Incubating green turtle (Chelonia mydas) eggs at constant temperatures: Hatching success, hatchling morphology and post-hatch growth

2022 ◽  
pp. 103182
Author(s):  
Yun-Tao Yao ◽  
Yu Du ◽  
Jia-Xin Pan ◽  
Chi-Xian Lin ◽  
Xiang Ji ◽  
...  
2020 ◽  
Vol 27 (5) ◽  
pp. 245-256
Author(s):  
Cemil Aymak ◽  
Aşkın Hasan Uçar ◽  
Yusuf Katılmış ◽  
Eyup Başkale ◽  
Serap Ergene

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.


2021 ◽  
Author(s):  
Callie A. Veelenturf ◽  
Elizabeth M. Sinclair ◽  
Peter Leopold ◽  
Frank V. Paladino ◽  
Shaya Honarvar

Abstract Hatching success in sea turtles is hindered 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 clutch 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 and sand conductivity also played significant roles in leatherback clutch hatching success. For leatherback clutches, 33% percent of experimental 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 m to -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.


2021 ◽  
Vol 4 (4) ◽  
pp. 321-330
Author(s):  
Randy Calderón Peña ◽  
Julia Azanza Ricardo

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).


2020 ◽  
Vol 653 ◽  
pp. 181-190
Author(s):  
DT Booth ◽  
A Dunstan ◽  
I Bell ◽  
R Reina ◽  
J Tedeschi

Because the sex of all sea turtle hatchlings is determined by incubation temperature, with low temperatures producing mainly males and high temperatures producing mainly females, sea turtle populations worldwide are threatened by feminization of hatchlings due to increases in global temperature. Data obtained by laparoscopic sexing of immature individuals captured from a major feeding ground indicates that over several decades there has been little recruitment of males into the northern Great Barrier Reef (nGBR) green turtle Chelonia mydas population, one of the largest sea turtle populations in the world. Over 2 nesting seasons, we measured nest temperatures at Raine Island, the most important nesting site for this nGBR population, and predicted that almost all nests would have produced all female hatchlings. The few nests that produced some male hatchlings were constructed at the very end of the nesting season, and these nests had the lowest hatching success. Taking into account monthly variations in nest construction, hatching success, and hatchling sex ratio, we estimate that over an entire nesting season only 0.7% of hatchlings produced are male. Hence, we conclude that the nGBR population of green turtles has likely recruited very few males in recent years.


2019 ◽  
Vol 7 (2) ◽  
pp. 195
Author(s):  
Abang Aldhian R. Putera ◽  
Laksmi Sulmartiwi ◽  
Wahju Tjahjaningsih

Abstract Indonesia is an archipelago that is rich in diversity of flora and fauna. One of these is a wealth of fauna species of sea turtles. All species of sea turtles in the world by the Convention on International Trade in Endangered Species of Wild Flora and Fauna (CITES) put in Appendix I as endangered and protected and not allowed to be traded. The purpose of this study was to determine effect the ratio of the depth from nest egg incubation and hatching percentage of green turtles (Chelonia mydas) nests at different depths in Sukamade, Betiri Meru National Park, Banyuwangi, East Java. The design of the study is a randomized block design (RGD). The groups as replicates for RGD, between groups or experimental material media are considered uniform. The results showed that the average incubation period was 58.87 +0.39 days, then the results were followed by Duncan's multiple range test, which showed that the highest yield obtained by the depth of 50 cm wasn’t significantly different (p> 0.05) with depth of 30 cm and 70 cm. While the results obtained at the lowest depth of 90 cm was significantly different (p <0.05) with the other depth (30 cm, 50 cm and 70 cm). While the percentage of hatching success obtained in average hatching was 88.12 + 0.38%. The Duncan's multiple range test analysis, showed that at a depth of 70 cm were not significantly different (p <0.05) from depth of 50 cm, but 70 and 50 cm depth was significantly different (p> 0.05) from another depth. Whereas the lowest hatching results obtained on depth of 90 cm are significantly different (p> 0.05) from the other depth (30 cm, 50 cm and 70 cm). The conclusion of this study was different depth of green turtle nests affect the egg incubation period and the percentage of egg hatching success of green turtles.


