Download or read book Surfacing Behavior of Loggerhead Caretta Caretta Sea Turtles in Estuarine and Coastal Waters of North Carolina written by Joanne Braun-McNeill and published by . This book was released on 2010 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: "To be in compliance with the Endangered Species Act, the United States Department of the Navy is required to assess the potential environmental impacts of conducting at-sea training operations on sea turtles. As a result, the National Marine Fisheries Service (NMFS) was contracted to examine the seasonal distribution and density of sea turtles within North Carolina's Core and Pamlico Sounds where the U.S. Navy Marine Corps Air Station (MCAS) Cherry Point performs at-sea bombing operations. The NMFS's current assessment of sea turtle populations likely underestimated sea turtle density because they did not account for surfacing behavior when calculating density (Goodman et al. 2007). To improve the assessment, we satellite tagged sea turtles to estimate the amount of time they spent at the surface of the water, and then applied a correction factor to previous density estimates"--Executive summary.
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 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 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 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 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 Atchafalaya Bay and Adjacent Waters Oyster Shell Dredging written by and published by . This book was released on 1987 with total page 374 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 Environmental Impact Research Program Life History and Environmental Requirements of Loggerhead Sea Turtles written by David A. Nelson and published by . This book was released on 1986 with total page 43 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the United States, scattered nestings of loggerhead sea turtles (Caretta caretta) may occur in most of its range from Texas to Florida and Florida to New Jersey; however, nesting concentrations occur on coastal islands of North Carolina, South Carolina, and Georgia and the coasts of Florida. The greatest portion of a loggerhead's life is spent in ocean and estuarine waters where they breed, feed, migrate, and hibernate. The remainder of their life is spent on coastal beaches where the female digs a nest and lays her eggs, the eggs hatch, and the hatchlings crawl to the water to become part of the aquatic system again. Mating is believed to occur in shallow water adjacent to nesting beaches just prior to nesting and egg laying. Nesting activity begins in the spring, peaks in midsummer, and declines until completion in late summer. A loggerhead female generally nests every other year or every third year. A small percentage nest at intervals less than 2 years or more than 3 years. When a loggerhead nests, it usually layes two to three cluthes of eggs per season (range one to five). Temperature is a major factor influencing sea turtle life histories. Sand temperature affects nest site selection by adult females, the incubation time and hatching success of eggs, and the sex and emergence timing of hatchlings, whereas water temperature affects nesting activity and movements of adults.
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 Proceedings of the Twentieth Annual Symposium on Sea Turtle Biology and Conservation 29 February Through 4 March 2000 Orlando Florida U S A written by Andrea Mosier and published by . This book was released on 2002 with total page 408 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 Assessment Update for the Kemp s Ridley and Loggerhead Sea Turtle Populations in the Western North Atlantic written by and published by . This book was released on 2000 with total page 136 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 124 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Oil and Sea Turtles written by Sarah Milton and published by . This book was released on 2003 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book PCS Phosphate Mine Continuation written by and published by . This book was released on 2008 with total page 574 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:
