Using data from nesting beach monitoring and satellite telemetry to improve estimates of marine turtle clutch frequency and population abundance

Santos, Armando José Barsante; Vieira, Daniel H. G.; Bellini, Cláudio; Corso, Gilberto; Ceriani, Simona A.; Fuentes, Mariana M. P. B.

doi:10.1007/s00227-021-03983-z

Cited by 5 publications

(6 citation statements)

References 98 publications

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“…Greater human resources would be necessary. Two other options to improve the inter‐nesting interval accuracy would be to: (1) use satellite tags on nesting females to better quantify nesting events (Hays & Hawkes, 2018; Santos et al, 2021), and (2) perform a genetic capture‐recapture study (Shamblin et al, 2017).…”

Section: Discussionmentioning

confidence: 99%

Assessment of the nesting population demography of loggerhead turtles (Caretta caretta) in La Roche Percée: First long‐term monitoring in New Caledonia

Barbier,

Lafage,

Bourgogne

et al. 2023

Aquatic Conservation

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1. Population monitoring is essential to assess, manage, and protect threatened species. Although the South Pacific loggerhead turtle (Caretta caretta) subpopulation is classified as Critically Endangered by the International Union for Conservation of Nature (IUCN), monitoring data are scarce. 2. This study reports the results of the first long-term monitoring of the nesting population of loggerhead turtle held by Bwärä Tortues Marines on La Roche Percée beach, New Caledonia.3. From 2006 to 2020, capture-mark-recapture was used to identify nesting individuals. Time and nesting success were recorded on site.4. A total of 452 different females were observed and tagged over 14 years. The number of different nesting individuals observed each year showed a significant increase over the time frame of the study. A remigration interval of 3.34 years was observed, and the overall nesting success was 59.02%. This study also reports the internesting intervals and monthly and hourly variabilities in visits to the nesting site.5. The conservation actions led by Bwärä Tortues Marines appear to be correlated with a higher nesting success. This study provides encouraging results and highlights the need to pursue the monitoring and conservation actions implemented by Bwärä Tortues Marines. Further management recommendations are also provided.

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Section: Discussionmentioning

confidence: 99%

Assessment of the nesting population demography of loggerhead turtles (Caretta caretta) in La Roche Percée: First long‐term monitoring in New Caledonia

Barbier,

Lafage,

Bourgogne

et al. 2023

Aquatic Conservation

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“…Because some beaches are difficult to be accessed or covered due to their extension, the probability of encountering a turtle could be low, ultimately affecting the estimation of RIs. Satellite telemetry for instance, has indicated that turtles can often go undetected, affecting the estimation of population parameters (Tucker 2010;Santos et al 2021).…”

Section: Discussionmentioning

confidence: 99%

When population-advantageous primary sex ratios are female-biased: changing concepts to facilitate climate change management in sea turtles

Tomillo

2022

Climatic Change

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Sea turtles have temperature-dependent sex determination. Because females are produced at high temperatures, increasing global temperature may lead to population feminization. Primary sex ratios (PSR) of sea turtle hatchlings are naturally female-biased, but this translates into a more balanced operational sex ratio because male turtles reproduce more often than females. As a consequence, a balanced PSR and the temperature that produces it (pivotal temperature) are of limited use to guide climate mitigation management because an equal PSR may be demographically suboptimal. Here, I define population-advantageous primary sex ratios (PA-PSR) as the PSR that will tend to be in equilibrium in a population and that will result in balanced operational sex ratios; I then estimate PA-PSR for different reproductive frequencies (years elapsed between reproductive seasons) of adult female and male turtles. I also define population equilibrium temperature (PET) as the temperature that would result in the equilibrium PSR of hatchlings (i.e., PA-PSR). These concepts may help assess the influence of rising temperatures on populations, as they can better indicate if PSRs depart from those at equilibrium. I compared PA-PSR and beach PSR for two populations of sea turtles for which male and female remigration intervals were known and found that a mild or no feminization over the PA-PSR may be occurring. Because PSR varies inter-annually, and hatchlings coming from beaches of different thermal conditions could recruit to the same population, it is critical to estimate beach PSR at the right temporal and spatial scales. Climate mitigation strategies based on these concepts could provide better management guidance for conservation practitioners. Similar approaches could be considered for other female-biased species with temperature-dependent sex determination.

