Turtle Hatchlings Research Articles

Forever chemicals don't make hero mutant ninja turtles: Elevated PFAS levels linked to unusual scute development in newly emerged freshwater turtle hatchlings (Emydura macquarii macquarii) and a reduction in turtle populations.

Per- and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants known to pose significant risks to human and wildlife health. Freshwater turtles (Emydura macquarii macquarii), as long-lived species inhabiting aquatic ecosystems, are particularly vulnerable to PFAS bioaccumulation. This study investigated the multifaceted impact of PFAS contamination on these turtles, focusing on metabolic disruptions, reproductive success, hatchling health, and population impacts. Comprehensive analyses, including proteomics, lipidomics, metabolomics, and histopathology, were conducted on turtles from PFAS-impacted, control, and reference sites. The findings reveal significant metabolic disruptions in PFAS-exposed turtles, with alterations in amino acid and lipid metabolism, energy production, and oxidative stress responses. Proteomic analysis identified several health biomarkers indicative of early disease progression. Despite high levels of PFAS in tissues and organs, no gross or histopathological phenotypical abnormalities were directly linked to PFAS exposure. Gravid females from contaminated sites exhibited altered egg composition, particularly in magnesium to calcium ratios, potentially affecting eggshell strength. Biochemical profiles of egg albumin and yolk indicated significant differences in metabolites and lipids between contaminated and reference sites, suggesting potential impacts on embryo development. Hatchling deformities were notably higher and with increased frequency in terms of the types of deformities at the PFAS-impacted sites, with common defects including abnormal intergular scale shapes and marginal scale counts. Furthermore, the demographic profile of the turtle population showed a lack of juvenile turtles at contaminated sites, indicating reduced recruitment and potential long-term population declines. This indicates a field-based demonstration of an Adverse Outcome Pathway, from elevated levels of PFAS in the turtles, to biochemical perturbations within the animals, and finally population effects. These findings underscore the urgent need for regulatory measures to address PFAS contamination and its detrimental effects on wildlife.

Swimming through sand: using accelerometers to observe the cryptic, pre-emergence life-stage of sea turtle hatchlings.

Animals that hatch within a subterranean nest, such as turtle hatchlings, expend some of their limited energy reserves digging out through sand or soil to reach the surface. In sea turtles, this emergence process can take the hatchlings 3-7 days. However, we have a poor understanding of this process as it is difficult to observe what is occurring underground. Here, we utilize a novel method to characterize digging-out behaviour: affixing an accelerometer directly to newly hatched green turtles (Chelonia mydas) to record movement until nest emergence. Our data revealed that buried hatchlings maintained a head-up orientation but did not move in the expected left and right swaying motion associated with alternating limb crawling. Rather, they moved using dorsal-ventral heaving and pitching as if swimming vertically through the sand to the surface. Movement activity was irregular and brief, interspersed by many short periods of inactivity, mostly lasting less than 10 min. The first 24 h of head-up activity displayed no diel patterns, but the last 24 h prior to emergence involved more intense movement during night-time hours compared with daytime hours. Thus, our results add valuable new insight, and in some cases change previous assumptions, regarding the digging behaviours during the egg-to-emergence life stage in sea turtles.

The Continued Presence of Antibiotic-resistant Bacteria and Heavy Metals at one of the World’s Most Important Green Turtles’ Nesting Location, Ras al-Jinz Reserve, Oman

Environmental contamination of marine habitats is a global concern, especially in areas that are crucial for endangered species’ life cycles. To gain a comprehensive understanding of environmental contamination, analyzing various biotic and abiotic components of ecosystems is necessary. Situated in the Arabian Peninsula, Ras al-Jinz Reserve serves as an invaluable nesting site for green sea turtles (Chelonia mydas). There, the prevalence of antibiotic-resistant microbial strains and heavy metals was assessed by collecting samples from diverse components of this ecosystem, including sand from turtle nests, dead turtle hatchlings, fresh turtle eggs, oviductal fluids from nestling turtles, turtle carapace smears, live crabs, and seawater. Microbial fauna was identified using a MALDI-TOF Biotyper. The concentration of heavy metals was measured by an inductively-coupled plasma mass spectrometry. Among the isolated bacterial strains, 70 heterotrophic species belonging to eleven genera were identified, with over 46% of isolates belonging to the Pseudomonas species. More than 85% of isolates displayed antibiotic resistance but had negligible resistance to chloride. Of the 23 heavy metals assessed, Titanium and, in lesser measure Vanadium, were found in the highest concentrations, reaching up to 12 µg g-1. While such concentrations might not be immediately alarming, they are significant enough to warrant attention due to the potential health and environmental impacts. These results obtained over a decade after the last monitoring in the Reserve provide compelling evidence of the persistent presence of antibiotic-resistant bacteria. Additionally, the study confirms the prevalence of heavy metals, the sources of which remain unknown but are likely from anthropogenic sources. It is crucial to implement measures that mitigate sea turtles’ exposure to contaminants in Ras al-Jinz Reserve. Regular monitoring efforts are required to assess the emergence of discernible contamination trends in this critically important area. Keywords: Chelonian conservation; Environmental contamination assessment; Microbial contamination; Biological reserve; Coastal pollution.

Hepatic Metabolomic Responses to Low-Temperature Stress in the Invasive Turtle, Trachemys scripta elegans.

Investigating the physiological and biochemical changes of ectothermic species before entering hibernation would contribute to the understanding of how they adapt to low-temperature environments. Here, red-eared slider turtle (Trachemys scripta elegans) hatchlings were maintained under different thermal treatments (24 °C, slowly decreasing temperatures from 24 °C to 14 °C, and to 4 °C). Hepatic metabolite alterations were measured to assess the metabolic impacts of low-temperature stress in this species. Of these differentially changed metabolites, some (e.g., raffinose, spermidine, allocholic acid, taurohyocholate, 2-ketobutyric acid, acetylcysteine) were shown to decrease, while others (e.g., stearolic acid, D-mannose) increased in low-temperature treatments. Our results indicated that short-term low-temperature stress might have limited impacts on lipid and energy metabolism in this species. The changes in other metabolites (e.g., allocholic acid, taurohyocholate, spermine, acetylcysteine) might be associated with a low food intake (and thus reduced digestive performance) and weakened immune ability of low-temperature-exposed animals.

Correlations between local geoclimatic variables and hatchling body size in the sea turtles Caretta caretta and Chelonia mydas

It has been widely demonstrated that air and sand temperatures influence the anatomy of sea turtle hatchlings. We examined the impact of precipitation during the nesting season on the hatchling body size of loggerhead and green turtles from 37 beaches worldwide. Longitudinal data collected between 2012 and 2018 from Florida (US) and from a sample on Bõa Vista Island (Cabo Verde) carried out in 2019 showed that loggerhead body size at hatching was negatively correlated with precipitation, while precipitation was not correlated with hatchling body size in green turtles. A meta-analysis revealed that precipitation is positively correlated with hatchling mass in loggerhead turtles, while it is positively correlated with straight carapace length and width in green turtle hatchlings. The strongest influence of precipitation was found in the middle of the incubation period of loggerhead turtles in Cabo Verde, and we posit that this is due to an increase in the uptake of water for embryonic growth. These findings highlight the great importance of understanding the correlated effects of regional environmental variables, such as precipitation, on the development of sea turtle hatchlings and will have an impact on the evaluation of ongoing conservation and climate change discussions.

Tingkat Partisipasi Masyarakat dalam Konservasi Penyu di Pantai Mampie Kecamatan Wonomulyo Kabupaten Polewali Mandar

Continuous maintenance, management and protection efforts are very important in turtle conservation to avoid extinction and damage. This research aims to calculate the level of community participation in turtle conservation activities using quantitative methods by distributing questionnaires. The population in this study was the entire Patoreang Mampie Hamlet community around the beach and the sample size was 40 respondents. The results of the research show that the level of community participation in the form of planning is included in the high category with a score of 2.71 because the community's environmental awareness is very high and the management of the turtle house has provided education related to maintaining and preserving the existence of turtles and the level of community participation in the form of management is included in the category high with a score of 2.75 as evidenced by community participation in turtle conservation activities, turtle festival activities, and the release of turtle hatchlings. Participation in the form of monitoring and evaluation is included in the high category with a score of 2.60, which means that the community often gives free time to monitor and oversee conservation activities around the turtle house area so that they run well and effectively. Keywords: Participation, community, conservation, turtle

New record of Epinephelus quoyanus (Valenciennes, 1830) predation on green sea turtle hatchlings at a turtle nesting site.

This paper presents the observations of predation by the grouper Epinephelus quoyanus on sea turtle hatchlings in Chagar Hutang bay, Redang Island, Malaysia. Two of the eight collected specimens had hatchlings in their guts, whereas the remaining specimens had empty stomachs. This field report provides an in-depth understanding of the E. quoyanus diet and new insights into its feeding behavior.

Sistem Kontrol Kadar Amonia Dan Tinggi Air Pada Kolam Penangkaran Tukik Penyu

Turtles are also one of the animals whose population is decreasing day by daydue to several factors ranging from climate change, disease, environmentaldamage and inadequate processing of conservation techniques and so on. Withthe status of turtles being endangered, special attention is needed for turtles inthe form of cultivating turtles, especially when the turtles are still 0-2 years oldor known as hatchlings. One of the important indicators in hatchling cultivationrequires good seawater quality management. One of the parameters of goodseawater quality is ammonia levels. This ammonia level can be formed naturallyby metabolic wastes and also food waste that decomposes in the water whichresults in the formation of ammonia levels. In turtle hatchling ponds it is alsonecessary to adjust the water level in the pond with a height of 5cm - 10cmbecause newborn hatchlings cannot dive. The importance of regular waterquality control such as ammonia levels and water level in ponds is veryimportant for the success of hatchling cultivation. Therefore, a research onmonitoring and controlling systems for ammonia levels and water levels usingthe TCS3200 color sensor is carried out to read the change in water color afteradministration of an ammonia test solution which will show the value ofammonia levels in water. Previously, water sampling was carried out by DCpumps and ultrasonic sensors to detect water level. Where this system canmonitor and control ammonia levels and height automatically and the resultscan be viewed using a smartphone through the Blynk application

Influence of sand grain size on the nest escape of green sea turtle hatchlings

Sea turtle hatchlings rely on their finite energy reserve to sustain embryonic development in underground nests and during the first few days of their post-hatch life, including nest escape, beach crossing, and swimming offshore. This study aimed to investigate if the grain size of the nest substrate has an impact on green sea turtle (Chelonia mydas) hatchlings’ energy usage during nest escape. About-to-hatch green sea turtle eggs were incubated in laboratory chambers filled with either coarse-grain sand (φ = 0.507 phi) or fine-grain sand (φ = 2.028) at a temperature of 28oC. Open-flow respirometry was used to measure the hatchlings’ oxygen consumption rate during nest escape, which was then converted to energy consumption values. Results showed that hatchling morphology, hatching success, emergence success, and synchronous emergence rate were not significantly different between the groups of hatchlings in coarse versus fine sand. Hatchlings that dug through coarse sand emerged significantly faster (168 ± 13.9 h) than those in fine sand (233.21 ± 12.6 h) (t (26) = –3.473, p = 0.002). Additionally, the hatchlings in coarse sand (310.55 ± 28.1 kJ) consumed significantly less energy than hatchlings in fine sand (474.85 ± 64.7 kJ) (t (17.739) = –2.328, p = 0.032). A difference in amount of energy reserve upon emergence was detected between coarse and fine sand groups. To improve hatchery management practices, relocating “doomed” clutches into coarse sand (φ = 0.507) could potentially maximise the hatchlings’ energy reserve.

Social media-based community science for turtle nest monitoring and conservation

In late 2020, a private volunteer group operating through a Facebook group approached Toronto and Region Conservation Authority (TRCA) with an interest in participating in the Citizen Science Nest Protection and Monitoring Volunteer Program. During the 2021 season, TRCA staff virtually trained volunteers in turtle nest detection, protection, and monitoring due to COVID-19 social constraints, and provided necessary supplies and equipment. In 2021 volunteers and staff detected 181 turtle nests and were able to protect 75 nests with simple predator-exclusion devices, while in 2022, 165 nests were detected, and 155 were protected. The volunteers also collected data, including nesting location, date, and species in addition to the number of successful hatchlings (2021 only). In 2021, the 75 protected nests yielded 81 Midland Painted Turtle and 665 Snapping Turtle hatchlings. Five Midland Painted Turtle’s eggs were also recovered from an injured turtle, and 44 Snapping Turtle eggs were recovered from a partially predated nest, transported to the Ontario Turtle Conservation Centre, incubated, hatched, and overwintered, and then released back into the local wetlands. The partnership with a local community group proved effective, and we would recommend this practice to other conservation organizations interested in turtle nest protection.

Sex Ratio Estimation of Green Turtle Hatchlings in Kazanlı Beach, Türkiye

Sea turtles are distributed worldwide, mostly in the tropical and subtropical waters. All seven species of sea turtles in the world have temperature-dependent sex determination. The pivotal temperature for hatchlings with a female:male ratio of 1:1 is usually around 29°C. Female hatchlings are observed at values higher than the pivotal temperature and male hatchlings at lower values. It is expected that wildlife threatened by global warming will be more severely affected, especially species that sex is determined by temperature. This study was carried out by measuring air, sand and nest temperatures during two nesting seasons at Kazanlı Beach, one of the largest nesting sites of Chelonia mydas (Green turtle) in the Mediterranean. Sand grain size was also measured, and gonads of dead hatchlings were examined histologically. Both sand (n=4) and nest (n=6) temperatures were above the pivotal temperature (between 29.1-31.6°C) in the study area. According to the estimation based on temperatures, hatchlings were female (♀>50%) biased. Of the hatchling samples, 75 were examined histologically. According to histological examination, the female:male ratio was 2:1. According to the direct examination and indirect estimation; the sex ratio of green turtle hatchlings in Kazanlı Beach, one of the highest hatchling producing nesting sites of the Mediterranean, was reported for the first time in this study. There is a need to fill the data gaps regarding sex ratios, especially for major beaches with high hatchling production. Knowing the temperature profiles in and around the nest and sex ratios of hatchlings is critical for the development of conservation measures for endangered sea turtles.

Climate change affects the early‐life history of a freshwater turtle in a severely drying region

AbstractFreshwater turtles are one of the most threatened vertebrate groups. Climate change is a major threat to these species, with impacts affecting all life‐history stages. There is currently a limited understanding of how changes in climate may alter the environmental triggers for hatching and emergence from the nests of freshwater turtle hatchlings. This precludes making predictions about how climate change may impact freshwater turtle recruitment success. The southwestern snake‐necked turtle (Chelodina oblonga) is endemic to south‐western Australia, a global biodiversity hotspot that has undergone severe climatic drying. Recruitment failure is thought to be occurring in many populations of the species. However, there is little understanding as to how environmental change may be influencing recruitment. This study aimed to: (1) determine the incubation duration and hatching and hatchling emergence success of C. oblonga, (2) determine if the species exhibits hatching or emergence synchrony and/or delayed emergence and (3) quantify the effects of temperature and rainfall on hatchling emergence. Using this information, the study assesses how climatic drying and warming may be impacting C. oblonga's early life‐history. Between 2018 and 2020 nest sites were monitored around a large urban wetland with weekly assessments of egg and hatchling status. Incubation duration and hatching and hatchling emergence success were calculated, and generalized linear models were built to determine how temperature and/or rainfall predicted emergence. Hatchlings either emerged shortly after hatching or overwintered in the nest, and both hatching and emergence were asynchronous. Both emergence periods were positively associated with temperature and rainfall. This study reveals that incubation duration, hatching success, hatchling emergence and survival are all likely to be impacted by recent and projected climate change, and especially drying. Warming and drying are predicted for many temperate regions globally, and it is therefore important that their impacts on the early life history of freshwater turtles be better understood.

Effect of noise on sand digging and emergence activities in green turtle (Chelonia mydas) hatchlings

Anthropogenic noise affects animal behavior and physiology. However, relatively few studies have been conducted on the effects of noise on beach-associated animals. This study evaluated the effects of noise on sound emission, sand digging activity, and emergence from the sand surface by green turtle (Chelonia mydas) hatchlings. Acoustic recorders and infrared cameras were used to investigate the behavior of hatchlings in sand-filled chambers under three acoustic conditions: 1) a control treatment, which was silent throughout the experiment; 2) an environmental noise treatment, which exposed the hatchlings to white noise (WN) at a sound pressure level (SPL) approximately 13 dB higher than that of the control, which is similar to that of a natural beach; and 3) a loud noise treatment, which exposed them to WN at an SPL approximately 25 dB higher than that of the control. The WN ranged from 0 to 4 kHz with a repeating cycle of 30 min sound emission and 2 h 30 min silence. Sound emissions from green turtle hatchlings were detected; however, the amount of sound emissions was too small to discuss their ecological significance. The time to emergence and total number of digging bouts in the 24 h pre-emergence periods were not significantly different among treatments; however, the number of digging bouts was significantly higher during loud noise exposure. The response to loud noises may play a role in allowing hatchlings to escape from threats and/or coordinate synchronous behavior among multiple individuals. However, because the number of digging bouts decreased after loud noise exposure, prolonged exposure to loud noise may have detrimental effects on hatchlings, such as depletion of the energy reserves available to the hatchlings. Thus, anthropogenic noise on or around beaches and it effect on animals should be carefully considered.

Exploring contaminants as a disruptor of temperature-dependent sex determination in sea turtle hatchlings

Sea turtle nesting beaches are experiencing increased sand temperatures as climate change progresses. In one major green turtle (Chelonia mydas) nesting beach in the northern Great Barrier Reef, over 99 percent of hatchlings are female. The effects of contaminants on sea turtle hatchling sex determination are not often explored. Liver samples were collected from green turtle hatchlings that were sacrificed for histological sex determination in a parallel study on the effects of sand cooling on sex ratios, and analysed for trace elements via acid digestion and organic contaminants via in vitro cytotoxicity bioassays. Chromium, antimony, barium, and cadmium have previously been demonstrated to be estrogenic, and concentrations of these elements were used to calculate three estrogenic indexes for each clutch: predicted relative estrogenic potency (PEEQA), the sum of percent trace elements above the median of all samples (TEOM), and the sum of percent estrogenic elements above the median of all samples (EstroEOM). Excluding an outlier clutch, cadmium, antimony, and EstroEOM had significant positive relationships with sex ratio deviation. Mean clutch cobalt, lead, antimony and barium, also had a significant positive relationship with clutch sex ratio. There was no relationship between in vitro cytotoxicity of liver extracts and sex ratio, however, 9% of hatchlings had organic contaminants high enough to suggest potential cellular damage. Contaminant effects on sex determination are likely to be caused by a mixture of contaminant interactions as well as temperature. Many trace elements detected in this study have also been linked to negative health effects on hatchlings in previous studies. Considering the risks of feminization due to climate change and potential contaminant effects on hatchling health and sex determination, future studies exploring contaminant effects on sea turtle hatchling sex determination are recommended.

Incubation in shaded hatcheries biases sex-determination but preserves Lepidochelys olivacea hatchling physiology

