Who are the important predators of sea turtle nests at Wreck Rock beach?

Excessive sea turtle nest predation is a problem for conservation management of sea turtle populations. This study assessed predation on nests of the endangered loggerhead sea turtle (Caretta caretta) at Wreck Rock beach adjacent to Deepwater National Park in Southeast Queensland, Australia after a control program for feral foxes was instigated. The presence of predators on the nesting dune was evaluated by tracking plots (2 × 1 m) every 100 m along the dune front. There were 21 (2014–2015) and 41 (2015–2016) plots established along the dune, and these were monitored for predator tracks daily over three consecutive months in both nesting seasons. Predator activities at nests were also recorded by the presence of tracks on top of nests until hatchlings emerged. In addition, camera traps were set to record the predator activity around selected nests. The tracks of the fox (Vulpes vulpes) and goanna (Varanus spp) were found on tracking plots. Tracking plots, nest tracks and camera traps indicated goanna abundance varied strongly between years. Goannas were widely distributed along the beach and had a Passive Activity Index (PAI) (0.31 in 2014–2015 and 0.16 in 2015–2016) approximately seven times higher than that of foxes (PAI 0.04 in 2014–2015 and 0.02 in 2015–2016). Five hundred and twenty goanna nest visitation events were recorded by tracks but no fox tracks were found at turtle nests. Camera trap data indicated that yellow-spotted goannas (Varanus panoptes) appeared at loggerhead turtle nests more frequently than lace monitors (V. varius) did, and further that lace monitors only predated nests previously opened by yellow-spotted goannas. No foxes were recorded at nests with camera traps. This study suggests that large male yellow-spotted goannas are the major predator of sea turtle nests at the Wreck Rock beach nesting aggregation and that goanna activity varies between years.

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Who are the important sea turtle nest predators at Wreck Rock beach?

10.7287/peerj.preprints.2850 ◽

2017 ◽

Author(s):

Juan Lei ◽

David T Booth

Keyword(s):

Nest Predation ◽

Activity Index ◽

Loggerhead Turtle ◽

Control Program ◽

Sea Turtle ◽

Large Male ◽

Camera Traps ◽

Loggerhead Sea Turtle ◽

Southeast Queensland ◽

Nesting Aggregation

Excessive sea turtle nest predation is a problem for conservation management of sea turtle populations. This study assessed the predation of the endangered loggerhead sea turtle (Caretta caretta ) nests at the Wreck Rock beach adjacent to Deepwater National Park in Southeast Queensland, Australia after a control program for feral foxes was instigated. The presence of predators on the nesting dune was evaluated by passive soil plots (2 x 1 m) every 100m along the dune front. There were 21 (2014-2015) and 41 (2015-2016) plots established along the dune and these were monitored for predator tracks daily over three consecutive months in both nesting seasons. Camera traps were also set to record the predator’s activity around selected nests. The tracks of the fox (Vulpes vulpes ) and goanna (lace monitor Varanus varius and/or yellow-spotted goanna V. panoptes; we could not distinguish these two species tracks from each other) were found on sand plots. Goannas were widely distributed along the beach and had an eight times higher Passive Activity Index (PAI) (0.31 in 2014-2015 and 0.16 in 2015-2016) compared to foxes (PAI 0.04 in 2014-2015 and 0.02 in 2015-2016). Camera trap data indicated that the appearance of yellow-spotted goannas at loggerhead turtle nests was more frequent than lace monitors and further that lace monitors only predated these nests after they had been previously opened by yellow-spotted goannas. No foxes were recorded at nests with camera traps. This study suggests that large male yellow-spotted goannas are the major predator of sea turtle nests at the Wreck Rock beach nesting aggregation.

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Who are the important sea turtle nest predators at Wreck Rock beach?

10.7287/peerj.preprints.2850v1 ◽

2017 ◽

Author(s):

Juan Lei ◽

David T Booth

Keyword(s):

Nest Predation ◽

Activity Index ◽

Loggerhead Turtle ◽

Control Program ◽

Sea Turtle ◽

Large Male ◽

Camera Traps ◽

Loggerhead Sea Turtle ◽

Southeast Queensland ◽

Nesting Aggregation

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Nesting activity of the Loggerhead sea turtle, Caretta caretta, in Calabria: 2016-2020 reproductive seasons

Mediterranean Marine Science ◽

10.12681/mms.26085 ◽

2021 ◽

Author(s):

MARIA DENARO ◽

TERESA MALITO ◽

CARMELA MANCUSO ◽

GIOVANNI PARISE ◽

SALVATORE URSO

Keyword(s):