2014 ◽  
Vol 19 (3) ◽  
pp. 159
Author(s):  
Edi Wibowo Kushartono ◽  
Endang Sri Susilo ◽  
Sayyidah Fatchiyyah

Salah satu usaha konservasi melindungi Penyu hijau (Chelonia mydas L.) yaitu dengan tindakan relokasi dengan memindahkan telur dari sarang alami ke tempat penetasan semi alami. Waktu pemindahan dan peletakan telur yang tepat sangat diperlukan untuk memperoleh daya tetas maksimal. Tujuan penelitian ini untuk mengetahui pengaruh selang waktu peletakan telur Penyu Hijau terhadap keberhasilan penetasannya. Rancangan penelitian adalah Rancangan Acak Kelompok berdasarkan 3 induk yang berbeda dengan perlakuan selang waktu peletakan yaitu 2, 7 dan 12 jam. Pengukuran dan pengamatan kondisi lingkungan dilakukan selama inkubasi. Pengamatan munculnya tukik mulai dilakukan pada hari ke 50 masa inkubasi.  Pembongkaran sarang dilakukan pada hari ke 60 masa inkubasi kemudian dilakukan pembedahan secara manual untuk mengamati telur yang gagal menetas. Hasil menunjukkan bahwa tidak ada pengaruh nyata secara signifikan adanya perbedaan selang waktu peletakan terhadap keberhasilan penetasan dan keberhasilan kemunculan. Namun selang waktu peletakan dengan nilai yang baik ditunjukkan pada 2 jam, dilanjutkan dengan 12 jam dan 7 jam. Kata kunci: penetasan, penyu hijau (Chelonia mydas L.), semi alami One of the conservation efforts undertaken to protect the green turtle (C. mydas L.) is by relocation of the nest where the eggs are removed from natural to semi-natural hatchery. A right time for the removal and burial of eggs are needed to obtain maximum hatching rate. The purpose of this study is to determine the impact of interval laying period on the hatching success of the green turtle eggs. Randomized block design is used which is based on three different turtles with treatment interval of burying, which is 2, 7, and 12 h. Measurements and observations were made during the environmental conditions of the incubation period. Observations hatchling emergence started on day 50 of incubation. Nest destruction was conducted on the 60th day incubation then eggs that failed to hatch were manually disected. The result showed that there is no significant influence of the time differences on the hatching success and emergence success. However, the best time was foound on 2h time treatment, folowed by 12h and 7h. Keywords: hatching, green turtle (Chelonia mydas L.), semi-natural hatchery


2016 ◽  
Vol 19 (2) ◽  
pp. 123
Author(s):  
Edi Wibowo Kushartono ◽  
CB. Ronaldi Chandra E ◽  
Retno Hartati