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“…This also minimized gaps that are common with data obtained from satellites, which is particularly problematic at low latitude locations (such as our study site) where Argos has lower coverage (CLS, 2016). Tags were attached as per Santos et al (2021a;2021b). In summary, turtles were restrained after nesting, the first vertebral scute of the carapace was sanded and cleaned with isopropyl alcohol, and the tag was attached with anchoring adhesive and painted with antifouling paint (see Santos et al, 2021a for the details).…”

Section: Transmitter Deployment and Tag Configurationmentioning

confidence: 99%

“…This accessibility has resulted in numerous studies exploring the behavior of post-nesting females, by using data from animal-borne devices deployed on females after they lay their eggs (Marcovaldi et al, 2012;Hays and Hawkes, 2018;Santos et al, 2021a). Although most studies have been focused on post-nesting migrations (e.g., Horrocks et al, 2001;Cuevas et al, 2008;Baudouin et al, 2015;Jim et al, 2022) some have focused on the internesting period, which refers to the interval between successive clutches within a nesting season (Sato et al, 1998;Hays et al, 2002;Hill et al, 2017;Santos et al, 2021b).…”

Section: Introductionmentioning

confidence: 99%

Decoding the internesting movements of marine turtles using a fine-scale behavioral state approach

Santos,

Cullen,

Vieira

et al. 2023

Front. Ecol. Evol.

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IntroductionAn understanding of animal behavior is critical to determine their ecological role and to inform conservation efforts. However, observing hidden behaviors can be challenging, especially for animals that spend most of their time underwater. Animal-borne devices are valuable tools to estimate hidden behavioral states.MethodsWe investigated the fine-scale behavior of internesting hawksbill turtles using the mixed-membership method for movement (M4) which integrated dive variables with spatial components and estimated latent behavioral states.ResultsFive latent behavioral states were identified: 1) pre-nesting, 2) transit, 3) quiescence, and 4) area restricted search within and 5) near the residence of turtles. The last three states associated with a residency period, showed lower activity levels. Notably, when compared to other behaviors the pre-nesting exhibited shallower and remarkably long dives of up to 292 minutes. We noted high fidelity to residence core areas and nesting beaches, within and between nesting seasons, with residence areas decreasing within a season.DiscussionThe latent behaviors identified provide the most detailed breakdown of turtle movement behaviors during the internesting period to date, providing valuable insights into their ecology and behavior. This information can inform marine turtle conservation and management efforts since utilization distributions of individual behavioral states can be used to determine spatially-explicit susceptibility of turtles to various threats based on their behavior. The analyses of utilization distribution revealed a minimal overlap with existing marine protected areas (0.4%), and we show how a new proposal would expand protection to 30%. In short, this study provides valuable guidance for conservation and management of internesting marine turtles at a fine spatiotemporal resolution and can be used to enhance national action plans for endangered species, including the expansion of existing Marine Protected Areas. By flexibly incorporating biologically informative parameters, this approach can be used to study behavior outside of the hawksbill breeding season or even beyond this species.

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Using data from nesting beach monitoring and satellite telemetry to improve estimates of marine turtle clutch frequency and population abundance

Cited by 5 publications

References 98 publications

Assessment of the nesting population demography of loggerhead turtles (Caretta caretta) in La Roche Percée: First long‐term monitoring in New Caledonia

Assessment of the nesting population demography of loggerhead turtles (Caretta caretta) in La Roche Percée: First long‐term monitoring in New Caledonia

When population-advantageous primary sex ratios are female-biased: changing concepts to facilitate climate change management in sea turtles

Decoding the internesting movements of marine turtles using a fine-scale behavioral state approach

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