Green Turtle Research Papers - Academia.edu (original) (raw)

Marine turtle fibropapillomatosis (FP) is a disease primarily affecting green turtles (Chelonia mydas) that is characterized by multiple cutaneous masses. In addition, the condition has been confirmed in other species of sea turtles. The... more

Marine turtle fibropapillomatosis (FP) is a disease primarily affecting green turtles (Chelonia mydas) that is characterized by multiple cutaneous masses. In addition, the condition has been confirmed in other species of sea turtles. The disease has a worldwide, circumtropical distribution and has been observed in all major oceans. Although reported since the late 1930s in Florida, it was not until the late 1980s that it reached epizootic proportions in several sea turtle populations. Long-term studies have shown that pelagic turtles recruiting to near shore environments are free of the disease. After exposure to these benthic ecosystems, FP manifests itself with primary growths in the corner of the eyes spreading to other epithelial tissue. One or more herpesviruses, a papillomavirus, and a retrovirus have been found associated with tumors using electron microscopy and molecular techniques; however, the primary etiological agent remains to be isolated and characterized. Field observations support that the prevalence of the disease is associated with heavily polluted coastal areas, areas of high human density, agricultural runoff, and/or biotoxin-producing algae. Marine turtles can serve as excellent sentinels of ecosystem health in these benthic environments. FP can possibly be used as an indicator but correlations with physical and chemical characteristics of water and other factors need to be made. Further research in identifying the etiologic agent and its association with other environmental variables can provide sufficient parameters to measure the health of coastal marine ecosystems, which serve not only as ecotourism spots but also as primary feeding areas for sea turtles.

Seagrass meadows cover about 0.05-0.15% of the world’s ocean and are some of the most productive systems on Earth. Direct and indirect human-derived impacts have led to significant seagrass declines worldwide and the alteration of... more

Seagrass meadows cover about 0.05-0.15% of the world’s ocean and are some of the most productive systems on Earth. Direct and indirect human-derived impacts have led to significant seagrass declines worldwide and the alteration of services linked to their biodiversity. Effective conservation and the provision of sustainable recovery goals for ecologically significant species, such as green turtles (Chelonia mydas), are limited by the absence of reliable information on seagrass extent. This is especially true for the Wider Caribbean Region (WCR) where many conservation initiatives are under way, but impaired by the lack of accurate baseline habitat maps. To assist with such a fundamental conservation need using high resolution remote sensing data, both environmental and methodological challenges need to be tackled. First, the diversity of environments, the heterogeneity of habitats, and the vast extent of the targeted region mean that local expertise and field data are seldom available. Second, large-scale high-resolution mapping requires several hundred Landsat 5 and 7 images, which poses substantial processing problems. The main goal of this study was to test the feasibility of achieving Landsatbased large-scale seagrass mapping with limited ground-truth data and acceptable accuracies. We used the following combination of methods to map seagrasses throughout the WCR: geomorphological segmentation, contextual editing, and supervised classifications. A total of 40 Landsat scenes (path-row) were processed. Three major classes were derived (“dense seagrass”, “medium-sparse seagrass”, and a generic “other” class). Products’ accuracies were assessed against (i) selected in situ data; (ii) patterns detectable with very high-resolution IKONOS images; and (iii) published habitat maps with documented accuracies. Despite variable overall classification accuracies (45-85%), the resulting thematic maps were deemed acceptable to (i) regionally provide, following their critical evaluation, an adequate baseline for further large-scale conservation programs and research actions; and (ii) regionally re-assess carrying capacity estimates for green turtles. They certainly should represent a drastic improvement relative to current regional databases.

The nutritional ecology of macroherbivores in seagrass meadows and the roles of grazing by urchins, fishes and green turtles in tropical systems and waterfowl in temperate systems are discussed in this review. Only a few species of... more

The nutritional ecology of macroherbivores in seagrass meadows and the roles of grazing by urchins, fishes and green turtles in tropical systems and waterfowl in temperate systems are discussed in this review. Only a few species of animals graze on living seagrasses, and apparently only a small portion of the energy and nutrients in seagrasses is usually channeled through these herbivores. The general paucity of direct seagrass grazers may be a function of several factors in the composition of seagrasses, including availability of nitrogen compounds, presence of relatively high amounts of structural cell walls, and presence of toxic or inhibitory substances. The macroherbivores, however, can have a profound effect on the seagrass plants, on other grazers and fauna associated with the meadow, and on chemical and decompositional processes occurring within the meadow. Grazing can alter the nutrient content and digestibility of the plant, as well as its productivity. Removal of leaf material can influence interrelations among permanent and transient faunal residents. Grazing also interrupts the detritus cycle. Possible consequences of this disruption, either through acceleration or through decreased source input, and the enhancement of intersystem coupling by increased export and offsite fecal production, are discussed. The extent and magnitude of these effects and their ecological significance in the overall functioning of seagrass meadows only can be speculated, and probably are not uniform or of similar importance in both tropical and temperate seagrass systems. However, areas grazed by large herbivores provide natural experiments in which to test hypotheses on many functional relations in seagrass meadows.

