Turtle Hatching Research Articles

Percentage of Hatching Success of Olive Ridley Turtle (Lepidochelyis oliviceae) Eggs in Natural and Semi-Natural Nests and the Quality of the Turtle Conservation Community (TCC), Lombok, Indonesia

Sea turtles are internationally and nationally protected marine reptiles. One of the turtle species that can be found in Indonesia is the Olive Ridley turtle or Lepidochelys oliviceae. This study aims to determine the percentage of hatching success of turtle eggs in semi-natural and natural nests at TCC (Turtle Conservation Community), Lombok, determine the physical characteristics of natural and semi-natural nests of turtle eggs, and determine the quality of hatchlings produced in natural and semi-natural nests. The research method used is the descriptive exploration method, including determining the location with purposive sampling, collecting data on the size of Olive Ridley turtle mothers, the number of eggs, the depth and diameter of turtle egg nests, beach slope, nest temperature, substrate grains, beach vegetation, threats to turtle eggs, and locomotor quality of hatchlings. The results of this study are, the percentage of success in natural nests of Olive Ridley turtles is lower at 71.99% and semi-natural nests as much as 59.01%. The average temperature of both nests was 28.67, which is still optimal for turtle egg nesting. The type of grain in the two types of nests is also relatively fine. The slope of the beach is also still relatively gentle. Based on the research conducted by TCC (Turtle Conservation Community), it is suitable to support the success of Olive Ridley turtle hatching.

Potential impacts of environmental bacteria on the microbiota of loggerhead (Caretta caretta) and green (Chelonia mydas) sea turtle eggs and their hatching success.

Sea turtle hatching success can be affected by many variables, including pathogenic microbes, but it is unclear which microbes are most impactful and how they are transmitted into the eggs. This study characterized and compared the bacterial communities from the (i) cloaca of nesting sea turtles (ii) sand within and surrounding the nests; and (iii) hatched and unhatched eggshells from loggerhead (Caretta caretta) and green (Chelonia mydas) turtles. High throughput sequencing of bacterial 16S ribosomal RNA gene V4 region amplicons was performed on samples collected from 27 total nests in Fort Lauderdale and Hillsboro beaches in southeast Florida, United States. Significant differences were identified between hatched and unhatched egg microbiota with the differences caused predominately by Pseudomonas spp., found in higher abundances in unhatched eggs (19.29% relative abundance) than hatched eggs (1.10% relative abundance). Microbiota similarities indicate that the nest sand environment, particularly nest distance from dunes, played a larger role than the nesting mother's cloaca in influencing hatched and unhatched egg microbiota. Pathogenic bacteria potentially derive from mixed-mode transmission or additional sources not included in this study as suggested by the high proportion (24%-48%) of unhatched egg microbiota derived from unknown sources. Nonetheless, the results suggest Pseudomonas as a candidate pathogen or opportunistic colonizer associated with sea turtle egg-hatching failure.

The effects of nest location and beach environment on hatching success for leatherback (Dermochelys coriacea) and green (Chelonia mydas) sea turtles on Bioko Island, Equatorial Guinea

Hatching success of sea turtle eggs can be reduced by a variety of biotic and abiotic factors. This study of the nesting ecology of leatherback (Dermochelys coriacea) and green (Chelonia mydas) sea turtles, investigated how several environmental factors and beach characteristics on Bioko Island, Equatorial Guinea influence sea turtle reproductive success. Average hatching success was 40.4% for green turtles and 41.73% for leatherback turtles. For leatherback turtles, clutch elevation relative to the high tide line (HTL) was found to be the most influential factor in determining hatching success, highlighting the sensitivity of this species to sea-level rise (SLR). Multiple linear regression analysis demonstrated that nest distance to vegetation, temperature, sand grain size, location on the beach, and sand conductivity also played significant roles in leatherback clutch hatching success. For leatherback clutches, 33% percent of nests were affected by inundation and 17% by predation. An optimum clutch elevation range for leatherback turtles was identified, where a distinct increase in hatching success was observed between − 0.286 and − 0.0528 m above the HTL. For green sea turtles, 64% of experimental nests were affected by predation, confounding conclusions about the roles of environmental characteristics in green turtle hatching success. We propose further investigation into influential characteristics in green turtle nests and confirmation of the observed optimum elevation range on Bioko Island and other nesting grounds. Identified sensitivities of each species to SLR and beach characteristics will be used to encourage the government of Equatorial Guinea to consider the vulnerability of their resident turtle populations when planning for future coastal development.

