Some of the key elements to assess the status of any wildlife population in a given geographical area are the levels of recruitment, survival and mortality. Whilst most of the information on marine turtles has been obtained from nesting sites, turtles spend most of their lives at sea. The conservation status of marine turtles in the southeast Pacific is poorly documented. This is particularly true for countries like Peru, where nesting events are very rare, although five species of turtles from populations from all over the Pacific basin, use these waters as foraging grounds. Little information exists on the threats to turtle populations in foraging areas or the magnitude of these impacts. Small-scale fisheries are a globally important economic activity serving as a source of food and employment for ca. 1 billion people; however we show that they also have serious impacts on marine turtle populations from all over the Pacific basin in the form of incidentally captured marine turtles. The five chapters that constitute this thesis are intended to increase our understanding of small-scale fisheries impacts on this taxon during their aquatic life stages. This work focuses on describing these fisheries, their impacts on marine turtles and proposes methodologies to monitor and assess the level of bycatch from small-scale fisheries. We also discuss alternative ways to prevent fisheries interactions and promote the involvement of artisanal fishermen in the southeast Pacific in implementing conservation solutions.

Recent studies show that sea turtles use both magnetic and visual cues to successfully orient. Juvenile green sea turtles from the near shore reefs of Palm Beach County, Florida were brought to the lab to determine whether the sun could serve as a visual orientation cue. When tethered during the day in a large outdoor tank west of the ocean, the turtles oriented east to northeast. To determine whether the sun's position was used to maintain their heading, I altered the turtles' perception of time by entraining them to a light cycle advanced by 7 h relative to the natural cycle. When tested afterward in the same outdoor tank the turtles oriented northwest, the predicted direction after compensating for the sun's movement over 7 h across the sky. Orientation was unchanged when the turtles bore magnets that negated the use of magnetic cues. These results are consistent with the hypothesis that the turtles used the sun for orientation. / by Cody Robert Mott. / Thesis (M.S.)--Florida Atlantic University, 2010. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2010. Mode of access: World Wide Web.

Due to an emergency status dune restoration project following Subtropical Storm Andrea in 2007 on Singer Island, Florida, nests needed to be moved during early to mid-incubation. Nesting success was compared between those moved mid-incubation, moved within 12h to either a native sand incubation area or a renourished sand incubation area, and those left in-situ. Nests moved within 12h to the native sand had a significantly larger proportion of pipped hatchlings. Nests moved mid-incubation had a significantly lower proportion of hatched eggs as well as emergent hatchlings. The stage in which embryonic development was arrested corresponded to the stage the embryos were in during the time of movement; indicating movement was the cause of death. When comparing nests moved within the initial 2.5 weeks of development to those moved after 2.5 weeks of development, there was no significant difference in hatching success. / by Natasha M. Ahles. / Vita. / Thesis (M.S.)--Florida Atlantic University, 2009. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2009. Mode of access: World Wide Web.

Orientador: Augusto Shinya Abe / Banca: Francisco Tadeu Rantin / Banca: Denis Vieira de Andrade / Banca: Luiz Edivaldo Pezzato / Banca: Roberto Goiten / Resumo: Com base no hábito alimentar da espécie, no potencial dos quelônios em utilizar matéria vegetal e na importância da fibra e de seus constituintes para alimentação animal, esta pesquisa estudou o crescimento da tartaruga-da-Amazônia (Podocnemis expansa), a disponibilidade de minerais e a digestibilidade dos nutrientes em dietas com diferentes teores de fibra bruta. Os estudos foram realizados na Universidade Estadual Paulista (UNESP), entre maio e novembro de 2008, com duração de sete meses, utilizando 160 exemplares de tartaruga-da-Amazônia provenientes do município de Ribeirão Cascalheira, região do Rio das Mortes/MT, Brasil. O aumento nos teores de fibra na dieta até 16% melhorou o crescimento da tartaruga-da-Amazônia, onde as características de crescimento apresentaram os maiores valores. Entre 16 a 20% de fibra na dieta o crescimento das tartarugas diminuiu. O maior crescimento se deu com teores semelhantes aos encontrados na dieta natural da espécie, reforçando seu potencial para utilização de dieta herbívora. A disponibilidade de minerais e a digestibilidade dos nutrientes foram influenciadas pelos teores de fibra na dieta. A tartaruga-da-Amazônia apresenta elevado potencial de digestão da fibra dietética, comparável ao de ruminantes e outros répteis herbívoros, com sua digestibilidade aumentando com o aumento do teor de fibra na dieta / Abstract: Taking in consideration the potential the chelonians have for using vegetal matter and based on the eating habit of the specie and on the importance of fiber and its constituents for animal feeding, the present study aimed at evaluating the growth of the Arrau sideneck turtle (Podocnemis expansa) fed with diets of different contents of crude fiber and the availability of minerals and the digestibility of nutrients. This study was carried out Universidade Estadual Paulista (UNESP), between the months of May and November, 2008, and lasted seven months. The turtles used were 160 specimens of the Arrau sideneck turtle from Projeto Quelônios da Amazônia, State of Mato Grosso. The increase in the contents of fiber in the diet up to 16% improved the Arrau sideneck turtle's growth, when the growth characteristics showed their best values. In diets including 20% of fiber, the turtle's growth decreased. In diets including between 16 and 20% of fiber, the turtle's growth decreased. The highest rate occurred when using contents similar to those found in the natural diet of the species, corroborating its potential to use herbivore diet. The availability of minerals and the digestibility of nutrients were influenced by the contents of fiber in the diet. The Arrau sideneck turtle presents a high potential for dietary fiber digestion, comparable to that of the ruminants and other herbivore reptiles, with its digestibility increasing as the contents of fiber increase / Doutor