The occurrence of marine turtles in the diet of white sharks, Carcharodon carcharias, is reviewed worldwide. Four records of chelonians eaten by white sharks in the Mediterranean Sea are described, which on the basis of carapace remnants... more

The occurrence of marine turtles in the diet of white sharks, Carcharodon carcharias, is reviewed worldwide. Four records of chelonians eaten by white sharks in the Mediterranean Sea are described, which on the basis of carapace remnants confirmed both the loggerhead Caretta caretta and green turtle Chelonia mydas to be preyed upon in those waters. The condition of these remains

The study area is located between Kandak Stream in the east and Kuğu Resort in the west in Mersin and it encloses Davultepe 100. Yıl facilities public beach and the picnic area run by Mersin Environmental Protection Foundation (MEÇEV).... more

The study area is located between Kandak Stream in the east and Kuğu Resort in the west in Mersin and it encloses
Davultepe 100. Yıl facilities public beach and the picnic area run by Mersin Environmental Protection Foundation (MEÇEV). Our
survey was conducted on the approximately 1.8 km beach from the end of July to the middle of September for 2009 nesting season.
A total of 68 (94.44 %) Chelonia mydas nests and 4 (5.56 %) Caretta caretta nests were recorded during our study. Special
protection measures were proposed for this beach.

Baseline blood biochemistry values were obtained for two foraging aggregations of clinically healthy wild, juvenile green turtles (Chelonia mydas) inhabiting Kaneohe Bay, Island of Oahu, and the Kona Coast, Island of Hawaii. Mean... more

Baseline blood biochemistry values were obtained for two foraging aggregations of clinically healthy wild, juvenile green turtles (Chelonia mydas) inhabiting Kaneohe Bay, Island of Oahu, and the Kona Coast, Island of Hawaii. Mean reference values were compared to values obtained from green turtles of similar size affected with fibropapillomas (FP) collected at Kaneohe Bay. Statistically significant differences were identified for total protein values, blood urea nitrogen, and enzyme values between healthy turtles and turtles with FP. In addition, turtles with severe FP were hypoproteinaemic, hypoalbuminaemic, hypoferraemic, azotaemic, and presented inverse calcium/phosphorus ratios, low cholesterol and triglyceride values, indicating the chronicity and severity of FP. It is concluded that blood reference values should be established for green turtles at the population level and by geographic area considering disease status, age, sex, and seasonal variations.

Heavy metals in the muscles, livers, kidneys and eggs of loggerhead turtles and green sea turtles were analysed to develop a non-killing method of heavy metal monitoring using eggs. Heavy metal concentrations were higher in the liver and... more

Heavy metals in the muscles, livers, kidneys and eggs of loggerhead turtles and green sea turtles were analysed to develop a non-killing method of heavy metal monitoring using eggs. Heavy metal concentrations were higher in the liver and kidney than in the muscle and eggs of loggerhead turtles. Within an egg, yolk contained the highest concentrations and burdens of heavy metals. Heavy metal concentrations in egg yolks within the oviducts of a single loggerhead turtle were uniform without significant intra-oviduct variation. Similarly, there were no inter-clutch differences of an individual green turtle during one nesting season. Heavy metal concentrations in the yolk of eggs from the oviduct indicate the accumulation levels in female turtles, suggesting that the analysis in yolks of sea turtle eggs collected randomly from any clutch enable the estimation of the heavy metal concentrations in nesting female turtles, since there is less fluctuation of heavy metal concentrations in yolks of eggs laid by nesting loggerhead and green turtles.