Leatherback sea turtle (Dermochelys coriacea) hatch success and essential and nonessential metals in eggs and embryos from nests in St. Kitts (2015)

Northwest Atlantic leatherback sea turtles (Dermochelys coriacea) are endangered and low hatch success limits potential for population recovery. We examined essential and nonessential metal concentrations in 43 eggs from nests on St. Kitts to determine if there was a relationship with hatch success. Whole homogenized embryos and undeveloped eggs contained detectable concentrations of arsenic, barium, copper, iron, selenium, vanadium, and zinc, but not beryllium, cadmium, chromium, cobalt, lead, mercury, molybdenum, and thallium. Of detected metals, only vanadium concentrations negatively correlated with hatch success (P = 0.01). Manganese and vanadium were associated with pneumonia occurring in the nest, and arsenic with renal mineralization. This study adds to the knowledge regarding baseline values for environmental contaminants in sea turtles, supporting the trend that leatherback eggs have relatively low concentrations of toxic metals, lacking a strong relationship with hatch success, and normally contain the essential elements copper, iron, selenium, and zinc.

Effects of nest management methods on hatching success and predation rates of hawksbill turtles on Cousine Island, Seychelles

Sea turtle populations have declined globally and are of conservation concern. We investigated the effects of nest management methods on hatching success and egg/hatchling predation rates of hawksbill turtles Eretmochelys imbricata on Cousine Island, Seychelles. We determined the effectiveness of two different crab-barrier methods (netted and fenced) on hatching success and predation rates. We examined the relative influence of nest-site cover (full sun, partial sun or full shade) and location (zones of high risk or low risk of predation) on hatching success and predation rates. We also examined temperature disparity between netted and control nests to estimate potential effects on sex ratios and measured typical beach-substrate temperatures in the different nesting habitats. We compared data from 40 netted, 40 fenced and 40 control nests during the 2014/2015 breeding season. Overall, hawksbill turtle hatching success was not significantly affected by treatment or cover; however, netted nests and nests incubating in full sun had the highest mean hatching success. Predation rate was generally low but variable, and the rates differed significantly between the three treatments. Nest temperatures differed significantly between the netted and control nests, with netting used to protect nests having a substantial cooling effect. Hatchling sex ratios for natural nests were skewed towards females and those for netted nests skewed towards males. With climate change and increasing ambient temperatures imminent, a better understanding of how the spatial distribution of nests and variations in environmental factors influence hawksbill turtle hatching success and the levels of predation on eggs and hatchlings will assist future conservation measures.

Nematode community characteristics are associated to loggerhead turtle hatching success

Abstract Nematodes represent an important group of animals in the decomposer food web, because of high diversities, abundances and functional roles supporting ecological processes, such as decomposition. They have been relatively well studied in numerous ecosystems, but have rather skipped attention in sea turtle nests at sandy shores, where a massive supply of nutrients is taking place after turtle egg hatching. Being excellent indicators of ecological functioning, we hypothesized that nematode community characteristics could be indicative of the ecological/functional state of sea turtle nests as affected by hatching characteristics (e.g. number of eggs, hatching success rate etc.). In our study, conducted in Zakynthos (Greece), we perform a pioneer in-depth analyses of nematode communities in Caretta caretta nests after egg hatching. We further explore whether turtle reproductive success, measured through a number of metrics reflecting stages and portion of alive/dead hatchlings, are linked to nematode community characteristics. We found 14 different nematode genera in total. Our analyses demonstrate that nematodes play a critical role in functionality and energy flow in sandy shore ecosystems and that sea turtle nests present an ephemeral micro-habitat hosting communities with specific characteristics. These include rather high nematode abundances and communities in early successional stages with a simple trophic structure, almost exclusively dominated by bacterivore nematodes (mostly opportunistic/c-p 1) and without top-down control. Variables either showing success or failure of hatching explained a large amount of variability of nematode community characteristics, supporting our hypothesis. The nematode Metabolic Footprint was strongly associated with the amount of dead hatchlings concentrated in the turtle nest. Nematode taxonomic diversity and richness were closely associated with an increased hatching success rate at nest level. Our findings can offer a base for developing a framework for comprehensive and standardized assessments of sea turtle nests that could ensure comparability of results over spatial or temporal scales in monitoring projects. Further research might show how increased diversity of nematode communities could be achieved so to improve reproduction output and success of loggerhead sea turtles.

