The gut bacterial microbiota of sea turtles differs between geographically distinct populations

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.

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Satellite tracking of rehabilitated sea turtles suggests a high rate of short-term survival following release

PLoS ONE ◽

10.1371/journal.pone.0246241 ◽

2021 ◽

Vol 16 (2) ◽

pp. e0246241

Author(s):

David P. Robinson ◽

Kevin Hyland ◽

Gerhard Beukes ◽

Abdulkareem Vettan ◽

Aneeshkumar Mabadikate ◽

...

Keyword(s):

Sea Turtles ◽

Sea Turtle ◽

Satellite Tracking ◽

Anthropogenic Factors ◽

Gulf Region ◽

Term Survival ◽

Turtle Species ◽

Movement Characteristics ◽

Loggerhead Turtles ◽

Hawksbill Turtles

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.

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Lipid profiling suggests species specificity and minimal seasonal variation in Pacific Green and Hawksbill Turtle plasma

PLoS ONE ◽

10.1371/journal.pone.0253916 ◽

2021 ◽

Vol 16 (7) ◽

pp. e0253916

Author(s):

Chelsea E. Clyde-Brockway ◽

Christina R. Ferreira ◽

Elizabeth A. Flaherty ◽

Frank V. Paladino

Keyword(s):

Sea Turtles ◽

Multiple Reaction Monitoring ◽

Chelonia Mydas ◽

Sea Turtle ◽

Lipid Classes ◽

Plasma Samples ◽

Lipid Profiling ◽

Eretmochelys Imbricata ◽

Species Specific ◽

Hawksbill Turtles

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.

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New genetic insights about hybridization and population structure of hawksbill and loggerhead turtles from Brazil

10.1101/2020.04.17.046623 ◽

2020 ◽

Cited By ~ 1

Author(s):

Larissa S. Arantes ◽

Sibelle T. Vilaça ◽

Camila J. Mazzoni ◽

Fabrício R. Santos

Keyword(s):

Population Structure ◽

Sea Turtles ◽

Phylogenetic Analyses ◽

Sea Turtle ◽

Brazilian Coast ◽

Eretmochelys Imbricata ◽

F1 Hybrid ◽

F2 Hybrids ◽

Loggerhead Turtles ◽

History Of

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.

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Unearthing the sand microbiome of sea turtle nests with disparate survivorship at a mass-nesting beach in Costa Rica

Aquatic Microbial Ecology ◽

10.3354/ame01941 ◽

2020 ◽

Vol 85 ◽

pp. 71-83

Author(s):

VS Bézy ◽

KM Hill-Spanik ◽

CJ Plante

Keyword(s):

Community Structure ◽

Microbial Community ◽

Costa Rica ◽

Hatching Success ◽

Microbial Community Composition ◽

Sea Turtle ◽

Microbial Pathogens ◽

Olive Ridley ◽

Microbial Composition ◽

Nesting Sites

For endangered sea turtle populations, microbial pathogens of developing embryos are of concern at nesting sites around the globe. For olive ridley turtles, hatching success is markedly lower at mass-nesting sites than at solitary nesting beaches, a case presumably resulting from the abundance of decomposing eggs generated by nesting turtles destroying adjacent eggs. This organic input drives microbial activity, affecting the nest environment (i.e. pO2 and temperature), and reducing embryo survivorship and hatching success. However, the composition of microbial communities in nest sand has not been studied in detail and the presence of potential pathogens can, therefore, not be discounted. As a part of a larger study that investigated microbial abundance in nests, we employed high-throughput DNA sequencing to compare fungal and bacterial composition in nest sand from areas of disparate embryo survivorship. While we found no differences in alpha-diversity (mean operational taxonomic unit diversity within each site) among nesting areas, the microbial community composition of each area was distinct, and differences in community structure corresponded with variable hatching success. Some sequences of potential sea turtle egg pathogens were obtained (e.g. Fusarium solani species complex), but were in low relative abundance, and their presence was not associated with low hatching success. Our results from the arribada beach at Ostional, Costa Rica, provide further evidence that the physical characteristics of the nest (including those that determine microbial composition and activity) are likely more relevant to hatching success than the presence of potential pathogens or microbial community structure alone.