New Technologies ◽

Survey Methods ◽

Loggerhead Turtle ◽

Sea Turtle ◽

Success Rates ◽

Monitoring Method ◽

Loggerhead Sea Turtle ◽

Emergence Success ◽

The Mean ◽

Nesting Activity

The nesting activity of the loggerhead turtle along the coast of Calabria during five reproductive seasons (2016-2020) is presented. From May to August, survey methods were conducted using traditional observations on foot and utilizing additional innovative technologies, including electric fat bikes and drones. Monitoring was intensively focused on a key nesting area of approximately 40 km located on the southernmost Ionian coast of Reggio Calabria, and, for only the 2020 season, the area was extended an additional 40 km northeast. In the five nesting seasons, 419 female emergences were recorded, 192 of which were classified as nests. Overall, 65.1% (n = 125) of nests were found along the area regularly monitored in all nesting seasons. The maximum nesting activity was observed during July, and the mean nesting success was 45.8%. The average number of eggs for all seasons was 92.2 (n = 163; S.D.: ± 21.1; range: 39-160). The mean hatching and emergence success rates were 70.8% and 62.5%, respectively. The mean incubation period was 49 days (n = 122; S.D.: ± 5.4; range: 42-82). Considering previous data from the same area, our study shows an actual increase in nesting activity, probably due to the implementation of an effective monitoring method that includes the use of new technologies, which made it possible to expand the regularly monitored area, and a greater awareness campaign in recent years. Regarding the reproductive parameters, our data is similar to that reported for other Mediterranean nesting grounds.

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Globally important refuge for the loggerhead sea turtle: Maio Island, Cabo Verde

Oryx ◽

10.1017/s0030605320001180 ◽

2021 ◽

pp. 1-9

Author(s):

Juan Patino-Martinez ◽

Leno Dos Passos ◽

Inês O. Afonso ◽

Arnau Teixidor ◽

Manjula Tiwari ◽

...

Keyword(s):

Management Strategy ◽

Hatching Success ◽

Management Strategies ◽

Loggerhead Turtle ◽

Sea Turtle ◽

Sandy Beaches ◽

Loggerhead Sea Turtle ◽

Artificial Lighting ◽

Cabo Verde ◽

Comprehensive Study

Abstract One of the largest nesting colonies of the Vulnerable loggerhead sea turtle Caretta caretta is in Cabo Verde. Here we present the first comprehensive study of loggerhead turtle nesting on the island of Maio in Cabo Verde. During 2016–2019 we monitored 38 km of undeveloped sandy beaches that have minimal artificial lighting and where all nesting on Maio takes place. We counted 4,063 nests in 2016, 5,429 in 2017, 14,364 in 2018 and 7,937 in 2019. The estimated total number of females was 1,016, 1,357, 3,591 and 1,984 in each of these years, respectively. Our findings suggest there are more loggerhead turtles nesting in Cabo Verde than previously estimated, and that this could be the species’ largest nesting subpopulation (followed by Florida, USA and Oman). The inter-annual hatching success (the proportion of eggs producing hatchlings) was 29–38% for the whole island but varied between sites. Our study of 250 clutches showed that flooding affected 38–61% and predation by crabs 40–42%, with hatching success on different beaches in the range of 1–59%. Poaching of eggs was rare (< 2% of clutches), but dogs predated 68.4% of all clutches on the beach nearest the largest human settlement. We evaluated different nest management strategies at multiple sites and estimated productivity of hatchlings (the number of hatchlings that would reach the sea for each management strategy), finding that hatcheries are not always the best option for nest management. As the beaches on Maio are relatively undisturbed, and there is a high abundance and density of turtle nests, the island should be protected as a globally important site for the conservation of the loggerhead turtle, and of coastal biodiversity more broadly.

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Transcriptional Analyses of Acute Exposure to Methylmercury on Erythrocytes of Loggerhead Sea Turtle

Toxics ◽

10.3390/toxics9040070 ◽

2021 ◽

Vol 9 (4) ◽

pp. 70

Author(s):

Javier Hernández-Fernández ◽

Andrés Pinzón-Velasco ◽

Ellie Anne López ◽

Pilar Rodríguez-Becerra ◽

Leonardo Mariño-Ramírez

Keyword(s):

Gene Expression ◽

De Novo ◽

Expression Patterns ◽

Constitutive Expression ◽

Loggerhead Turtle ◽

Early Response ◽

Sea Turtle ◽

Regulation Of Transcription ◽

Loggerhead Sea Turtle ◽

Altered Gene

To understand changes in enzyme activity and gene expression as biomarkers of exposure to methylmercury, we exposed loggerhead turtle erythrocytes (RBCs) to concentrations of 0, 1, and 5 mg L−1 of MeHg and de novo transcriptome were assembled using RNA-seq. The analysis of differentially expressed genes (DEGs) indicated that 79 unique genes were dysregulated (39 upregulated and 44 downregulated genes). The results showed that MeHg altered gene expression patterns as a response to the cellular stress produced, reflected in cell cycle regulation, lysosomal activity, autophagy, calcium regulation, mitochondrial regulation, apoptosis, and regulation of transcription and translation. The analysis of DEGs showed a low response of the antioxidant machinery to MeHg, evidenced by the fact that genes of early response to oxidative stress were not dysregulated. The RBCs maintained a constitutive expression of proteins that represented a good part of the defense against reactive oxygen species (ROS) induced by MeHg.

