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 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 Post nesting Movements and Behavior of Loggerhead Sea Turtles Caretta Caretta Departing from East Central Florida Nesting Beaches written by C. Kenneth Dodd and published by . This book was released on 2003 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nest Success and the Survival and Movement of Hatchlings of the Loggerhead Sea Turtle Caretta Caretta on Cape Lookout National Seashore written by Joseph S. Ferris and published by . This book was released on 1986 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Movement Patterns and Marine Habitat Associations of Juvenile Loggerhead Sea Turtles Caretta Caretta in the Southwestern Atlantic Ocean written by Caren Barceló and published by . This book was released on 2011 with total page 75 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bycatch, or the incidental capture of non-target species, has been implicated as one of the main factors leading to population declines of many large marine vertebrates, including sea turtles. To effectively manage and conserve these long-lived species, their marine distribution, high use areas, foraging habitats, and regions of highest likelihood of interaction with fisheries must be understood. I analyzed the movements and habitat use of satellite tracked juvenile loggerhead sea turtles (Caretta caretta) in the Southwestern Atlantic Ocean, a poorly studied region with high turtle-fisheries interactions. Between July 2006 and March 2010, 27 satellite transmitters were deployed at sea on juvenile loggerheads captured as bycatch in the Uruguayan and Brazilian pelagic longline fishing vessels. I characterized the broad-scale behavioral patterns, inter-seasonal variability, and general high use areas for 26 juvenile turtles, which were tracked for 259±159 days between latitudes of 25-45°S and longitudes 35-54°W. The high use areas for the tracked turtles were over the continental shelf and slope within the Uruguayan and Brazilian Economic Exclusive Zones, and in oceanic international waters between the Rio Grande Rise and the continental slope off of southern Brazil. Diving information was available for 5 of the tagged turtles; the maximum dive depth recorded varied between 100-300m depths, and two turtles demonstrated potential bottom-feeding behaviors by diving to depths that corresponded with the bathymetry at their location. The mean sea surface temperature encountered by turtles was 19.8±2.3°C (10.21°C-28.4°C) and turtles showed an affinity for mesotrophic waters (0.458±1.012 mg/m3 chlorophyll-a). Overall, broad scale latitudinal movements of juvenile loggerheads varied by season and sea surface temperature. Because recent studies on marine megafauna movements have highlighted that ocean currents can have an important effect on movement paths, I decoupled active foraging behavior from likely passive movement of tracked juvenile loggerheads in ocean currents. Using First Passage Time analysis; a method to measure changes in movement patterns along a pathway through the environment, and generalized additive mixed models, I quantified similarities in the movement patterns and habitat "affinities" of the turtles and surface drifters in the ocean. Turtles and drifters both exhibited movement patterns that could be classified as likely "foraging behavior" at a spatial scale of 80km. This corresponds to the identified scale of eddies in the Southwestern Atlantic Ocean, which may suggest that passive movement of turtles in ocean currents largely drives their scale of search. Current velocity and sea floor depth were the most important variables correlated with both turtle and drifter movement patterns at that scale. Both turtles and drifters generally showed a negative relationship between first passage time and current velocities. Some differences between turtle and drifter behavior were evident, particularly on the continental shelf; deviations in turtle behavior from the patterns of drifters is likely indicative of active movement on the turtles part. There were no seasonal or annual effects on the fine scale movements of turtles or drifters. Interestingly, turtle search behavior was not correlated with temperature or chlorophyll a in this scale of analysis. I suggest that evaluation of drifter movements in the area of study is an important addition to satellite tracking work that attempts to identify foraging behavior in sea turtles or other large marine vertebrates that may take advantage of ocean currents for transport and feeding.
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 Marine Turtles in the Mediterranean written by Brian Groombridge and published by Council of Europe. This book was released on 1990-01-01 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Movement and Surfacing Behavior Patterns of Loggerhead Sea Turtles in and Near Canaveral Channel Florida written by Andrew Joseph Kemmerer and published by . This book was released on 1983 with total page 43 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Proceedings of the Twenty seventh Annual Symposium on Sea Turtle Biology and Conservation written by Alan F. Rees and published by . This book was released on 2008 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Defining Habitat Preferences of Pelagic Loggerhead Sea Turtles Caretta Caretta in the North Atlantic Through Analysis of Behavior and Bycatch written by Abigail L. McCarthy and published by . This book was released on 2007 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: For many species of marine turtle the characteristics that define pelagic habitat have yet to be fully identified. A better understanding of these habitat characteristics is critical to reduce high seas fisheries interactions with turtles, especially as the status of many turtle populations has placed them on the threatened or endangered species list. The combination of high-resolution satellite-tracking data with remotely sensed oceanographic data makes it possible to identify habitat for loggerhead turtles by analyzing the behavior of individual animals. Bycatch of loggerhead turtles in longline fisheries can also be examined using the same high-resolution oceanographic data to determine if there are identifiable habitat differences in high- and low- bycatch areas. I analyzed the tracks of ten loggerhead turtles tagged in the spring and fall of 1998 near Madeira, Portugal in relation to the marine environment they occupied. To determine the relationship between an individual turtle and its environment, some measure of behavior was necessary. I calculated the straightness index (SI), the ratio of the displacement of the animal to the total distance traveled, for individual weekly segments of the ten tracks as a measure of individual behavior. I then extracted information about the chlorophyll, sea-surface