With 226-343 individual/ha, population density of Chelodina longicollis in the dams of the University of Western Sydney-Hawkesbury Richmond campus were in the range of other studies around Australia. Their size extremes (24.3 -223.3 mm) were within the range of previous studies, and the overall sex ratio was skewed toward males. The annual growth rates varied and were weakly correlated with animal size. Scute shedding occurred between September and April and peaked in December. Turtles were generally in excellent condition, indicating that sufficient food resources were available in local habitats. Only 3.4% of the population were in poor condition and few animals (8.8 %) carried signs of past injury. No gross abnormalities were recorded, however, there has been low levels of recruitment to the population compared with other Australian studies. Despite a maximum distance dams sampled of 2.8 km and ample evidence of interchange between dams, there was a great variation in animal size, cohort structure, sex ratio among dams. There are a range of factors which have the potential to bias sampling results. Turtles were not influenced by a dominance hierarchy or by the presence of eels, however, they appeared to be capable of avoidance behaviour when nets are set at a specific location. Different cohorts were caught differentially and this varied with month, season and year. In addition, catchability varied among cohorts. Juveniles were least likely, and sub-adult males were most likely, to be recaptured. In some dams there was evidence that animals moved at random while in others movement did not conform to this pattern. These results could not be accounted for in terms of dam size, physical structure of the dam or the distribution and abundance of vegetation. / Master of Science (Hons)

<p>Sea turtles, marine mammals and sea birds are vulnerable to higher mortality rates as a direct function of incidental capture (bycatch) in marine fisheries. Their migratory behavior exposes them to multiple fishing gear types and fishing practices and efforts to understand the rates of interaction between these taxa and fishing necessarily entails analysis of data over large spatial areas (ocean-basin) and multiple types of fishing activities. The acquisition the requisite data, however, requires considerable resources and many regions in the world are data-poor with respect to bycatch, including the Wider Caribbean Region (WCR) in the west central Atlantic Ocean basin. This dissertation presents the results of multiple strategies used to assess sea turtle, marine mammal and seabird bycatch in the WCR, with a particular focus on sea turtle bycatch. The research incorporated a synthetic review of the literature, expert consultation, statistical techniques, and geospatial analyses to assess the bycatch seascape for the region. I conclude that sea turtle bycatch in the WRC is significantly linked to turtle rookeries, especially those on the continental land mass and in the southern section of the Caribbean basin, in large part because of the near shore artisanal nature of the fisheries and the importance of these habitats for foraging and reproduction. The limited information on marine mammal bycatch does not permit robust inferences, but it clearly identifies threats to at least one vulnerable marine mammal species, the tucuxi (Sotalia fluviatilis). Information on seabird bycatch was even more limited; the most vulnerable seabird populations occur in the higher latitudes (temperate zones) while the seabird populations in the WCR face significant threats from habitat loss and over-exploitation. This dissertation proposes specific recommendations for improving and advancing the information base for a regional, ecosystem-level management and mitigation of bycatch.</p> / Dissertation

