Off-the-shelf GPS technology to inform marine protected areas for marine turtles

Snape, Robin; Bradshaw, Phil J.; Broderick, Annette C.; Fuller, Wayne J.; Stokes, Kimberley L.; Godley, Brendan J.

doi:10.1016/j.biocon.2018.09.029

Cited by 20 publications

(16 citation statements)

References 75 publications

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“…The turtles tracked in this study used smaller habitats at night in all study sites, which reinforces the hypothesis that sea turtles decrease their activity during night-time [15,17,84]. Such behaviour has also been observed in other species such as the loggerhead [20,85] and the hawksbill [21,86], suggesting a tactic to reduce predation risk [22], as turtles generally rest close to reef structures where they can find shelter in small caves and under reef ledges [17,87]. This is probably the case in La Reunion [75], Glorieuses and Mayotte (Ballorain, personal communication), where many juvenile turtles are commonly observed resting in small caves.…”

Section: Nocturnal Habitatssupporting

confidence: 86%

Contrasted habitats and individual plasticity drive the fine scale movements of juvenile green turtles in coastal ecosystems

Chambault

Dalleau

Nicet³

et al. 2020

Mov Ecol

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Background: A strong behavioural plasticity is commonly evidenced in the movements of marine megafauna species, and it might be related to an adaptation to local conditions of the habitat. One way to investigate such behavioural plasticity is to satellite track a large number of individuals from contrasting foraging grounds, but despite recent advances in satellite telemetry techniques, such studies are still very limited in sea turtles.Methods: From 2010 to 2018, 49 juvenile green turtles were satellite tracked from five contrasting feeding grounds located in the South-West Indian Ocean in order to (1) assess the diel patterns in their movements, (2) investigate the inter-individual and inter-site variability, and (3) explore the drivers of their daily movements using both static (habitat type and bathymetry) and dynamic variables (daily and tidal cycles). Results: Despite similarities observed in four feeding grounds (a diel pattern with a decreased distance to shore and smaller home ranges at night), contrasted habitats (e.g. mangrove, reef flat, fore-reef, terrace) associated with different resources (coral, seagrass, algae) were used in each island. Conclusions: Juvenile green turtles in the South-West Indian Ocean show different responses to contrasting environmental conditions -both natural (habitat type and tidal cycle) and anthropogenic (urbanised vs. uninhabited island) demonstrating the ability to adapt to modification of habitat.

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Section: Nocturnal Habitatssupporting

confidence: 86%

Contrasted habitats and individual plasticity drive the fine scale movements of juvenile green turtles in coastal ecosystems

Chambault

Dalleau

Nicet³

et al. 2020

Mov Ecol

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Section: Discussionmentioning

confidence: 99%

“…While this distribution makes green turtles relatively easy to protect, it also makes them vulnerable because inadequate protection at major sites can result in population crashes. Loggerhead turtles, in contrast, generally have a complex movement pattern during (Snape et al., 2016, 2018; Tucker, 2010) and outside of the breeding season (Dujon et al., 2018; Haywood et al., 2020 a ; Snape et al., 2016), which may make them particularly susceptible to anthropogenic activities (Lewison et al., 2014; Wallace et al., 2008). Additionally, loggerhead turtles recruit to neritic foraging habitats at a larger size than green turtles and continue to transition between pelagic and neritic feeding and among neritic feeding areas as juveniles (Snape et al., 2020).…”

Section: Discussionmentioning

confidence: 99%

Investigating differences in population recovery rates of two sympatrically nesting sea turtle species

Omeyer

Stokes

Beton³

et al. 2021

Animal Conservation

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Estimating life-history traits and understanding their variation underpins the management of long-lived, migratory animals, while knowledge of recovery dynamics can inform the management of conservation-dependent species. Using a combination of nest counts and individual-based life-history data collected since 1993, we explore the drivers underlying contrasting population recovery rates of sympatrically nesting loggerhead (Caretta caretta) and green (Chelonia mydas) turtles in North Cyprus. We found that nest counts of loggerhead and green turtles from 28 beaches across the island increased by 46% and 162%, respectively over the past 27 years. A Bayesian state-space model revealed that, at our individual-based monitoring site, nesting of green turtles increased annually at four times the rate of that of loggerhead turtles. Furthermore, we found that loggerhead turtles nesting at the individual-based monitoring site had stable reproductive parameters and average adult survival for the species and are the smallest breeding adults globally. Based on results from multiple matrix model scenarios, we propose that higher mortality rates of individuals in all age classes (likely driven by differences in life history and interaction with fisheries), rather than low reproductive output, are impeding the recovery of this species. While the increase in green turtles is encouraging, the Mediterranean population is estimated to have around 3,400 adults and is restricted to the Eastern Basin. The recovery of loggerhead turtles is likely to be compromised until mortality rates in the region are adequately quantified and mitigated. As survival of immature individuals is a powerful driver for sea turtle population numbers, additional efforts should target management at pelagic and neritic foraging areas. Understanding threats faced by immature life stages is crucial to accurately parameterise population models and to target conservation actions for long-lived marine vertebrates.

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Section: Methodsmentioning

confidence: 99%

“…Argos location data were handled using Satellite Tracking Analysis Tool (STAT), which also provides estimates of sea surface temperature, speed of travel, and sea depth at filtered locations (for details see: Coyne & Godley, 2005) of the same preferred LC remained within a given day, the median of these locations was used (Snape et al, 2018). Habitat utilization distributions (UDs) of 90% and 50% were calculated to determine total and core habitat use respectively (Börger et al, 2006) whilst 20% UDs were used to determine areas of intense utilization (Casale, Broderick, et al, 2012;Snape et al, 2018). Using filtered tracking data, the number of days that each turtle spent in oceanic habitats was calculated by summing periods where more than one consecutive location occurred in depths >200 m. To summarize cumulative habitat use across the three turtles, within Drini Bay, data were pooled across individuals and analysed as above, while 50% habitat UDs of individual turtles were also calculated separately to show individual variation and degree overlap.…”

Section: Methodsmentioning

confidence: 99%

Delineating foraging grounds of a loggerhead turtle population through satellite tracking of juveniles

Snape

Schofield

White³

2020

Aquatic Conservation

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1. Tracking of juvenile sea turtles is a research priority to inform the protection of relevant habitats and ensure sustainable rates of recruitment into adult populations. Based on satellite tracking, mixed stock analysis, and mark-recapture studies, Drini Bay in the South Adriatic Sea, Central Mediterranean, has been confirmed as an important foraging site used by loggerhead turtles from all major rookeries in the Mediterranean subpopulation.2. Three juvenile loggerhead turtles (Caretta caretta) from Drini Bay were tracked for 763, 364, and 211 days respectively. All turtles exhibited different movement patterns.3. The two smaller turtles ranged widely beyond the bay. One of these (69.5 cm curved-carapace length; CCL) used the coldest region of the Mediterranean during the first winter of tracking where mean weekly temperatures dipped below 12 C but moved southwards to warmer waters during the second winter. In com-

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Off-the-shelf GPS technology to inform marine protected areas for marine turtles

Cited by 20 publications

References 75 publications

Contrasted habitats and individual plasticity drive the fine scale movements of juvenile green turtles in coastal ecosystems

Contrasted habitats and individual plasticity drive the fine scale movements of juvenile green turtles in coastal ecosystems

Investigating differences in population recovery rates of two sympatrically nesting sea turtle species

Delineating foraging grounds of a loggerhead turtle population through satellite tracking of juveniles

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