Green Turtle Nests Research Articles

Influence of Sandy Coast Vegetation on the Reproductive Success of Green Turtles at Cuban Nesting Beaches

Vegetation has been shown to influence nest environment (temperature, humidity), affecting hatchling's development as well as emergence success, and has also been used as a cue during the selection of a nesting site. For green turtles, Chelonia mydas, nest density is typically higher in the vegetated zones. This study evaluated the influence of vegetation presence and percent cover on the nesting success and embryonic development of green turtles in Guanahacabibes Peninsula, Cuba. The vegetation cover had a positive and significant relationship with the number of nests (r = 0.56, p = 0.01, n = 17). Two vegetation patches are identified with different vegetation cover values: 29% for the first (closer to the high tide line) and 37% for the second. We found the highest nesting success (70%) and nest relative frequency (15% of total nesting) around the first patch of vegetation. Median hatchling emergence success was 88% (40%–96%, n = 54) in the first patch and 93% (78%–100%, n = 40) in the second. The incubation period was lower in the first patch (mean = 51 d, range = 48–60 d, n = 44) and higher in the second (mean = 54 d, range = 45–67 d, n = 39). This is the first study that reveals the positive impact of sandy coast vegetation on Guanahacabibes' green turtle nesting and will be useful in conservation actions such as native vegetation restoration plans and temperature control using shade management with vegetation.

The microbial community in a green turtle nesting beach in the Mediterranean: application of the Biolog EcoPlate approach for beach pollution.

This study aims to characterize the microbial community and its relationship with heavy metal pollution in the beaches of Sugözü, an important nesting site for the green turtle. Heavy metal concentrations of sand samples from subregions of Sugözü were determined using ICP-MS. The microbial community was analyzed using the Biolog® EcoPlate. The relationship between microbial catalytic activity and heavy metal levels were analyzed using canonical correspondence analysis. Levels of 27Al, 57Fe, 55Mn, and 52Cr were quite high (4332.34, 13,764.77, 590.98, and 48.21 mg/kg, respectively). The microbial community in subregions with high levels of metals was found to use carboxylic acid as a carbon source. Bioactivity, substrate utilization, diversity, and evenness values indicated negative correlations concentrations of 27Al, 56Fe, and 52Cr (-0.820, -0.508, and -0.560, respectively). It was also found that microbial diversity decreased in the subregions where heavy metal concentration increased. Embryonic deaths were found highest at early stage (0.1 to 0.2 eggs) and lowest at middle stage for whole study sites by inspecting a total 6408 eggs of 63 green turtle nests. The Biolog EcoPlate was firstly applied to determine pollution, and our findings clearly demonstrate the applicability and effectiveness of this method in assessing nesting beaches.

Cayman Islands Sea Turtle Nesting Population Increases Over 22 Years of Monitoring

Given differing trajectories of sea turtle populations worldwide, there is a need to assess and report long-term population trends and determine which conservation strategies are effective. In this study, we report on sea turtle nest monitoring in the Cayman Islands over a 22-year period. We found that green (Chelonia mydas) and loggerhead (Caretta caretta) nest numbers increased significantly across the three islands since monitoring began in 1998, but that hawksbill nest numbers remained low with a maximum of 13 nests recorded in a season. Comparing the first 5 years of nest numbers to the most recent 5 years, the greatest percentage increase in green turtle nests was in Grand Cayman from 82 to 1,005 nests (1,126%), whereas the greatest percentage increase for loggerhead turtle nests was in Little Cayman from 10 to 290 nests (3,800%). A captive breeding operation contributed to the increase in the Grand Cayman green turtle population, however, loggerhead turtles were never captive-bred, and these populations began to increase after a legal traditional turtle fishery became inactive in 2008. Although both species have shown significant signs of recovery, populations remain at a fragment of their historical level and are vulnerable to threats. Illegal harvesting occurs to this day, with multiple females taken from nesting beaches each year. For nests and hatchlings, threats include artificial lighting on nesting beaches, causing hatchlings to misorient away from the sea, and inundation of nests by seawater reducing hatch success. The impacts of lighting were found to increase over the monitoring period. Spatial data on nest distribution was used to identify critical nesting habitat for green and loggerhead turtles and is used by the Cayman Islands Department of Environment to facilitate remediation of threats related to beachside development and for targeted future management efforts.

Heavy Metal Tolerance Potential of Aspergillus alliaceus Isolated from a Green Turtle Nesting Site

Heavy metals are naturally present in the environment. As a result of human activities and some natural events, mixing of these metals in water, air and soil is one of the most serious global problems. The toxicity of these metals is also a serious global problem due to their accumulation in living things and non-biodegradable characteristics. Increasing heavy metal pollution in aquatic and terrestrial environments requires improvement strategies such as bioremediation to remove these metals from the environment for human and environmental health. In this study, fungal isolation was performed to examine fungi with heavy metal remediation potential using sand samples from Sugözü Beaches where are subjected to intense environmental effects due to human activities including industrial facilities and marine traffic. This beach is also an important nesting area for the green turtle. Aspergillus alliaceus isolated from this beach was identified using primers of internal transcribed spacer 1 and 4. To determine the tolerance of A. alliaceus to iron, zinc, cobalt and copper, the fungus was inoculated into media containing metal at different concentrations (200, 400, 600, 800, and 1000 ppm). Daily mycelium growths were recorded during a ten day incubation at 30°C. A.alliaceus was found to tolerate Fe and Zn at all concentrations. Besides, it tolerated Co and Cu up to 400 and 600 ppm, respectively. In this study, the tolerance of A. alliaceus to Fe, Zn, and Co was determined for the first time and it is recommended that it can be used efficiently in bioremediation studies.

Nesting habitat characteristics of green sea turtle (Chelonia mydas) in the Tambelan archipelago, Indonesia

Six species of sea turtles are recognized living in the Indonesia Archipelago and four of them are known for their nesting habitats. The study of sea turtles nesting habitats has been conducted at several locations in Indonesia. Almost all islands in Indonesia are suitable for sea turtles nesting sites, including Tambelan Archipelago in the Karimata Strait and habitat conditions are known to play a vital role in sea turtle nesting activity. Unfortunately, the study of sea turtle ecology, particularly nesting habitats, in this region are still scarce. This study aimed to describe nesting habitat characteristics of green sea turtles (Chelonia mydas) in Tambelan Archipelago. In-situ observation were conducted from March – May, 2019. A total of eleven nesting sites of green sea turtles were found during the period of study. The Tambelan Archipelago have ecological characteristics with natural, functional, and suitable area for a green sea turtle nesting activity. Coastal communities around nesting sites were found to be ideal for sea turtle nesting habitats. This condition will be able to survive if location can be conserved and sustainably managed.

Incubation temperatures, hatching success and congenital anomalies in green turtle nests from Guanahacabibes Peninsula, Cuba

Elevated incubation temperatures of sea turtle nests decrease hatching success and alter the resulting hatchlings' morphology. There is an absence of studies assessing the relationships between temperature and hatching success in Cuba, even when they could improve understanding the limits of thermal tolerance in these species. This study evaluated the influence of incubation temperature on hatching success and phenotypic malformations in green turtle hatchlings (Chelonia mydas); and analyzed the temporal variation in hatching success on the studied beaches. In 48 green turtles nests distributed along two beaches, incubation temperature and hatching success were recorded between 2014 and 2019. Increasing incubation temperature caused a decrease in the hatching success and an increase in the frequency of supernumerary scutes. Despite the elevated temperatures (average > 30°C), hatching was higher than 80%. Significant differences in hatching success were only observed among seasons for nests in Antonio Beach (lower values in 2016 and 2019 compared to 2014).

Impact of heavy rainfall events and shading on the temperature of sea turtle nests

While most studies assessing the ecological impacts of climate change have examined impacts from warming temperatures, less attention has been given to other parameters such as increased rainfall events. At a nesting rookery in the northern Great Barrier Reef, Australia, we used data loggers to examine the impact of heavy rainfall and shade on the nest temperatures for green (Chelonia mydas) and hawksbill (Eretmochelys imbricata) turtles clutches, which have temperature-dependent sex determination. In the middle of the nesting season (December–March), on 21 January 2019, 125 mm of rain fell over two days, causing the temperature to initially decrease by an average of ~ 3.6 °C in hawksbill turtle nests (n = 18) and ~ 3.5 °C in green turtle nests (n = 9). For shaded clutches during the 20-day cooling period after the rainfall event, we report average nest temperatures of ~ 27.9 °C and ~ 28.2 °C for hawksbill and green turtle clutches respectively, falling well into the male-producing range for sex determination. This was profoundly cooler than the average nest temperatures of clutches without shade and prior to the heavy rainfall, which was ~ 31.3 °C for both species. Extreme rainfall events are predicted to increase around Australia due to climate change but may help counteract impacts of atmospheric warming on sea turtle offspring sex-ratios. Our results also show the potential for artificially cooling nests by applying a combination of shade and irrigation, to counter the expected increases in the feminisation of sea turtle hatchling production worldwide.

The Effect of Invertebrate Infestation on Green Turtle (<i>Chelonia mydas</i>) Nests on Kazanlı Beach, Mersın, Turkey

In this study invertebrate infestation in green turtle (Chelonia mydas) nests were recorded for the first time for Kazanlı beach, Mersin, Turkey. For this aim, in 2006 nesting season, 294 natural intact green turtle nests were sampled to examine their contents and invertebrate infestation was found in 76 (25.85% of the total sampling green turtle nests). These infested nests were examined in terms of the invertebrate faunal composition. The specimens found in the green sea turtle nests were identified to order, family or genus levels and they were represented in 5 orders. These invertebrate groups are Elater sp. larvae (Elateridae; Coleoptera), Pimelia sp. larvae (Tenebrionidae; Coleoptera), Enchytraeidae (Oligochaeta), Cyrptostigmata (Acari), Oniscidae (Isopoda), Formicidae (Hymenoptera). Elater sp. was the most common invertebrate group in the green turtle nests. According to student t test, we found statistically significant differences between 7 independent variables and invertebrate species presence. Furthermore, logistic regression analysis explained that there is a negative relationship between hatching success rate and invertebrate species presence.

Nesting failure of sea turtles in Ecuador - causes of the loss of sea turtle nests: the role of the tide

The nesting environment is known to significantly affect the breeding success of sea turtles. Sandy beach habitats, where sea turtles nest, are frequently affected by high tides and waves on Ecuadorian beaches during windy events. The objectives of this study were: i) to determine the variables that affect nest site selection by two sea turtle species, Eretmochelys imbricata and Chelonia mydas in Ecuador, ii) to compare features of the nesting places of successful vs. failed clutches and iii) to quantify the changes in the intensity and frequency of the tide and its relation to the loss of eggs for the last 10 years. We monitored 15 hawksbill and 26 green turtle nests for two years on five beaches on the mainland coast of Ecuador. The results show that the presence of a dune scarps negatively affected successful nesting, while the proportion of eggs lost was positively associated with road distance, sea distance and nest depth. In addition, the results showed that the loss of eggs was greater for the green turtle, the presence of dune scarps and tides. Finally, using the data available on hatching success over the last 10 years we found a significant relationship between the intensity of the tides and the loss of eggs during this period. We conclude that nest site selection and hatching success vary with beach microhabitats and therefore local information is needed to protect suitable habitats.

