Temperature variation within and between nests of the green sea turtle, Chelonia mydas (Chelonia: Cheloniidae) on Heron Island, Great Barrier Reef

2001 ◽  
Vol 49 (1) ◽  
pp. 71 ◽  
Author(s):  
David T. Booth ◽  
Katherine Astill
Keyword(s):  
Sex Ratio ◽  
Chelonia Mydas ◽  
Sea Turtle ◽  
Diurnal Fluctuation ◽  
Nest Temperature ◽  
Green Sea Turtle ◽  
Data Loggers ◽  
Opposite Sex ◽  
Biased Sex Ratio ◽  
Nesting Season

Four temperature data-loggers were placed in each of five green sea turtle nests on Heron Island in the 1998–99 nesting season. Temperatures in all nests increased as incubation progressed due to general sand heating and increased metabolic heat production of the developing embryos. Even at the top of nests no daily diurnal fluctuation in temperature was evident. The temperature of eggs in the middle of the nest increased above those in the nest periphery during the last third of incubation. However, this metabolic nest heating would have little effect on hatchling sex ratio because it occurred after the sex-determining period. Small differences in temperature between regions of a nest persisted throughout incubation and may be important in ensuring the production of at least some individuals of the opposite sex in nests that have temperatures close to either the all-male or all-female determining temperatures. Location and degree of shading of nests had little effect on mean nest temperature, but deeper nests were generally cooler and therefore were predicted to produce a higher proportion of males than were shallower nests. Nest temperature profile data indicated that the 1998–99 nesting season on Heron Island would have produced a strongly female-biased sex ratio amongst hatchlings.

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

2020 ◽  
Vol 68 (3) ◽  
Author(s):  
Randy Calderón-Peña ◽  
Ryan Betancourt-Avila ◽  
Elizabeth Rodríguez-Fajardo ◽  
Yoel Martínez-González ◽  
Julia Azanza Ricardo
Keyword(s):  
Sex Ratio ◽  
Incubation Period ◽  
Chelonia Mydas ◽  
Sea Turtle ◽  
Nest Temperature ◽  
Data Loggers ◽  
Incubation Periods ◽  
The Mean ◽  
Study Sites ◽  
Incubation Temperatures

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.

Sex ratios of two species of sea turtle nesting in Suriname

1984 ◽  
Vol 62 (11) ◽  
pp. 2227-2239 ◽  
Author(s):  
N. Mrosovsky ◽  
P. H. Dutton ◽  
C. P. Whitmore
Keyword(s):  
Sex Ratio ◽  
Parental Investment ◽  
Sexual Differentiation ◽  
Seasonal Changes ◽  
Chelonia Mydas ◽  
Sea Turtle ◽  
Dermochelys Coriacea ◽  
Green Turtles ◽  
Nesting Season

The green turtle (Chelonia mydas) and the leatherback (Dermochelys coriacea) nest on the same beach in Suriname. For both species there are seasonal changes in the sex ratio of the hatchlings, with more males being produced during the wetter cooler months of the nesting season and more females during the drier warmer months. This shows that temperature determination of sexual differentiation has considerable demographic consequences in natural circumstances. Leatherbacks require slightly higher (ca. 0.5 °C) temperatures for female differentiation than green turtles and leatherbacks nest in relatively greater numbers during the warmer parts of the season. Estimates of overall sex ratio for hatchling green turtles (53.9% female) and for leatherbacks (49.0% female) were obtained by multiplying sex ratio and nesting frequency for different portions of the season. These estimates are tentative because there were differences between different years both in sand temperatures on the beach and in nesting distribution. Also discussed are the problems in assessing parental investment in the two sexes when the direction of sexual differentiation is determined after parental investment ends.

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

2020 ◽  
Vol 27 (5) ◽  
pp. 245-256
Author(s):  
Cemil Aymak ◽  
Aşkın Hasan Uçar ◽  
Yusuf Katılmış ◽  
Eyup Başkale ◽  
Serap Ergene
Keyword(s):  
Green Turtle ◽  
Hatching Success ◽  
Negative Relationship ◽  
Chelonia Mydas ◽  
Sea Turtle ◽  
Faunal Composition ◽  
Independent Variables ◽  
Invertebrate Species ◽  
First Time ◽  
Nesting Season

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.

