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

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.

Going back to the roots: finding a strategy for the management of nesting loggerhead sea turtles in New Caledonia

2018 ◽  
Vol 66 (6) ◽  
pp. 394
Author(s):  
Tyffen C. Read ◽  
Marion Petit ◽  
Marion Magnan ◽  
David Booth
Keyword(s):  
Hatching Success ◽  
Incubation Temperature ◽  
New Caledonia ◽  
Loggerhead Turtle ◽  
Sea Turtle ◽  
Vital Role ◽  
Morning Glory ◽  
Root Penetration ◽  
Loggerhead Sea Turtles ◽  
Emergence Success

Incubation temperature plays a vital role in sea turtle life history because it influences embryonic growth, sex determination and hatchling attributes such as body size, residual yolk size, self-righting ability, crawling speed and swimming speed. For these reasons there is concern that predicted increases in air temperature, as a result of global warming, will increase nest temperatures and result in decreased hatching success, decrease or cease male hatchling production, and decreased hatchling quality. In a previous study examining incubation temperature at a loggerhead turtle (Caretta caretta) rookery located at La Roche Percée, New Caledonia, high nest temperatures and root invasion by beach morning glory (Ipomoea pes-caprae) were found to adversely affect hatching success and locomotor performance. In the current study, we relocated loggerhead turtle nests into shaded hatcheries. Shading nests decreased sand and nest temperatures and was predicted to increase male hatchling production slightly, but nest emergence success was decreased due to invasion of cottonwood (Hibiscus tiliaceus) roots into some nests. Using shaded structures is a viable and affordable management option to counteract the high sand temperatures found on some sea turtle nesting beaches, but these shade structures need to be located some distance from trees and other plants to ensure that root penetration into nests does not adversely affect nest emergence success.

scholarly journals Impact of the fire ant pesticide AMDRO on loggerhead turtle nest productivity and seafinding orientation

2020 ◽  
Vol 41 ◽  
pp. 339-347
Author(s):  
HE Smith ◽  
SR Hoover ◽  
M Salmon ◽  
H Seaman ◽  
CM Coppenrath ◽  
...  
Keyword(s):  
Nest Site ◽  
Hatching Success ◽  
Loggerhead Turtle ◽  
Sea Turtle ◽  
Fire Ants ◽  
Fire Ant ◽  
Typical Application ◽  
Ghost Crabs ◽  
Emergence Success ◽  
Nesting Beaches

Invasive fire ants prey on a variety of organisms in the southeastern USA, including the pipped eggs and hatchlings within sea turtle nests. The granular fire ant bait AMDRO® (active ingredient hydramethylnon) is currently used at some rookeries to protect nests, but no studies have been conducted to determine if the pesticide negatively impacts the eggs or the hatchlings. We examined the pesticide’s effect on loggerhead (Caretta caretta) nests at Juno Beach, Florida, USA, specifically targeting how exposure affected hatching success, hatchling emergence success, and the ability of the turtles to orient visually from the nest to the sea. Pesticide granules were placed within a 30 cm diameter circle on the sand directly above the nest during the final 5-10 days of incubation, representative of its typical application at nesting beaches. Cornmeal granules in soybean oil and untreated natural nests served as controls. AMDRO had no significant effect on hatching success or emergence success, nor did it result in any deficiencies in hatchling orientation accuracy. However, the pesticide and cornmeal control attracted other predators (Atlantic ghost crabs and avian species), in addition to fire ants, to the nest site, thus revealing the nest’s location and potentially increasing its vulnerability. Consequently, we suggest that its usage may not be beneficial at sites where predators other than ants are especially abundant.

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

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.

Effect of nest temperature on hatchling phenotype of loggerhead turtles (Caretta caretta) from two South Pacific rookeries, Mon Repos and La Roche Percée

2012 ◽  
Vol 60 (6) ◽  
pp. 402 ◽  
Author(s):  
Tyffen Read ◽  
David T. Booth ◽  
Colin J. Limpus
Keyword(s):  
Thermal Tolerance ◽  
Hatching Success ◽  
New Caledonia ◽  
Loggerhead Turtle ◽  
Caretta Caretta ◽  
Nest Temperature ◽  
Genetic Stock ◽  
Upper Limit ◽  
Emergence Success ◽  
The Mean