Some studies have associated ex situ conservation with cerebral and gonadal developmental delay, as well as decreased motor performance in Lepidochelys olivacea offspring. Ex situ management is also related to a more mature spleen and a differential leukocyte count in newly emerged Lepidochelys olivacea hatchlings. The physiological relevance of a more mature spleen is unknown in sea turtles, but studies in birds suggest an increased immune response. Because egg relocation to hatcheries is a common conservation practice, it is imperative to know its impact on hatchling physiology. Herein, plasma activity of superoxide dismutase, alkaline phosphatase and the alternative complement pathway, as well as total antioxidant capacity and hydrogen peroxide concentrations were quantified in hatchlings from in situ and ex situ nests under basal conditions at nest emergence. Toll-like receptor 4 (tlr4), heat shock proteins (hsp) 70 and hsp90 expression were quantified in the spleen and liver of the hatchlings. Hepatocyte density and nuclear area were quantified in histological sections of the liver and all turtles were sexed by histological sectioning of the gonads. Total antioxidant capacity and hydrogen peroxide concentrations in plasma were lower in turtles from ex situ nests, while tlr4 and hsp70 mRNA expression was higher in the spleen but not in the liver. Ex situ incubation produced 98% male hatchlings, whereas in situ incubation produced 100% females. There were no other differences in the attributes sampled between hatchlings emerging from ex situ and in situ treatments. The results suggest that ex situ relocated turtles may be less prone to oxidative stress than in situ incubated hatchlings and could have more mature splenic function. Together, the data suggest that ex situ relocation to shaded hatcheries biased sex determination but preserved the general physiological condition of sea turtle hatchlings.

First successful head-start program of leatherback sea turtles (Dermochelys coriacea) in Thailand and proposed dietary strategy.

Leatherback sea turtle (Dermochelys coriacea) hatchlings have previously been kept alive for over a year in captive conditions but these were the few survivors of initially larger groups. In this report, newly hatched leatherback sea turtles were randomly harvested from two nests in Thailand and successfully reared before release back to the wild. In captivity, the survival of the turtles decreased sharply during the first 4 or 5 months, and then steadied until the end of the 12-month trial. The survival of yearlings from one nest was 13.3% and from the other nest 46.7%. Their growth was exponential, reaching 1.36-3.35 kg (n = 9) at the end of program. The causes of death of the reared turtles were accidents (25.0-38.5%) and infections from water and live food (61.5-75.0%). The dietary requirements of the turtles were investigated by determining the digestibility of protein and carbohydrate in vitro, using enzymes from the digestive tracts of hatchlings that had died in an accident (70.1-92.9 g body weight). The results indicated that the most suitable source of protein was wheat gluten, followed by soybean meal, nonruminant meat and bone meal, fish meal, nonruminant meat meal, pork meal, and skimmed milk, while suitable carbohydrate sources were mashed cassava, corn, wheat flour, and alpha starch, followed by cereal meal and rice flour. Findings from the current report provide a practical protocol for head-starting leatherback sea turtles, and indicate the possible basis of an effective artificial diet for this species.

THE EFFECT OF TEMPERATURE DIFFERENCES ON HATCHING RATES OF LEKANG TURTLE (Lepidochelys olivacea) EGGS IN SEMI-NATURAL NESTS

This research was conducted on August 31, 2021 – December 7, 2021, at the UPTD KPSDKP, West Sumatra Province. The purpose of this study was to determine the effect of temperature differences on incubation time, hatching rate, and survival rate of turtle hatchlings (Lepidochelys olivacea). The method used in this study is an experiment that uses 3 trials plus 1 control, with 3 repetitions. Turtle eggs were incubated with the same depth and number of eggs with the addition of different temperatures from incandescent lamps with different powers. Then proceed with the calculation of incubation time, percentage of hatching, and survival of hatchling. Based on the results of the research, for the calculation of incubation time, the experimental unit with the shortest incubation period was produced by experimental unit B, with a temperature range of 27.5–29.5⁰C, which was 58 days. The incubation period that took the longest was the control experimental unit with an average temperature of 25⁰C, which was 65 days. For the results, the most optimal hatching rate was produced by experimental unit B, with an average hatching rate of 86%. Meanwhile, the lowest hatching rate was obtained from experimental unit C with an average hatching rate of only 53.3%. Then for the survival of the hatchlings after being quarantined for one week, all of them show the number 100%, which means that no hatchlings died during the quarantine

Hatcheries efficiency for hawksbill sea turtle (Eretmochelys imbricata) conservation in the Persian Gulf: Over a decade monitoring of emergence success and incubation period