One of the conservation efforts undertaken to protect the green turtle (C. mydas L.) is by relocation of the nest where the eggs are removed from natural to semi-natural hatchery. The depth of proper needed to achieve the maximum level of hatching and emergence success.The purpose of this research that is to know the level of hatching catch and the emergence success of a nest at a different depth. The methods that used is an experimental research. Treatment that given is the different depth of nest with the green turtle as repetition. The depth of treatment is in 40 cm, 60 cm, and 80 cm, the amount of eggs is 30 eggs in each nest. Measurement and observation environmental conditions carried out during the incubation period. Observation the emergence of hatchlings started in day 50 of the incubation. Nest destruction was conducted on the 66th day incubation then eggs that failed to hatch were manually disected. The results showed that the levels of different depths does not effect the temperature inside the nest and hatching success, but the effect on the success rate of appearance. hatching success at all depths ranging between 93,33% - 94.44% (the same height), but increasingly in the depth of the nest success rate of appearance tends to decrease. Figures shown good appearance at a depth of 40 cm (86.67%), followed by 60 and 80 cm depth is 64.44% and 48.89% (sequential). The results of visual observations of the morphometry and performance lokomotori, hatchlings hatched at a depth of 60 and 80 cm better than hatchlings hatched at a depth of 40 cm both in the size and aggressiveness lokomotori swing flipper. Keyword: hatching success, green turtle (Chelonia mydas L.), semi-natural hatchery Salah satu usaha konservasi yang dilakukan untuk melindungi Penyu hijau (Chelonia mydas L.) yaitu dengan tindakan relokasi yang mana telur dipindahkan dari sarang alami ke tempat penetasan semi alami. Kedalaman yang tepat dibutuhkan untuk mendapatkan tingkat penetasan dan keberhasilan kemunculan yang maksimal. Tujuan penelitian ini yaitu untuk mengetahui tingkat keberhasilan penetasan dan keberhasilan kemunculan pada kedalaman sarang yang berbeda. Metode yang dipakai dalam penelitian adalah experimental research dengan 3 perlakuan yaitu penanaman telur penyu hijau pada kedalaman 40, 60 dan 80 cm, dengan kepadatan 30 butir telur setiap sarang. Pengukuran dan pengamatan kondisi lingkungan juga dilakukan selama masa inkubasi. Pengamatan munculnya tukik mulai dilakukan pada hari ke 50 masa inkubasi.  Pembongkaran sarang dilakukan pada hari ke 66 masa inkubasi kemudian dilakukan pembedahan secara manual untuk mengamati telur yang gagal menetas. Hasil yang didapat menunjukkan bahwa tingkat kedalaman yang berbeda tidak berpengaruh terhadap suhu dalam sarang dan keberhasilan penetasan, tetapi berpengaruh terhadap tingkat keberhasilan kemunculan. Angka keberhasilan penetasan pada semua kedalaman berkisar antara 93,33% - 94,44% (sama-sama tinggi), namun semakin dalam tingkat kedalaman sarang tingkat keberhasilan kemunculan cenderung mengalami penurunan. Angka kemunculan yang baik ditunjukkan pada kedalaman 40 cm (86,67%), diikuti kedalaman 60 dan 80 cm yaitu 64,44% dan 48,89% (secara berurut). Hasil pengamatan secara visual terhadap morfometri dan performa lokomotori, tukik yang ditetaskan pada kedalaman 60 dan 80 cm lebih baik dibandingkan tukik yang ditetaskan pada kedalaman 40 cm baik dari ukuran maupun lokomotori agresifitas ayunan  flipper.  Kata kunci: Keberhasilan penetasan, Penyu hijau, Semi alami 


2015 ◽  
Vol 2 (7) ◽  
pp. 150127 ◽  
Author(s):  
David A. Pike ◽  
Elizabeth A. Roznik ◽  
Ian Bell

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.


2019 ◽  
Vol 1 (02) ◽  
pp. 64-67
Author(s):  
Meilisha Putri Pertiwi ◽  
Suci Siti Lathifah

Research on the condition of the nesting habitat of Chelonia mydas (green turtle) in Pangumbahan Beach, Ujung Genteng, South Sukabumi has been carried out. Data retrieval is done 6 times for 2 days, 27-28 November 2017 at 3 observation stations. The abiotic parameters measured include surface temperature and depth of 50 cm, surface humidity and depth of 50 cm, beach width, beach slope, and the size of sand grains. While the biotic parameters measured were density, relative density, the frequency of attendance, and distribution patterns of Pandanus tectorius (sea pandanus) vegetation. Based on the results of data processing, the biophysical conditions in Pangumbahan Beach are still suitable for the Chelonia mydas nesting habitat. It also got clear evidence of the many Chelonia mydas landings during the data collection.


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