La Roche Percée, in New Caledonia, is the most important loggerhead turtle rookery outside of Australia for the eastern Pacific genetic stock. The females nesting on this beach are genetically similar to the females found at the Mon Repos rookery in Queensland, Australia. This study shows how nest temperature affects the phenotype of genetically similar populations. During the 2010–11 breeding season, mean nest temperatures were significantly higher at La Roche Percée (31.8°C) than at Mon Repos (29.5°C) and the mean for the three-days-in-a-row maximum nest temperatures was also significantly higher at La Roche Percée (34.6°C), than at Mon Repos (31.7°C). Differences were found in mean hatching success (La Roche Percée 83 ± 3%, Mon Repos 96 ± 2%) and emergence success (La Roche Percée 76 ± 3%, Mon Repos 93 ± 3%). Hatchlings from La Roche Percée also had significantly lower fitness characteristics, having smaller carapace size (La Roche Percée 1565 ± 7 mm2, Mon Repos 1634 ± 5 mm2), slower self-righting times (La Roche Percée 4.7 ± 0.1 s, Mon Repos 2.7 ± 0.1 s) and slower crawling speed in terms of both absolute speed and body lengths per second (La Roche Percée 2.5 ± 0.2 cm s–1 or 0.57 ± 0.05 body lengths s–1, Mon Repos 4.6 ± 0.1 cm s–1 or 1.04 ± 0.02 body lengths s–1). Nest temperatures at La Roche Percée approached the upper limit of embryo thermal tolerance towards the end of incubation (34°C) and this condition may contribute to the lower hatching and emergence success and lower fitness characteristics of hatchlings at the La Roche Percée rookery.

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

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.

Green turtle (Chelonia mydas) nesting on Atol das Rocas, north-eastern Brazil, 1990–2008

2012 ◽  
Vol 93 (4) ◽  
pp. 1117-1132 ◽  
Author(s):  
Claudio Bellini ◽  
Armando J.B. Santos ◽  
Alice Grossman ◽  
Maria A. Marcovaldi ◽  
Paulo C. R. Barata
Keyword(s):  
Green Turtle ◽  
Carapace Length ◽  
Temporal Distribution ◽  
Chelonia Mydas ◽  
Sea Turtle ◽  
Annual Number ◽  
Eastern Brazil ◽  
North Eastern ◽  
The Mean ◽  
Nesting Activity

In this paper, information is presented on green turtle (Chelonia mydas) nesting on Atol das Rocas (Rocas Atoll), north-eastern Brazil. The temporal distribution of nesting events per season, annual number of nests, carapace length of nesting females, clutch size, hatching success, incubation period, internesting interval, clutch frequency, observed reproductive lifespan, and remigration period are reported. The study period included the nesting seasons from 1990 to 2008, but no regular beach monitoring was carried out in 1998 and 1999. Two sorts of methods were applied to the estimation of the annual number of nests in some seasons. Taking into account the estimated annual numbers of nests, the mean annual number of nests in the study period, excluding 1998–1999, was 335 (standard deviation = 139, range = 136–563, N = 17). An analysis of the available data indicates that the average nesting levels at the beginning of the study period (the first five seasons) and at its end (the last five seasons) were roughly the same. The mean curved carapace length of the nesting turtles decreased significantly during the study period, from 115.9 cm in 1990–1992 to 112.9 cm in 2006–2008. Atol das Rocas was established as a federal biological reserve in 1979, but regular sea turtle conservation activities actually started there in 1990. Since that year, the killing of nesting turtles has ceased, nesting activity by the turtles can proceed in an undisturbed fashion, and their clutches can incubate in a protected environment.

scholarly journals Exposure of Loggerhead Sea Turtle Nests to Waves in the Florida Panhandle

2021 ◽  
Vol 13 (14) ◽  
pp. 2654
Author(s):  
Matthew Ware ◽  
Simona A. Ceriani ◽  
Joseph W. Long ◽  
Mariana M.P.B. Fuentes
Keyword(s):  
Management Strategies ◽  
Significant Risk ◽  
Threat Assessment ◽  
Sea Turtle ◽  
Wave Exposure ◽  
Wave Runup ◽  
Loggerhead Sea Turtle ◽  
Emergence Success ◽  
Florida Panhandle ◽  
Wave Wash

Wave wash-over poses a significant threat to sea turtle nests, with sustained exposure to waves potentially resulting in embryonic mortality and altered hatchling locomotor function, size, and sex ratios. Identifying where and under what conditions wave exposure becomes a problem, and deciding what action(s) to take (if any), is a common issue for sea turtle managers. To determine the exposure of sea turtle nests to waves and identify potential impacts to hatchling productivity, we integrated a geographic information system with remote sensing and wave runup modeling across 40 nesting beaches used by the Northern Gulf of Mexico Loggerhead Recovery Unit. Our models indicate that, on average, approximately 50% of the available beach area and 34% of nesting locations per nesting beach face a significant risk of wave exposure, particularly during tropical storms. Field data from beaches in the Florida Panhandle show that 42.3% of all nest locations reported wave exposure, which resulted in a 45% and 46% decline in hatching and emergence success, respectively, relative to their undisturbed counterparts. Historical nesting frequency at each beach and modeled exposure to waves were considered to identify priority locations with high nesting density which either experience low risk of wave exposure, as these are good candidates for protection as refugia for sustained hatchling production, or which have high wave exposure where efforts to reduce impacts are most warranted. Nine beaches in the eastern Florida Panhandle were identified as priority sites for future efforts such as habitat protection or research and development of management strategies. This modeling exercise offers a flexible approach for a threat assessment integration into research and management questions relevant to sea turtle conservation, as well as for other beach species and human uses of the coastal environment.

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

Oryx ◽  
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.

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

Toxics ◽  
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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