Green turtles (Chelonia mydas (Linnaeus, 1758)) are primarily herbivorous as adults, consuming minimal amounts of sponge tissue in the Hawaiian Islands (<1 % gut content) with occasional higher consumption rates in areas where sponges are... more

Green turtles (Chelonia mydas (Linnaeus, 1758)) are primarily
herbivorous as adults, consuming minimal amounts of sponge tissue
in the Hawaiian Islands (<1 % gut content) with occasional higher consumption rates in areas where sponges are more abundant. Here we report repetitive field observations of C. mydas feeding on sponges in Maunalua Bay (adjacent to Honolulu, Oʻahu, Hawaiʻi) as originally reported by Oʻahu Diving on October 10, 2009

Morphological differences between female and male hatchlings of green sea turtle (Chelonia mydas) were investigated to identify key morphological characters for sex determination. A total of 152 dead hatchlings of green sea turtles were... more

Morphological differences between female and male hatchlings of green sea turtle (Chelonia mydas) were investigated to identify key morphological characters for sex determination. A total of 152 dead hatchlings of green sea turtles were examined for 14 morphometric and seven meristic characters in the 2008 and 2009 nesting seasons on Samandag Beach in the northeastern Mediterranean Sea, Turkey. The sex of dead hatchlings was determined with gonad histology. Multivariate statistics revealed significant differences in three morphometric characters between females and males. The males had a longer curved carapace width (CCW), hind limb length (HLL) and plastron– cloaca length (PCL) than the females. Principal component analysis also supported the detected differences between sexes.

Catch per unit effort and population structure of the Pacific green turtle (Chelonia mydas) in the Golfo Dulce, Costa Rica. The Golfo Dulce is one of the few tropical fjords in the world, and has recently been declared a Marine Area for... more

Catch per unit effort and population structure of the Pacific green turtle (Chelonia mydas) in the Golfo Dulce, Costa Rica. The Golfo Dulce is one of the few tropical fjords in the world, and has recently been declared a Marine Area for Responsible Fisheries (AMPR), harboring mangrove ecosystems, coral reefs
and seagrass beds, which are important feeding areas for green turtles (Chelonia mydas). In this study we estimate the catch per unit effort (CPUE) and population structure in a site in the western sector of the Golfo Dulce. Between August 2010 and March 2013, were captured a total of 253 green turtles (including 20 recaptures) using entanglement nets. The annual CPUE (CPUE, 1 unit: 100m of net for 7h) during the study ranged between 0.19
and 0.45, decreasing gradually over the years, possibly prompted by mass mortality occurred in January 2013. We found that seasonality and temporality influence the CPUE according to the best-fit model. About 78.17% were considered adult females, with an average length of curved carapace (LCC) of 79.6±0.9cm. The female recaptured has been tagged previously in the Galapagos Archipelago. While none of the turtles tagged in the Golfo Dulce was reported nesting on any other beach. Our results suggest that the Golfo Dulce is an important area for green turtles, where individuals congregate for adults and subadults would feed on seagrasses and the fleshy parts of the mangroves. The area also represents a major challenge for international conservation, possibly because we captured adult females from nesting beaches of Panama and Colombia, which requires multilateral agreements that promote the recovery of the East Pacific green turtle. We suggest the continuation of this conservation project to use sea turtles as umbrella species to protect ecosystems in the Golfo Dulce.

Seagrasses are the only flowering plants (monocotyledonous Angiosperms) that have adapted themselves to living in marine and estuarine habitats, and are submerged most of the time. They are rooted in sediments on the sea bottom, with... more

Seagrasses are the only flowering plants (monocotyledonous Angiosperms) that have adapted themselves to living in marine and estuarine habitats, and are submerged most of the time. They are rooted in sediments on the sea bottom, with shoots appearing above the substrate. ...

Small, irregular isolated bones identified as remains of leatherback turtles (Dermochelys coriacea) were recovered from Mid to Late Holocene sites at Ra’s al-Hamra and Ra’s al-Hadd, coastal Oman. These provide the third instance of this... more

Small, irregular isolated bones identified as remains of leatherback turtles (Dermochelys coriacea) were recovered from Mid to Late Holocene sites at Ra’s al-Hamra and Ra’s al-Hadd, coastal Oman. These provide the third instance of this animal being documented from any prehistoric site anywhere, and the records provide one of the oldest, if not the oldest, dates for this distinctive chelonian—even though they do not refer to fossils. Decades of research in this region has yielded vast amounts of archaeological information, including abundant evidence of intense exploitation and utilization of marine turtles from about 6,500 to 4,000 BP. During part of this period, turtle remains in human burials have been extraordinary; the turtle involved, Chelonia mydas, has been abundant in the region during modern times. Yet despite intense and varied forms of prehistoric marine resource exploitation, and major, long-term archaeological work, no other turtle species has been previously authenticated from these, or other coastal sites.
The documentation of remains of the largest and most distinctive of living marine turtles, D. coriacea, at Ra’s al-Hamra and Ra’s al-Hadd, presented herein, provide detailed information that serves as the basis for future interpretations and discussions regarding incomplete, disarticulated remains from the Mid to Late Holocene, particularly in reference to taphonomic questions and diverse environmental conditions.