Immunological studies with the gonadotropins and their subunits from the green sea turtle Chelonia mydas

1977 ◽  
Vol 33 (2) ◽  
pp. 231-241 ◽  
Author(s):  
Paul Licht ◽  
Duncan S. MacKenzie ◽  
Harold Papkoff ◽  
Susan Farmer
Keyword(s):  
Chelonia Mydas ◽  
Sea Turtle ◽  
Green Sea Turtle

scholarly journals ASPEK MORFOLOGI, REPRODUKSI, DAN PERILAKU PENYU HIJAU (Chelonia mydas) Di PANTAI PANGUMBAHAN, KABUPATEN SUKABUMI, JAWA BARAT

2017 ◽  
Vol 3 (2) ◽  
pp. 93
Author(s):  
Adriani Sri Nastiti Krismono ◽  
Achmad Fitriyanto ◽  
Ngurah Nyoman Wiadnyana
Keyword(s):  
Green Turtle ◽  
Carapace Width ◽  
Chelonia Mydas ◽  
Sea Turtle ◽  
Stratified Sampling ◽  
Hatching Rate ◽  
Brood Stock ◽  
Green Turtles ◽  
And Behavior ◽  
Nesting Season

Penyu hijau (Chelonia mydas) termasuk dalam phylum Chordata dan famili Cheloniideae. Jumlah penyu hijau yang singgah ke Pantai Pangumbahan untuk bertelur semakin menurun karena tidak terkendalinya masyarakat melakukan penangkapan induk penyu dan pengambilan telurnya. Penelitian tentang morfologi, reproduksi, dan perilaku penyu hijau sebagai salah satu dasar pengelolaan telah dilakukan di Pantai Pangumbahan pada bulan Agustus 2008. Metode penelitian yang digunakan pengambilan contoh berstrata. Penelitian ini dilaksanakan pada bulan Agustus 2008 (pada saat puncak peneluran). Parameter yang diamati antara lain ukuran penyu dari 89 ekor jumlah penyu bersarang, jumlah telur dan tingkat penetasan, serta perilaku pada saat penyu bertelur. Hasil penelitian menunjukan yang diamati diperoleh panjang karapas berkisar antara 97-15 cm dan lebar karapas 83,5-108 cm, jumlah penyu naik ke pantai 89 ekor dan penyu yang bertelur 39 ekor. Jumlah telur penyu hijau berhasil dihitung 80-105 butir per induk penyu. Bulan Agustus 2008 merupakan puncak musim peneluran. Kegiatan peneluran penyu hijau dibagi menjadi enam tahap. Upaya konservasi yang sudah dilakukan adalah penetasan telur penyu semi alami, restocking tukik, dan menjaga keamanan sarang telur penyu. Green turtles (Chelonia mydas), including the phylum Chordata and families Cheloniideae. The number of green turtles come to lay eggs Pangumbahan beach to decline because of increasingly unmanageable public do making arrests turtles brood stock and their eggs. Research on the morphology, reproduction, and behavior of green turtles as one of the basic management has been conducted on the Pangumbahan Beach in August 2008. The method used stratified sampling. The experiment was conducted in August 2008 (at the peak of nesting). Other parameters were observed between the size of the 89 tail number of turtles nesting turtles, the number of eggs and hatching rate and behavior during turtle nesting. Results obtained showed that the observed length ranges from 97- 15 cm carapace and carapace width from 83.5-108 cm, the number went up to the beach 89 sea turtle and sea turtle nesting tail as much as 39 tails. The number of green turtle eggs had counted as many as 80-105 eggs per turtles brood stock. Month August 2008 is the peak nesting season of green turtle nesting activities are divided into six stages. Conservation efforts that have been done is semi natural turtle hatchery, restocking hatchlings, and nest of turtle eggs to maintain security.

Identification of Papilloma-Like Virus Particles in Cell Lines Derived from Green Sea Turtle (Chelonia Mydas) With Fibropapilloma

1998 ◽  
Vol 4 (S2) ◽  
pp. 1158-1159
Author(s):  
Yuanan Lu ◽  
Vivek R. Nerurkar ◽  
Tina M. Weatherby ◽  
Richard Yanagihara
Keyword(s):  
Cell Lines ◽  
Soft Tissues ◽  
Chelonia Mydas ◽  
Sea Turtle ◽  
Green Sea Turtle ◽  
Virus Particles ◽  
Green Sea Turtles ◽  
Multiple Organs ◽  
Isolation And Characterization

The near epidemic occurrence of fibropapilloma in green sea turtle (Chelonia my das) (Figure 1) significantly threatens the survival of this species which is protected under the U.S. Endangered Species Act. Although collective evidence suggests a viral etiology, the causative virus of green sea turtle fibropapilloma has not been isolated. To facilitate the isolation and characterization of the causative virus(es), we established 13 cell lines from multiple organs/tissues (tumor, kidney, lung, heart, gall bladder, testis, and skin) of green sea turtles with fibropapilloma. Serial subcultivation of cell lines derived from lungs, testis, eye soft tissues and tumors resulted in the formation of tumor-like aggregates, which attained sizes of 1-2 mm in diameter within two weeks (Figure 2). Media from such cultures, when inoculated onto cells derived from healthy turtle embryos, produced similar tumor-like aggregates, suggesting the presence of a transmissible agent.

The Green sea turtle (Chelonia mydas): mating, nesting and hatching on a farm

2009 ◽  
Vol 177 (3) ◽  
pp. 411-423 ◽  
Author(s):  
Marlin H. Simon ◽  
Glenn F. Ulrich ◽  
Alan S. Parkes
Keyword(s):  
Chelonia Mydas ◽  
Sea Turtle ◽  
Green Sea Turtle
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