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Cucullanus carettae Baylis, 1923, in a loggerhead sea turtle (Caretta caretta) from the Adriatic sea: first detection and molecular characterization

Parasitology Research ◽

10.1007/s00436-020-06936-5 ◽

2020 ◽

Author(s):

L. Di Renzo ◽

L. Di Gialleonardo ◽

E. Marchiori ◽

G. Di Francesco ◽

V. Curini ◽

...

Keyword(s):

Molecular Characterization ◽

Adriatic Sea ◽

Loggerhead Turtle ◽

Caretta Caretta ◽

Sea Turtle ◽

Loggerhead Sea Turtle ◽

Coprological Examination ◽

Loggerhead Turtles ◽

Bio Monitoring ◽

The Mediterranean

Abstract Cucullanus carettae Baylis, 1923 (Nematoda: Cucullanidae) is found worldwide in loggerhead turtles (Caretta caretta). Regarding the Mediterranean, C. carettae has been identified in the Tyrrhenian and the Ionian Sea and a unique description of a Cucullanus sp. specimen in loggerheads from the Adriatic Sea has been reported in the literature so far. In the framework of a bio-monitoring project of the Abruzzo and Molise coasts, a parasitological survey was performed on stranded and by-caught sea turtles, at the Istituto Zooprofilattico of Abruzzo and Molise “G. Caporale.” During necropsy, the gastrointestinal system of 72 stranded loggerhead turtles was analyzed for the presence of endoparasites and fecal samples were collected for coprological examination. Adult C. carettae (n = 123) was found in the upper intestine of one loggerhead turtle, associated with chronic lymphoplasmocytic enteritis. Additionally, five stool samples (6.9%) were positive for Cucullanus sp. eggs. Molecular characterization of adult nematodes was carried out to study phylogenetic relationships among the Cucullanus species. To our knowledge, this is the first morphological and molecular identification of C. carettae in loggerhead turtles from the Adriatic Sea. Additional studies on the distribution of this parasite in the Mediterranean are encouraged.

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Eimeria caretta sp.nov. (Apicomplexa: Eimeriidae) from the loggerhead sea turtle, Caretta caretta (Testudines)

Canadian Journal of Zoology ◽

10.1139/z90-189 ◽

1990 ◽

Vol 68 (6) ◽

pp. 1268-1269 ◽

Cited By ~ 11

Author(s):

Steve J. Upton ◽

Daniel K. Odell ◽

Michael T. Walsh

Keyword(s):

Atlantic Coast ◽

Polar Granule ◽

Loggerhead Turtle ◽

Caretta Caretta ◽

Sea Turtle ◽

Stieda Body ◽

Loggerhead Sea Turtle ◽

Thin Filaments ◽

Sporocyst Residuum ◽

Oocyst Residuum

Eimeria caretta sp.nov. (Apicomplexa: Eimeriidae) is described from the feces of a stranded loggerhead turtle, Caretta caretta (Testudines), rescued from the Atlantic coast near Jensen Beach, Hutchinson Island, Martin County, Florida. Oocysts are subspherical to ellipsoidal, 24.5 × 22.0 (21.4–28.0 × 18.4–24.0) μm, with a smooth, bilayered wall. Micropyle, polar granule, and oocyst residuum are absent. Sporocysts are ovoid, 14.3 × 8.9(12.8–16.0 × 8.2–10.0) μm, and possess a Stieda body but no substieda body. The Stieda body is unusual in that 12–20 long, thin filaments project from its surface. Sporozoites are elongate, each with two refractile bodies. The sporocyst residuum consists only of scattered granules. This coccidian is most similar to Eimeria filamentifera Wacha and Christiansen 1979 from the common snapping turtle, Chelydra serpentina, but differs because it possesses more numerous and elongate filaments associated with the Stieda body and lacks an oocyst residuum.

