Natural temperature regimes for loggerhead and green turtle nests in the eastern Mediterranean

1998 ◽  
Vol 76 (4) ◽  
pp. 723-729 ◽  
Author(s):  
Y Kaska ◽  
R Downie ◽  
R Tippett ◽  
R W Furness
Keyword(s):  
Sex Ratio ◽  
Incubation Period ◽  
Green Turtle ◽  
Eastern Mediterranean ◽  
Loggerhead Turtle ◽  
Chelonia Mydas ◽  
Maximum Temperature ◽  
Diel Cycles ◽  
Mean Temperature ◽  
The Mean

Temperatures of green turtle (Chelonia mydas) and loggerhead turtle (Caretta caretta) nests on the beaches of northern Cyprus and Turkey were examined. Electronic continuous-temperature recorders programmed by computer were placed at the top, middle, and bottom of the nests. The sex of 3-7 hatchlings from each level was determined from gonadal histology. The maximum temperature increase during the incubation period was 9.6oC for both species. The mean temperature during the middle third of the incubation period is a good indicator of the sex ratio of the clutch. The percentage of female embryos increased with temperature, 50% being female at 29°C. The mean temperature over the entire incubation period is not a good indicator of sex ratio but can be used to predict the duration of incubation period. The temperature differences within the clutch were larger in loggerhead than in green turtle nests. Eggs at the top of the nest experienced generally warmer (up to 1.4°C) conditions than eggs at the bottom of the same nest, and this caused variation in sex ratio within nests. Over all nests, the sex ratio (percent female) of hatchlings was 91% at the top, 83% at the middle, and 69% at the bottom. There was considerable interbeach thermal variation. Marked diel cycles of up to 1.5°C were detected in loggerhead turtle nests but not in the deeper nests of green turtles.

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.

scholarly journals Hatchling sex ratio, body weight and nest parameters for Chelonia mydas nesting on Sugözü beaches (Turkey)

2014 ◽  
Vol 37 (2) ◽  
pp. 177-182
Author(s):  
Ç Kılıç ◽  
◽  
O. Candan ◽  
Keyword(s):  
Body Weight ◽  
Sex Ratio ◽  
Incubation Period ◽  
Green Turtle ◽  
Chelonia Mydas ◽  
Nest Temperature ◽  
Apparent Relationship ◽  
Embryo Sex ◽  
Female Bias ◽  
The Relationship

We investigated the relationship between nest parameters, hatchling body mass, and sex ratio of green turtle, Chelonia mydas, embryos and hatchlings at the temperate nesting rookery of Sugözü Beach (Adana–Turkey). Mean nest temperature and distance from the sea were correlated, while mean nest temperature and incubation period were inversely related. There was no apparent relationship between incubation period and hatchling mass. Hatchling and embryo sex ratios, determined by histological examination, showed a 70.5% and 93.5% female bias, respectively. There was no correlation between sex and body weight of hatchlings,

Nest temperatures and sex-ratio estimates of loggerhead turtles at Patara beach on the southwestern coast of Turkey

2004 ◽  
Vol 82 (1) ◽  
pp. 94-101 ◽  
Author(s):  
M Öz ◽  
A Erdoğan ◽  
Y Kaska ◽  
S Düşen ◽  
A Aslan ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Incubation Period ◽  
Sea Turtles ◽  
Chelonia Mydas ◽  
Sea Turtle ◽  
Beach Erosion ◽  
Electronic Temperature ◽  
Sand Temperature ◽  
Loggerhead Turtles ◽  
The Mean

During the nesting period in 2000 and 2001 on Patara beach, total emergence and non-nesting emergence of loggerhead turtles (Caretta caretta), nest distribution, and nest distance from the sea were recorded . The main nesting seasons for sea turtles (family Cheloniidae) were during June and July. Loggerhead turtles comprised the majority of sea turtle emergence records; only two green turtle (Chelonia mydas) emergences were recorded. The small nesting population (52 and 53 nests in 2000 and 2001, respectively) of sea turtles on Patara beach was due to low hatching success resulting from a rise in seawater levels, owing to beach erosion, and the subsequent inundation of most nests. The temperatures of four nests and sand at different distances from the sea were measured with electronic temperature loggers, which recorded mean nest temperatures of 28.8–30.7 °C, with the mean temperature in the middle third of the incubation period from 28.5 to 31.0 °C. The mean temperatures, incubation periods, temperature during the middle third of the incubation period, and percentage of hatchling sexes were evaluated with respect to sand and nest temperatures. The results showed a female-dominated sex ratio, which was probably the result of predation of nests far from the sea and the seawater inundation of nests close to the sea, as the sand temperature was different at sites close and far from the sea.

scholarly journals Dietary analysis of two sympatric marine turtle species in the eastern Mediterranean

2021 ◽  
Vol 168 (6) ◽  
Author(s):  
Josie L. Palmer ◽  
Damla Beton ◽  
Burak A. Çiçek ◽  
Sophie Davey ◽  
Emily M. Duncan ◽  
...  
Keyword(s):  
Green Turtle ◽  
Eastern Mediterranean ◽  
Chelonia Mydas ◽  
Marine Turtle ◽  
Dietary Analysis ◽  
Low Frequencies ◽  
Turtle Species ◽  
Dietary Shift ◽  
Green Turtles ◽  
Loggerhead Turtles

