Isotopic niche overlap among foraging marine turtle species in the Gulf of Mexico.

Sympatric species may overlap in their use of habitat and dietary resources, which can increase competition. Comparing the ecological niches and quantifying the degree of niche overlap among these species can provide insights into the extent of resource overlap. This information can be used to guide multispecies management approaches tailored to protect priority habitats that offer the most resources for multiple species. Stable isotope analysis is a valuable tool used to investigate spatial and trophic niches, though few studies have employed this method for comparisons among sympatric marine turtle species. For this study, stable carbon, nitrogen, and sulfur isotope values from epidermis tissue were used to quantify isotopic overlap and compare isotopic niche size in loggerhead (Caretta caretta), green (Chelonia mydas), and Kemp's ridley (Lepidochelys kempii) turtles sampled from a shared foraging area located offshore of Crystal River, Florida, USA. Overall, the results revealed high degrees of isotopic overlap (>68%) among species, particularly between loggerhead and Kemp's ridley turtles (85 to 91%), which indicates there may be interspecific competition for resources. Samples from green turtles had the widest range of isotopic values, indicating they exhibit higher variability in diet and habitat type. Samples from loggerhead turtles had the most enriched mean δ34S, suggesting they may forage in slightly different micro-environments compared with the other species. Finally, samples from Kemp's ridley turtles exhibited the smallest niche size, which is indicative of a narrower use of resources. This is one of the first studies to investigate resource use in a multispecies foraging aggregation of marine turtles using three isotopic tracers. These findings provide a foundation for future research into the foraging ecology of sympatric marine turtle species and can be used to inform effective multispecies management efforts.

Concentrations of polycyclic aromatic hydrocarbons (PAHs) in liver samples of green turtles Chelonia mydas stranded in the Potiguar Basin, northeastern Brazil.

Sea turtles are affected by pollutants worldwide, and the polycyclic aromatic hydrocarbons (PAHs) have been detected in different types of samples and at high levels in some cases. The present study brings concentrations of 37 PAHs in liver samples of 17 green turtles Chelonia mydas stranded in northeastern Brazil [four with cutaneous tumors of fibropapillomatosis (FP), being classified as FP+]. Six PAHs were detected in 100% of the liver samples, and all alkylated PAHs were frequently quantified. High levels of phenanthrene (771.20 and 794.43 ng g-1 d.w.) and fluorene (1882.36 ng g-1 d.w.) were found in three females FP- (without FP cutaneous tumors). On the other hand, one green turtle FP+ had the higher level of naphthalene (531.70 ng g-1 d.w.), compound detected in 82.35 % of the samples. Our study brings additional baseline of organic pollutants in green turtles, improving knowledge on bioaccumulation of these compounds in sea turtles.

Natal Origin and Spatiotemporal Distribution of Leatherback Turtle (Dermochelys coriacea) Strandings at a Foraging Hotspot in Temperate Waters of the Southwest Atlantic Ocean.

Leatherback turtles migrate long distances between nesting beaches and distant foraging areas worldwide. This study analyzes the genetic diversity, life history stage, spatiotemporal distribution, and associated threats of a foraging aggregation in the Southwest Atlantic Ocean. A total of 242 leatherbacks stranded or bycaught by artisanal fisheries were recorded from 1997 to 2021 in Uruguay, with sizes ranging from 110.0 to 170.0 cm carapace lengths, indicating that the aggregation is composed of large juveniles and adults. Results of Bayesian mixed-stock analysis show that leatherbacks come primarily from the West African rookeries, based on mitochondrial DNA sequences obtained from 59 of the turtles representing seven haplotypes, including a novel one (Dc1.7). The main threat identified in the area is the fisheries bycatch but most of the carcasses observed were badly decomposed. There was significant seasonal and interannual variability in strandings that is likely associated with the availability of prey and the intensity of the fishing effort. Taken together, these findings reinforce the importance of these South American foraging areas for leatherbacks and the need to determine regional habitat use and migratory routes across the broader Atlantic region, in order to develop effective conservation measures to mitigate threats both at nesting beaches and foraging areas.

