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 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 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 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 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 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 Somatic Growth Function for Immature Loggerhead Sea Turtles Caretta Caretta in Southeastern U S Waters written by Karen A. Bjorndal and published by . This book was released on 2001* with total page 14 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 Effects of Petroleum on the Development and Survival of Marine Turtle Embryos written by Thomas H. Fritts and published by . This book was released on 1982 with total page 52 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 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 124 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Life Cycle and Ecology of the Loggerhead Turtle Caretta Caretta Linnaeus 1758 written by and published by . This book was released on 2016 with total page 217 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 A Seasonal and Latitudinal Assessment of Early Growth Rates in Northern and Southeastern Loggerhead Sea Turtles Caretta Caretta L written by Lesley Stokes and published by . This book was released on 2003 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Analysis of Stranded Loggerhead Sea Turtles Caretta Caretta in North and South Carolina written by Kristen T. Mazzarella and published by . This book was released on 2007 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Evaluation of Length Distributions and Growth Variance to Improve Assessment of the Loggerhead Sea Turtle Caretta Caretta written by Jason R. Vaughan and published by . This book was released on 2010 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nest counts from the largest subpopulation of the loggerhead sea turtle (Caretta caretta) in the Atlantic, peninsular Florida, have been declining since 1998. Analyzing trends of nests and adult females is insufficient to determine the overall status of a sea turtle population, due to variation in nesting frequency and a 25 - 35 year time lag between hatching and maturation. While nest numbers of this threatened species have declined by 50% since 1998, catches of juvenile turtles in many areas have increased. Better assessment of population status and diagnosis of the causes of population trends are possible if we examine existing data on changes in abundance and size distribution from in-water surveys of juvenile and subadult turtles as well as adults. I have plotted the length frequency data and catch rates of neritic turtles (juvenile, subadult and adult turtles that inhabit nearshore waters) collected from 1980 - 2007 at 4 in-water sites ranging from North Carolina to Florida (N=10,486). I also examined the length distributions recorded from strandings of dead turtles found on beaches in the Gulf of Mexico (N=4,308) and along the U.S. east coast (N=10,918) from 1990 - 2005. I found a similar pattern in length distribution shifts over time, which provides compelling evidence that the data are revealing true population change. The data suggest an increase in the overall abundance of juvenile turtles in the southeast U.S. since the late 1990s and an increase in the median size of neritic juveniles (40 - 90 cm) since 1990. There has also been a reduction in the number and proportion of small (

Download or read book Modeling and Mapping Isotopic Patterns in the Northwest Atlantic Derived from Loggerhead Sea Turtles written by and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: