Search Results (132)

Human exploitation has been a major driver of marine turtle population declines, particularly affecting naturally scarce species such as the pantropical hawksbill turtle. Although hawksbill sea turtles have been documented in the Gulf of California since the early 20th century, data on their historical demography during periods of high exploitation in this region are nonexistent. We investigated the size structure of hawksbill turtles from the Western Central Gulf of California by examining a unique sample of decorative taxidermies, corresponding to 31 specimens captured during fishing operations near Santa Rosalía, Baja California Sur, Mexico, between 1980 and 1990. An analysis of the curved carapace measures revealed a length range (nuchal notch to posterior of supracaudals) of 29.5–59.5 cm (mean = 38.75 ± 6.67 cm) and a width range of 25.0–51.5 cm (mean = 33.63 ± 5.66 cm), with 87% of specimens having lengths between 30 and 45 cm. Based on the carapace length measurements, we estimated the ages to be between 7 and 20 years, indicating that the population included juveniles. Our findings provide baseline data for an understudied period and region, suggesting that this area previously served as an important juvenile habitat. These results contribute essential historical demographic information for conservation planning. Full article

In farmed animals, body color is not only an ecological trait but also an important trait that influences the commercial value of the animals. Melanin plays an important role in the formation of body color in animals, while the tyrosinase (TYR) gene family is a group of key enzymes that regulate melanogenesis. The Chinese soft-shelled turtle (Pelodiscus sinensis) is one of the most important reptiles in freshwater aquaculture. However, the potential role of the TYR gene family in the body color formation of P. sinensis remains unclear. This study aimed to investigate the expression and conservation of the TYR gene family in relation to body color variation in P. sinensis. Three core members of this gene family were identified from the P. sinensis genome. Following identification, the genomic features were analyzed. They shared similar physicochemical properties and conserved domains. Chromosome mapping showed that the three genes of P. sinensis were all located on the autosomes, while phylogenetic and collinearity analysis suggested that the protein functions of the three genes in the studied species were highly conserved. Amino acid sequence alignment indicated high conservation among the three TYR gene family proteins (TYR, TYRP1, and DCT) in multiple critical regions, particularly in their hydrophobic N-/C-terminal regions and cysteine/histidine-rich conserved domains. The qRT-PCR revealed that the TYR and DCT genes were highly expressed in the eyes of individuals with different body colors. The expression levels of TYR and TYRP1 genes in the skin were significantly higher in dark-colored individuals than in light-colored ones (p < 0.05). These results will lay the groundwork for functional studies and breeding programs targeting color traits in aquaculture. Full article

Bahía de Los Ángeles (BLA) is located on the peninsular coast of the Gulf of California, near to the midriff islands. It is a greatly diverse ecosystem and a marine protected area due to its importance for whale sharks, turtles, and reef fishes. The bay also supports commercial fisheries that require ecological information for the integrated management of resources. Zooplankton studies are required as is an essential link in the trophic webs. There are few zooplankton studies in BLA focused mainly on the major taxa and species of copepods and cladocerans. Only one study addressed the seasonal variation in zooplankton but with gaps in the sampling. Here, we report the monthly changes in the zooplankton abundance and the composition of the major groups and cladoceran species. Eighty-one samples were collected between September 2017 and January 2019. The holoplankton taxa identified numbered 17, which accounts for 93% of the mean abundance (range 71–100%), with copepods and cladocerans being dominant. The meroplankton consisted of 15 taxa with a greater presence during the warm months (summer–autumn), dominated by the larval stages of bivalves, gastropods, and barnacles. In contrast, many copepod nauplii were found in January associated with low temperatures. Only cladacerans were identified to the species level. They showed strong seasonal fluctuations, reaching a third of the total zooplankton from spring to autumn, with Penilia avirostris being the most abundant species. These results are compared with other temperate and tropical coastal locations of the eastern Pacific. Full article

The critically endangered Vietnamese Pond Turtle (Mauremys annamensis), an endemic species occurring in a small lowland area in central Vietnam, has been virtually extirpated from its natural range. As a result, reintroduction of held individuals worldwide, especially from Europe, the United States, and Vietnam, will play a vital role in species recovery programs. Nevertheless, the discordance between different molecular markers in inferring the placements of two closely related species, M. annamensis and M. mutica, and the existence of two distinct mitochondrial lineages within M. annamensis, have hindered conservation strategies to properly maintain the genetic integrity of held populations to release individuals back to their natural habitat in the future. In this study, we sequenced 732 bps of a mitochondrial gene (ND4) and 1038 bps of an intron fragment of the RNA fingerprint protein 35 (R35) gene for 18 samples collected from the local trade in five provinces in Vietnam and 20 samples from founders in the Turtle Conservation Centre, Cuc Phuong National Park, Vietnam. DNA sequences analyzed by Bayesian Inference, Maximum Likelihood, and NeighborNet methods show that the Vietnamese Pond Turtle is a well-defined species and that the population of M. mutica from Hainan Island likely evolved through introgression between a lineage distantly related to true M. mutica and M. annamensis and a lineage closely related to the two mitochondrial haplotypes of M. annamensis. Interestingly, our analyses of samples collected from the local trade and those with known localities reveal that the two extant mitochondrial lineages within M. annamensis are geographically isolated and evolutionarily significant. Based upon the new findings, we recommend genetic screening for all held populations in Vietnam and elsewhere and that animals with different genetic histories be managed separately. In addition, it is important to use other molecular markers, such as microsatellites and single nucleotide polymorphisms (SNPs), to determine potential hybrids between the two mitochondrial haplotypes and remove them from conservation breeding programs before releasing the turtles back to their natural habitat. Full article

The European Turtle Dove (Streptopelia turtur) has experienced significant population declines across its European breeding range, primarily due to habitat loss. Our study aimed to provide a new reference for the conservation of Turtle Doves in Evros province, a biodiversity hotspot. We used Maximum Entropy (MaxEnt) modeling to assess Turtle Dove breeding habitat suitability and account for the area of suitable habitats that is not protected or have been affected by a recent mega-fire. The best performing model identified tree cover density, the percent cover of permanently irrigated land and heterogenous agricultural areas, proximity to non-irrigated agricultural land, and forest edge length as the most important predictors of habitat suitability, signifying the importance of an interplay between open and forested land. Our results indicate that 39% of the study area provides a suitable breeding habitat, with the majority located in central and southeastern regions. Conversely, irrigated agricultural areas in the northeast are unsuitable. We found that more than 60% of suitable habitats fall within the Natura 2000 network, underscoring the importance of protected areas for conservation. However, wildfires pose a major threat, with almost 25% of suitable habitats being affected by a recent mega-fire, highlighting the need for recovery in these areas. Our study provides a foundation for targeted habitat management and restoration efforts in NE Greece and contributes to the broader understanding of the species’ habitat requirements across its breeding range. Full article

Background/Objectives: The Chinese soft-shelled turtle (Pelodiscus sinensis) is an important species in freshwater aquaculture. Genetic admixture and degradation due to rapid industry expansion threaten sustainable development. This study aims to assess the genetic diversity and structure of six P. sinensis populations for better management. Methods: We combined morphological analysis and microsatellite markers to evaluate the genetic diversity of six populations. A discriminant function based on morphology was developed, achieving 71.4% classification accuracy. Two SSR markers were identified to specifically distinguish the HS population. Results: The six populations were classified into three subgroups. Frequent gene flow was observed among the CY, W, and DT populations, with most genetic variation occurring within individuals. However, significant genetic differentiation was detected between populations. While gene flow enhanced diversity, it suppressed differentiation. Conclusions: This study provides insights into the genetic structure and diversity of six P. sinensis populations. The discriminant function and SSR markers offer a basis for germplasm conservation and management, supporting sustainable aquaculture development. Full article

Background/Objectives: Antimicrobial resistance (AMR) is a major global health concern with profound implications for human, animal, and environmental health. Marine ecosystems are emerging as reservoirs of resistant bacteria due to contamination from anthropogenic activities. This study aimed to investigate fluoroquinolone-resistant and multidrug-resistant bacteria in loggerhead sea turtles (Caretta caretta). Methods: Cloacal swabs were collected from 28 loggerhead sea turtles at a rescue center in southern Italy. Swabs were cultured in nutrient media supplemented with enrofloxacin. Bacterial isolates underwent identification by MALDI-TOF, antimicrobial susceptibility testing, and assessment for multidrug resistance. Conjugation experiments evaluated the transferability of enrofloxacin resistance. Results: Thirty-six enrofloxacin-resistant bacterial strains were isolated from 22 turtles. The identified species included Vagococcus fluvialis (13 strains), Citrobacter freundii (5), Escherichia coli (6), and Pseudomonas mendocina (4). Thirty-five isolates exhibited multidrug resistance, with resistance to critically important antibiotics such as imipenem observed in C. freundii and Enterobacter faecium. Conjugation experiments showed no transfer of resistance genes. Conclusions: The study highlights the prevalence of fluoroquinolone-resistant and multidrug-resistant bacteria in C. caretta, implicating marine environments as reservoirs of AMR. The findings underscore the need for stricter regulation of antimicrobial use and monitoring of resistance dissemination in marine ecosystems. These results contribute to understanding AMR dynamics within the One Health framework, emphasizing the interconnectedness of environmental, animal, and human health. Full article

To develop safe and effective management policies, it is important to understand the physiologic effects of fishing interactions and scientific research methods on endangered marine species. In the present study, validated assays for plasma corticosterone, free thyroxine (fT4), and aldosterone were used to assess the endocrine status of 61 presumed healthy, wild Kemp’s ridley sea turtles (Lepidochelys kempii) that were captured for separate ecological studies using two capture methods (trawl net n = 40; manual capture n = 21). Plasma hormone concentrations were also assessed in relation to eight clinical plasma biochemical analytes. Corticosterone and aldosterone concentrations were moderately high after capture, with significantly higher concentrations in turtles captured by trawl net vs. manual capture. Free thyroxine concentrations were within previously published ranges for healthy individuals of this species. Clinical biochemical data revealed moderately elevated potassium and lactate concentrations in many individuals, with significantly greater lactate concentrations in trawl-captured turtles. Aldosterone concentrations were positively correlated with corticosterone. The results of the present study indicate that Kemp’s ridley sea turtles have robust adrenocortical activity immediately after capture, resulting in high plasma concentrations of corticosterone and aldosterone. Researchers who use such methods to access sea turtles can consider these results in planning careful and efficient field studies. Full article

Numerous interactions between human activities and wildlife currently impact various species. In recent decades, these activities have contributed to declining sea turtle populations. The waters around Spain serve as important staging areas for sea turtles, particularly Caretta caretta, which spend part of their life cycle there. However, these same waters threaten turtles because of various causes of stranding. This study aims to comprehensively understand the rehabilitation process for these animals at the Wildlife Rehabilitation Center (WRC) La Tahonilla in Tenerife, Canary Islands. It also seeks to explore rehabilitation efforts at different centers focused on recovering sea turtles in both the mainland and the Canary Islands. Additionally, we have examined the procedures for addressing stranded sea turtles where a recovery center does not exist. Our findings reveal the existence of varying protocols among different centers in Spain’s mainland and islands. Improving and unifying these protocols is essential for enhancing the rehabilitation of sea turtles in Spain. Full article

The conservation of the olive ridley turtle (Lepidochelys olivacea) is increasingly critical due to declining global populations. This study investigates the influence of hydrometeorological conditions on the nesting season and annual hatchling sex ratios conducted at the Playón de Mismaloya Federal Reserve in Tomatlán, Jalisco, Mexico. The research specifically examines variations in sand temperature at both the beach surface and nesting depths, with extended measurements taken at multiple depths (20, 40, 60, 80, and 100 cm) to analyze the vertical temperature gradient along the beach. Atmospheric parameters were modeled using Newton’s Cooling Law and solved with the finite difference method to estimate heat loss rates from beach sand to its surroundings, shedding light on microclimatic effects on incubation and embryonic development. Meteorological data were gathered from an automatic weather station, while sand temperatures were monitored with thermographs. During the warm period (approximately 32 °C), sand temperature showed a negative correlation with depth (20–100 cm), indicating cooler temperatures at greater depths. These conditions were associated with female-biased hatchling production. Conversely, the cold period (approximately 28 °C) led to male-biased hatchling production, with a positive correlation between sand and air temperatures. This study emphasizes the importance of monitoring in situ environmental conditions and extending the protection season until February to avoid the loss of male hatchlings. Full article

Body size is one of the most important traits in the life history of vertebrates. In this work, we analyzed the morphometric traits of breeding males of the eastern Pacific green sea turtle population known as the black sea turtle on the coast of Michoacan, Mexico. The morphometric analysis indicates that males have the smallest body size compared to other males in other Chelonia populations. The size of male black sea turtles is even smaller (by 15.2 cm in average CCL) in carapace curve length (70.5 cm CCL) than females (85.7 CCL) of the same population. This suggests that males reach maturity at an earlier age than females and would have implications for mating success. The assessment of the operational sex ratio was conducted over a multi-year period (2004, 2009, 2017, and 2023). From a total of 336 h of observation, we identified 653 mating groups containing 1986 males and 669 females. The estimated operational sex ratio (OSR) during the study period was 2.96 males for every female. Among the mating groups, 34.3% consisted of only one male, while 65.7% included two or more males, with the number of males per female ranging from 2 to 17. The analysis revealed that there are interannual and monthly variations in OSR values, with observations showing a range from 2.3:1 (male to female) in 2023 to 4.3:1 (male to female) in 2009. The OSR variations show an evolving trend that can inform future strategies. In September, the ratio was 2.8:1, which changed to 3:1 in October and November, and then reached 3.3:1 in December (male/female). This gradual increase provides a clear opportunity to delve deeper into these dynamics and take proactive measures to address them positively. Full article