Neoctangium travassosi (Digenea: Microscaphidiidae) in sea turtles from South America / Neoctangium travassosi (Digenea: Microscaphidiidae) em tartarugas marinhas da América do Sul

Sea turtles are endangered animals that present cosmopolitan distribution. Anthropic actions have been considered important causes for the reduction of sea turtle population, but natural aspects such as parasitism may also contribute to their decline. This study aimed to report the occurrence of parasites in stranded dead sea turtles found in an area known as Potiguar Basin, northeastern Brazil, from 2010 to 2019. They were identified and classified according to the carapace length. At post-mortem analyses all organs were examined, parasites collected and morphologically identified. Ecological parasitic indexes as prevalence (P), mean intensity (MI) and mean abundance (MA) were calculated. A total of 80 Chelonia mydas and 5 Eretmochelys imbricata were assessed. Neoctangium travassosi was detected in both species presenting P = 20%, MI = 4.19 and MA = 0.84 for C. mydas and P = 60%, MI = 1.67 and MA = 1.0 for E. imbricata. This is the first report of N. travassosi parasitizing E. imbricata in South America. Finally, the retrieval of these parasites is a warning regarding the need for further studies to assess the impact of this parasitism on the health and conservation of sea turtles.

As tartarugas marinhas são animais ameaçados de extinção que apresentam distribuição cosmopolita. Ações antrópicas têm sido consideradas causas importantes para a redução da população de tartarugas marinhas, mas aspectos naturais, como o parasitismo, também, podem contribuir para o seu declínio. Este estudo objetivou relatar a ocorrência de parasitos em tartarugas marinhas, encalhadas mortas, encontradas em uma área conhecida como Bacia Potiguar, nordeste do Brasil, de 2010 a 2019. Essas foram identificadas e classificadas de acordo com o comprimento da carapaça. Nas análises post mortem, todos os órgãos foram examinados, e os parasitos coletados e identificados morfologicamente. Foram calculados índices parasitários ecológicos, como prevalência (P), intensidade média (IM) e abundância média (AM). Um total de 80 Chelonia mydas e cinco Eretmochelys imbricata foi estudado. Neoctangium travassosi foi detectado em ambas as espécies, apresentando P = 20%, MI = 4,19 e MA = 0,84 para C. mydas e P = 60%, IM = 1,67 e AM = 1,0 para E. imbricata. Este é o primeiro relato de N. travassossi parasitando E. imbricata na América do Sul. Conclui-se que a recuperação desses parasitos soa como um alerta para a necessidade de mais estudos para avaliar o impacto desse parasitismo na saúde e na conservação das tartarugas marinhas.

Origins of juvenile green sea turtles (Chelonia mydas) in the Bahamas: A comparison of recent and historical rookery contributions.

Conservation of green sea turtles (Chelonia mydas) benefits from knowledge of population connectivity across life stages. Green turtles are managed at the level of genetically discrete rookeries, yet individuals from different rookeries mix at foraging grounds; therefore, rookeries may be impacted by processes at foraging grounds. Bimini, Bahamas, hosts an important foraging assemblage, but rookery contributions to this assemblage have never been resolved. We generated mitochondrial DNA sequences for 96 foraging green turtles from Bimini and used Mixed Stock Analysis to determine rookery contributions to this population using 817 and 490 base pair (bp) rookery baseline data. The MSA conducted with 817 bp data indicated that Quintana Roo, Mexico, and Central Eastern Florida contributed most to the Bimini population. The MSA conducted with 490 bp data indicated that Southwest Cuba and Central Eastern Florida contributed the most to Bimini. The results of the second MSA differ from a previous study undertaken with 490 bp data, conducted in Great Inagua, Bahamas, which suggested that Tortuguero, Costa Rica, contributed the most to that foraging assemblage. Large credible intervals in our results do not permit explicit interpretation of individual rookery contributions, but our results do indicate substantial relative differences in rookery contributions to two Bahamian foraging assemblages which may be driven by oceanic currents, rookery sizes, and possibly juvenile natal homing. Our findings may implicate a shift in contributions to the Bahamas over two decades, highlighting the importance of regularly monitoring rookery contributions and resolving regional recruitment patterns to inform conservation.

Leucism: the prevalent congenital malformation in the olive ridley sea turtle of northwestern Mexico.

Despite being the most abundant sea turtle in the world, the olive ridley turtle Lepidochelys olivacea is classified as Vulnerable by the IUCN. There is evidence of congenital malformations in hatchlings, and the associated causes are multifactorial, with both genetic and environmental sources. Santuario Playa Ceuta (SPC) is a sanctuary for the olive ridley, located at the northernmost region of its nesting range in the Mexican Pacific. The objective of this study was to identify and quantify the prevalence and severity of congenital malformations in olive ridley embryos/hatchlings in SPC during the 2017 nesting season. We collected 62907 eggs from 643 relocated nests that were moved to a hatchery, of which 4242 eggs with obvious development did not hatch and were analyzed for this study. Hatching success was 53.9%, with 22.5% of nests (n = 145) and 0.54% of eggs (n = 344) showing embryos or hatchlings with malformations. The nest severity index was 2.4 (range: 1-10) malformed embryos or hatchlings per nest, and the organism severity index was 1.4 (range: 1-7) malformations per malformed embryo or hatchling. Leucism was the most prevalent malformation (34.4%; 170/494 total observed), with the craniofacial region showing the greatest diversity of malformations (17/35 types). Given the geographical position of SPC, extreme environmental conditions (e.g. cold, heat, and dryness) could be one of the main causes of teratogenesis in this species. However, more studies are needed regarding the presence of contaminants, genetic factors, health assessments of nesting females, and malformation rates of nests that remain in situ versus those that are relocated.

Threats and Vulnerabilities for the Globally Distributed Olive Ridley (Lepidochelys olivacea) Sea Turtle: A Historical and Current Status Evaluation.

The olive ridley (Lepidochelys olivacea) is the most abundant of all seven sea turtles, found across the tropical regions of the Atlantic, Pacific, and Indian Oceans in over 80 different countries all around the globe. Despite being the most common and widely distributed sea turtle, olive ridley populations have been declining substantially for decades. Worldwide, olive ridleys have experienced a 30-50% decline, putting their populations at risk and being considered an Endangered Species by the IUCN. Natural habitat degradation, pollution, bycatch, climate change, predation by humans and animals, infectious diseases and illegal trade are the most notorious threats to explain olive ridley populations rapidly decline. The present review assesses the numerous dangers that the olive ridley turtle has historically faced and currently faces. To preserve olive ridleys, stronger conservation initiatives and strategies must continue to be undertaken. Policies and law enforcement for the protection of natural environments and reduction in the effects of climate change should be implemented worldwide to protect this turtle species.

Fibropapillomatosis Prevalence and Distribution in Immature Green Turtles (Chelonia mydas) in Martinique Island (Lesser Antilles).

Fibropapillomatosis (FP) threatens the survival of green turtle (Chelonia mydas) populations at a global scale, and human activities are regularly pointed as causes of high FP prevalence. However, the association of ecological factors with the disease's severity in complex coastal systems has not been well established and requires further studies. Based on a set of 405 individuals caught over ten years, this preliminary study provides the first insight of FP in Martinique Island, which is a critical development area for immature green turtles. Our main results are: (i) 12.8% of the individuals were affected by FP, (ii) FP has different prevalence and temporal evolution between very close sites, (iii) green turtles are more frequently affected on the upper body part such as eyes (41.4%), fore flippers (21.9%), and the neck (9.4%), and (iv) high densities of individuals are observed on restricted areas. We hypothesise that turtle's aggregation enhances horizontal transmission of the disease. FP could represent a risk for immature green turtles' survival in the French West Indies, a critical development area, which replenishes the entire Atlantic population. Continuing scientific monitoring is required to identify which factors are implicated in this panzootic disease and ensure the conservation of the green turtle at an international scale.

First report of fibropapillomatosis (FP) and Chelonid alphaherpesvirus 5 (ChHV5) in a green sea turtle (Chelonia mydas) from the historically fibropapillomatosis-free Fernando de Noronha Archipelago, Northeastern Brazil / Primeiro caso de fibropapilomatose (FP) e de Chelonid alphaherpesvirus 5 (ChHV5) em tartaruga-verde (Chelonia mydas) no Arquipélago de Fernando de Noronha, Nordeste do Brasil

Fibropapillomatosis (FP) is an infectious disease caused by Chelonid alphaherpesvirus 5 (ChHV5). Nevertheless, its clinical manifestations are considered multifactorial. Due to its relevance, FP is currently monitored in sea turtle populations in the United States, Australia, Caribbean, and Brazil. Between 2000 and 2020, the TAMAR Project/ TAMAR Project Foundation analyzed the prevalence of FP in nine states and oceanic islands along the Brazilian coast, including Fernando de Noronha Archipelago (FNA), a historically FP-free area. A total of 4,435 green sea turtles (Chelonia mydas) were monitored from 2010 to 2016. Additionally, in 2012 and 2014, 43 FP-free skin samples were analyzed for ChHV5 using a qualitative PCR for the UL30 polymerase (pol) sequence. In 2015, a bilateral ocular nodule characterized as an FP tumor was reported in one of the monitored individuals undergoing rehabilitation. Tissue samples were collected following surgical removal of the tumor. Characterization of a 454 bp UL30 polymerase gene revealed a ChHV5 sequence previously reported in other areas of the Atlantic Brazilian coast. In the years following this finding from January 2017 to March 2020, a total of 360 C. mydas were monitored in the same area and no FP tumors were detected. This is the first report of FP and the first detection of ChHV5 in FNA, a finding of great concern considering this site's historical absence of FP occurrence. This study highlights the importance of monitoring this disease in historically FP-free areas of the Brazilian Atlantic coast.(AU)

A fibropapilomatose (FP) é uma doença infecciosa causada pelo Chelonid alphaherpesvirus 5 (ChHV5). No entanto, as manifestações clínicas da doença são consideradas multifatoriais. Esta doença é monitorada atualmente em populações de tartarugas marinhas nos EUA, Austrália, Caribe e Brasil. Desde 2000, o Projeto TAMAR/Fundação Projeto TAMAR analisa a presença de FP em nove estados da costa brasileira e ilhas oceânicas, incluindo o arquipélago de Fernando de Noronha, uma área historicamente livre de FP. Um total de 4.435 indivíduos de Chelonia mydas foram monitorados de 2010 a 2016 e 43 amostras de pele foram analisadas para detectar ChHV5 em 2012 e 2014 com o objetivo de avaliar a presença do vírus em tecidos sem FP, usando uma PCR qualitativa para detecção de sequências do gene da UL30 polimerase. Em 2015, uma tartaruga verde (C. mydas) foi relatada com um nódulo ocular bilateral caracterizado como FP. Amostras de tecido foram coletadas durante sua reabilitação e procedimento cirúrgico para remover o tumor. A caracterização parcial de uma sequência de 454 bp do gene UL30 polimerase detectou ChHV5 anteriormente relatado em outras áreas da costa atlântica brasileira. Após estes achados, de janeiro de 2017 a março de 2020, um total de 360 indivíduos de C. mydas foram monitorados e nenhum caso de FP foi registrado. Este é o primeiro relato de FP e a primeira caracterização de ChHV5 no arquipélago de Fernando de Noronha, uma questão preocupante e que ressalta a importância do monitoramento desta doença em áreas historicamente livres de FP na costa atlântica brasileira.(AU)

Persistent organic pollutants in plasma and stable isotopes in red blood cells of Caretta caretta, Chelonia mydas and Lepidochelys olivacea sea turtles that nest in Brazil.

Studies of persistent organic pollutants (POPs), such as polychlorinated biphenyls (PCBs), organochlorinated pesticides (OCPs), and polybrominated diphenyl ethers (PBDEs), in sea turtles are reported, but there are still spatial data gaps worldwide. POP contamination of live female blood plasma from Caretta caretta (n = 28), Chelonia mydas (n = 31) and Lepidochelys olivacea (n = 19), which nest in Brazil and feed along the South Atlantic Ocean, was investigated. Carbon and nitrogen stable isotopes from red blood cells (RBC) were also evaluated to obtain information about trophic ecology. C. caretta had the highest POP concentrations, followed by L. olivacea and C. mydas. PCBs predominated in all species, and the major OCPs were the DDTs (dichlorodiphenyltrichloroethane and derivatives) and Lindane. POPs and stable isotopes revealed intra- and interspecific variations, which reflect the high plasticity in the use of habitat and food resources, making individuals within the same population susceptible to different exposures to pollutants.

Prevalence and phenotypic characterization of Salmonella enterica isolates from three species of wild marine turtles in Grenada, West Indies.

BACKGROUND AND AIM: Salmonella enterica causes enteric disease in mammals and may potentially be transmitted from marine turtles that shed the pathogen in the environment. Marine turtle-associated human salmonellosis is a potential public health concern in Grenada, as the island supports populations of leatherback turtles (Dermochelys coriacea), hawksbill turtles (Eretmochelys imbricata), and green turtles (Chelonia mydas) that interface with veterinarians and conservation workers, the local population, and the thousands of visitors that frequent the island yearly. To date, the prevalence of S. enterica has only been examined in a small subset of marine turtles in the Caribbean and no studies have been conducted in Grenada. The aim of this study was to quantify the prevalence of S. enterica in leatherback, hawksbill and green turtles in Grenada, characterize phenotypes and DNA profiles, and explore the potential risk to human health in the region. MATERIALS AND METHODS: A total of 102 cloacal swabs were obtained from nesting leatherback turtles and foraging hawksbill and green turtles. Samples were cultured on enrichment and selective media and isolates were phenotypically characterized using serotyping, pulsed-phase gel electrophoresis, and antibiotic susceptibility. Enrichment broths were additionally screened by polymerase chain reaction (PCR) using S. enterica-specific primers. RESULTS: S. enterica was cultured from 15/57 (26.3%) leatherback turtles, 0/28 hawksbill, and 0/17 green turtles. This included S. enterica serovars Montevideo, S. I:4,5,12:i:-, Salmonella Typhimurium, Salmonella Newport, S. I:6,7:-:-, and S. I:4,5,12:-:-. Five/15 leatherback turtles carried multiple serovars. Eight pulsotype groups were identified with multiple clustering; however, there was no clear association between pulsotype group and serotype profile. Five/71 isolates showed resistance to streptomycin or ampicillin. Twenty-one/57 leatherback turtles, 14/28 hawksbill turtles, and 8/17 green turtles tested positive for S. enterica by quantitative PCR. CONCLUSION: Nesting leatherback turtles actively shed S. enterica and poses a risk for zoonosis; however, the presence of viable pathogen in green and hawksbill species is unclear. These findings help elucidate the role of marine turtles as potential sources of zoonotic S. enterica and provide baseline data for one health research in Grenada and the wider Caribbean region.

Sex ratio of the green sea turtle Chelonia mydas (Testudines: Cheloniidae) hatchlings in the Guanahacabibes Peninsula, Cuba / Proporción sexual de las crías de la tortuga verde Chelonia mydas (Testudines: Cheloniidae) en la Península de Guanahacabibes, Cuba

Introduction: Sea turtles have temperature dependent sex determination. The increase in global temperature leads to higher nest temperatures that can cause a prevalence of females, threatening the future of these species. Objective: The present work aims to evaluate the trend of incubation temperatures and the incubation period, as well as to estimate the sex ratio in nests of Chelonia mydas at Antonio and La Barca beaches, Southwestern Cuba, during the seasons from 2012 to 2018. Methods: Temperature data loggers were placed in green turtle nests with a representativeness that varied between the years analyzed. To assess the temporal variation of temperatures and incubation periods, a Kruskal-Wallis test was performed in each case. Sex ratio was estimated from its relation with temperature and incubation duration. Results: At La Barca beach, there was a 1.5 °C increase in the mean nest temperature from 2012 to 2018, although no differences were found in the period from 2015 to 2018. At Antonio beach, there is no trend since no differences were found in the mean nest temperature except for the years 2013 and 2017, which had lower temperatures than the other seasons. In both beaches mean nest temperature exceeded 30 °C in most of the years. As a result, there was a predominance of nests with incubation periods shorter than 55 days. With these values, a female hatchling production over 90 % is expected in both study sites. Conclusions: In correspondence with the registered temperature and incubation period values, most of the years reflect a hatchling production biased towards females in both beaches.

Introducción: La determinación del sexo en tortugas marinas depende de la temperatura. El aumento de la temperatura global conlleva a temperaturas más altas en los nidos, lo cual puede provocar un predominio de las hembras, amenazando el futuro de estas especies. Objetivo: El presente trabajo busca evaluar la tendencia de las temperaturas y los períodos de incubación, así como estimar la proporción sexual en nidos de Chelonia mydas,en las playas Antonio y La Barca, suroeste de Cuba, durante las temporadas del 2012 al 2018. Métodos: Se colocaron sensores para registrar la temperatura en los nidos de esta especie con una representatividad que varió entre los años analizados. Para evaluar la variación temporal de las temperaturas y los periodos de incubación, se realizó una prueba de Kruskal-Wallis en cada caso. Las estimaciones de las proporciones sexuales se realizaron a partir de la temperatura y duración de la incubación. Resultados: En playa La Barca, hubo un incremento de 1.5 °C en la temperatura promedio del nido del 2012 al 2018, aunque no se encontraron diferencias en el periodo de 2015-2018. En playa Antonio, no hay tendencia ya que no se encontraron diferencias en la temperatura promedio del nido, excepto para el 2013 y 2017, los cuales tuvieron temperaturas menores que en las otras temporadas. En ambas playas la temperatura promedio del nido excedió 30 °C en la mayoría de los años. Como resultado, hubo un predominio de nidos con periodos de incubación inferiores a 55 días. Con estos valores, se espera una producción de hembras en las crías superior al 90 % en ambos sitios de estudio. Conclusiones: En correspondencia con los valores de temperatura y periodo de incubación registrados, la mayoría de los años refleja una producción de crías sesgada hacia las hembras en ambas playas.

Fingers zipped up or baby mittens? Two main tetrapod strategies to return to the sea.

The application of network methodology in anatomical structures offers new insights on the connectivity pattern of skull bones, skeletal elements and their muscles. Anatomical networks helped to improve our understanding of the water-to-land transition and how the pectoral fins were transformed into limbs via their modular disintegration. Here, we apply the same methodology to tetrapods secondarily adapted to the marine environment. We find that these animals achieved their return to the sea with four types of morphological changes, which can be grouped into two different main strategies. In all marine mammals and the majority of the reptiles, the fin is formed by the persistence of superficial and interdigital connective tissues, like a 'baby mitten', whereas the underlying connectivity pattern of the bones does not influence the formation of the forefin. On the contrary, ichthyosaurs 'zipped up' their fingers and transformed their digits into carpal-like elements, forming a homogeneous and better-integrated forefin. These strategies led these vertebrates into three different macroevolutionary paths exploring the possible spectrum of morphological adaptations.

Genetic Analysis of Chelonid Herpesvirus 5 in Marine Turtles from Baja California Peninsula.

