Fine‐scale movement and habitat use of juvenile, subadult, and adult green turtles (<scp><i>Chelonia mydas</i></scp>) in a foraging ground at Ningaloo Reef, Australia

Pillans, Richard D.; Whiting, Scott D.; Tucker, Anton D.; Vanderklift, Mathew A.

doi:10.1002/aqc.3832

Cited by 7 publications

(9 citation statements)

References 72 publications

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“…Similar to the findings of Babcock et al [45], both telemetry approaches provided comparable overall tracking durations in this study [45]. Our satellite tracking durations (20 to 234 d) were equivalent to those reported in recent studies tracking juvenile green turtles [92,93]; however, the acoustic tracking durations (8 to 237 d) were considerably shorter than those in the current literature, which have tracked individuals for over a year and even up to 2.5 years [94,95]. Range distributions in particular are heavily influenced by the number of times an individual crosses its range (i.e.…”

Section: Discussionsupporting

confidence: 84%

Comparing acoustic and satellite telemetry: an analysis quantifying the space use of Chelonia mydas in Bimini, Bahamas

Hardin,

Cullen,

Fuentes

2024

R. Soc. Open Sci.

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Passive acoustic and Argos satellite telemetry are common methods for tracking marine species and are often used similarly to quantify space use. However, data-driven comparisons of these methods and their associated ecological inferences are limited. To address this, we compared temporal durations, spatial resolutions, financial costs and estimates of occurrence and range distributions for each tracking approach using nine juvenile green turtles ( Chelonia mydas ) in Bimini, Bahamas. Tracking durations were similar, although acoustic tracking provided higher spatiotemporal resolution than satellite tracking. Occurrence distributions (95%) estimated from satellite telemetry were 12 times larger than those from acoustic telemetry, while satellite range distributions (95%) were 89 times larger. While individuals generally remained within the extent of the acoustic receiver array, gaps in coverage were identified. These gaps, combined with the lower accuracy of satellite telemetry, were likely drivers for the larger satellite distributions. Costs differed between telemetry methods, with acoustic telemetry being less expensive at larger sample sizes with a previously established array. Our results suggest that acoustic and satellite telemetry may not provide similar inferences of individual space use. As such, we provide recommendations to identify telemetry methods appropriate for specific study objectives and provide discussion on the biases of each.

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Section: Discussionsupporting

confidence: 84%

Comparing acoustic and satellite telemetry: an analysis quantifying the space use of Chelonia mydas in Bimini, Bahamas

Hardin,

Cullen,

Fuentes

2024

R. Soc. Open Sci.

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“…We observed no correlation between 90% UD (home range) and turtle size. Other studies have reported a positive relationship between turtle size and home range size [43,53]. The absence of correlation in our study may be due to the narrow range of sizes of tracked turtles (48.4-69.4 cm SCL), rather than a sampling of the full range of neritic juveniles (25-80 cm) that occur in Bermuda.…”

Section: Home Rangecontrasting

confidence: 72%

“…In a comparison of telemetry methods used with marine turtles, Thomson et al [41] (Table 1) showed that both passive and active acoustic tracking have similar location accuracy to data from Fastloc-GPS, i.e., tens to hundreds of meters. Thus, along with Fastloc-GPS studies, results from acoustic tracking of juvenile green turtles in benthic developmental habitats in which locations were taken either by mobile observers [50,51] or fixed arrays [52,53] appear to provide more useful comparisons to our study than results based on Argos or combined Argos and GPS location data.…”

Section: Plos Onementioning

confidence: 84%

Daily, seasonal, and long-distance movements inferred from Fastloc-GPS telemetry of immature green turtles (Chelonia mydas) at a high-latitude, mid-ocean developmental site

Hardy,

Meylan,

Gray

et al. 2023

PLoS ONE

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To characterize the movements and habitat use of juvenile green turtles (Chelonia mydas) in benthic developmental habitat, we deployed Fastloc-GPS-enabled satellite transmitters on 16 individuals captured as part of a multi-decade study of green turtles on the Bermuda Platform. We characterized residence areas, distinct use areas within them, and seasonal movements based on an average of 562 Fastloc-GPS positions and 284 tracking days per turtle. We estimated residence area sizes using traditional home range methods, e.g., 90% utilization distribution (UD) (mean 2.29 ±2.71 km2) and 50% UD (mean 0.54 ±0.69 km2). Total residence area size increased significantly over the 8-year study, from <1 km2 before 2013 to ≥3 km2 in 2018 (R2 = 0.51, F1,14 = 14.55, p = 0.0019), corresponding to a period of decline in seagrass habitat and suggesting increased foraging effort. We identified three types of distinct use areas within residence areas where tracked turtles typically exhibited behavioral fidelity: foraging, resting, and cool weather refugia. These distinct use areas were smaller than high-use areas from previous studies; e.g., seagrass meadow foraging areas averaged 0.05 km2. Most turtles made daily transits between foraging and resting sites; for some individuals, these involved crossing frequently used vessel navigation channels. Seasonal variation in behavior suggested that the overwintering strategy for green turtles on the Bermuda Platform involves “optional dormancy,” during which turtles spent less time on seagrass meadows and made brief excursions to distinct deeper habitats. Four individuals made directed (mean path straightness = 0.93 ±0.02 SD) developmental migrations away from Bermuda toward known adult foraging range. Results of our study further knowledge of the green turtle life cycle at a high-latitude site; they demonstrate that green turtles show fidelity to distinct use areas within developmental habitats over many years and exhibit seasonal movements.

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“…We investigated ontogenetic changes in the diet of C. mydas in a tropical coastal lagoon in north-western Australia. C. mydas at this location are long-term residents that show size-related changes in home range size, home range location, and diet (Pillans et al, 2022;Stubbs et al, 2022). Size is a good predictor of age (Mayne et al, 2022), and here we use size as a proxy for age to further explore ontogenetic patterns in the home range location and diet of C. mydas.…”

Section: Introductionmentioning

confidence: 99%

Ontogenetic changes in green turtle (Chelonia mydas) diet and home range in a tropical lagoon

et al. 2023

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Ontogenetic changes in habitat and diet are widespread among marine species. Most species of sea turtles are characterized by extreme ontogenetic changes in habitat use and diet, with large changes occurring in early developmental stages (e.g., neonates to juveniles). Changes can continue even after recruitment to shallow coastal habitats. In places where substantial transitions in habitat occur across short distances, it is possible that the distances of developmental movements from one habitat to another could be short. We investigated ontogenetic changes in home range size, home range location and diet of Chelonia mydas in a tropical coastal lagoon in north-western Australia by combining acoustic telemetry with stable isotope analysis. There was a substantial (but nonlinear) increase in home-range size (kernel utilization distribution: KUD) with length, and an increase in the average distance of the center of home ranges from shore with length: larger turtles tended to occupy larger areas further from the shore. These patterns were accompanied by complex nonlinear changes in δ13C, δ15N and δ34S of red blood cells and nails; changes were rapid from 36 cm (the length of the smallest individual captured) to 50 cm, before reversing more gradually with increasing size. δ15N and δ34S (but not δ13C) of red blood cells and nails increased monotonically with KUD and distance from shore. Seagrass was likely an important food for all sizes, macroalgae was potentially important for small (< 60 cm CCL) individuals, and the proportion of scyphozoan jellyfish in diet increased monotonically with size. The combination of acoustic telemetry and stable isotope analysis revealed ontogenetic shifts in use of space and diet across short distances in a tropical coastal lagoon.

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Fine‐scale movement and habitat use of juvenile, subadult, and adult green turtles (Chelonia mydas) in a foraging ground at Ningaloo Reef, Australia

Cited by 7 publications

References 72 publications

Comparing acoustic and satellite telemetry: an analysis quantifying the space use of Chelonia mydas in Bimini, Bahamas

Comparing acoustic and satellite telemetry: an analysis quantifying the space use of Chelonia mydas in Bimini, Bahamas

Daily, seasonal, and long-distance movements inferred from Fastloc-GPS telemetry of immature green turtles (Chelonia mydas) at a high-latitude, mid-ocean developmental site

Ontogenetic changes in green turtle (Chelonia mydas) diet and home range in a tropical lagoon

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