Incubation temperature, energy expenditure and hatchling size in the green turtle (Chelonia mydas), a species with temperature-sensitive sex determination

2001 ◽  
Vol 49 (4) ◽  
pp. 389 ◽  
Author(s):  
David T. Booth ◽  
Katherine Astill
Keyword(s):  
Oxygen Consumption ◽  
Production Cost ◽  
Incubation Temperature ◽  
Chelonia Mydas ◽  
Temperature Sensitive ◽  
Barrier Reef ◽  
Body Dimensions ◽  
Green Turtles ◽  
The Difference ◽  
Hatchling Size

Eggs from the Heron Island, Great Barrier Reef, nesting population of green turtles (Chelonia mydas) were incubated at all-male-determining (26˚C) and all-female-determining (30˚C) temperatures. Oxygen consumption and embryonic growth were monitored throughout incubation, and hatchling masses and body dimensions were measured from both temperatures. Eggs hatched after 79 and 53 days incubation at 26˚C and 30˚C respectively. Oxygen consumption at both temperatures increased to a peak several days before hatching, a pattern typical of turtle embryos, and the rate of oxygen was higher at 30˚C than 26˚C. The total amount of energy consumed during incubation, and hatchling dimensions, were similar at both temperatures, but hatchlings from 26˚C had larger mass, larger yolk-free mass and smaller residual yolks than hatchlings from 30˚C. Because of the difference in mass of hatchlings, hatchlings from 30˚C had a higher production cost.

scholarly journals Contributions of source population and incubation temperature to phenotypic variation of hatchling Chinese skinks

2020 ◽  
Author(s):  
Hong-Liang Lu ◽  
Yan-Fu Qu ◽  
Hong Li ◽  
Xiang Ji
Keyword(s):  
Body Mass ◽  
Phenotypic Variation ◽  
Incubation Temperature ◽  
Tail Length ◽  
Population Variation ◽  
Phenotypic Traits ◽  
Source Population ◽  
Relative Importance ◽  
The Difference ◽  
Hatchling Size

Abstract Phenotypic plasticity and local adaptation are viewed as the main factors that result in between-population variation in phenotypic traits, but contributions of these factors to phenotypic variation vary between traits and between species and have only been explored in a few species of reptiles. Here, we incubated eggs of the Chinese skink (Plestiodon chinensis) from 7 geographically separated populations in Southeast China at 3 constant temperatures (24, 28, and 32 °C) to evaluate the combined effects of clutch origin, source population, and incubation temperature on hatchling traits. The relative importance of these factors varied between traits. Nearly all examined hatchling traits, including body mass, snout–vent length (SVL), tail length, head size, limb length, tympanum diameter, and locomotor speed, varied among populations and were affected by incubation temperature. Measures for hatchling size (body mass and SVL) varied considerably among clutches. Source population explained much of the variation in hatchling body mass, whereas incubation temperature explained much of the variation in other examined traits. Our results indicate that between-population variation in hatchling traits of P. chinensis likely reflects the difference in natural incubation conditions and genetic divergence.

Hibernation, temperature and rates of oxidative phosphorylation by heart mitochondria

1960 ◽  
Vol 198 (2) ◽  
pp. 463-466 ◽  
Author(s):  
Frank E. South
Keyword(s):  
Oxygen Consumption ◽  
Oxidative Phosphorylation ◽  
Incubation Temperature ◽  
Regression Line ◽  
Vertical Displacement ◽  
Heart Mitochondria ◽  
Oxidative Enzymes ◽  
Effect Of Temperature ◽  
The Difference

The effect of temperature on rates of oxidative phosphorylation (pyruvate substrate) by heart mitochondria obtained from hibernating hamsters, control hamsters and rats was studied. Apparent energies of activation ( Ea) determined between 5° and 24°C were, respectively, 20.4, 20.8 and 28.3 Kcal. for the rates of oxygen consumption and 20.6, 21.4 and 29.5 Kcal. for the rates of phosphorylation. The difference between the rats and either group of hamsters were significant statistically. The slope of the regression line fitted to the data obtained from hibernating animals did not differ significantly from that of the control hamsters. However, a parallel vertical displacement of the lines indicated a probable increase in these oxidative enzymes upon preparation for, or during, hibernation. No significant alterations in the efficiency of oxidative phosphorylation with variations in the incubation temperature were noted in any of the preparations.

The green turtle, Chelonia mydas, in Queensland: breeding males in the southern Great Barrier Reef

1993 ◽  
Vol 20 (4) ◽  
pp. 513 ◽  
Author(s):  
CJ Limpus
Keyword(s):  
Great Barrier Reef ◽  
Green Turtle ◽  
Carapace Length ◽  
Chelonia Mydas ◽  
Barrier Reef ◽  
Adult Males ◽  
Green Turtles ◽  
Adult Females ◽  
Breeding Seasons ◽  
Slow Growing

Breeding male green turtles, Chelonia mydas, at any one courtship area in the southern Great Barrier Reef mate with females that will nest on rookeries spread throughout the region. In comparison with the breeding females from the same breeding unit, the males are smaller in curved carapace length, and a higher proportion of males remigrate for additional breeding seasons at 1-2-year intervals. Like the adult females, adult males are slow-growing, averaging 0.046 cm year-1. Each male appears to display a fidelity to a particular courtship area, to which it returns in successive breeding migrations. At the conclusion of the courtship period, the males disperse to widely scattered feeding areas.

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

2021 ◽  
Vol 4 (4) ◽  
pp. 321-330
Author(s):  
Randy Calderón Peña ◽  
Julia Azanza Ricardo
Keyword(s):  
Congenital Anomalies ◽  
Green Turtle ◽  
Thermal Tolerance ◽  
Elevated Temperatures ◽  
Hatching Success ◽  
Incubation Temperature ◽  
Chelonia Mydas ◽  
Sea Turtle ◽  
Green Turtles ◽  
Incubation Temperatures

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).

scholarly journals Closing the gap: mixed stock analysis of three foraging populations of green turtles (Chelonia mydas) on the Great Barrier Reef

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5651
Author(s):  
Karina Jones ◽  
Michael Jensen ◽  
Graham Burgess ◽  
Johanna Leonhardt ◽  
Lynne van Herwerden ◽  
...  
Keyword(s):  
Great Barrier Reef ◽  
Spatial Ecology ◽  
New Caledonia ◽  
Relative Proportion ◽  
Chelonia Mydas ◽  
Barrier Reef ◽  
Green Turtles ◽  
Mixed Stock Analysis ◽  
Stock Analysis ◽  
Mixed Stock

A solid understanding of the spatial ecology of green turtles (Chelonia mydas) is fundamental to their effective conservation. Yet this species, like many marine migratory species, is challenging to monitor and manage because they utilise a variety of habitats that span wide spatio-temporal scales. To further elucidate the connectivity between green turtle rookeries and foraging populations, we sequenced the mtDNA control region of 278 turtles across three foraging sites from the northern Great Barrier Reef (GBR) spanning more than 330 km: Cockle Bay, Green Island and Low Isles. This was performed with a newly developed assay, which targets a longer fragment of mtDNA than previous studies. We used a mixed stock analysis (MSA), which utilises genetic data to estimate the relative proportion of genetically distinct breeding populations found at a given foraging ground. Haplotype and nucleotide diversity was also assessed. A total of 35 haplotypes were identified across all sites, 13 of which had not been found previously in any rookery. The MSA showed that the northern GBR (nGBR), Coral Sea (CS), southern GBR (sGBR) and New Caledonia (NC) stocks supplied the bulk of the turtles at all three sites, with small contributions from other rookeries in the region. Stock contribution shifted gradually from north to south, although sGBR/CS stock dominated at all three sites. The major change in composition occured between Cockle Bay and Low Isles. Our findings, together with other recent studies in this field, show that stock composition shifts with latitude as a natural progression along a coastal gradient. This phenomenon is likely to be the result of ocean currents influencing both post-hatchling dispersal and subsequent juvenile recruitment to diverse coastal foraging sites.

scholarly journals Surfacers change their dive tactics depending on the aim of the dive: evidence from simultaneous measurements of breaths and energy expenditure

2014 ◽  
Vol 281 (1795) ◽  
pp. 20140040 ◽  
Author(s):  
Junichi Okuyama ◽  
Runa Tabata ◽  
Kana Nakajima ◽  
Nobuaki Arai ◽  
Masato Kobayashi ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Energy Expenditure ◽  
Direct Observation ◽  
Time Allocation ◽  
Chelonia Mydas ◽  
Air Breathing ◽  
Green Turtles ◽  
Simultaneous Measurements ◽  
In The Wild ◽  
Overall Dynamic Body Acceleration

Air-breathing divers are assumed to have evolved to apportion their time between surface and underwater periods to maximize the benefit gained from diving activities. However, whether they change their time allocation depending on the aim of the dive is still unknown. This may be particularly crucial for ‘surfacers’ because they dive for various purposes in addition to foraging. In this study, we counted breath events at the surface and estimated oxygen consumption during resting, foraging and other dives in 11 green turtles ( Chelonia mydas ) in the wild. Breath events were counted by a head-mounted acceleration logger or direct observation based on an animal-borne video logger, and oxygen consumption was estimated by measuring overall dynamic body acceleration. Our results indicate that green turtles maximized their submerged time, following this with five to seven breaths to replenish oxygen for resting dives. However, they changed their dive tactic during foraging and other dives; they surfaced without depleting their estimated stores of oxygen, followed by only a few breaths for effective foraging and locomotion. These dichotomous surfacing tactics would be the result of behavioural modifications by turtles depending on the aim of each dive.

scholarly journals Polyandry pays off: The effects of multiple mating and number of fathers on morphological traits and survival in clutches of nesting green turtles at Tortuguero

2014 ◽  
Author(s):  
Alonzo Alfaro-Núñez ◽  
Michael P. Jensen ◽  
F. Alberto Abreu-Grobois
Keyword(s):  
Morphological Traits ◽  
Incubation Temperature ◽  
Multiple Mating ◽  
Chelonia Mydas ◽  
Environmental Variable ◽  
Green Turtles ◽  
Exact Number ◽  
Paternal Contribution ◽  
Emergence Success ◽  
Significant Difference

Despite the long debate of whether or not multiple mating benefits the offspring, studies still show contradicting results. Multiple mating takes time and energy. Thus, if females fertilize their eggs with a single mating, why to mate more than once? We investigated and inferred paternal identity and number of sires in 12 clutches (240 hatchlings) of green turtles (Chelonia mydas) nests at Tortuguero, Costa Rica. Paternal alleles were inferred through comparison of maternal and hatchling genotypes, and indicated multiple paternity in at least 11 of the clutches (92%). The inferred average number of fathers was three (ranging from 1 to 5). This in returns suggests that most females successfully got fecundated by at least three males. Moreover, regression analyses were used to investigate for correlation of inferred clutch paternity with morphological traits of hatchlings fitness (emergence success, length, weight and crawling speed); and size of the mother; and an environmental variable (incubation temperature). We suggest and propose two different comparative approaches for evaluating morphological traits and clutch paternity, in order to infer greater offspring survival. First, clutches coded by the exact number of fathers and second by the exact paternal contribution (fathers who gives greater proportion of the offspring per nest). We found significant differences (P < 0.05) in clutches coded by the exact number of fathers for all morphological traits, where a tendency of higher values in offspring sired by two to three fathers was found. The second approach analysing the paternal contribution showed no significant difference (P > 0.05) for any of the traits. The main conclusion is that multiple mating analysed by the exact number of inferred fathers significantly affects the survival of the offspring regardless of morphological trait measured.

Low male production at the world’s largest green turtle rookery

2020 ◽  
Vol 653 ◽  
pp. 181-190
Author(s):  
DT Booth ◽  
A Dunstan ◽  
I Bell ◽  
R Reina ◽  
J Tedeschi
Keyword(s):  
Green Turtle ◽  
Hatching Success ◽  
Incubation Temperature ◽  
Chelonia Mydas ◽  
Sea Turtle ◽  
Green Turtles ◽  
Nesting Site ◽  
Almost All ◽  
Monthly Variations ◽  
Nesting Season

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.

Migration of green (Chelonia mydas) and loggerhead (caretta caretta) turtles to and from eastern Australian rookeries

1992 ◽  
Vol 19 (3) ◽  
pp. 347 ◽  
Author(s):  
CJ Limpus ◽  
JD Miller ◽  
CJ Paramenter ◽  
D Reimer ◽  
N McLachlan ◽  
...  
Keyword(s):  
Great Barrier Reef ◽  
Indigenous People ◽  
Chelonia Mydas ◽  
Caretta Caretta ◽  
Commercial Fishing ◽  
High Fidelity ◽  
Barrier Reef ◽  
Migratory Behaviour ◽  
Green Turtles ◽  
Feeding Ground

Feeding-ground captures of green (Chelonia mydas) and loggerhead (Caretta caretta) turtles tagged while nesting at eastern Australian rookeries over a 21-year period are summarised. These turtles which nest in the Great Barrier Reef region range widely throughout the Arafura and Coral seas. The tag recoveries include many from turtles that live in neighbouring countries and migrate to breed in Australia. The breeding female shows a high fidelity to her home feeding ground as well as to her nesting beach. Most recaptures of the green turtles occurred during hunting for food by indigenous people while most recaptures of loggerhead turtles were incidental captures in commercial fishing activities. Migratory behaviour, imprinting and navigation are discussed.

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