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Gas Exchange in the Loggerhead Sea Turtle Caretta Caretta

Journal of Experimental Biology ◽

10.1242/jeb.131.1.365 ◽

1987 ◽

Vol 131 (1) ◽

pp. 365-372 ◽

Cited By ~ 2

Author(s):

M. E. LUTCAVAGE ◽

P. L. LUTZ ◽

H. BAIER

Keyword(s):

Blood Flow ◽

Pulmonary Blood Flow ◽

Sea Turtles ◽

Venous Blood ◽

Loggerhead Turtle ◽

Caretta Caretta ◽

Sea Turtle ◽

Aerobic Performance ◽

Breathing Patterns ◽

Loggerhead Sea Turtle

Pulmonary CO diffusion capacity (DLCO), lung volume (VL), oxygen uptake (Vo2) and pulmonary blood flow (QL) were measured simultaneously in the loggerhead sea turtle Caretta caretta (Linnaeus) (8–11 kg) using a gas rebreathing technique (syringe pump ventilation). Calculated DLCO and Vo2 values in the loggerhead turtle are approximately twice those of non-varanid reptiles and about 25 % of values for resting mammals. Evidence based on an estimated lung-capillary O2 gradient, δPo2, shows that only a small driving gradient is required for O2 conductance across the loggerhead turtle lung. Pulmonary blood flow values are high compared to those for other reptiles; on the basis of the Fick principle, this implies a substantial blood convection requirement. Differences in oxygen transport mechanisms between the loggerhead sea turtle and other highly aerobic but terrestrial reptiles may result from divergent lung structures and breathing patterns. In sea turtles, the coupling of respiration with locomotory behaviour is one factor that may limit aerobic performance. Since sea turtles have only intermittent access to air, they are required to load both arterial and venous blood with O2 before submerging

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Description of cloacoscopy in the loggerhead sea turtle (Caretta caretta)

Acta Veterinaria Brno ◽

10.2754/avb201685040367 ◽

2016 ◽

Vol 85 (4) ◽

pp. 367-370 ◽

Cited By ~ 1

Author(s):

Filippo Spadola ◽

Manuel Morici ◽

Matteo Oliveri ◽

Zdeněk Knotek

Keyword(s):

Distal Part ◽

Loggerhead Turtle ◽

Caretta Caretta ◽

Sea Turtle ◽

Urogenital Sinus ◽

Terminal Part ◽

Loggerhead Sea Turtle ◽

Fluid Infusion ◽

Urethral Orifice ◽

Flexible Colonoscope

The aim of the study was to describe cloacoscopy in the loggerhead turtle (Caretta caretta) and to evaluate its efficacy in clinical practice. Cloacoscopy was performed on 31 turtles, 23 females and 8 males. Thirty minutes before anaesthesia, meloxicam (0.4 mg/kg) was administered intramuscularly. Turtles were anaesthetised with a combination of 0.04 mg/kg dexmedetomidine and 4 mg/kg ketamine administered intramuscularly. Cloacoscopy was performed with a diagnostic telescope (10 mm diameter, 30 cm long, 0°, with an operating sheath) or with a flexible colonoscope (13 mm diameter, 160 cm long). Turtles were placed in dorsal recumbence and endoscope was inserted through the vent. In the distal part of the proctodeum, phallus or clitoris were easily visualized. A finger and thumb were placed around the vent to act as a valve in order to control the fluid infusion. Flushing the cloaca with warm saline and 0.6% lidocaine allowed clear view. The urethral orifice was located centrally within the urogenital sinus. Further proximally, the slit of the urodeum with the distal sphincter of the colon could be visualized. Passing gently through the urethral orifice allowed direct visualization of the urinary bladder. After withdrawing and re-directing the endoscope into the coprodeum, the terminal part of the intestine was reached. From 31 loggerhead turtles examined, fishing lines were found in 23 animals. Cloacoscopy proved to be a feasible diagnostic method and it is suggested as a routine diagnostic tool for clinical assessment of loggerhead turtle patients.

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Sex Ratio Estimations of Loggerhead Sea Turtle Hatchlings at Kuriat Islands, Tunisia: Can Minor Nesting Sites Contribute to Compensate Globally Female-Biased Sex Ratio?

The Scientific World JOURNAL ◽

10.1155/2014/419410 ◽

2014 ◽

Vol 2014 ◽

pp. 1-8 ◽

Cited By ~ 4

Author(s):

Imed Jribi ◽

Mohamed Nejmeddine Bradai

Keyword(s):

Sex Ratio ◽

Sex Ratios ◽

Loggerhead Turtle ◽

Sea Turtle ◽

Electronic Temperature ◽

Loggerhead Sea Turtle ◽

Nesting Site ◽

Nesting Sites ◽

Biased Sex Ratio ◽

A Minor

Hatchling sex ratios in the loggerhead turtleCaretta carettawere estimated by placing electronic temperature recorders in seven nests at Kuriat islands (Tunisia) during the 2013 nesting season. Based on the mean temperatures during the middle third of the incubation period, and on incubation duration, the sex ratio of hatchlings at Kuriat islands was highly male-biased. Presently, the majority of hatchling sex ratio studies are focused on major nesting areas, whereby the sex ratios are universally believed to be heavily female-biased. Here we present findings from a minor nesting site in the Mediterranean, where the hatchling sex ratio was found to be male-biased, suggesting a potential difference between major and minor nesting sites.

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