Green Turtle (Chelonia mydas) Nesting Underscores the Importance of Protected Areas in the Northwestern Gulf of Mexico

Knowledge of the spatial and temporal distribution of green sea turtle (Chelonia mydas) nesting is crucial for management of this species. Limited data exist on the nesting patterns of green turtles along the northwestern Gulf of Mexico (GOM) coast. From 1987 to 2019, 211 green turtle nesting activities were documented on the Texas coast, including 111 confirmed nests and 100 non-nesting emergences. Of the 111 nests, 99 were located on North Padre Island (97 at Padre Island National Seashore (PAIS), 2 north of PAIS) and 12 on South Padre Island (6 within the Laguna Atascosa or Lower Rio Grande Valley National Wildlife Refuges (NWR), 6 outside of a NWR). Of the 100 non-nesting emergences, 75 were on North Padre Island (70 at PAIS, 5 north of PAIS), 21 on South Padre Island (9 within a NWR, 12 outside of a NWR), 1 on Boca Chica Beach, 2 on San Jose Island, and 1 on Mustang Island. Nearly all of the nests (92.8%) and most of the non-nesting emergences (79.0%) were on property protected by the U.S. Department of the Interior as PAIS or a NWR, and confirmed nest density was largest at PAIS, highlighting the importance of these federally protected lands as nesting habitat for this threatened species. Of the 111 located nests, 8 were predated. Mean hatching success of the 103 non-predated nests was 77.4%, and 9,475 hatchlings were released from the predated and non-predated nests. The largest annual number of green turtle nests documented was 29 in 2017. Nesting appeared to increase since 2010, but at a much lower rate than at other GOM nesting beaches. To aid with recovery, efforts should be undertaken to monitor long-term nesting trends, protect nesting turtles and nests, and investigate potential causes for the slower recovery in Texas. Additionally, the genetic structure of the population that nests in Texas should be determined to reveal if the population warrants recognition as a unique management unit, or if it is part of a broader unit that is a shared nesting resource with Mexico which is already being considered as a unique management unit.

Sex ratio of the green sea turtle Chelonia mydas (Testudines: Cheloniidae) hatchlings in the Guanahacabibes Peninsula, Cuba

Introduction: Sea turtles have temperature dependent sex determination. The increase in global temperature leads to higher nest temperatures that can cause a prevalence of females, threatening the future of these species. Objective: The present work aims to evaluate the trend of incubation temperatures and the incubation period, as well as to estimate the sex ratio in nests of Chelonia mydas at Antonio and La Barca beaches, Southwestern Cuba, during the seasons from 2012 to 2018. Methods: Temperature data loggers were placed in green turtle nests with a representativeness that varied between the years analyzed. To assess the temporal variation of temperatures and incubation periods, a Kruskal-Wallis test was performed in each case. Sex ratio was estimated from its relation with temperature and incubation duration. Results: At La Barca beach, there was a 1.5 °C increase in the mean nest temperature from 2012 to 2018, although no differences were found in the period from 2015 to 2018. At Antonio beach, there is no trend since no differences were found in the mean nest temperature except for the years 2013 and 2017, which had lower temperatures than the other seasons. In both beaches mean nest temperature exceeded 30 °C in most of the years. As a result, there was a predominance of nests with incubation periods shorter than 55 days. With these values, a female hatchling production over 90 % is expected in both study sites. Conclusions: In correspondence with the registered temperature and incubation period values, most of the years reflect a hatchling production biased towards females in both beaches.

Reproductive seasonality and environmental effects in green turtle (Chelonia mydas) nesting at Penang Island, Malaysia

AbstractFor species with environmental sex determination, understanding the relationship between reproduction and environmental factors is important for predicting their reproductive output. Here, we study intra-annual variation in green turtle nesting during the 2010–2016 seasons at Penang Island (5°16′28″–5°28′15″N 100°10′52″–100°11′55″E), Malaysia. The additive modelling on a monthly-basis number of nests shows that fluctuation in the number of nests relates to temperature in addition to month of year, rather than precipitation. The number of nests tended to be higher in response to higher temperature during March–July, whereas the lower temperature during August–February also tended to result in a relatively higher number of nests. Concentration of nests during March–July resulted from a shorter inter-nesting interval during warm temperatures, whereas relatively low temperatures may homogenize the temporal distribution of the number of nests. This study provides fundamental information for green turtle nesting seasonality in response to environmental change.

