Download or read book Assessing Resource Use Patterns of Mediterranean Loggerhead Sea Turtles Caretta Caretta Linnaeus 1758 Through Stable Isotope Analysis written by and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Sequential Isotopic Analysis to Characterize Ontogenetic Shifts and Growth Dynamics of Loggerhead Sea Turtles Caretta Caretta written by Matthew D. Ramirez and published by . This book was released on 2015 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ontogenetic niche theory predicts that as organisms grow they make size-specific changes in habitat use and diet to optimize growth and survival. A variety of factors contribute to growth and survival in different habitats, ultimately leading to variation in life history that can affect population dynamics. An understanding of the variation in timing of habitat shifts and fidelity to those habitats is critical for population dynamics modeling and evaluation of conservation strategies, especially for species whose population vital rates are sensitive to changes in growth and survival of critical life stages, such as the loggerhead sea turtle (Caretta caretta). Isotopic analysis of sequentially deposited structures, such as sea turtle humerus bone, provides a means of studying intraspecific life history variation. I sequentially analyzed the annual humerus bone growth increments of 84 juvenile loggerhead sea turtles for stable isotopes ([delta]13C, [delta]15N) to reconstruct the diet and habitat use histories of turtles undergoing an oceanic-to-neritic ontogenetic shift. I also used skeletochronological methods to evaluate the growth dynamics surrounding this transition. Generated isotopic transects were used to classify individuals into alternative life history pattern groups and were combined with body size and growth data obtained from skeletal analyses to evaluate differences in the duration, timing, and growth dynamics of ontogenetic shifts. Sea turtles that displayed increases in nitrogen stable isotope ratios ([delta]15N) greater than 3.0[per mille] over one or more years were presumed to have transitioned from oceanic to neritic diets and/or habitats based on oceanic and neritic prey isotopic information collected from the literature, and were classified into one of two life history pattern groups: discrete shifters (n = 23) completed this transition within year, while facultative shifters (n = 16) completed this transition in up to eight years. As differences in isotopic values between neritic and oceanic prey are most likely driven by differences in isotopic baselines, I propose the gradual increases in [delta]15N values within facultative shifters over multiple years is indicative of foraging in both oceanic and neritic habitats within growth years. Size-at-transition between habitats was similar between discrete shifters (55.1 ± 7.6 cm straightline carapace length, SCL) and facultative shifters (52.8 ± 6.9 cm SCL). Growth variance was higher for facultative shifters versus discrete shifters. Yet, mean size at transition, size-at-age relationships, and mean increment-specific growth rates were similar between turtles with alternative life history patterns. Annual growth rates generally peaked within one year of transition (31/38 of turtles), providing support for a short-term (i.e., 1-2 year) ontogenetic shift-associated growth advantage. However, there was considerable variation in the timing of maximal growth rate among turtles with some individuals exhibiting maximal growth in years prior to the ontogenetic shift (14/38 turtles). The lack of substantial differences in the timing of transition and growth dynamics between discrete and facultative shifters likely limits the influence of these alternative life history patterns on time to sexual maturity in this species, though differences in habitat-specific survival probabilities could affect loggerhead population dynamics. This study demonstrates the value of paired isotopic and skeletal analyses to the study of long-term sea turtle life history variation and its affect on growth.
Download or read book Using Stable Isotope Analysis delta13C and Delta 15N of Blood and Skin from Mid Atlantic Loggerhead Sea Turtles Caretta Caretta to Understand Foraging Patterns and Fishery Interactions written by Samantha Louise Badgett and published by . This book was released on 2018 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Assessment of the Loggerhead Turtle Population in the Western Northern Atlantic Ocean written by Southeast Fisheries Science Center (U.S.). Turtle Expert Working Group and published by . This book was released on 2009 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Tracking Turtles Back in Time written by Calandra N. Turner Tomaszewicz and published by . This book was released on 2016 with total page 219 pages. Available in PDF, EPUB and Kindle. Book excerpt: Of the five species of sea turtles that inhabit the east Pacific Ocean, two, the North Pacific loggerhead (Caretta caretta) and East Pacific green turtle (Chelonia mydas), experience some of the highest rates of globally documented mortality in a productive foraging hotspot near the Baja California Peninsula (BCP), Mexico. This area, the Gulf of Ulloa, overlaps with high levels of fishing, resulting in thousands of dead turtles, many that wash up on the beach of Playa San Lázaro on the BCP. It is unknown how long loggerheads inhabit distinct regions of the North Pacific, and to what degree juvenile individuals in the population demonstrate variation in their life history patterns. Similarly, it is unknown how long green turtles occupy oceanic regions of the eastern Pacific before settling into more nearshore habitats, or how they use the Gulf of Ulloa. My research determined the residency duration at different foraging grounds within the eastern Pacific, as well as basic demographic information such as age-at-settlement, age-at-maturation, and timing of ontogenetic shifts, for these two endangered sea turtle populations. By determining life history parameters and the length of time individuals in these populations spend in distinct high-risk habitats, managers can better understand exposure to spatially explicit threats and prioritize conservation approaches. I focused particularly on duration of time spent in the high-bycatch waters of the Gulf of Ulloa. To this end, I developed a novel technique that combined skeletochronology (the study of growth and age increments in bones) with sequential stable carbon ([delta]13C) and nitrogen ([delta]15N) isotope analysis of humerus bone growth layers. Naturally occurring stable isotope gradients exist in ocean systems such that habitats and foraging behaviors can be distinguished (i.e. nearshore vs. offshore habitats or high vs. low trophic levels). Given these isotope gradients, the combination of skeletochronology with stable isotope analysis of sequentially sampled growth layers provides a multi-year record of location, diet, size, age, and annual growth of individual turtles, allowing the reconstruction of life history and long-term habitat use patterns. The combination of these techniques allowed me to address questions that could not be answered using either technique alone.
