematic comparison of incubation between crocodilians, turtles and squamates. In addition to reviewing current information, the authors briefly look towards the future and outline areas where further research is needed.
Download or read book Sea Turtles Natural History and Conservation written by H. Robert Bustard and published by . This book was released on 1973 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Sea turtles in the Mediterranean Distribution threats and conservation priorities written by Paolo Casale and published by IUCN. This book was released on 2010 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Assessment of Sea Turtle Status and Trends written by National Research Council and published by National Academies Press. This book was released on 2010-10-07 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt: All six species of sea turtles found in U.S. waters are listed as endangered or threatened, but the exact population sizes of these species are unknown due to a lack of key information regarding birth and survival rates. The U.S. Endangered Species Act prohibits the hunting of sea turtles and reduces incidental losses from activities such as shrimp trawling and development on beaches used for nesting. However, current monitoring does not provide enough information on sea turtle populations to evaluate the effectiveness of these protective measures. Sea Turtle Status and Trends reviews current methods for assessing sea turtle populations and finds that although counts of sea turtles are essential, more detailed information on sea turtle biology, such as survival rates and breeding patterns, is needed to predict and understand changes in populations in order to develop successful management and conservation plans.
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 346 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
Download or read book The Evolution and Extinction of the Dinosaurs written by David E. Fastovsky and published by Cambridge University Press. This book was released on 2005-02-07 with total page 504 pages. Available in PDF, EPUB and Kindle. Book excerpt: This 2005 edition of The Evolution and Extinction of the Dinosaurs is a unique, comprehensive treatment of this fascinating group of organisms. It is a detailed survey of dinosaur origins, their diversity, and their eventual extinction. The book can easily be used as a teaching textbook for a class, but it is also written as a series of readable, entertaining essays covering important and timely topics appealing to non-specialists and all dinosaur enthusiasts: birds as 'living dinosaurs', the new feathered dinosaurs from China, 'warm-bloodedness'. Along the way, the reader learns about dinosaur functional morphology, physiology, and systematics using cladistic methodology - in short, how professional paleontologists and dinosaur experts go about their work, and why they find it so rewarding. The book is spectacularly illustrated by John Sibbick, a world-famous illustrator of dinosaurs, commissioned exclusively for this book.