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

Journal of Heredity ◽

10.1093/jhered/esaa024 ◽

2020 ◽

Vol 111 (5) ◽

pp. 444-456

Author(s):

Larissa S Arantes ◽

Sibelle T Vilaça ◽

Camila J Mazzoni ◽

Fabrício R Santos

Keyword(s):

Population Structure ◽

Sea Turtles ◽

Phylogenetic Analyses ◽

Sea Turtle ◽

Brazilian Coast ◽

Eretmochelys Imbricata ◽

F1 Hybrid ◽

F2 Hybrids ◽

Loggerhead Turtles ◽

History Of

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.

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Effects of Ground Transport in Kemp’s Ridley (Lepidochelys kempii) and Loggerhead (Caretta caretta) Turtles

Integrative Organismal Biology ◽

10.1093/iob/obaa012 ◽

2020 ◽

Vol 2 (1) ◽

Author(s):

K E Hunt ◽

C Merigo ◽

E A Burgess ◽

C Loren Buck ◽

D Davis ◽

...

Keyword(s):

Stress Response ◽

Sea Turtles ◽

Clinical Status ◽

Caretta Caretta ◽

Sea Turtle ◽

Cape Cod ◽

Lepidochelys Kempii ◽

Turtle Species ◽

The Usa ◽

Kemp's Ridley

Synopsis Many juvenile Kemp’s ridley (Lepidochelys kempii) and loggerhead (Caretta caretta) turtles strand during fall on the beaches of Cape Cod (MA, USA), with total stranding numbers sometimes exceeding 300 turtles per year. Once rehabilitated, turtles must be released at beaches with appropriate water temperatures, often requiring transportation to southeastern coastal states of the USA. These transportation events (transports) may approach or exceed 24 h in duration. Kemp’s ridley turtles are known to exhibit an adrenal stress response during such transports, but the effect of transport duration has been unclear, and no other sea turtle species has been investigated. To assess whether transport duration and/or species affects physiological reactions to transport, we studied pre- and post-transport physiological measures in Kemp’s ridley and loggerhead turtles transported by ground for <6, ∼12, ∼18, or ∼24 h, comparing with matched “control events” in which turtles were studied without transport. Blood samples were analyzed for four stress-associated measures (corticosterone, glucose, total white blood cell [WBC] count, and heterophil/lymphocyte ratio [H/L]) and nine measures of clinical status (pH, pO2, pCO2, HCO3, sodium, potassium, ionized calcium, lactate, and hematocrit). In both species, stress-associated measures elevated significantly during transport, while handling without transport had no significant effects. Loggerheads exhibited a greater stress response than Kemp’s ridleys across all transport durations. These results indicate that sea turtles do react physiologically to ground transport; therefore, minimizing transport time and streamlining transport logistics (where feasible) may help ensure release of rehabilitated turtles to sea in the best possible condition. Nonetheless, both species remained in good clinical condition even after 24 h transport, indicating that current transport protocols are generally safe for sea turtles from a clinical perspective.

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INVITED ARTICLE FROM THE 2021 TEXAS ACADEMY OF SCIENCE TEXAS DISTINGUISHED SCIENTIST

Texas Journal of Science ◽

10.32011/txjsci_73_1_tds ◽

2021 ◽

Vol 73 (1) ◽

Author(s):

Donna J. Shaver

Keyword(s):

Sea Turtles ◽

Sea Turtle ◽

Leadership Role ◽

Scientific Publications ◽

Corpus Christi ◽

Lifetime Achievement ◽

The Usa ◽

Padre Island ◽

Conservation Projects ◽

Kemp's Ridley

Donna Shaver is the Chief of the Division of Sea Turtle Science and Recovery at Padre Island National Seashore and the Texas Coordinator of the U.S. Sea Turtle Stranding and Salvage Network. She received the Lifetime Achievement Award from the International Sea Turtle Society in 2018, the 2013 U.S. Fish and Wildlife Service Endangered Species Recovery Champion Award for Agency Partner in 2014, the Corpus Christi Caller Times 2011 Newsmaker of the Year in 2012, and she was the ABC World News Tonight’s Person of the Week on July 29, 2005. She has studied Texas sea turtles since 1980 and is well known for her leadership role in the recovery of the critically endangered Kemp’s ridley sea turtle. Her studies describing sea turtle migratory and foraging habitat use, as well as nesting and stranding trends, have led to increased protections for sea turtles in Texas and beyond. With over 400 scientific publications and presentations, Shaver is distinguished as one of the top sea turtle biologists in the USA and was named the 2021 Texas Distinguished Scientist at the annual meeting of the Texas Academy of Science. Shaver oversees a variety of sea turtle research and conservation projects conducted in Texas, collaborates with other researchers in the USA and Mexico, and provides training and leadership to hundreds of biologists and volunteers working with sea turtles in Texas.

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Occurrence and diet analysis of sea turtles in Korean shore

Journal of Ecology and Environment ◽

10.1186/s41610-021-00206-w ◽

2021 ◽

Vol 45 (1) ◽

Author(s):

Jihee Kim ◽

Il-Hun Kim ◽

Min-Seop Kim ◽

Hae Rim Lee ◽

Young Jun Kim ◽

...

Keyword(s):

Dna Analysis ◽

Sea Turtles ◽

Sea Turtle ◽

Diet Analysis ◽

Portunus Trituberculatus ◽

Olive Ridley ◽

Leatherback Turtle ◽

Turtle Species ◽

Green Turtles ◽

Loggerhead Turtles

Abstract Background Sea turtles, which are globally endangered species, have been stranded and found as bycatch on the Korean shore recently. More studies on sea turtles in Korea are necessary to aid their conservation. To investigate the spatio-temporal occurrence patterns of sea turtles on the Korean shore, we recorded sampling locations and dates, identified species and sexes and measured sizes (maximum curved carapace length; CCL) of collected sea turtles from the year 2014 to 2020. For an analysis of diets through stomach contents, we identified the morphology of the remaining food and extracted DNA, followed by amplification, cloning, and sequencing. Results A total of 62 stranded or bycaught sea turtle samples were collected from the Korean shores during the study period. There were 36 loggerhead turtles, which were the dominant species, followed by 19 green turtles, three hawksbill turtles, two olive ridley turtles, and two leatherback turtles. The highest numbers were collected in the year 2017 and during summer among the seasons. In terms of locations, most sea turtles were collected from the East Sea, especially from Pohang. Comparing the sizes of collected sea turtles according to species, the average CCL of loggerhead turtles was 79.8 cm, of green turtles was 73.5 cm, and of the relatively large leatherback turtle species was 126.2 cm. In most species, the proportion of females was higher than that of males and juveniles, and was more than 70% across all the species. Food remains were morphologically identified from 19 stomachs, mainly at class level. Seaweeds were abundant in stomachs of green turtles, and Bivalvia was the most detected food item in loggerhead turtles. Based on DNA analysis, food items from a total of 26 stomachs were identified to the species or genus level. The gulfweed, Sargassum thunbergii, and the kelp species, Saccharina japonica, were frequently detected from the stomachs of green turtles and the jellyfish, Cyanea nozakii, the swimming crab, Portunus trituberculatus, and kelps had high frequencies of occurrences in loggerhead turtles. Conclusions Our findings support those of previous studies suggesting that sea turtles are steadily appearing in the Korean sea. In addition, we verified that fish and seaweed, which inhabit the Korean sea, are frequently detected in the stomach of sea turtles. Accordingly, there is a possibility that sea turtles use the Korean sea as feeding grounds and habitats. These results can serve as basic data for the conservation of globally endangered sea turtles.

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Genomic evidence of recent hybridization between sea turtles at Abrolhos Archipelago and its association to low reproductive output

Scientific Reports ◽

10.1038/s41598-020-69613-8 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Larissa Souza Arantes ◽

Lucas Cabral Lage Ferreira ◽

Maximilian Driller ◽

Fernando Pedro Marinho Repinaldo Filho ◽

Camila Junqueira Mazzoni ◽

...

Keyword(s):

Reproductive Output ◽

Sea Turtles ◽

Sea Turtle ◽

Northeastern Brazil ◽

F1 Hybrids ◽

Turtle Species ◽

Turtle Conservation ◽

Loggerhead Turtles ◽

Need To Evaluate ◽

Sea Turtle Conservation

Abstract Hybridization between sea turtle species occurs with particularly high frequency at two adjacent nesting areas in northeastern Brazil. To understand the outcomes of hybridization and their consequences for sea turtle conservation, we need to evaluate the extent of hybridization occurrence and possible deleterious effects in the hybrid progeny. Thus, we investigated the hypothesis of the existence of a new hybrid spot offshore of Brazil’s northeastern coast. The Abrolhos Archipelago is surrounded by the largest and richest coral reefs in the South Atlantic and is known to be a nesting site for loggerhead turtles (Carettacaretta). In this study, we performed a multidisciplinary investigation into levels of hybridization in sea turtles and their reproductive output in the Abrolhos beaches. Genetic data from mitochondrial DNA (mtDNA) and six autosomal markers showed that there are first-generation hybrid females nesting in Abrolhos, resulting from crossings between hawksbill males (Eretmochelysimbricata) and loggerhead females, and backcrossed hatchlings from both parental species. The type and extent of hybridization were characterized using genomic data obtained with the 3RAD method, which confirmed backcrossing between F1 hybrids and loggerhead turtles. The reproductive output data of Abrolhos nests suggests a disadvantage of hybrids when compared to loggerheads. For the first time, we have shown the association between hybridization and low reproductive success, which may represent a threat to sea turtle conservation.

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Nest temperatures and sex-ratio estimates of loggerhead turtles at Patara beach on the southwestern coast of Turkey

Canadian Journal of Zoology ◽

10.1139/z03-200 ◽

2004 ◽

Vol 82 (1) ◽

pp. 94-101 ◽

Cited By ~ 24

Author(s):

M Öz ◽

A Erdoğan ◽

Y Kaska ◽

S Düşen ◽

A Aslan ◽

...

Keyword(s):

Sex Ratio ◽

Incubation Period ◽

Sea Turtles ◽

Chelonia Mydas ◽

Sea Turtle ◽

Beach Erosion ◽

Electronic Temperature ◽

Sand Temperature ◽

Loggerhead Turtles ◽

The Mean

During the nesting period in 2000 and 2001 on Patara beach, total emergence and non-nesting emergence of loggerhead turtles (Caretta caretta), nest distribution, and nest distance from the sea were recorded . The main nesting seasons for sea turtles (family Cheloniidae) were during June and July. Loggerhead turtles comprised the majority of sea turtle emergence records; only two green turtle (Chelonia mydas) emergences were recorded. The small nesting population (52 and 53 nests in 2000 and 2001, respectively) of sea turtles on Patara beach was due to low hatching success resulting from a rise in seawater levels, owing to beach erosion, and the subsequent inundation of most nests. The temperatures of four nests and sand at different distances from the sea were measured with electronic temperature loggers, which recorded mean nest temperatures of 28.8–30.7 °C, with the mean temperature in the middle third of the incubation period from 28.5 to 31.0 °C. The mean temperatures, incubation periods, temperature during the middle third of the incubation period, and percentage of hatchling sexes were evaluated with respect to sand and nest temperatures. The results showed a female-dominated sex ratio, which was probably the result of predation of nests far from the sea and the seawater inundation of nests close to the sea, as the sand temperature was different at sites close and far from the sea.

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