POTENSI PENYU HIJAU (Chelonia mydas L.) SEBAGAI STRATEGI PENGEMBANGAN WISATA EDUKASI DI KAWASAN PANTAI PANGUMBAHAN UJUNG GENTENG SUKABUMI JAWA BARAT

Pangumbahan beach is one of the areas that has the potential of diverse resources ranging from tourism, agriculture, forestry and especially marine resources and fisheries one green turtle. Pangumbahan into turtle nesting areas and potentially Education tourist, but turtle selling still occurs illegally. For this purpose, this study aims to examine the Green Turtle potential including laying, incubation, and turtle hatching, to find out the visitor's interest in Green Turtle, and to plan the development of Green Turtle-based Education Tourist program to Green Turtle conservation manager. The research method used quantitative and qualitative methods of SWOT analysis with field observation, interview with purposive sampling, and questionnaire. The results showed that in the Pangumbahan Coast Region yielded IFAS 0.64 and EFAS 0.60 from the results then the location of the strategy is in quadrant I.

Factors Influencing Loggerhead (Caretta caretta) and Green Turtle (Chelonia mydas) Reproductive Success on a Mixed Use Beach in Florida

Abstract Although estimates of sea turtle reproductive success are important to quantify population status and effects from threats, published representative values of these rates are rare. Most assessments involving hatching success have taken place as part of experimental analyses that did not spatiotemporally represent a population. To fill this gap, we analyzed an 11-yr time series (2004–2014) of sea turtle hatching and emergence success data for a 7-km stretch of Florida beach backed by mixed suburban and resort/recreational land use. Our analysis examined potential egg-mortality factors associated with the incubation of these nests. The data set included representative sampling of loggerhead (Caretta caretta) nests (n = 2,543, 34.4% of all nests made during the period) and green turtle (Chelonia mydas) nests (n = 972, 44.7% of all nests). Mean (± SD) annual hatching success was 68.6% ± 35.5% for loggerheads and 59.6% ± 39.5% for green turtles, and mean emergence success was 66.6% ± 35.7% for logger...

Nest inundation from sea-level rise threatens sea turtle population viability.

Contemporary sea-level rise will inundate coastal habitats with seawater more frequently, disrupting the life cycles of terrestrial fauna well before permanent habitat loss occurs. Sea turtles are reliant on low-lying coastal habitats worldwide for nesting, where eggs buried in the sand remain vulnerable to inundation until hatching. We show that saltwater inundation directly lowers the viability of green turtle eggs (Chelonia mydas) collected from the world's largest green turtle nesting rookery at Raine Island, Australia, which is undergoing enigmatic decline. Inundation for 1 or 3 h reduced egg viability by less than 10%, whereas inundation for 6 h reduced viability by approximately 30%. All embryonic developmental stages were vulnerable to mortality from saltwater inundation. Although the hatchlings that emerged from inundated eggs displayed normal physical and behavioural traits, hypoxia during incubation could influence other aspects of the physiology or behaviour of developing embryos, such as learning or spatial orientation. Saltwater inundation can directly lower hatching success, but it does not completely explain the consistently low rates of hatchling production observed on Raine Island. More frequent nest inundation associated with sea-level rise will increase variability in sea turtle hatching success spatially and temporally, due to direct and indirect impacts of saltwater inundation on developing embryos.

Olive ridley sea turtle hatching success as a function of the microbial abundance in nest sand at Ostional, Costa Rica.

Several studies have suggested that significant embryo mortality is caused by microbes, while high microbial loads are generated by the decomposition of eggs broken by later nesting turtles. This occurs commonly when nesting density is high, especially during mass nesting events (arribadas). However, no previous research has directly quantified microbial abundance and the associated effects on sea turtle hatching success at a nesting beach. The aim of this study was to test the hypothesis that the microbial abundance in olive ridley sea turtle nest sand affects the hatching success at Ostional, Costa Rica. We applied experimental treatments to alter the microbial abundance within the sand into which nests were relocated. We monitored temperature, oxygen, and organic matter content throughout the incubation period and quantified the microbial abundance within the nest sand using a quantitative polymerase chain reaction (qPCR) molecular analysis. The most successful treatment in increasing hatching success was the removal and replacement of nest sand. We found a negative correlation between hatching success and fungal abundance (fungal 18S rRNA gene copies g-1 nest sand). Of secondary importance in determining hatching success was the abundance of bacteria (bacterial 16S rRNA gene copies g-1 g-1 nest sand). Our data are consistent with the hypothesis that high microbial activity is responsible for the lower hatching success observed at Ostional beach. Furthermore, the underlying mechanism appears to be the deprivation of oxygen and exposure to higher temperatures resulting from microbial decomposition in the nest.