Bacterial diversity of the green turtle (Chelonia mydas) nest environment

The green turtle is an endangered species that is highly sensitive to environmental pollution that can adversely affect the healthy development of eggs. Moreover, the presence of some bacteria in nests can be regarded as an indicator of the pollution level in nesting areas.In our study, nest sand and egg contents were collected from Sugözü Beaches (Turkey), in the Mediterranean. Phenotypic and genotypic identification of bacteria were carried out by using conventional phenotypic methods, 16S rRNA gene sequencing respectively. The extended-spectrum beta-lactamase presence and carbapenem resistance of bacteria isolated from egg contents were determined. This is the first report of carbapenem resistance in the eggs. All strains were evaluated in three different categories including growth promoters in agriculture and aquaculture, pathogens that are found in human and animal, and biomonitoring aquatic pollution. According to our analysis, 67 bacterial species were identified from samples. This study is the first record of Alcaligenes, Zobellella, Lysinibacillus, Sphingobacterium, Achromobacter, Acinetobacter, Alcanivorax, Ochrobactrum, Microbacterium, Rhodococcus, and Stenotrophomonas isolated from sea turtles.Pathogens detected in the bacterial flora can threaten both sea turtles and field workers. These data can contribute to the development of new conservation strategies on the treatment of sea turtles, nest protection, and pollution detection on nesting beaches.

Estimates of marine turtle nesting populations in the south-west Indian Ocean indicate the importance of the Chagos Archipelago

AbstractGlobal marine turtle population assessments highlight the importance of the south-west Indian Ocean region, despite data gaps for the Chagos Archipelago. The archipelago hosts nesting hawksbill Eretmochelys imbricata and green turtles Chelonia mydas, both heavily exploited for 2 centuries until protection in 1968–1970. We assessed available nesting habitat and spatial distribution of nesting activity during rapid surveys of 90% of the archipelago's coastline in 1996, 1999, 2006 and 2016. We quantified seasonality and mean annual egg clutch production from monthly track counts during 2006–2018 along a 2.8 km index beach on Diego Garcia island. An estimated 56% (132 km) of coastline provided suitable nesting habitat. Diego Garcia and Peros Banhos atolls accounted for 90.4% of hawksbill and 70.4% of green turtle nesting. Hawksbill turtles showed distinct nesting peaks during October–February, and green turtles nested year-round with elevated activity during June–October. Estimates of 6,300 hawksbill and 20,500 green turtle clutches laid annually during 2011–2018 indicate that nesting on the Chagos Archipelago has increased 2–5 times for hawksbill turtles and 4–9 times for green turtles since 1996. Regional estimates indicate green turtles produce 10 times more egg clutches than hawksbill turtles, and the Chagos Archipelago accounts for 39–51% of an estimated 12,500–16,000 hawksbill and 14–20% of an estimated 104,000–143,500 green turtle clutches laid in the south-west Indian Ocean. The improved status may reflect > 40 years without significant exploitation. Long-term monitoring is needed to captureinterannual variation in nesting numbers and minimize uncertainty in population estimates.

Embryonic mortality in green (Chelonia mydas) and loggerhead (Caretta caretta) sea turtle nests increases with cumulative exposure to elevated temperatures

As climate change continues, sea turtle nests will be increasingly exposed to elevated incubation temperatures. Higher incubation temperatures influence many aspects of sea turtle development including sex determination and incubation length, but also survival. If temperatures in the nest increase above a thermal tolerance limit, then embryonic mortality may increase. The purpose of this research was to determine if there are differences in vulnerability to elevated temperatures across different stages of embryonic development and between loggerhead (Caretta caretta) and green (Chelonia mydas) sea turtles. Temperature dataloggers recorded nest temperature in the approximate center of loggerhead and green nests laid on the Boca Raton, Florida beach during the 2016 and 2017 nesting seasons. All unhatched eggs were collected from these nests following hatchling emergence. The eggs were dissected and the developmental stage at embryonic death was determined. The point of embryonic death was compared to the nest temperatures during that stage of the incubation period to determine if death corresponded to specific periods of elevated temperatures. Elevated nest temperatures increased embryonic mortality, but no developmental stage had higher mortality rates when exposed to any specific elevated temperatures compared to embryos that had not been exposed to that temperature. The most significant relationship was between mortality and the percent of time embryos were exposed to temperatures above 34 °C. This resulted in greater mortality of more developed embryos, as those embryos had a longer cumulative exposure to elevated temperatures. Loggerhead turtles exhibited higher rates of mortality compared to green turtles for almost all temperature exposure periods above 34 °C. Although few green nests reached 34 °C, green sea turtle embryos in south Florida may also have a higher thermal tolerance than loggerheads. Due to the increased embryonic mortality, and therefore, decreased hatching success, future management strategies may need to protect sea turtle nests from extended periods at elevated temperatures.

