Ontogeny of the dispersal migration of green turtle (Chelonia mydas) hatchlings

Okuyama, Junichi; Abe, Osamu; Nishizawa, Hideaki; Kobayashi, Masato; Yoseda, Kenzo; Arai, Nobuaki

doi:10.1016/j.jembe.2009.08.008

Cited by 25 publications

(27 citation statements)

References 11 publications

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“…Although such studies are difficult to perform with hatch ling sea turtles and evidence of a passive pe lagic stage is mostly indirect, it is reasonable to sus pect that ocean currents play an important role in the movements of hatchlings and early juveniles of all sea turtle species. In fact, recent work by Okuyama et al (2009) visually and radio-tracked the movements of newborn green turtles that had been reared for a variety of days (classified into 1 d, 7 d and 28-56 d age groups) and released into the sea, and demonstrated that ocean surface currents affected turtle migration in all studied age groups.…”

Section: Discussionmentioning

confidence: 99%

Green turtle Chelonia mydas mixed stocks in the western South Atlantic, as revealed by mtDNA haplotypes and drifter trajectories

Proietti¹,

Reisser²,

Kinas³

et al. 2012

Mar. Ecol. Prog. Ser.

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Genetic structure and natal origins of green turtle mixed stocks in southern Brazil were assessed based on analyses of mtDNA control region sequences from the Arvoredo Island (n = 115) and Cassino Beach (n = 101) feeding areas. These were compared to other mixed aggregations to examine structuring, and to Atlantic Ocean nesting colonies to evaluate natal origins through Bayesian mixed stock analysis (MSA). In order to develop novel priors, surface drifter trajectories in the Atlantic were analyzed and combined with rookery data, and we used KulbackLeibler information measures in order to compare the difference of information among the 4 proposed priors. Each study area presented 12 haplotypes, 10 of which were shared at similar frequencies. Haplotypes CM-A8 and CM-A5 represented ~60 and 20%, respectively, and remaining haplotypes accounted for < 5% of samples. The 2 study areas were genetically similar to all feeding grounds in the western South Atlantic except Almofala, in northeast Brazil, and genetically different from Caribbean and North American mixed stocks. Drifter trajectory analysis revealed that drifters from Ascension and Trindade Islands have a larger chance of reaching Brazil. The priors drifter data and rookery size/drifter data combined contained the most information, but stock estimates were not greatly changed. MSA indicated that Ascension, Aves/Surinam and Trindade were the main stock contributors to the study areas. Since impacts on mixed stocks may affect populations thousands of km away, the results presented here have important implications for the conservation of this endangered species.KEY WORDS: Green turtle · Feeding grounds · South Brazil · Genetic structure · Natal origins · Dispersal patternsResale or republication not permitted without written consent of the publisher

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Section: Discussionmentioning

confidence: 99%

Green turtle Chelonia mydas mixed stocks in the western South Atlantic, as revealed by mtDNA haplotypes and drifter trajectories

Proietti¹,

Reisser²,

Kinas³

et al. 2012

Mar. Ecol. Prog. Ser.

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“…Our observed hatchling travel speeds, which were faster than predicted swimming and modelled flow speeds combined, thus highlight the role small-scale turbulence and wave/tide-induced motions (not represented or resolved by models) play in influencing their transport. These findings thus clearly highlight the strong necessity for increased in situ tracking studies [29,31] and the improved representation of mesco-scale features in the upper surface layer of models used to investigate drift patterns. Nonetheless, both in situ tracking and model flow data highlighted that hatchlings from this region do not have to swim far to reach favourable current flows that transport them away from predator-rich coastal areas to much safer oceanic development habitats.…”

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confidence: 81%

Nano-tags for neonates and ocean-mediated swimming behaviours linked to rapid dispersal of hatchling sea turtles

Scott

Biastoch

Roder³

et al. 2014

Proc. R. Soc. B.

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Dispersal during juvenile life stages drives the life-history evolution and dynamics of many marine vertebrate populations. However, the movements of juvenile organisms, too small to track using conventional satellite telemetry devices, remain enigmatic. For sea turtles, this led to the paradigm of the 'lost years' since hatchlings disperse widely with ocean currents. Recently, advances in the miniaturization of tracking technology have permitted the application of nano-tags to track cryptic organisms. Here, the novel use of acoustic nano-tags on neonate loggerhead turtle hatchlings enabled us to witness first-hand their dispersal and behaviour during their first day at sea. We tracked hatchlings distances of up to 15 km and documented their rapid transport (up to 60 m min 21 ) with surface current flows passing their natal areas. Tracking was complemented with laboratory observations to monitor swimming behaviours over longer periods which highlighted (i) a positive correlation between swimming activity levels and body size and (ii) population-specific swimming behaviours (e.g. nocturnal inactivity) suggesting local oceanic conditions drive the evolution of innate swimming behaviours. Knowledge of the swimming behaviours of small organisms is crucial to improve the accuracy of ocean model simulations used to predict the fate of these organisms and determine resultant population-level implications into adulthood.

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“…However, becoming beached was a major cause of failure for flatback turtles at the Broome site, particularly in summer (wet season) when winds were generally from the west, so the highest rates of success would likely be achieved during the dry season. In reality, success would likely be higher across all sites and seasons than the models predict, as turtle's swimming ability would decrease the likelihood of beaching (Carr, 1987;Polovina et al, 2000;Bentivegna et al, 2007;Okuyama et al, 2009). While the model does not accurately give the probabilities for success for flatback turtles in some regions due to high beaching rates, the results do indicate where currents act to retain particles nearshore, which is ideal for this species.…”

Section: Discussionmentioning

confidence: 95%

“…Whilst directional swimming is clearly a component of post-hatchling and neonate turtle's migratory paths (Hamann et al, 2011;Putman and Mansfield, 2015;Christiansen et al, 2016), ocean currents strongly influence their movement (Carr, 1987;Polovina et al, 2000;Gaspar et al, 2006;Bentivegna et al, 2007;Okuyama et al, 2009). The proximity of nesting beaches to favorable ocean currents highlights the importance of ocean currents to sea turtles, with higher nest densities found close to currents that promote hatchling dispersal to suitable habitats (Putman et al, 2010;Shillinger et al, 2012;Ascani et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Use of Particle Tracking to Determine Optimal Release Dates and Locations for Rehabilitated Neonate Sea Turtles

et al. 2017

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Sea turtles found stranded on beaches are often rehabilitated before being released back into the wild. The location and date of release is largely selected on an informal basis, which may not maximize the chance of survival. As oceanic conditions have a large influence on the movements of neonate sea turtles, this study aimed to identify the best locations and months to release rehabilitated sea turtles that would assist in their transport by ocean currents to the habitat and thermal conditions required for their survival. A particle tracking model, forced by ocean surface velocity fields, was used to simulate the dispersal pathways of millions of passively drifting particles released from different locations in Western Australia. The particles represented rehabilitated, neonate turtles requiring oceanic habitats [green (Chelonia mydas), hawksbill (Eretmochelys imbricata) and loggerheads (Caretta caretta)] and flatback turtles (Natator depressus) which require neritic habitats. The results clearly identified regions and months where ocean currents were more favorable for transport to suitable habitats. Tantabiddi, near Exmouth on the north-west coast, was consistently the best location for release for the oceanic species, with dominant offshore-directed currents and a very narrow continental shelf reducing the time taken for particles to be transported into deep water. In contrast, release locations with more enclosed geography, wide continental shelves, and/or proximity to cooler ocean temperatures were less successful. Our results produced a decision support system for the release of neonate marine turtles in Western Australia and our particle tracking approach has global transferability.

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Ontogeny of the dispersal migration of green turtle (Chelonia mydas) hatchlings

Cited by 25 publications

References 11 publications

Green turtle Chelonia mydas mixed stocks in the western South Atlantic, as revealed by mtDNA haplotypes and drifter trajectories

Green turtle Chelonia mydas mixed stocks in the western South Atlantic, as revealed by mtDNA haplotypes and drifter trajectories

Nano-tags for neonates and ocean-mediated swimming behaviours linked to rapid dispersal of hatchling sea turtles

Use of Particle Tracking to Determine Optimal Release Dates and Locations for Rehabilitated Neonate Sea Turtles

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