We investigated sea turtle landing and spawning behavior along 1.4 km of Kili-Kili Beach in East Java, Indonesia, by combining aerial photographs and field survey data. In the study, we surveyed marks of sea turtles landing and spawning on the beach and utilized aerial photographs, beach profile survey records, grain size measurements of the beach material, and tide records to understand the behavior of the turtles. Firstly, aerial photographs are processed into ortho-mosaics, and beach surfaces are classified into land cover categories. Then, we calculate the number of spawning and non-spawning instances for each category, visualizing landing positions to identify local concentrations. Spawning distances from the waterline are estimated, and beach stability is evaluated by analyzing the temporal elevation change through standard deviation. Our findings reveal preferred spawning locations on bare sand surfaces, around 8 to 45 m from the waterline, with beach elevations ranging from 1 to 5 m. The standard deviations of beach elevation were between 0.0 and 0.7 m, with a mean slope of 0.07. This information is important for effectively conserving sandy beaches that serve as spawning sites for sea turtles. Full article

Resilience plays a crucial role in overcoming the adversities and challenges faced by young people during adolescence. Current research focuses on understanding the factors that contribute to the development of resilience at this stage, with the goal of promoting the well-being and mental health of young people. In this descriptive cross-sectional study, we examined the relationship between social skills, creativity and resilience in a sample of 743 students aged 14 to 19 years from different educational centers in the province of Almería (Spain). We used the Social Skills Questionnaire (CHASO), the Turtle Creativity Questionnaire and the reduced resilience scale CDRISC-10 to collect data. Data analysis was performed using correlation analysis, Student’s t-test for differences according to sex, analysis of variance to test for differences according to resilience groups, multiple regression analysis for predictors of resilience and simple mediation analysis. The results showed a positive and significant relationship between social skills, creativity, and resilience. The differences found suggest that being male and having a higher level of resilience increases the likelihood of having higher social skills and resilience. Social skills and creativity predicted resilience and social skills mediated the relationship between creativity and social skills. These findings highlight the importance of strengthening social skills and promoting creativity to enhance resilience in adolescents, which may have practical implications for the design of intervention and support programs. Full article

The Chinese soft-shelled turtle (Pelodiscus sinensis) is an economically important species in aquaculture, and its growth pattern is characterized by significant sexual dimorphism. However, the underlying molecular mechanisms of this phenomenon have mostly been investigated in the gonadal tissues of P. sinensis, and there are no articles on sex differentiation from the brain of P. sinensis. Here, we analyzed transcriptomes of the brains of adult male and female P. sinensis using high-throughput Illumina sequencing technology, establishing a set of differential genes and differential transcription factors. The data showed that there were 908 genes with significant differences in expression, of which 357 genes were up-regulated and 551 genes were down-regulated. We annotated using Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG), and screened some genes and pathways related to growth. There were 282 growth-related differential genes and 181 sex-related differential genes. We screened the genes’ growth hormone receptor (GHR) and vascular endothelial growth factor A (VEGFA), which may be related to the growth of P. sinensis. The pathways related to the growth and development of P. sinensis are the growth hormone synthesis, secretion, and action pathway; the MAPK (mitogen-activated protein kinase) pathway; and the calcium signaling pathway. In addition, through gene set enrichment analysis (GSEA), we screened out two genes, LIM homeobox protein 1 (LHX1) and fibroblast growth factor 7 (FGF7), which are related to both growth and sex differentiation, and through protein interaction analysis of these genes, we screened out eight genes, including LHX1, FGF7, GHR, fibroblast growth factor 4 (FGF4), EGFR, BMP3, GLI family zinc finger 2 (GLI2), and neuronal differentiation 1 (NEUROD1), and verified the expression levels of these eight genes in the brain of the P. sinensis by real-time quantitative PCR (qRT-PCR), which supported the reliability and accuracy of our transcriptome analysis. Our study provides a solid foundation for analyzing the mechanisms of sexual-dimorphic growth of P. sinensis and even other turtles. Full article

The Caretta caretta is the only known sea turtle that nests along the coasts of the Mediterranean Sea. It is considered a vulnerable species by the International Union for Conservation of Nature (IUCN) because it is threatened by human activities. The aim of this work was to analyze biochemical parameters in different age groups of C. caretta subjects recovered at the Centro di Referenza Nazionale sul Benessere, Monitoraggio e Diagnostica delle Malattie delle Tartarughe Marine (C.Re.Ta.M.), Sicily. Biometric parameters were recorded for each subject. Peripheral blood was collected and centrifuged, and 18 biochemical parameters were analyzed. Glucose and total proteins showed lower values in juvenile turtles than in sub-adult and adult subjects. Since blood biochemical parameters can be influenced by several factors (age, sex, infectious disease, or trauma), we evaluated differences in the values of some parameters between the reproductive and non-reproductive seasons of adult turtles whose sex and cause of stranding could be determined. Despite the small number of subjects, it would seem that, in adult turtles, the values of ALP, γ-GT, Fe, and LDH are higher during the reproductive season. These biochemical variations showed important differences in the parameters, underlining their importance in assessing the health status of turtles and better understanding their physiology during different stages of their lives. Full article