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 Global Biodiversity in a Changing Environment written by Osvaldo E. Sala and published by Springer Science & Business Media. This book was released on 2001-08-24 with total page 414 pages. Available in PDF, EPUB and Kindle. Book excerpt: Climatic change, conservation biology
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 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 Life History and Environmental Requirements of Loggerhead Turtles written by David A. Nelson and published by . This book was released on 1988 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Recovery Plan for U S Pacific Populations of the Loggerhead Turtle Caretta Caretta written by and published by . This book was released on 1998 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Using Stable Isotopes to Study Dietary Patterns and Foraging Ground Theory in the Loggerhead Sea Turtle Caretta Caretta written by Brigid Elyse Carr and published by . This book was released on 2016 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Life History and Environmental Requirements of Loggerhead Turtles written by David Arthur Nelson and published by . This book was released on 1988 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book European Seagrasses written by Jens Borum and published by . This book was released on 2004 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt: The goal of the report project is to define the habitat requirements of seagrasses in the European coasts, the present threats to the sustainability of the ecosystem they form, and their resilience to disturbance in order to strengthen our forecast capacity and formulate cost-effective monitoring plans and management strategies.
Download or read book Movements Behaviors and Threats to Loggerhead Turtles Caretta Caretta in the Mediterranean Sea written by Samir Harshad Patel and published by . This book was released on 2013 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this study was to determine the at-sea behavior of loggerhead turtles (Caretta caretta) in the Mediterranean Sea in order to gain a better understanding of the various environmental factors that play a role in their survival. By determining the environmental conditions that have a controlling force over foraging and nesting success, more accurate projections can be made on the future of this declining subpopulation of loggerheads. I deployed 20 satellite transmitters on postnesting adult loggerhead turtles from Rethymno, Crete, Greece, with 19 functioning through migration. Using a changepoint analysis model, I determined that loggerheads in the Mediterranean exhibited 5 behavior modes. Within these modes were migration, foraging and overwintering, along with newly discovered transition modes between each established sea turtle behavior. Overall, the turtles exhibited 3 unique postnesting strategies, 9 migrated to the North African coast, 6 migrated into the Aegean Sea and 4 remained within the waters of Crete. These three strategies corresponded to fitness differences between the turtles. The northern turtles were larger and had larger clutch sizes than those foraging near Crete and Africa. This corresponded to the abundance of prey from each region. The benthic environment of the Aegean had the largest prey abundance compared to the other sites. Around Crete there is very limited benthic environment to support loggerhead foraging, and in the Gulf of Gabes the prey abundances are reduced due to a high influx of industrial runoff. The Gulf of Gabes is home to ~40% of loggerheads nesting in Greece, and as global warming continues, the rising temperature is expected to exacerbate the deterioration of the benthic environment. Furthermore, there is already a strong female bias in sex ratio for Mediterranean loggerheads, which is expected to continue to get stronger as beach temperatures rise and precipitation declines. Loggerheads may be able to compensate for these changes, and I found that their nesting phenology is expected to shift earlier by as much as 52 - 74 days by 2100; however the factors threatening the survival of this species may be too strong to overcome.
Download or read book Synopsis of the Biological Data on the Loggerhead Sea Turtle written by C. Kenneth Dodd and published by . This book was released on 1988 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ancient Animals New Challenges written by Manuel Maldonado and published by Springer. This book was released on 2015-03-21 with total page 343 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book summarizes the latest advances in sponge science through a concise selection of studies presented at the VIII World Sponge Conference. The collection of articles reflects hot, ongoing debates in molecular research, such as the monophyletic versus paraphyletic nature of the sponge group, or the new awareness on pros and cons of standard barcodes and other markers in sponge taxonomy and phylogeny. It also features articles showing how the new sequencing technologies reveal the functional and phylogenetic complexity of the "microbial universe" associated to sponge tissues. The ecological interactions of sponges, the effects of nutrients and pollutants, the variability in reproductive patterns, and the processes generating genotypic and phenotypic variability in sponge populations are covered in several contributions. Zoogeography, population structure and dynamics are also approached with both traditional and molecular tools. The effect of anthropogenic disturbance on the natural environment finds its place in this volume with papers dealing with metal accumulation and the potential role of sponges as biomonitors. Biodiversity data from unexplored tropical and deep sea areas are presented. We hope readers will enjoy the selection of papers, which we believe represent collectively a significant contribution to our current understanding of sponges. Previously published in Hydrobiologia, vol. 687, 2012
