Seasonal shifts in the movement and distribution of green sea turtles Chelonia mydas in response to anthropogenically altered water temperatures

Crear, Daniel P.; Lawson, D. D.; Seminoff, Jeffrey A.; Eguchi, Tomoharu; LeRoux, Robin A.; Lowe, Christopher G.

doi:10.3354/meps11696

Cited by 21 publications

(33 citation statements)

References 40 publications

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“…Along the western coast of the U. S., the northernmost resident foraging aggregations of green turtles inhabit San Diego Bay (SDB) and the Seal Beach National Wildlife Refuge (SBNWR) (Eguchi et al, 2010;MacDonald et al, 2012;Crear et al, 2016). SDB is home to a major U.S. Navy base and subject to other anthropogenic activities such as ship maintenance, dredging, fishing, and boating, which have resulted in the bay being listed (303D) as an impacted body of water (Fairey et al, 1998).…”

Section: Introductionmentioning

confidence: 99%

“…SDB is home to a major U.S. Navy base and subject to other anthropogenic activities such as ship maintenance, dredging, fishing, and boating, which have resulted in the bay being listed (303D) as an impacted body of water (Fairey et al, 1998). SBNWR is located within a naval weapons station and green turtles have been shown to forage in the surrounding area (Crear et al, 2016;Crear et al, 2017). The SBNWR is within 15 km of the Port of Los Angeles, has a naval weapons station, and has input from many impacted waterways and water bodies influenced by industrial and residential runoff (Schiff et al, 2011;Dodder et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

“…Previous studies on green turtles have shown that SDB green turtles bioaccumulate anthropogenic contaminants such as trace metals (Komoroske et al, 2011). However, the green turtle aggregation in the SBNWR was only recently discovered as a permanent foraging aggregation and has not been previously studied for trace metals accumulation levels (Crear et al, 2016). Considering the different sediment trace metal profiles (Dodder et al, 2016), the high site fidelity green turtles exhibit (Eguchi et al, 2010;Crear et al, 2016), and previous research demonstrating green turtle trace metal bioaccumulation from urbanized habitats (Komoroske et al, 2011), we hypothesized that green turtles from the SBNWR and SDB would have location-based differences in trace metal bioaccumulation.…”

Section: Introductionmentioning

confidence: 99%

“…However, the green turtle aggregation in the SBNWR was only recently discovered as a permanent foraging aggregation and has not been previously studied for trace metals accumulation levels (Crear et al, 2016). Considering the different sediment trace metal profiles (Dodder et al, 2016), the high site fidelity green turtles exhibit (Eguchi et al, 2010;Crear et al, 2016), and previous research demonstrating green turtle trace metal bioaccumulation from urbanized habitats (Komoroske et al, 2011), we hypothesized that green turtles from the SBNWR and SDB would have location-based differences in trace metal bioaccumulation. By assessing trace metal concentrations in both aggregations we can: (1) determine whether there are differences in trace metal concentrations between sampling locations, (2) assess if trace metal concentrations have changed since previous studies in SDB green turtles, and (3) compare SBNWR and SDB turtle trace metal concentrations with those found in previous research around the world.…”

Section: Introductionmentioning

confidence: 99%

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Trace metals in green sea turtles (Chelonia mydas) inhabiting two southern California coastal estuaries

et al. 2019

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Foraging aggregations of east Pacific green sea turtles (Chelonia mydas) inhabit the Seal Beach National Wildlife Refuge (SBNWR) and San Diego Bay (SDB), two habitats in southern California, USA, located near urbanized areas. Both juvenile and adult green turtles forage in these areas and exhibit high site fidelity, which potentially exposes green turtles to anthropogenic contaminants. We assessed 21 trace metals (TM) bioaccumulated in green turtle scute and red blood cell (RBC) samples collected from SBNWR (n = 16 turtles) and SDB (n = 20 turtles) using acid digestion and inductively coupled plasma mass spectrometry. Principal component analyses of TM composition indicate that SBNWR and SDB turtles have location-specific contaminant signatures, characterized by differences in cadmium and selenium concentrations: SBNWR turtles had significantly more cadmium and selenium in RBC and more selenium in scute samples, than SDB turtles. Cadmium and selenium concentrations in RBC had a strong positive relationship, regardless of location. SBNWR turtles had higher selenium in RBCs than previously measured in other green turtle populations globally. Due to different retention times in blood vs. scute, these results suggest that SBNWR turtles have high long-and short-term selenium exposure. Turtles