Olive Ridley Sea Turtle Hatching Success as a Function of Microbial Abundance and the Microenvironment ofIn SituNest Sand at Ostional, Costa Rica

Sea turtle hatching success at mass nesting beaches is typically lower than at solitary nesting beaches, presumably due in part to high rates of microbial metabolism resulting from the large input of organic matter from turtle eggs. Therefore, we tested the hypothesis that hatching success varies across areas of the beach in conjunction with differences in the physical nest environment and microbial abundance of in situ olive ridley sea turtle nests at Ostional, Costa Rica. We marked natural nests in high-density, low-density, and tidal-wash nesting areas of the beach and monitored clutch pO2and temperature throughout the incubation period. We quantified hatching success and collected samples of nest sand during nest excavations. We quantified microbial abundance (bacteria and fungi) with a quantitative polymerase chain reaction (qPCR) analysis. Hatching success was lower in nests with lower pO2, higher temperatures, higher organic matter content, and higher microbial abundance. Our results suggest that the lower oxygen within the nest environment is likely a result of the high microbial abundance and rates of decomposition in the nest sand and that these factors, along with increased temperature of clutches in the high-density nesting area, are collectively responsible for the low hatching success at Ostional.

Factors Affecting Hatch Success of Hawksbill Sea Turtles on Long Island, Antigua, West Indies

Current understanding of the factors influencing hawksbill sea turtle (Eretmochelys imbricata) hatch success is disparate and based on relatively short-term studies or limited sample sizes. Because global populations of hawksbills are heavily depleted, evaluating the parameters that impact hatch success is important to their conservation and recovery. Here, we use data collected by the Jumby Bay Hawksbill Project (JBHP) to investigate hatch success. The JBHP implements saturation tagging protocols to study a hawksbill rookery in Antigua, West Indies. Habitat data, which reflect the varied nesting beaches, are collected at egg deposition, and nest contents are exhumed and categorized post-emergence. We analyzed hatch success using mixed-model analyses with explanatory and predictive datasets. We incorporated a random effect for turtle identity and evaluated environmental, temporal and individual-based reproductive variables. Hatch success averaged 78.6% (SD: 21.2%) during the study period. Highly supported models included multiple covariates, including distance to vegetation, deposition date, individual intra-seasonal nest number, clutch size, organic content, and sand grain size. Nests located in open sand were predicted to produce 10.4 more viable hatchlings per clutch than nests located >1.5 m into vegetation. For an individual first nesting in early July, the fourth nest of the season yielded 13.2 more viable hatchlings than the initial clutch. Generalized beach section and inter-annual variation were also supported in our explanatory dataset, suggesting that gaps remain in our understanding of hatch success. Our findings illustrate that evaluating hatch success is a complex process, involving multiple environmental and individual variables. Although distance to vegetation and hatch success were inversely related, vegetation is an important component of hawksbill nesting habitat, and a more complete assessment of the impacts of specific vegetation types on hatch success and hatchling sex ratios is needed. Future research should explore the roles of sand structure, nest moisture, and local weather conditions.

Integrated risk factors for vertebrate roadkill in southern Ontario

AbstractRoad mortality of animals (roadkill) threatens public safety and wildlife populations. As mitigation tools, predictive models of roadkill are becoming more common in the published literature; however, few models generalize across multiple taxa, and thus are less useful for management scenarios that account for multiple target species. Using a dataset of 653 vertebrate roadkills collected from 2 parks in southern Ontario, we constructed generalized linear mixed models to determine the simultaneous risk factors for bird, frog, mammal, five‐lined skink (Eumeces fasciatus), snake, toad, and turtle hatchling roadkills from among a set of 8 potential predictor variables. Posted road speed limit was the dominant roadkill predictor (positive coefficient), followed by maximum daily temperature (positive), habitat diversity (positive), and distance from wetlands (negative). All else being equal, as road speed limits increase from 20 km/hr to 50 km/hr, the model predicted the season's mean roadkill probability for a given location to increase from less than 0.1 to 0.75. Conversely, roadkill probability declined from 0.55 to 0.29 as distance from wetland edges increases from 0 km to 1 km. Model diagnostics calculated from randomly resampled cross‐validation datasets indicated that the best model formulation had an averaged predictive accuracy of 67.5% and an area under the curve (AUC) of 0.867. The best model also reflected seasonal patterns of animal behavior, including late‐summer frog movements and fall turtle hatching events. The best model also compared favorably to single‐taxon equivalent models. To reduce the incidence of vertebrate roadkill, we recommend that managers lower road speed limits, especially on roads near diverse habitats and near wetlands, and on warmer days if temporary signage is used. © 2012 The Wildlife Society.