Mesocarnivore presence and behavior on a barrier island during sea turtle nesting season

Red fox (Vulpes vulpes) management has been conducted on Masonboro Island Reserve, a component of the North Carolina National Estuarine Research Reserve, North Carolina, USA, since 2013 to reduce depredation on loggerhead sea turtle (Caretta caretta) and green sea turtle (Chelonia mydas) nests. Depredation rates have varied among years indicating either an influx of red fox onto the island post cull or other mesocarnivores preying on sea turtle nests. We investigated the presence of red fox and other mesocarnivores on Masonboro Island Reserve after a culling event in 2016 to characterize mesocarnivore behavior and interactions during the turtle nesting season. We systematically placed 17 Moultrie® panoramic 150 passive infrared cameras every 0.80 km along the base of the dunes on the shoreline of Masonboro Island Reserve during May–October 2016. Of 81,509 pictures taken by the cameras, we observed 2 red fox and 1 Virginia opossum (Didelphis virginianus). There was 1 documented mammalian depredation event on turtle nests in 2016 and the number of false crawls (where females return to the ocean without laying eggs) was lower than the previous 5 years. Given that we only recorded 3 pictures on 2 different nights of mesocarnivores, our results may indicate that the 2016 cull was successful. Mesocarnivores, especially red fox and raccoons (Procyon lotor), on the mainland may temporarily shift their home range during the onset of the turtle nesting season to procure food for their offspring. By early fall, most mammal offspring disperse and likely recolonize the island annually, suggesting management efforts to reduce mammalian predators should continue. Human and domestic dog (Canis familiaris) presence on the island is abundant and also may influence turtle nest success.

Nest Productivity for Green Turtles (Chelonia mydas) at Qilianyu of Xuande Islands, South China Sea, P.R. China: Preliminary Findings

Abstract In August and September 2017, a total of 95 green turtle (Chelonia mydas) nests were geolocated on 5 islands of the Qilianyu cluster, Xuande Islands, South China Sea; North Island had the ...

Assessing climate change associated sea-level rise impacts on sea turtle nesting beaches using drones, photogrammetry and a novel GPS system.

Climate change associated sea-level rise (SLR) is expected to have profound impacts on coastal areas, affecting many species, including sea turtles which depend on these habitats for egg incubation. Being able to accurately model beach topography using digital terrain models (DTMs) is therefore crucial to project SLR impacts and develop effective conservation strategies. Traditional survey methods are typically low-cost with low accuracy or high-cost with high accuracy. We present a novel combination of drone-based photogrammetry and a low-cost and portable real-time kinematic (RTK) GPS to create DTMs which are highly accurate (<10cm error) and visually realistic. This methodology is ideal for surveying coastal sites, can be broadly applied to other species and habitats, and is a relevant tool in supporting the development of Specially Protected Areas. Here, we applied this method as a case-study to project three SLR scenarios (0.48, 0.63 and 1.20m) and assess the future vulnerability and viability of a key nesting habitat for sympatric loggerhead (Caretta caretta) and green turtle (Chelonia mydas) at a key rookery in the Mediterranean. We combined the DTM with 5years of nest survey data describing location and clutch depth, to identify (a) regions with highest nest densities, (b) nest elevation by species and beach, and (c) estimated proportion of nests inundated under each SLR scenario. On average, green turtles nested at higher elevations than loggerheads (1.8m vs. 1.32m, respectively). However, because green turtles dig deeper nests than loggerheads (0.76m vs. 0.50m, respectively), these were at similar risk of inundation. For a SLR of 1.2m, we estimated a loss of 67.3% for loggerhead turtle nests and 59.1% for green turtle nests. Existing natural and artificial barriers may affect the ability of these nesting habitats to remain suitable for nesting through beach migration.