This study evaluated how three conservation approaches implemented by the Brazilian Sea Turtle Conservation Program (the TAMAR Project) are related to local support for sea turtle conservation in Praia do Forte, Brazil. Four species of sea turtles nest in Praia do Forte. In Praia do Forte, locals harvested sea turtles for their meat and eggs on a regular basis to support subsistence needs. The three conservation strategies analyzed are employment opportunities and alternative sources of income from sea turtle ecotourism; enforcement of federal sea turtle protection laws; and implementation of environmental education programs via sea turtle ecotourism. These conservation strategies, which are implemented since 1982, represent both top-down and bottom-up conservation paradigms. Qualitative and quantitative data were gathered through nine months of fieldbased research (between May 2006 and September 2008), using tools of participant observation, semi-structured interviews, and key informant interviews. Results indicate that conservation strategies implemented by TAMAR seem to influence local support for sea turtle conservation. Income and environmental education programs to the local children are cited as the main benefits sea turtle conservation brings to the community. Enforcement caused resentment when first implemented, but is now perceived as a necessary strategy to protect sea turtles. The relative lack of community participation in sea turtle conservation seems not to have hampered local support for sea turtle conservation. In fact, the majority of respondents perceive TAMAR as the most appropriate entity to manage sea turtles, and only a minority believes the community should co-manage sea turtle conservation with TAMAR. Though these three conservation strategies seem to help maintain traditional ecological knowledge, the future of this knowledge across generations is uncertain. Though community-based sea turtle conservation is working at the community scale, external factors associated with tourism development at the larger scale seem to influence both livelihoods and sea turtle survival. On a negative side, larger scale tourism development is associated with an increase in the cost of living, the introduction of drugs, violence and greater sense of insecurity, changes in the local fishing culture, and with ongoing threats to sea turtle survival. Tourism development is associated with benefits as well, including improvements in the local infrastructure, employment opportunities, and alternative sources of income. Since tourism development, at both local and regional scales, is unlikely to decrease any time soon, sea turtle survival no longer solely depends in getting local support for sea turtle conservation, but also in addressing the external factors that drive conservation and consumption of sea turtles. Overall, sea turtle ecotourism is one part of a larger strategy for meeting local socioeconomic needs while also protecting sea turtles in Praia do Forte.

The green turtle, Chelonia mydas, is a circumglobal species that exhibits several important developmental or ontogenetic shifts throughout its life history. The first major shift occurs when juvenile turtles migrate from pelagic habitat, where they forage as omnivores, to coastal neritic habitat, where they become primarily herbivores, foraging on algae and seagrass. Anecdotal evidence and gut-content analyses suggest that juvenile green turtles in south Texas bays, such as the lower Laguna Madre and Aransas Bay, undergo an additional ontogenetic shift during this important life history stage. Evidence from stable isotope analysis (SIA) of scute tissues of green turtles from Texas' lower Laguna Madre and Aransas Bay supports an intermediate stage between this species' shift from pelagic waters to seagrass beds in neritic waters; this additional shift comprises an initial recruitment of post-pelagic juveniles to jetty habitat located on the channel passes Gulf-ward of adjacent bays before subsequently recruiting to seagrass beds in these bays. Examination of stable carbon ([delta]¹³C) and nitrogen ([delta]¹⁵N) isotopes in microlayers of scute tissue from several size classes of green turtles from the lower Laguna Madre and Aransas Bay was used to confirm the occurrence of two ontogenetic shifts. Smaller green turtles (< 35 cm SCL) exhibited more depleted [delta]¹³C signatures and more enriched [delta]¹⁵N signatures, consistent with jetty habitat, compared to those of larger counterparts (> 45 cm SCL) that displayed enriched [delta]¹³C signatures and depleted ¹⁵N signatures, consistent with seagrass habitat. Changes in the isotopic composition between these size classes indicate distinct shifts in diet. Post-pelagic juveniles first recruit to jetty habitat and forage primarily on algae, before subsequently shifting to seagrass beds and foraging primarily on seagrass. These findings indicate the use of a characteristic sequence of distinct habitats by multiple life history stages of green turtles in Texas bays, a conclusion with broad management implications for this endangered species.

Thesis (M.S.)--North Carolina State University, 2003. / Title from PDF t.p. (viewed on Dec. 18, 2005). Includes vita. Includes bibliographical references.

Thesis (DTech. degree in Nature Conservation.)--Tshwane University of Technology, 2010. / Hawksbill sea turtles (Eretmochelys imbricata) have been reduced by more than 80% worldwide in the last century and are considered critically endangered. Although nesting populations have been subject to numerous studies, there is a considerable lack of knowledge pertaining to the in-water behaviour and ecological functions of wild foraging hawksbill populations. This is especially true for the Western Indian Ocean as important topics such as habitat use and dietary items have scarcely been explored. Between 2006 and present, more than 178 hours of in-water observations of foraging hawksbill activity was recorded on a small insular reef at D'Arros Island, Seychelles. Most of the 827 sightings were of known, resident turtles (> 90%), facilitating analyses on both a population and individual level. Habitat types were identified and described, turtle densities estimated, population dynamics established, home ranges calculated, food items identified, food intake quantified, feeding behavior described, food resources quantified, diet selectivity indices calculated, intra/interspecific competition quantified and activity and dive patterns were described.