74 research outputs found
Increase of nesting habitat suitability for green turtles in a warming Mediterranean Sea
No full textClimate change is reshaping global ecosystems at an unprecedented rate, with major impacts on biodiversity. Therefore, understanding how organisms can withstand change is key to identify priority conservation objectives. Marine ectotherms are being extremely impacted because their biology and phenology are directly related to temperature. Among these species, sea turtles are particularly problematic because they roam over both marine and terrestrial habitats throughout their life cycles. Focusing on green turtles (Chelonia mydas) in the Mediterranean Sea, we investigated the future potential changes of nesting grounds through time, assuming that marine turtles would shift their nesting locations. We modeled the current distribution of nesting grounds including both terrestrial and marine variables, and we projected the potential nesting distribution across the Mediterranean basin under alternative future greenhouse gas emission scenario (2000–2100). Our models show an increase in nesting probability in the western Mediterranean Sea, irrespective of the climate scenario we consider. Contrary to what is found in most global change studies, the worse the climate change scenario, the more suitable areas for green turtles will potentially increase. The most important predictors were anthropogenic variables, which negatively affect nesting probability, and sea surface temperature, positively linked to nesting probability, up to a maximum of 24–25 °C. The importance of the western Mediterranean beaches as potential nesting areas for sea turtles in the near future clearly call for a proactive conservation and management effort, focusing on monitoring actions (to document the potential range expansion) and threat detection
Large-scale movements in the oceanic environment identify important foraging areas for loggerheads in central Mediterranean Sea
No full textLoggerhead sea turtles (Caretta caretta) are known to display a wide range of movement patterns during the different stages of their life cycle, but empirical information to document this extensive behavioural plasticity is still limited. This is especially true for large, adult-sized individuals, that are thought to mainly forage in neritic areas. In the present paper, eight adult-sized loggerhead turtles were tracked using satellite telemetry to identify the location of their foraging grounds in the seas along the western coast of the Italian peninsula. Tracked turtles mostly stayed in the region between the Italian peninsula and the islands of Sicily and Sardinia, that was reached following quick, directed movements by the turtles from a release site to the north. In this area, two turtles took up residence in spatially limited neritic sites along the coast, while the remaining six alternated circumscribed coastal stays with long-distance, circuitous movements in the oceanic environment. An utilization distribution analysis clearly identified an area, mostly comprising oceanic waters, that was continuously used by turtles in different seasons and years. The present results contribute to the still-limited knowledge of the spatial ecology of loggerheads frequenting the Western Mediterranean Sea and highlight the presence of a potentially important oceanic region in the Southern Tyrrhenian Sea where adult-sized turtles forage for extended periods. These findings increase our knowledge of complex life history traits of loggerhead turtles and provide important information to be considered for evidence-based conservation measures
Adult sex ratios of loggerhead sea turtles (Caretta caretta) in two Mediterranean foraging grounds
No full textSea turtles show temperature-dependent sex determination (TSD) and information on sex ratios at different life stages is necessary both for population dynamics models for conservation and to shed light on the possible adaptive value of TSD. Adults represent the less abundant class of sea turtle populations and adult sex ratios at foraging grounds are very difficult to obtain. We first analysed biometric data of 460 juvenile and adult loggerhead sea turtles ranging from 60 to 97.5 cm curved carapace length (CCL), in which a clear bimodal distribution of tail length (the main secondary sexual character of adult males) was observed in the size class >75 cm CCL. We then sexed 142 adult turtles in this size class collected from the Tunisian shelf and from the southeastern Tyrrhenian Sea, observing a proportion of females of 51.5% (95% CI: 41.2-61.8%; n=97) and 40.0% (95% CI: 25.7-55.7%; n=45) respectively. Our results complement previous studies and support their findings of similar and more balanced sex ratios in adult and juvenile loggerhead turtles in the Mediterranean, in contrast with highly female-biased sex ratios of hatchlings. © 2014 CSIC
Loggerhead sea turtles as sentinels in the western Mediterranean: antibiotic resistance and environment-related modifications of Gram-negative bacteria
No full textSea turtles possess relevant characteristics to serve as sentinel species for monitoring the health of marine ecosystems, which is currently threatened. This study examined 35 loggerhead turtles from the western Mediterranean, focusing on the oral and cloacal prevalence of aerobic Gram-negative bacteria, their antibiotic resistance and the influence of several variables linked both to the animal and the environment (i.e. estimated life stage; area, season and cause of recovery; plastic ingestion). Conventional bacteriology methods led to the isolation of bacterial families commonly regarded as opportunistic pathogens (i.e. Aeromonadaceae; Enterobacteriaceae; Pseudomonadaceae; Shewanellaceae; Vibrionaceae), but pointing out sea turtles as carriers of potential zoonotic agents. The high rates of antibiotic resistance, here detected, raise important concerns on the dissemination of this phenomenon in marine environments. Moreover, several of the examined variables showed a significant influence on the prevalence of bacterial families, strengthening the role of sea turtles as mirrors of their ecosystems
Aeromonas induced polyostotic osteomyelitis in a juvenile loggerhead sea turtle Caretta caretta.
No full textBacterial bone infections have been occasionally reported in wild sea turtles. This study reports on a sub-adult Caretta caretta affected by Aeromonas hydrophila osteomyelitis, with extensive involvement of cranial and caudal flippers. The turtle was severely debilitated, had limited flipper mobility and showed signs of pain in reaction to manipulation. Radiographs and computed tomography revealed multiple lytic bone lesions. Since an infectious polyostotic osteomyelitis was suspected, the turtle was subjected to echo-assisted fine needle aspiration to characterize the etiology of the disease. Bacterial cultures and antibiotic susceptibility testing led to the isolation of Aeromonas hydrophila responsive to amikacin and doxycycline. Therefore, the turtle was treated with these antibiotics and monitored through repeat bacterial cultures and diagnostic imaging. The turtle was released 17 mo after admission, upon resolution of clinical signs. The documentation of this case provides a treatment approach that may improve the outcome of Aeromonas-associated osteomyelitis, especially in endangered wildlife species
Multidirectional migrations from a major nesting area in Turkey support the widespread distribution of foraging sites for loggerhead turtles in the Mediterranean
No full textSatellite tracking studies have identified some of the migratory corridors and foraging sites of Mediterranean loggerhead sea turtle (Caretta caretta) rookeries over the past few decades. However, due to a lack of information for breeding rookeries in Libya and Turkey, our understanding of the distribution and connectivity of adult loggerheads is limited. We satellite-tracked 17 female loggerhead turtles breeding in one of the main nesting areas in Turkey to identify (1) migratory pathways, and (2) their foraging areas. Females were tracked for 96-657 d (mean: 271 d), and followed 3 general migratory directions (southeast, southwest and northwest/west). While migrating, individuals alternated oceanic and neritic movements, generally travelling significantly slower when in neritic waters (average speed reduction: 20%). Five turtles stopped between 1 to 3 times in stopover sites for 6 d before resuming their migration. While 1 turtle resided in oceanic foraging areas, the remaining 16 loggerheads settled in 12 distinct neritic foraging grounds; 2 turtles shared one site and 4 turtles shared another site. The identified foraging grounds were widely distributed across the Eastern and Central basin, in locations known to be frequented by loggerhead turtles from other rookeries. The present findings reveal links between foraging areas and one of the main breeding sites in Turkey, providing useful information for species conservation.Turkish Ministry of Environment and Urbanization; RAC-SPA; Baku-Tbilisi-Ceyhan Pipeline Company; TUI Care Foundation; MAVA Foundation; US Fish and Wildlife Ser vice under the Marine Turtle Conservation Act [PL 108-266]; University of PisaWe thank Dr. Flegra Bentivegna, Dr. Fulvio Maffucci and all DEKAMER volunteers for their help during field activities. Dr. Cheryl Sanchez (Pisa, IT) kindly revised the English text. Funding was provided by the Turkish Ministry of Environment and Urbanization, RAC-SPA, Baku-Tbilisi-Ceyhan Pipeline Company, TUI Care Foundation, MAVA Foundation, the US Fish and Wildlife Ser vice under the Marine Turtle Conservation Act (award no. PL 108-266), and the University of Pisa
Riquet_PCIEvolBiol_2018_INFILE
No full textArchived data
- from Florentine Riquet, Cathy Liautard-Haag, Lucy Woodall, Carmen Bouza, Patrick Louisy, Bojan Hamer, Francisco Otero-Ferrer, Philippe Aublanc, Vickie Béduneau, Olivier Briard, Tahani El Ayari, Sandra Hochscheid, Khalid Belkhir, Sophie Arnaud-Haond, Pierre-Alexandre Gagnaire, Nicolas Bierne,
- for "Parallel pattern of differentiation at a genomic island shared between clinal and mosaic hybrid zones in a complex of cryptic seahorse lineages",
- and recommended by Peer Community In Evolutionary Biology (https://dx.doi.org/10.24072/pci.evolbiol.100056).
The file is in excel format containing SNP data for all individuals analyzed.
Columns are headed as follow: sampling location, the individual code followed by the 286 balletic SNPs (one column for one locus and each allele is coded in 1-digit).
Contact: Florentine RIQUET
Institut des Sciences de l’Evolution de Montpellier
Université Montpellier
Montpellier, France
[email protected]
Genomic parallelism in adaptation orthogonal environments in sea horses
No full textInternational audienceA recommendation of the preprint:Florentine Riquet, Cathy Liautard-Haag, Lucy Woodall, Carmen Bouza, Patrick Louisy, Bojan Hamer, Francisco Otero-Ferrer, Philippe Aublanc, Vickie Béduneau, Olivier Briard, Tahani El Ayari, Sandra Hochscheid, Khalid Belkhir, Sophie Arnaud-Haond, Pierre-Alexandre Gagnaire, Nicolas Bierne. Parallel pattern of differentiation at a genomic island shared between clinal and mosaic hybrid zones in a complex of cryptic seahorse lineages bioRxiv, 2018, 161786, ver. 4. https://doi.org/10.1101/161786 version
Environmental and human factors affecting nesting success of loggerhead turtles on a new emerging nest site
No full textThe loggerhead sea turtle (Caretta caretta) faces increasing threats from anthropogenic activities along coastal regions. This study presents an analysis of loggerhead nesting activity in an emerging new nesting area in the Western Mediterranean, specifically in the Campania Region, SW Italy. Utilizing a combination of traditional on-foot observations and innovative technologies such as electric bikes and drones, surveys were conducted from June to August 2023. A total of 141 female emergences were recorded, of which 54 resulted in successful nesting whereas the remaining 87 were “false crawls”. The overall nesting success rate in the Campania region was 38.3%, which is inline with nesting success rates observed on Eastern Mediterranean beaches. Mapping the nesting activity using QGIS revealed an incidence of nests in the municipality of Castel Volturno and a notable occurrence of false crawls in Camerota, while the Cilento area exhibited the highest rate of nesting success (39.4%). Despite trends indicating more nesting attempts on equipped beaches, no significant differences were detected in false crawl and nest distributions concerning light pollution and beach type. Turtle ascent distances were notably shorter on equipped beaches (mean 36.22m) compared to free beaches (mean 59.33m), with a significant p-value of 0.000013, indicating potential deterrent effects of beach structures. Analysis of turtle ascent lengths revealed no significant differences in length distribution concerning light pollution and beach position (p-value = 0.5385). Moreover, free beaches exhibited a higher average total length (40.6m) compared to equipped beaches (32.8m) suggestive of fewer obstacles hindering turtle ascent on free beaches. Ongoing monitoring of nesting activity is crucial for informing conservation strategies in the Western Mediterranean, highlighting the need for continued research to enhance our understanding and protection of loggerhead sea turtles in the region
Thermoregulation, metabolism and buoyancy regulation in sea turtles
No full text1. This study was performed to investigate a mechanism of heat exchange in sea turtles and how temperature and different acclimation time affects their metabolic rates. In another part of this thesis I aimed to test the possibility of a correlation between dive duration and both metabolic rate and state of buoyancy known to be regulated via the gas volume in the lungs of Chelonian sea turtles. 2. All experiments were conducted on captive loggerhead (Caretta caretta) and green turtles (Chelonia mydas) housed in a individual tanks with circulating seawater from the adjacent Gulf of Naples (Western Mediterranean). The total range of body masses of turtles used encompassed 2 to 60 kg. 3. It was demonstrated, using Doppler ultrasound, that sea turtles change blood flow in their appendages in response to external cooling and heating. Although this was efficient to accelerate whole body warming and delay the cooling of the body, turtles eventually equilibrated their body temperatures with that of the surrounding water. 4. The Q10 effect on metabolic rate of sea turtles subject to acute exposure to varying temperatures was 1.3. However, during long term exposure to seasonally decreasing water temperatures turtles showed a more pronounced reducted of metabolic rate (O10 = 5.4). Contemporaneously food intake and general activity were greatly reduced as well and dive durations increased. Body temperatures showed the same seasonal trend as the decreasing water temperatures. 5. Oxygen consumption rates of individual turtles, measured over 24-h-periods, peaked at different times of the day and no specific dynamic action after feeding could be detected.EThOS - Electronic Theses Online ServiceGBUnited Kingdo
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