Samandağ Kumsalı Yeşil Deniz Kaplumbağası (Chelonia mydas) Yuvalarında Memeli Predasyonunun Zamansal ve Mekansal Değişiminin İncelenmesi

Yuva predasyonu, birçok nesli tükenmekte olan kuş ve sürüngen türünün korunması için önemli bir pratik zorluktur ve yavru başarısını azaltma ve tehdit altındaki popülasyonların iyileşmesini yavaşlatma potansiyeline sahiptir. Yuva predasyonunun zamansal ve mekansal değişiminin tahmin edilmesi predasyon yönetimini optimize etme potansiyeline sahiptir. Bu çalışmada, Samandağ kumsalında yeşil deniz kaplumbağası (Chelonia mydas) yuvalarında memeli predasyonunun zamansal ve mekansal değişimleri araştırıldı. 2012 ve 2017 yılları arasında 733'ü metal ızgaralı kafes ile korunan, 231'i ise metal ızgara ile korumaya alınmamış kontrol yuvaları olan toplam 964 yuva araştırıldı. En etkili yuva predatörü Çakal olarak tespit edildi. Yuvaların metal ızgaralı kafes ile korunması yavru başarısını etkin bir şekilde arttırdı. Predasyona uğrayan yuva sayısı yıllara göre pozitif bir eğilim gösterdi, ancak bu eğilim istatistiksel olarak anlamlı değildi. Predasyon olasılığı kuluçka döneminin sonuna doğru arttı ve deniz ve bitki örtüsüne olan mesafeye göre mekansal değişimde farklılık ortaya çıkmadı. Ayrıca, kumsalın sonuna doğru predasyon olasılığı arttı. Yuva yoğunluğu ve yuva derinliklerine bağlı predasyon olma ihtimalinin ileride araştırılması önemlidir. Ayrıca Samandağ sahilinde baskın yırtıcı olan Çakalların populasyon ekolojisi ve statüsünün araştırılması da her iki tür için de önemlidir.

Relationship between Metabolic Heating and Nest Parameters in Green Turtles (Chelonia mydas, L. 1758) on Samandağ Beach, Turkey.

Acquiring information about metabolic heating is necessary for the improved understanding of nesting beaches. However, there are limited studies on metabolic heating of green turtle (Chelonia mydas, L. 1758) on Mediterranean beaches. The present study sought to determine the metabolic heating, and its effect on the feminization of green turtle hatchlings during 2016 and 2017 nesting season on Samandağ Beach, Hatay, Turkey. Moreover, the relations between metabolic heating and nest parameters, and spatio-temporal differences of metabolic heating were evaluated. Nest temperatures were recorded by using data loggers placed at the center of nests (n = 18), and the same depth was used to determine the sand temperature that was 50 cm back of the egg chamber. The mean incubation duration was calculated as 51.1 days, and the mean distance of nests from sea and the mean nest depth were measured as 32.4 meters and 67.70 cm, respectively. The mean numbers of embryo that is early, middle and late embryonic stages were found as 110.8, 93.2 and 93.05, respectively. The mean clutch size was found as 110.8. Mean metabolic heating was 0.37°C in the middle third of incubation for both years. The metabolic heating in both years was close to the as reported in the other green turtles nesting beaches in the Mediterranean. The feminization effect of metabolic heating was calculated as 6.8% in the green turtle nests on Samandağ Beach. Metabolic heating did not vary spatially, and the clutch size was the most important factor in metabolic heating and explained a large proportion of the variation in metabolic heating.