Nest Site Preference and Hatching Success of Green (Chelonia mydas) and Loggerhead (Caretta caretta) Sea Turtles at Akyatan Beach, Turkey

We studied nesting site preferences and hatching success of loggerhead (Caretta caretta) and green turtles (Chelonia mydas) on Akyatan Beach, Turkey. The distribution of nests varied annually, with green turtles nesting most often in vegetated areas and loggerhead turtles most commonly in nonvegetated areas. Green turtle hatching success was higher at vegetated vs. nonvegetated nest sites (p < 0.001).

Blood Gasses Contents of Green Turtle (Chelonia mydas) Hatch Treated by Different Temperatures

The aim of this research was to gain the profile of blood gasses of green turtle (Chelonia mydas) hatch. Blood gas of the green turtle was analysed after exposuring them at 28 °C and 50% of humidity for 24 hours in a pvc tube and at 34 °C under sunlight exposured with 47% of humidity for 30 minutes. The result showed the different values of blood gas contents. This result showed indication of metabolism activities and poikilothermic adaptation of green turtle hatch. This information can be used to support for turtle hatchery in Indonesia.

Myoglobin Expression in Chelonia mydas Brain, Heart and Liver Tissues

An understanding of the underpinning physiology and biochemistry of animals is essential to properly understand the impact of anthropogenic changes and natural catastrophes upon the conservation of endangered species. An observation on the tissue location of the key respiratory protein, myoglobin, now opens up new opportunities for understanding how hypoxia tolerance impacts on diving lifestyle in turtles. The respiratory protein, myoglobin has functions other than oxygen binding which are involved in hypoxia tolerance, including metabolism of reactive oxygen species and of the vascular function by metabolism of nitric oxide. Our work aims to determine whether myoglobin expression in the green turtle exists in multiple non muscle tissues and to confirm the hypothesis that reptiles also have a distributed myoglobin expression which is linked to the hypoxia-tolerant trait. This initial work in turtle hatch Chelonia mydas confirms the presence of myoglobin transcriptin brain, heart and liver tissues. Furthermore, it will serve as a tool for completing the sequence and generating an in situ hybridization probe for verifying of cell location in expressing tissues.

Variations in leatherback turtle nest environments: consequences for hatching success

Physical and biological conditions of nests in which sea turtle embryos develop can vary among and within nesting beaches. Monitoring these conditions and their effects on embryonic development should be considered when assessing conservation efforts to increase sea turtle hatch- ling production. Sandy Point National Wildlife Refuge (SPNWR), St. Croix, US Virgin Islands, hosts a leatherback turtle Dermochelys coriacea nesting colony that has increased exponentially in the past 2 decades, due in part to an ongoing egg relocation program. We characterized the influence of nest environment conditions (e.g. partial pressures of oxygen, pO2, and carbon dioxide, pCO2, and tem- perature) on hatching success of relocated eggs at 3 different sites at SPNWR to evaluate potential intra-beach variation in nest environment conditions and hatching success. Although nest conditions varied significantly among sites, hatching success did not vary significantly among relocation sites. Among all clutches and sites, hatching success varied significantly with minimum pO2, maximum pCO2, and maximum temperatures measured in leatherback nests. Thus, leatherback embryos col- lectively affected their nest environment (i.e. decreased pO2, increased pCO2, and temperature), and appeared to show developmental sensitivity to low pO2 and high levels of pCO2 and temperature in nests. Our study shows the importance of considering sea turtle nest environment conditions when designing and executing beach-based conservation strategies such as egg relocation programs.

Hatching Success and Nest Predation in the Green Sea Turtle, Chelonia Mydas, at Tortuguero, Costa Rica

Green turtle hatching success and nest predation were investigated at Tortuguero, Costa Rica, during July—November 1977. Forty—two percent of 350 study area nests and 57% of 237 beach survey nests produced emerging young; 38% and 24%, respectively, were destroyed by dogs, coatis, and vultures. The mean emergence percentage for the successful study area nests was 83%. About 13% of all eggs deposited did not hatch. A mean incubation period of 62 d and a mean clutch size of 104 eggs were recorded. Emergence success was not influenced by other recorded parameters (nest position on beach, rainfall, turtle's tag year, time of season, incubation period, and clutch size). Incubation period was related to nest position and clutch size. Dogs, coatis, and black and turkey vultures were the chief predators at Tortuguero; dogs did the most damage. Dogs and coatis found nests at all stages of development, but destroyed more nests containing hatchlings than nests containing unhatched eggs. Predation was related to nest position, but not to nest density. Nests were destroyed in equal proportion on the entire 35.4 km of beach. Predator activity was not consistent throughout the season; proportionally more nests were destroyed near the end of the nesting season than during the beginning.