temperature (SST), bathymetry, and geostrophic current of the ocean in a 20km buffer surrounding the tracks, and examined the relationship between the straightness index and those characteristics using logistic regression. Chlorophyll a value, bathymetry, and movement of the turtle with geostrophic currents were consistently related to the straightness index of the tracks of all ten animals (two-sided p-value from Wald's test: 0.005, 0.0017, and 0.0018, respectively). Tracks were less straight in high chlorophyll regions and in shallower ocean areas, and animals were more likely to be moving with prevailing geostrophic currents during straighter track segments. These results confirm comparable analyses of loggerhead tracks in the Pacific, and indicate that sea turtles alter their behavior (likely representing a shift from traveling to foraging) when they encounter high-chlorophyll regions. Turtles with highly sinuous tracks spend more time in a given area or habitat than those who pass straight through, and therefore may be more susceptible to incidental capture by fisheries operating in those habitats. To address the fisheries bycatch/ habitat interactions I analyzed longline bycatch data to determine whether the marine environmental variables identified in the first part of my study were related to the probability of catching a turtle on a given longline set. I performed a logistic regression analysis using bycatch of turtles as the response variable, and bathymetry, SST, SST gradient (indicative of frontal activity), chlorophyll a, and chlorophyll a gradient as the independent variables. I also included the location and the date of the longline sets as potential predictor variables. I found that the most important variables predicting the odds that a turtle would be caught on a given set were chlorophyll a value in the area of the haul ( Wald's test, p=0.009) and the latitude at the beginning of the haul (Wald's test, p=0.0005). Turtles were more likely to be caught on sets in lower chlorophyll regions and in higher latitude regions of the data set, and there was no indication of important effects of bathymetry. These results disagree with my predictions from the tracking analysis, either because the fisheries-dependent bycatch data set did not provide enough contrast of habitat types, or because bycatch probability is not related to turtle behavior. My results indicate a difference between the critical variables selected as predictors of turtle habitat using the bycatch data and those selected using the behavior of individual tracked animals. While bycatch information is important, the distribution of fisheries data is highly biased towards frontal zones and regions of historic high catch. Judgments about turtle behavior based on only fisheries interactions could lead to incorrect conclusions about where animals spend the majority of their time. Assuming that animals are more likely to have an increased probability of interaction with longlines in areas where they spend more time foraging, fishing pressure should be reduced in those areas of high-use for pelagic loggerheads. It is crucial to base fisheries time-area closures and the design of marine protected areas on the behavior of tracked animals, and not just on fisheries bycatch data.
Download or read book Sea Turtles written by James R. Spotila and published by JHU Press. This book was released on 2004-11-12 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt: Marine biologist James R. Spotila has spent much of his life unraveling the mysteries of these graceful creatures and working to ensure their survival. In "Sea Turtles," he offers a comprehensive and compelling account of their history and life cycle based on the most recent scientific data and suggests what we can be done to save them. Illustrated with stunning, full-color photographs. 0-808-8007-6$24.95 / Johns Hopkins University Press
Download or read book Sea Turtles written by Blair E. Witherington and published by Voyageur Press (MN). This book was released on 2006 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt: Streamlined and equipped with flippers, sea turtles seem uniquely adapted for water-yet remain firmly attached to land, where the females lay their eggs each year. They sport the many colors of the rainbow, range in weight from 100 to 1,300 pounds, and figure in the mythology and folklore of cultures around the world. And still, they currently risk extinction. In this book, marine biologist Blair Ernest Witherington, who has devoted decades to these ancient creatures, offers readers an in-depth look into their mysterious world. Accompanied by exquisite photographs, his descriptions comprise a personal introduction to these strangely graceful marine reptiles. Detailed, lively, and up-to-date imagery tells the story of sea turtles’ distant origins, their specialized form and undersea challenges, senses and life cycle, world voyages and navigational talents—and their ecological roles. The most comprehensive overview of sea turtles to date, this book portrays each of the seven species in close-up, offering information on appearance, distribution, movements, life history, reproduction, diet, unique traits, and conservation.
Download or read book The Biology of Sea Turtles written by Jeanette Wyneken and published by CRC Press. This book was released on 2013-03-25 with total page 479 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the first volume of The Biology of Sea Turtles was published in 1997, the field has grown and matured in ways few of the authors would have predicted—particularly in the areas of physiology, behavior, genetics, and health. Volume III presents timely coverage of emerging areas as well as the integration of approaches and information that did not exist even a decade ago. The book assembles the foremost experts in each topic to provide the most up-to-date and comprehensive book on sea turtles available today. New areas covered include in vivo imaging of structure, spatial distributions of marine turtles at sea, epibiosis, imprinting, parasitology, and climatic effects. Life history is explored in three chapters covering age determination, predator-prey interactions, and mortality from bycatch. The Biology of Sea Turtles, Volume III will inspire scientists and students to explore and expand their understanding of these intriguing animals. The book provides clear baseline summaries, thoughtful syntheses, and effective presentation of the most fundamental topics spanning form and function, health, distributions, behavior, genetics, evolution, and ecology. Its scope and depth make it the definitive go-to reference in the field.
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 Marine Fisheries Review written by and published by . This book was released on 2012 with total page 490 pages. Available in PDF, EPUB and Kindle. Book excerpt:
