scholarly journals New Genetic Insights About Hybridization and Population Structure of Hawksbill and Loggerhead Turtles From Brazil

2020 ◽  
Vol 111 (5) ◽  
pp. 444-456
Author(s):  
Larissa S Arantes ◽  
Sibelle T Vilaça ◽  
Camila J Mazzoni ◽  
Fabrício R Santos

Abstract An extremely high incidence of hybridization among sea turtles is found along the Brazilian coast. This atypical phenomenon and its impact on sea turtle conservation can be elucidated through research focused on the evolutionary history of sea turtles. We assessed high-quality multilocus haplotypes of 143 samples of the 5 species of sea turtles that occur along the Brazilian coast to investigate the hybridization process and the population structure of hawksbill (Eretmochelys imbricata) and loggerhead turtles (Caretta caretta). The multilocus data were initially used to characterize interspecific hybrids. Introgression (F2 hybrids) was only confirmed in hatchlings of F1 hybrid females (hawksbill × loggerhead), indicating that introgression was either previously overestimated and F2 hybrids may not survive to adulthood, or the first-generation hybrid females nesting in Brazil were born as recent as few decades ago. Phylogenetic analyses using nuclear markers recovered the mtDNA-based Indo-Pacific and Atlantic lineages for hawksbill turtles, demonstrating a deep genetic divergence dating from the early Pliocene. In addition, loggerhead turtles that share a common feeding area and belong to distinct Indo-Pacific and Atlantic mtDNA clades present no clear genetic differentiation at the nuclear level. Finally, our results indicate that hawksbill and loggerhead rookeries along the Brazilian coast are likely connected by male-mediated gene flow.

Author(s):  
Larissa S. Arantes ◽  
Sibelle T. Vilaça ◽  
Camila J. Mazzoni ◽  
Fabrício R. Santos

AbstractAn extremely high incidence of hybridization among sea turtles is found along the Brazilian coast. To understand this atypical phenomenon and its impact on sea turtle conservation, research focused in the evolutionary history of sea turtles is fundamental. We assessed high quality multilocus haplotypes of 143 samples of the five species of sea turtles that occur along the Brazilian coast to investigate the hybridization process and the population structure of hawksbill (Eretmochelys imbricata) and loggerhead turtles (Caretta caretta). The multilocus data were initially used to characterize interspecific hybrids. Introgression (F2 hybrids) was only confirmed in hatchlings of F1 hybrid females (hawksbill × loggerhead), indicating that introgression was either previously overestimated and F2 hybrids may not survive to adulthood, or the first-generation hybrid females nesting in Brazil were born as recent as few decades ago. Phylogenetic analyses using nuclear markers recovered the mtDNA-based Indo-Pacific and Atlantic lineages for hawksbill turtles, demonstrating a deep genetic divergence dating from the early Pliocene. In addition, loggerhead turtles that share a common feeding area and belong to distinct Indo-Pacific and Atlantic mtDNA clades present no clear genetic differentiation at the nuclear level. Finally, our results indicate that hawksbill and loggerhead rookeries along the Brazilian coast are likely connected by male-mediated gene flow.


2020 ◽  
Vol 42 ◽  
pp. 95-108
Author(s):  
TF Scheelings ◽  
RJ Moore ◽  
TTH Van ◽  
M Klaassen ◽  
RD Reina

The microbiota of metazoans can be influenced by a variety of factors including diet, environment and genetics. In this study we sampled multiple populations from 2 host species that do not overlap in distribution, in order to test whether their bacterial microbiotas are species-specific or more variable. Intestinal swabs were collected from loggerhead turtles originating from Florida, USA, and Queensland, Australia, as well as from flatback turtles from Crab Island, Queensland, and Port Hedland, Western Australia. We then manually extracted bacterial DNA and used 16S rRNA sequencing to explore bacterial microbial community composition and structure. Our investigation showed that the bacterial microbiota of sea turtles is heavily influenced by geography, with loggerhead turtles originating from the USA and Australia harbouring significantly different bacterial microbial populations in terms of composition. Similarly, we also found that flatback turtles from Crab Island had significantly less diverse microbiotas, with a predominance of the bacterial phylum Firmicutes, in comparison to their genetically similar counterparts from Port Hedland. Factors that may explain these observed differences between populations include host genetics, differences in foraging habitat quality and differences in migratory distance (and thus durations of inappetence) between foraging and breeding grounds. The mechanisms by which these factors may influence bacterial microbial composition of sea turtle gastrointestinal tracts warrants further investigation. The results of this study highlight the importance of interpreting microbiota data of wild animals in the context of geography.


2017 ◽  
Vol 9 (1) ◽  
pp. 171-177
Author(s):  
Adrian Bonilla Salazar ◽  
Oscar Brenes Arias

Groups of hawksbill sea turtles have been observed over the years, close to the coast of the Marino Ballena National Park. For this reason, in February 2015, we monitored its coast to identify aggregation sites. Turtle size estimates, and identification, were done by direct observation by the divers and from the boat. From February to December 2015, fourteen monitor records per sampling point were done and 41 turtles were recorded. They were 30cm - 80cm long and 59% of the individuals aggregated in one sample point. Five genera of sponges were registered as potential food: Haliclona sp, Spirastrella sp, Mycale sp, Aplyscina sp and Axinella sp and one tunicate, Rhopalaea birkelandi. The E. imbricata population was mainly composed of juveniles, and the turtles were found in zones where they have not been previously reported.


PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0246241
Author(s):  
David P. Robinson ◽  
Kevin Hyland ◽  
Gerhard Beukes ◽  
Abdulkareem Vettan ◽  
Aneeshkumar Mabadikate ◽  
...  

The rehabilitation of wildlife can contribute directly to the conservation of threatened species by helping to maintain wild populations. This study focused on determining the post-rehabilitation survival and spatial ecology of sea turtles and on comparing the movements of individuals with flipper amputations (amputees) to non-amputee animals. Our aims were to assess whether rehabilitated sea turtles survive after release, to compare and contrast the movement characteristics of the different species of sea turtles we tracked, and to examine whether amputees and non-amputees within species behaved similarly post-release. Twenty-six rehabilitated sea turtles from four species, including hawksbill Eretmochelys imbricata (n = 12), loggerhead Caretta caretta (n = 11), green Chelonia mydas (n = 2), and olive ridley Lepidochelys olivacea (n = 1) sea turtles from the United Arab Emirates were fitted with satellite tags before release. Rehabilitation times ranged from 89 to 817 days (mean 353 ± 237 days). Post-release movements and survival were monitored for 8 to 387 days (mean 155 ± 95 days) through satellite tracking. Tag data suggested that three tracked sea turtles died within four days of release, one after 27 days, and one after 192 days from what are thought to be anthropogenic factors unrelated to their pre-rehabilitation ailments. We then compared habitat use and movement characteristics among the different sea turtle species. Although half of all turtles crossed one or more international boundaries, dispersal varied among species. Loggerhead turtles had a high dispersal, with 80% crossing an international boundary, while hawksbill turtles displayed higher post-release residency, with 66% remaining within UAE territorial waters. Amputee turtles moved similarly to non-amputee animals of the same species. Loggerhead turtles travelled faster (mean ± sd = 15.3 ± 8 km/day) than hawksbill turtles (9 ± 7 km/day). Both amputee and non-amputee sea turtles within a species moved similarly. Our tracking results highlight that rehabilitated sea turtles, including amputees, can successfully survive in the wild following release for up to our ~one-year monitoring time therefore supporting the suitability for release of sea turtles that have recovered from major injuries such as amputations. However, more broadly, the high mortality from anthropogenic factors in the Arabian Gulf region is clearly a serious issue and conservation challenge.


PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0253916
Author(s):  
Chelsea E. Clyde-Brockway ◽  
Christina R. Ferreira ◽  
Elizabeth A. Flaherty ◽  
Frank V. Paladino

In this study, we applied multiple reaction monitoring (MRM)-profiling to explore the relative ion intensity of lipid classes in plasma samples from sea turtles in order to profile lipids relevant to sea turtle physiology and investigate how dynamic ocean environments affect these profiles. We collected plasma samples from foraging green (Chelonia mydas, n = 28) and hawksbill (Eretmochelys imbricata, n = 16) turtles live captured in North Pacific Costa Rica in 2017. From these samples, we identified 623 MRMs belonging to 10 lipid classes (sphingomyelin, phosphatidylcholine, free fatty acid, cholesteryl ester, phosphatidylserine, phosphatidylinositol, phosphatidylglycerol, phosphatidylethanolamine, ceramide, and triacylglyceride) and one metabolite group (acyl-carnitine) present in sea turtle plasma. The relative ion intensities of most lipids (80%) were consistent between species, across seasons, and were not correlated to body size or estimated sex. Of the differences we observed, the most pronounced was the differences in relative ion intensity between species. We identified 123 lipids that had species-specific relative ion intensities. While some of this variability is likely due to green and hawksbill turtles consuming different food items, we found indications of a phylogenetic component as well. Of these, we identified 47 lipids that varied by season, most belonging to the structural phospholipid classes. Overall, more lipids (n = 39) had higher relative ion intensity in the upwelling (colder) season compared to the non-upwelling season (n = 8). Further, we found more variability in hawksbill turtles than green turtles. Here, we provide the framework in which to apply future lipid profiling in the assessment of health, physiology, and behavior in endangered sea turtles.


Animals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1490
Author(s):  
Amanda James ◽  
Annie Page-Karjian ◽  
Kate E. Charles ◽  
Jonnel Edwards ◽  
Christopher R. Gregory ◽  
...  

Chelonid alphaherpesvirus 5 (ChHV5) is strongly associated with fibropapillomatosis, a neoplastic disease of sea turtles that can result in debilitation and mortality. The objectives of this study were to examine green (Chelonia mydas), hawksbill (Eretmochelys imbricata), and leatherback (Dermochelys coriacea) sea turtles in Grenada, West Indies, for fibropapillomatosis and to utilize ChHV5-specific PCR, degenerate herpesvirus PCR, and serology to non-invasively evaluate the prevalence of ChHV5 infection and exposure. One-hundred and sixty-seven turtles examined from 2017 to 2019 demonstrated no external fibropapilloma-like lesions and no amplification of ChHV5 DNA from whole blood or skin biopsies. An ELISA performed on serum detected ChHV5-specific IgY in 18/52 (34.6%) of green turtles tested. In 2020, an adult, female green turtle presented for necropsy from the inshore waters of Grenada with severe emaciation and cutaneous fibropapillomas. Multiple tumors tested positive for ChHV5 by qPCR, providing the first confirmed case of ChHV5-associated fibropapillomatosis in Grenada. These results indicate that active ChHV5 infection is rare, although viral exposure in green sea turtles is relatively high. The impact of fibropapillomatosis in Grenada is suggested to be low at the present time and further studies comparing host genetics and immunologic factors, as well as examination into extrinsic factors that may influence disease, are warranted.


2021 ◽  
Vol 16 (4) ◽  
pp. 521-538
Author(s):  
Raísa da Silva Costa Rêgo ◽  
Eric Azevedo Cazetta ◽  
Caio Henrique Gonçalves Cutrim ◽  
Amanda Soares Miranda ◽  
Ana Paula Albano Araújo ◽  
...  

The south-western region of the Atlantic Ocean has feeding and nesting areas for the five species of sea turtles registered in Brazil, which are in different degrees of extinction threat, mainly due to anthropogenic factors. Fishing and the ingestion of solid waste, were identified as causing stranding and the mortality of sea turtles. In this work, data from the monitoring of beaches in the Municipalities of Macaé and Rio das Ostras, important oil zone in Brazil, in the north-central region of the State of Rio de Janeiro, were used in order to analyse the effects of seasonality on the sea turtle stranding. The monitoring was carried out daily from September 2017 to June 2019, in a study area covering 23.8 km long beach. Stranding data were obtained from active (n = 126) and passive (n = 66) monitoring of beaches and included the records of Chelonia mydas (n = 151), Caretta caretta (n = 23), Lepidochelys olivacea (n = 14), Dermochelys coriacea (n = 2) and Eretmochelys imbricata (n = 1). The largest stranding record occurred in the summer (n = 61) and spring (n = 60), a period compatible with the reproductive season of the species. The results obtained in this study emphasise the importance of the analysis of strandings of sea turtles, which provide relevant data on the biology of the group, the intra and interspecific dynamics and the state of conservation of these animals.


2012 ◽  
Vol 13 (2) ◽  
pp. 239 ◽  
Author(s):  
L. GAROFALO ◽  
A. ZACCARONI ◽  
D. SCARAVELLI ◽  
G. INSACCO ◽  
M.P. ZANGRILLI ◽  
...  

A putative hybrid sea turtle juvenile was evaluated with discriminant DNA markers. When compared with standard values for sea turtles, the general morphological features assigned the specimen to Caretta caretta, while the shape and coloration of the head and the beak profile fell within the Eretmochelys imbricata range; the front flippers were instead like those of a Chelonia mydas. Moreover, prefrontal scale number was outside the putative parental species’ ranges. The mitochondrial D-loop sequence was from C. caretta, and matched haplotype CC-A2.1, the most common in the Mediterranean. Sequence profiles at three nuclear loci withspecies-specific substitutions (Cmos, BDNF and R35) revealed only C. caretta variants, thus excluding that the individual wasan F1 hybrid. This study highlights the importance of integrating different methodological approaches to understand reproductive animal biology and to set the boundaries for specific morphological traits. In particular, we propose the genetic analysis of a new combination of mitochondrial and nuclear markers as a standard procedure which can be adopted in the identification of sea turtlehybrids.


1998 ◽  
Vol 49 (5) ◽  
pp. 409 ◽  
Author(s):  
A. R. Pople ◽  
A. N. Gordon ◽  
J. Ng

The concentrations of some or all of arsenic (As), cadmium (Cd), mercury (Hg), selenium (Se) and zinc (Zn) were determined in the livers and kidneys of 50 stranded sea turtles (38 Chelonia mydas, eight Caretta caretta, three Eretmochelys imbricata, one Lepidochelys olivacea) from the Moreton Bay region of south-eastern Queensland, Australia. Concentrations of Cd, Se and Zn in the kidney tended to decrease with age, whereas concentrations of Zn in the liver tended to increase. Concentrations of Cd in all sea turtle species (1.7–75.9 µg g-1 wet weight) were amongst the highest recorded for marine vertebrates globally. Although there was no obvious association between metal concentrations and particular diseases in C. mydas, the high concentrations of Cd found in edible turtle tissues may pose a threat to the health of indigenous people whose diet includes C. mydas.


2020 ◽  
Author(s):  
Ruth Maggeni ◽  
William E Feeney

AbstractSea turtle populations are declining and evidence-based methods for supporting their populations are required. Captive breeding and release programs can be effective, offering the opportunity to supplement nature populations; however, sea turtles require specific conditions to successfully breed. Here, we present insights gained from a 16 year Hawksbill sea turtle (Eretmochelys imbricata) captive breeding program that was conducted at the Underwater Observatory Marine Park, Eilat, Israel, between 1982-1997. As the first program of its kind for the Hawksbill sea turtle, insights were gained largely through trial-and-error and word of mouth advice. The key insight gained during this program was the critical importance of pre-breeding separation of the sexes; turtles did not breed prior to pre-breeding separation being implemented, but it became predictably regular once it was. Over the course of the program, 161 two-three years old hatchlings were introduced to the Red Sea, which was enabled largely as a result of pre-breeding separation being implemented.


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