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Trace metals in green sea turtles (Chelonia mydas) inhabiting two southern California coastal estuaries

et al. 2019

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“…This is a local resident population that historically represents the northernmost sizable foraging population for C. mydas in the Northeast Pacific, consisting primarily of the Revillagigedo Islands and Michoacán breeding populations in Mexico (Dutton et al, 2019). In the past, C. mydas has been largely absent or rare in coastal waters along the US West coast, but the species appears to be increasingly present at foraging areas north of their historic range in Baja California, Mexico and the US Border region of San Diego (Crear et al, 2016;Crear et al, 2017;Dutton et al, 2019;personal observation). This change in distribution has created a need to incorporate the detection of C. mydas into habitat surveys in ways that were previously not considered.…”

Section: Introductionmentioning

confidence: 99%

Finding Crush: Environmental DNA Analysis as a Tool for Tracking the Green Sea Turtle Chelonia mydas in a Marine Estuary

et al. 2020

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Environmental DNA (eDNA) analysis is a rapid, non-invasive method for species detection and distribution assessment using DNA released into the surrounding environment by an organism. eDNA analysis is recognised as a powerful tool for detecting endangered or rare species in a range of ecosystems. Although the number of studies using eDNA analysis in marine systems is continually increasing, there appears to be no published studies investigating the use of eDNA analysis to detect sea turtles in natural conditions. We tested the efficacy of two primer pairs known to amplify DNA fragments of differing lengths (488 and 253 bp) from Chelonia mydas tissues for detecting C. mydas eDNA in water samples. The capture, extraction, and amplification of C. mydas eDNA from aquaria (Sea World, San Diego, CA, United States) and natural water (San Diego Bay, CA, United States) were successful using either primer set. The primer pair providing the shorter amplicon, LCMint2/H950g, demonstrated the ability to distinguish cross-reactive species by melt curve analysis and provided superior amplification metrics compared to the other primer set (LTCM2/HDCM2); although primer dimer was observed, warranting future design refinement. Results indicated that water samples taken from deeper depths might improve detection frequency, consistent with C. mydas behaviour. Overall, this pilot study suggests that with refinement of sampling methodology and further assay optimisation, eDNA analysis represents a promising tool to monitor C. mydas. Potential applications include rapid assessment across broad geographical areas to pinpoint promising locations for further evaluation with traditional methods.

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Should I stay or should I go? The influence of environmental conditions on green turtle residence time and outward transit in foraging areas

Webster,

Duce,

Hamann

et al. 2024

Mar Biol

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Foraging animals move through the environment to satisfy their requirements for food, rest, reproduction and risk-avoidance. Understanding how animals respond to changing environmental conditions can help to characterise favourable habitat and determine whether they might be motivated to depart when those habitats become unsuitable. Foraging green turtles are typically residents that scarcely move in response to environmental changes or disturbances. Some individuals though, exhibit high mobility at fine scales. We developed an analysis of Fastloc GPS tracks of 61 green turtles using cox regression models and generalised linear mixed models to investigate the influence of a suite of environmental characteristics on the length of residence time and probability of turtles transitioning between two behavioural modes, “stay” or “go”. Decisions to move (“go”) were influenced by short-term changes in the local environmental conditions. Individuals were more likely to “stay” when temperature increased during their stay and were more likely to “go” when turbidity decreased, and they entered deeper habitats. This result implies that foraging and resting (“staying”) primarily occurs in benthic, shallow, warm habitats, while transit (“going”) is facilitated in deeper, clear water. We also determined that individuals within the green turtle foraging aggregation respond differently to environmental cues to move and hypothesise that a diversity of strategies within a foraging aggregation could confer its resilience to disturbance events. Our study provides new evidence of the factors influencing movements in green turtles and can aid in predicting how they may respond to future changes and enhance risk mitigation efforts through dynamic and adaptive planning.

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Seasonal shifts in the movement and distribution of green sea turtles Chelonia mydas in response to anthropogenically altered water temperatures

Cited by 21 publications

References 40 publications

Trace metals in green sea turtles (Chelonia mydas) inhabiting two southern California coastal estuaries

Trace metals in green sea turtles (Chelonia mydas) inhabiting two southern California coastal estuaries

Finding Crush: Environmental DNA Analysis as a Tool for Tracking the Green Sea Turtle Chelonia mydas in a Marine Estuary

Should I stay or should I go? The influence of environmental conditions on green turtle residence time and outward transit in foraging areas

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