The Chelonid herpesvirus 5 (ChHV5) is the primary etiological agent associated with fibropapillomatosis (FP), a neoplastic disease in marine turtles. In this study, we report for the first time ChHV5 in marine turtles and a leech from Baja California Peninsula. Eighty-seven black, olive or loggerhead turtle species, one FP tumor and five leeches were analyzed. The tumor sample from an olive, a skin sample from a black and a leech resulted positive of ChHV5 for conventional PCR. Two viral variants were identified and grouped within the Eastern Pacific phylogenetic group, suggesting a possible flow of the virus in this region.

Recent advances on the estimation of the thermal reaction norm for sex ratios.

Temperature-dependent sex determination, or TSD, is a widespread phenomenon in reptiles. The shape of the relationship between constant incubation temperature and sex ratio defines the TSD pattern. The TSD pattern is considered a life-history parameter important for conservation because the wider the range of temperatures producing both sexes, the more resilient the species is to climate change impacts. We review the different published equations and methodologies that have been used to model TSD patterns. We describe a new flexible model that allows for an asymmetrical pattern around the pivotal temperature, which is the constant temperature producing both sexes in equal proportions. We show that Metropolis-Hastings with Markov chain produced by a Monte Carlo process has many advantages compared to maximum likelihood and is preferred. Finally, we apply the models to results from incubation experiments using eggs from the marine turtle Lepidochelys olivacea originating in Northeast Indian, East Pacific, and West Atlantic Regional Management Units (RMUs) and find large differences in pivotal temperatures but not in transitional ranges of temperatures.

Accumulation of trace elements in leatherback turtle (Dermochelys coriacea) eggs from the south-western Caribbean indicates potential health risks to consumers.

Trace metal and metalloid levels were measured in eggs of the NW Atlantic leatherback turtle (Dermochelys coriacea) from nesting grounds in the Bocas del Toro province, Panama, to infer exposure and associated risks to local communities. Samples were analyzed for a set of 26 essential and non-essential elements using inductively coupled plasma techniques. Median concentrations of Fe, Zn, As, Se and Sr in D. coriacea eggs were higher than previously reported for this species, which likely reflects differential contamination levels of specimens during foraging. The evaluation of non-carcinogenic human health risks from ingesting leatherback eggs has revealed potential deleterious effects due to high concentrations of As, Se and Sr for all examined age and gender groups, while Hg and Zn levels were above international standards for children. Hazard index (HI) values exceeded unity in all cases indicating serious health impacts related to possible additive effects of multiple metals co-occurring in the eggs. Our findings suggest that exposure to high (inorganic) As and Cr(VI) levels is associated with an increased carcinogenic risk, significantly exceeding the acceptable lifetime risk of 10-6 for both adults and children. Despite some limitations, such as unclear As and Cr speciation, our results demonstrated that the ingestion of D. coriacea eggs poses considerable health risks to local communities, and their consumption should not exceed 3.4 × 10-4 g (5.0 × 10-6 eggs) kg BW d-1. Resource managers and conservationists should focus their attention to human health effects as an alternative tool to address egg poaching and consumption.

Ingestion of plastic marine litter by sea turtles in southern Brazil: abundance, characteristics and potential selectivity.

The ingestion of plastic marine litter (PML) by sea turtles is widespread and concerning, and the five species that occur in the southwestern Atlantic - green, loggerhead, olive ridley, leatherback and hawksbill - are vulnerable to this pollution. Here, we quantified and characterized PML ingested by these species in southern Brazil, and observed PML ingestion in 49 of 86 sampled individuals (~57.0%). Green turtles presented the highest rates and variety of ingested plastics, and such ingestion has been high at least since 1997. Omnivorous turtles presented higher PML ingestion than carnivorous ones. Loggerheads displayed a negative correlation between body size and number of ingested items. Green turtles ingested mostly flexible transparent and flexible/hard white plastics; loggerheads ate mainly flexible, hard and foam fragments, in white and black/brown colors. These results help us better understand PML ingestion by sea turtles, highlighting the seriousness of this threat and providing information for prevention and mitigation strategies.

La epibiosis en los grandes vertebrados marinos de México: una revisión y su relevancia ecosistémica / Epibiosis in the large marine vertebrates from Mexico: a review and their ecosystemic relevance

En este trabajo se revisan los casos de epibiosis reportados en los grandes vertebrados de México. La revisión de literatura incluye las publicaciones realizadas al mes de junio de 2018 considerando los 17 estados del litoral costero de la república mexicana. Se encontraron 21 trabajos de investigación, los cuales reportan un total de 73 especies epibiontes de flora y fauna asociados superficialmente a ocho especies de grandes vertebrados marinos: Lepidochelys olivácea, Eretmochelys imbricata, Chelonia mydas, Trichechus manatus manatus, Fe resa attenuata, Crocodylus acutus, C. moreletii, Caiman crocodilus chiapasius . El grupo epibionte dominante fueron los crustáceos, especialmente los cirrípedos. La interacción predominante fue el comensalismo, sin embargo se reconocieron grupos parasitarios como los copépodos del genero Balaenophilus que afectan principalmente a tortugas marinas. Se analizó la relevancia del estudio del biofilm, así como sus implicaciones ecológicas, taxonómicas por la presencia de nuevas especies para la ciencia y de conservación de las especies basibiontes para establecer criterios que ayuden a comprender su importancia en los ecosistemas marinos y por lo tanto fomentar su estudio en la región.

The aims of this work is review epibiosis reported on the large marine vertebrates from Mexico. The literature review include reporting cases on any of 17 states of the littoral coast of the Mexican Republic, and those published until June 2018. Twenty one papers were found, which report a total of 73 species of flora and fauna superficially associated with eight species of large marine vertebrates: Lepidochelys olivacea, Eretmochelys imbricata, Chelonia mydas, Trichechus manatus manatus, Feresa attenuata, Crocodylus acutus, C. moreletii, Caiman crocodilus chiapasius . The dominant epibiont group was the crustaceans, especially barnacles. The predominant interaction was commensalism, however, parasitic groups were recognized such as the copepods genus Balaenophilus that affects mainly to sea turtles. The relevance of the study of the biofilm, as well as the ecological implications, the presence of new marine species and the conservation of the basibionts species were analyzed to establish criteria that help to understand the importance in marine ecosystems and therefore encourage their study in the region.

Microplastic at nesting grounds used by the northern Gulf of Mexico loggerhead recovery unit.

Microplastics can impact key habitats used by endangered species, such as marine turtles. They impact the environment by transporting toxicants and altering sediment properties affecting temperature and sediment permeability. Our study determined the exposure of the ten most important nesting sites for the Northern Gulf of Mexico Loggerhead Recovery Unit to microplastic. Sand samples were obtained at each nesting site during the 2017 nesting season and analyzed for abundance and characteristics of microplastic. Microplastic was found at all sites, with an average abundance of 61.08 ±â€¯34.61 pieces/m2, and 59.9% located at the dunes, where turtles primarily nest. A gradual decrease in microplastics abundance was observed from the most western nesting ground to the east. The results from this study indicate that microplastic accumulation on nesting sites for the Northern Gulf of Mexico may be of great concern, and could negatively affect the incubating environment for marine turtles.

Carapace asymmetry: A possible biomarker for metal accumulation in adult olive Ridleys marine turtles?

The Olive Ridley marine turtle (Lepidochelys olivacea) is characterized by individual morphological variability in the number and shape of scutes. The influence of pollutants on developmental instability and one of its consequences, the asymmetry of individuals, has been demonstrated in several species, especially invertebrates and some birds. However, the use of this asymmetry as a biomarker of contamination in adult individuals has never been explored. We developed an index to quantify developmental instability (DIx) based on the number and relative size of costal carapace scutes. The link between DIx and inorganic elements concentrations was explored in various tissues of stranded turtles from the Southern Mexican Pacific. The relationships between adult contamination and DIx could directly or indirectly reflect (i) the disruption of metal elimination in the adult stage dependent on embryonic perturbation and thus determining DIx, (ii) the difference in metal absorption dependent on DIx status, or (iii) DIx linked to other unknown factors.