Conservation of the critically endangered hawksbill sea turtles (Eretmochelys imbricata) is an important global concern that requires attention. There is currently a lot of debate surrounding the use of hatcheries as a technique for ex-situ conservation. Over the past decade, hatchery sites were established with the aim of reducing the embryonic mortality and increasing the number of hatchlings on Kish Island. Out of a total of 415 hawksbill turtle nests, 216 nests were monitored in their original location (in-situ) whereas the remaining nests were relocated to a hatchery site (ex-situ) due to several threats, including feral predators, coastal development, ecotourism pressure, and waves of monsoon storms. The aim of this study is to investigate the effectiveness of a hatchery site in the emergence success and incubation period compared to natural nests by analyzing the data from thirteen nesting seasons (2010–2022). In most years, the emergence success rate in ex-situ conditions has been significantly higher than in-situ (P < 0.05). Furthermore, a notable variation in the incubation period was noticed among various ex-situ years (P < 0.05), whereas it was not observed in in-situ. The incubation period in the ex-situ condition (57.38 ± 7.39 days) was 3.68 days shorter than the in-situ nests (61.25 ± 8.46 days). Delays in transferring eggs to the hatchery site from distant shores were found to be linked with a decrease in emergence success, 47.02% vs. 58.18% (P < 0.05). As a result, nest relocation in a minimum time, could significantly enhance turtle hatchlings’ emergence success and survival. On the other hand, reducing the incubation period due to ex-situ method maybe an important challenge in the future. Further research should be done to investigate the influence of nest relocation on morphological, physiological, immunological, and biometric offspring features, as well as on sex ratio.

Minor metabolomic disturbances induced by glyphosate-isopropylammonium exposure at environmentally relevant concentrations in an aquatic turtle, Pelodiscus sinensis

The ecotoxicological and environmental impacts of glyphosate-based herbicides have received considerable attention due to their extensive use globally. However, the potential for adverse effects in cultured non-fish vertebrate species are commonly ignored. In this study, effects on growth, indicators of functional performance, gut microbial diversity, liver antioxidant responses and metabolite profiles were evaluated in soft-shelled turtle hatchlings (Pelodiscus sinensis) exposed to different concentrations of glyphosate-isopropylammonium (0, 0.02, 0.2, 2 and 20 mg/L). No significant changes in growth or functional performance (food intake, swimming speed), gut microbiota, and liver antioxidant responses (SOD and CAT activities, MDA content) were observed in exposed turtles. However, hepatic metabolite profiles revealed distinct perturbations that primarily involved amino acid metabolism in turtles exposed to environmentally relevant concentrations. Overall, our results suggested that metabolite profiles may be more sensitive than phenotypic or general physiological endpoints and gut microbiota profiling, and indicate a potential mechanism of hepatotoxicity caused by glyphosate-isopropylammonium based on untargeted metabolomics analysis. Furthermore, the toxicity of glyphosate at environmentally relevant concentrations might be relatively minor in aquatic turtle species.

Multidecadal fluctuations in green turtle hatchling production related to climate variability

The state of Campeche, Mexico, harbors one of the largest green turtle (Chelonia mydas) rookeries of the Wider Caribbean Region. Since the 1970s, harvesting of this population was common practice, but it has since ceased, and the population is rebounding as a consequence. In this rookery, during the past 37 years (1984–2020), the positive relationship between the annual number of nesting females and the number of hatchlings they produce has revealed a long-term population signal that we postulate could be related to environmental factors. To investigate this relationship more deeply, we adopt a stock-recruitment (SR) approach, which is commonly used in fisheries. Regression analysis methods for the SR relationship, including a dynamic version of the model that incorporates the effect of sea surface temperature, show that the number of recruits produced and the number of hatchlings per unit nester were significantly and inversely correlated with a 26-year cycle of the Atlantic Multidecadal Oscillation (AMO) with a three year lag. A possible explanation for this finding is that environmental conditions during warming periods of the 26-year AMO cycle may negatively affect hatchling production by altering the nest moisture content during the incubation period, and increasing embryonic mortality, while the annual female abundance at nesting beaches may decrease due to trophic effects. The time series of abundance corresponding to other population units of green turtles as well as other species of sea turtles in the Gulf of Mexico present a similar behavior to that evaluated here, suggesting a basin-wide environmental effect.