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1.
The collection of eggs from wild rookeries for incubation and hatching on the Mariculture Ltd farm on Grand Cayman Island, BWI, was described in the previous paper. It was realized, however, that this method of stocking the farm must sooner or later be superseded by the production of farm-laid eggs, and at an early stage a start was made on the task of establishing a breeding colony. The necessary collection of adult turtles and progress in breeding to the end of 1973 is described in the present paper.  相似文献   

2.
Glenn F.  Ulrich  Alan S.  Parkes 《Journal of Zoology》1978,185(2):237-251
Mating, nesting and hatching of the Green sea turtle on Mariculture Ltd's farm on Grand Cayman Island, BWI in 1973 were recorded in a previous paper. The results described were the first of their kind, so that events in the farm breeding colony in the following year were awaited with much interest, especially as to hatchability of the eggs. The observations made in 1974, which extended and mainly confirmed those made in 1973, are described below.  相似文献   

3.
Marlin H.  Simon  Alan S.  Parkes 《Journal of Zoology》1976,179(2):153-163
The collection of eggs of Chelonia mydas from beaches on Ascension Island and elsewhere for hatching at the Mariculture Ltd farm on Grand Cayman was described in a previous paper (Simon, 1975). Improved organization of these collections has made it possible to record many incidental observations which throw light on the nesting behaviour and performance of the female Chelonia , and Ascension Island, because of its small size, numerous beaches and good communications, proved to be particularly favourable for such research. The present paper records observations made in February and March 1973 and 1974. The second author has contributed only by the analysis of the data and the preparation of the paper.  相似文献   

4.
The amino acid sequence of the main component myoglobin from skeletal muscle of Pacific green sea turtle (Chelonia mydas caranigra) has been determined. The globin is 153 residues in length and has a free amino-terminus. The heme-binding and internal residues are as found in mammalian myoglobins. Ten substitutions are observed between this myoglobin and that from map turtle. About 38, 52, 47 and 86 substitutions are noted in comparison with the myoglobins of other reptiles, mammals, birds and fish, respectively. The inferred pattern of structural stabilization and conservation of two loci are typical of tetrapod myoglobin.  相似文献   

5.
Distribution patterns of epibiotic barnacles on green sea turtles were investigated in waters neighboring Okinawa, Japan. A number of barnacle species were found to coexist on the turtles and were classified into three genera: Chelonibia, Platylepas and Stomatolepas. Attachment sites on the turtles varied among the barnacle species, suggesting that there is niche partitioning with respect to their microhabitat selection. Turtle bodies offer a “patchy” environment for barnacles, so we also analyzed coexistence patterns in the context of an aggregation model. Within each genus, individual barnacles showed a clumped distribution. The different genera do not have mutually exclusive distribution patterns, but instead occur on the same turtle to various degrees. However, when turtles were divided into two size classes, both the level of aggregation and the degree of interspecific overlap among the barnacles was significantly lower on large turtles. We suggest that obtaining basic information on turtle epibionts will shed light on the biology of wild turtles, which is still largely unknown.  相似文献   

6.
Ecologists have long theorized that apex predators stabilize trophic systems by exerting a net protective effect on the basal resource of a food web. Although experimental and observational studies have borne this out, it is not always clear what behavioural mechanisms among the trophically connected species are responsible for this stability. Fear of intraguild predation is commonly identified as one such mechanism in models and mesocosm studies, but empirical evidence in natural systems remains limited, as the complexity of many trophic systems renders detailed behavioural studies of species interactions challenging. Here, we combine long-term field observations of a trophic system in nature with experimental behavioural studies of how all the species in this system interact, in both pairs and groups. The results demonstrate how an abundant, sessile and palatable prey item (sea turtle eggs, Chelonia mydas) survives when faced by three potential predators that all readily eat eggs: an apex predator (the stink ratsnake, Elaphe carinata) and two mesopredators (the brown rat, Rattus norvegicus, and kukri snake, Oligodon formosanus). Our results detail how fear of intraguild predation, conspecific cannibalism, habitat structure and territorial behaviour among these species interact in a complex fashion that results in high egg survival.  相似文献   

7.
Lung volumes, oxygen uptake (VO2), end-tidal PO2, and PCO2, diffusing capacity of the lungs for CO (DLCO), pulmonary blood flow (QL) and respiratory frequency were measured in the green sea turtle (Chelonia mydas) (49-127 kg body wt). Mean lung volume (VL) determined from helium dilution was 57 ml/kg and physiological dead space volume (VD) was about 3.6 ml/kg. QL, determined from acetylene uptake during rebreathing, increased in proportion to VO2 with temperature. Therefore, constant O2 content difference was maintained between pulmonary arterial and venous blood. DLCO, measured using a rebreathing technique, was 0.04 ml X kg-1 X min-1 X Torr-1 at 25 degrees C. Several cardiopulmonary characteristics in C. mydas are advantageous to diving: large tidal volume relative to functional residual capacity promotes fast exchange of the alveolar gas when the turtle surfaces for breathing: and the concomitant rise of pulmonary blood flow and O2 uptake with temperature assures efficient O2 transport regardless of wide temperature variations encountered during migrations.  相似文献   

8.
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10.
A novel sea turtle egg incubator was developed in which the heating element is placed above the clutch, which more closely simulates solar heating in nature. An electronic thermometer in conjunction with a thermostat located in sand beneath a heater plate was used to obtain the desired temperature in the placed eggs, as compared to previous methods of controlling global temperature within the interior of a chamber. To test the new incubator, Lepidochelys olivacea eggs were incubated under different thermal conditions in order to identify the temperature-dependent sex determination (TSD) period more precisely. Four incubation experiments were designed to test the performance of the incubator where the temperature was lowered from 32 to 28 °C during 60 h and then reestablished at 32 °C until hatching occurred. A significant mean hatching success rate of 89.6% was obtained for all the experiments. The main result from these preliminary findings was that the sex determination period to produce males was reduced from 15 (days 15–30) to eight days (days 19–27). Overall, the incubator provides precise control and simulates a natural thermal environment that may improve control of TSD in sea turtles.  相似文献   

11.
Pulmonary surfactant, consisting predominantly of phosphatidylcholine (PC), is secreted from Type II cells into the lungs of all air-breathing vertebrates, where it functions to reduce surface tension. In mammals, glucocorticoids and thyroid hormones contribute to the maturation of the surfactant system. It is possible that phylogeny, lung structure, and the environment may influence the development of the surfactant system. Here, we investigate the ontogeny of PC secretion from cocultured Type II cells and fibroblasts in the sea turtle, Chelonia mydas, following 58, 62, and 73 d of incubation and after hatching. The influence of glucocorticoids and thyroid hormones on PC secretion was also examined. Basal PC secretion was lowest at day 58 (3%) and reached a maximal secretion rate of 10% posthatch. Dexamethasone (Dex) alone stimulated PC secretion only at day 58. Triiodothyronine (T(3)) stimulated PC secretion in cells isolated from days 58 and 73 embryos and from hatchling turtles. A combination of Dex and T(3) stimulated PC secretion at all time points.  相似文献   

12.
Summary The duct system of the lachrymal salt gland of the green sea turtle comprises central canals, secondary ducts and a sac-like main duct. Distally the central canals consist of large columnar cells with lateral membranes folded into plicae which interdigitate in adjacent cells to form complex intercellular spaces. More proximally the central canals, secondary ducts and main duct consist of epithelia which are stratified or pseudostratified. The cells of these epithelia are separated by wide and complex inter-cellular spaces: they are joined by frequent maculae adherentes junctions. Complex intracellular webs of tonofilaments are associated with these junctions. At the luminal border of the epithelia of the secondary and main ducts is a layer of mucocytes. The mucocytes increase in density towards the proximal extremity of the main duct and secrete a thick luminal layer of mucus. The duct system is very well vascularised. It is suggested that it is unlikely to be merely a passive conduit and that it may have a role in the modification of the fluid secreted by the gland.  相似文献   

13.
Summary A continuous line of epithelioid cells was established from explant skin tissues of the green sea turtle,Chelonia mydas. These cells, designated GTS, have been subcultured more than 60 times in commercially available mammalian cell culture medium supplemented with 5% bovine calf serum. Of those temperatures tested, optimal growth was achieved at 30°C although replication occurred between 16 and 37°C. These cells may be held as monolayers at 8°C or stored frozen in growth medium containing 10% dimethylsulfoxide at −70 or −196°C. The modal number of 55 chromosomes per cell is in agreement with the heterogametic female diploid number of this species. The GTS line represents the first established culture of normal epithelioid skin cells to be reported for a poikilothermic species.  相似文献   

14.
 We studied the control of salt gland secretion in hatchling Chelonia mydas. The threshold salt load to activate salt secretion was between 400 μmol NaCl 100 g bodymass (BM)−1 and 600 μmol NaCl 100 g BM−1, which caused an increase in plasma sodium concentration of 13% to 19%. Following a salt load of 2700 μmol NaCl 100 g BM−1, salt gland secretion commenced in 12 ± 1.3 min and reached maximal secretory concentration within 2–7 min. Maximal secretory rate of a single gland averaged 415 μmol Na 100 g BM−1 h−1. Plasma sodium concentration and total osmotic concentration after salt loading were significantly higher than pretreatment values within 2 min. Adrenalin (25 μg kg BM−1) and the cholinergic agonist methacholine (1 mg kg BM−1) inhibited salt gland activity. Atropine (10 mg kg BM−1) reversed methacholine inhibition and stimulated salt gland secretion when administered with a subthreshold salt load. Arginine vasotocin produced a transient reduction in sodium secretion by the active gland, while atrial natriuretic factor, vasoactive intestinal peptide and neuropeptide Y had no measurable effect on any aspect of salt gland secretion. Our results demonstrated that secretion of the salt gland in C. mydas can be modified by neural and hormonal chemicals in vivo and that the cholinergic and adrenergic stimulation of an exocrine gland do not appear to have the typical, antagonist actions on the chelonian salt gland. Accepted: 28 September 1999  相似文献   

15.
Linda May 《Hydrobiologia》1987,147(1):335-338
Sediment samples from Loch Leven, Scotland, were incubated at 5°C, 10°C and 15°C to induce hatching of rotifer resting eggs. The emergent animals were identified and counted. The temperature which induced hatching varied among the nine species studied. These results are discussed in relation to seasonality and temperature preferences previously recorded for the most abundant species. Resting egg densities of 2.2–13.9 eggs cm–3 were recorded in the upper 5 cm of sediment.  相似文献   

16.
Reproductive data from southern Queensland indicate that vitellogenesis in female Chelonia mydas takes approximately 8 months and is followed by a migration to a breeding area. At Heron Island, females lay multiple clutches over approximately 3 months. To investigate how females mobilise and store lipid during the breeding season we collected plasma, yolk, and fat tissue samples from females at a variety of stages during the nesting season. In breeding females, concentrations of plasma triglyceride increased seasonally. They reached peak concentrations during vitellogenesis and courtship, remained high throughout the nesting season, and then declined to a nadir after the last clutch. Plasma protein concentration increased throughout the breeding season, peaking following the last clutch for the season. Yolk lipids were highest during courtship and were similar throughout the nesting season, suggesting that uptake of lipid by ovarian follicles is completed prior to the beginning of the nesting season. Plasma triglyceride decreases in females with prolonged periods of unsuccessful nesting, and total lipid levels in adipose tissue and follicle yolks were significantly lower in atretic females. It appears that: (1) endogenous energy reserves can be reduced by stochastic environmental events (such as those reducing nesting success), and (2) a metabolic shift signalling the end of the nesting season is characterised by a drop in plasma triglycerides and slight increase in total plasma protein.  相似文献   

17.
We present data on 29 new single nucleotide polymorphism assays for the green sea turtle, Chelonia mydas. DNA extracts from 39 green turtles were used for two methods of single nucleotide polymorphism discovery. The first approach employed an amplified fragment length polymorphism technique. The second technique screened a microsatellite library. Allele-specific amplification assays were developed for high-throughput single nucleotide polymorphism genotyping and tested on two Pacific C. mydas nesting populations. Observed heterozygosities ranged from 0 to 0.95 for a Hawaiian population and from 0 to 0.85 for a Galapagos population. Each of the populations had one locus out of Hardy-Weinberg equilibrium, SSCM2b and SSCM5 for Hawaii and Galapagos, respectively. No loci showed significant genotypic linkage disequilibrium across an expanded set of four Pacific nesting populations. However, two loci, SSCM4 and SSCM10b showed linkage disequilibrium across three populations indicating possible association.  相似文献   

18.
The continual development of ecological models and availability of high-resolution gridded climate surfaces have stimulated studies that link climate variables to functional traits of organisms. A primary constraint of these studies is the ability to reliably predict the microclimate that an organism experiences using macroscale climate inputs. This is particularly important in regions where access to empirical information is limited. Here, we contrast correlative models based on both ambient and sea surface temperatures to mechanistic modelling approaches to predict beach sand temperatures at depths relevant to sea turtle nesting. We show that mechanistic models are congruent with correlative models at predicting sand temperatures. We used these predictions to explore thermal variation across 46 mainland and island beaches that span the geographical range of sea turtle nesting in Western Australia. Using high resolution gridded climate surfaces and site-specific soil reflectance, we predict almost 9 °C variation in average annual temperatures between beaches, and nearly 10 °C variation in average temperatures during turtle nesting seasons. Validation of models demonstrated that predictions were typically within 2 °C of observations and, although most sites had high correlations (r2 > 0.7), predictive capacity varied between sites. An advantage of the mechanistic model demonstrated here is that it can be used to explore the impacts of climate change on sea turtle nesting beach temperatures as, unlike correlative models, it can be forced with novel combinations of environmental variables.  相似文献   

19.
The loggerhead sea turtle, Caretta caretta, is the most common species of sea turtle nesting in Brazil and is listed as endangered by the IUCN. Our study characterizes the genetic structure of loggerheads in Brazil based on mitochondrial DNA control region variability and presents a hypothesis for the colonization of Brazilian rookeries. We analyzed 329 samples from Brazilian rookeries and an oceanic foraging ground, and we compared our results with previously published data for other loggerhead populations. Brazilian rookeries had four haplotypes, none of which have been reported for rookeries outside Brazil. Six haplotypes were found in the foraging aggregation. The presence of the CC-A4 haplotype at all sampled sites and the low nucleotide diversity suggest a common origin for all rookeries, with CC-A4 being the ancestral haplotype of the Brazilian populations. The occurrence of three haplotypes in the foraging aggregation that are known only from rookeries outside of Brazil is consistent with the transoceanic migratory behavior of loggerheads. Our results indicated that the colonization of Brazilian rookeries probably occurred from the southern USA stock. This recent colonization most likely followed a north to south route along the Brazilian coastline, influenced by the Brazilian warm current. Our results further suggest the existence of two genetic population units of loggerheads in Brazil and corroborate natal homing behavior in loggerheads.  相似文献   

20.
Summary The effect of two different incubation media, sand and vermiculite, on the water exchange of eggs and the mass of hatchlings of snapping turtles (Chelydra serpentina) was assessed. The eggs were incubated fully buried in either sand or vermiculite at 30 °C and egg mass was measured periodically throughout incubation. The wet and dry masses of each hatchling and its residual yolk were measured at the end of incubation. The media had similar water potentials () but their thermal conductivities differed 2.8-fold. The eggs experienced a net water gain during incubation. The rates of water uptake between treatments were not statistically different throught the first 36 days of incubation but were statistically different thereafter, with eggs incubating in sand taking up water at about twice the rate of eggs incubating in vermiculite. Hatchling masses were similar to both media but hatchling water contents were significantly different. Hatchlings incubated in sand had lower water contents than hatchlings incubated in vermiculite even though the eggs in sand took up more water. Hatchling mass was correlated with egg water exchange for eggs incubated in vermiculite but not for eggs incubated in sand. The difference in egg water exchange in the two media appears to be attributable to differences in the thermal conductivity of the media. The presence of such a thermal effect supports the hypothesis that the eggs exchanged water with the media as water vapor. Egg water exchange was limited by the shell and shell membranes and not by the media. The shell and shell membranes appear to present an effective barrier to water uptake.Abbreviations M H 2 O water flux (cm3·day-1) - L p hydraulic conductivity (cm·day-1·kPa-1) - A shell area (cm2) - A p pore area (cm2) - l shell thickness (cm) - r pore radius (cm) - viscosity (kPa·day) - P EH 2 O egg water potential (kPa) - P AH 2 O medium water potential (kPa) - G H 2 O water vapor conductance (cm3·day-1·kPa-1) - D H 2 O diffusion coefficient (cm2·day-1) - R gas constant (cm3·kPa·K-1·cm-3) - T temperature (K) - P EH 2 O egg water vapor pressure (kPa) - P AH 2 O medium water vapor pressure (kPa) - d egg diameter - K soil hydraulic conductivity (cm2·day-1·kPa-1) - DHM hatchling dry mass - WHM hatchiling wet mass - WU water uptake - IM initial egg mass  相似文献   

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