AbstractDietary studies provide key insights into threats and changes within ecosystems and subsequent impacts on focal species. Diet is particularly challenging to study within marine environments and therefore is often poorly understood. Here, we examined the diet of stranded and bycaught loggerhead (Caretta caretta) and green turtles (Chelonia mydas) in North Cyprus (35.33° N, 33.47° E) between 2011 and 2019. A total of 129 taxa were recorded in the diet of loggerhead turtles (n = 45), which were predominantly carnivorous (on average 72.1% of dietary biomass), foraging on a large variety of invertebrates, macroalgae, seagrasses and bony fish in low frequencies. Despite this opportunistic foraging strategy, one species was particularly dominant, the sponge Chondrosia reniformis (21.5%). Consumption of this sponge decreased with increasing turtle size. A greater degree of herbivory was found in green turtles (n = 40) which predominantly consumed seagrasses and macroalgae (88.8%) with a total of 101 taxa recorded. The most dominant species was a Lessepsian invasive seagrass, Halophila stipulacea (31.1%). This is the highest percentage recorded for this species in green turtle diet in the Mediterranean thus far. With increasing turtle size, the percentage of seagrass consumed increased with a concomitant decrease in macroalgae. Seagrass was consumed year-round. Omnivory occurred in all green turtle size classes but reduced in larger turtles (> 75 cm CCL) suggesting a slow ontogenetic dietary shift. Macroplastic ingestion was more common in green (31.6% of individuals) than loggerhead turtles (5.7%). This study provides the most complete dietary list for marine turtles in the eastern Mediterranean.

THE TEMPERATURES OF SURFACE FIRES IN JACK PINE BARREN: I. THE VARIATION IN TEMPERATURE WITH TIME

1966 ◽  
Vol 44 (10) ◽  
pp. 1285-1292 ◽  
Author(s):  
David W. Smith ◽  
John H. Sparling
Keyword(s):  
Jack Pine ◽  
Maximum Temperature ◽  
Surface Fires ◽  
Mean Temperature ◽  
The Mean ◽  
Maximum Temperatures

The temperatures of 18 fires in an open jack pine barren near Timmins, Ontario, have been recorded. The maximum temperature recorded was 545 °C, although in other determinations fire temperatures in excess of 1000 °C were reached. The mean temperature of all fires was 340.6 ± 133.2 °C. Three fires at 230, 345, and 545 °C were considered in detail.The maximum temperature of a fire was normally recorded at heights of 5 cm or 10 cm above the surface. Maximum temperatures of hotter fires usually occurred at greater heights than cooler ones. Duration and the temperature ("intensity") of the fire are important aspects of fire studies.

A study about the linearity of trends between extreme and mean temperatures in Argentina

2021 ◽  
Author(s):  
Solange Suli ◽  
Matilde Rusticucci ◽  
Soledad Collazo
Keyword(s):  
Linear Regression ◽  
Linear Relationship ◽  
Statistical Significance ◽  
Coefficient Of Determination ◽  
Maximum Temperature ◽  
Mean Temperature ◽  
Change In The Mean ◽  
The Mean ◽  
Student’S T ◽  
Cold Extremes

<p>Small variations in the mean state of the atmosphere can cause large changes in the frequency of extreme events. In order to deepen and extend previous results in time, in this work we analyzed the linear relationship between extreme and mean temperature (Τ) on a climate change scale in Argentina. Two monthly extreme indices, cold nights (TN10) and warm days (TX90), were calculated based on the quality-controlled daily minimum and maximum temperature data provided by the Argentine National Meteorological Service from 58 conventional weather stations located over Argentina in the 1977–2017 period. Subsequently, we evaluated the relationship between the linear trends of extremes and mean temperature on a seasonal basis (JFM, AMJ, JAS, and OND). Student's T-test was performed to analyze their statistical significance at 5%. Firstly, positive (negative) and significant linear regressions were found between TX90 (TN10) trends and mean temperature trends for the four studied seasons. Therefore, an increase in the Τ-trend maintains a linear relationship with significant increase (decrease) of warm days (cold nights). Moreover, we found that JFM was the one with the highest coefficient of determination (0.602 for hot extremes and 0.511 for cold extremes), implying that 60.2% (51.1%) of the TX90 (TN10) trend could be explained as a function of the Τ-trend by a linear regression. In addition, in the JFM (OND) quarter, the TX90 index increased by 7.02 (6.02) % of days each with a 1 ºC increase in the mean temperature. Likewise, the TN10 index decreased by 4.94 (and 4.99) % of days from a 1ºC increase in the mean temperature for the JFM (AMJ) quarter. Finally, it is worthwhile to highlight the uneven behavior between hot and cold extremes and the mean temperature. Specifically, it was observed that the slopes of the linear regression calculated for the TX90 index and Τ presented a higher absolute value than those registered for the TN10 index and Τ. Therefore, a change in the mean temperature affects hot extremes to a greater extent than cold ones in Argentina.</p>

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