Genetic composition of loggerhead turtle feeding aggregations: migration patterns in the North Pacific

Nishizawa, Hideaki; Narazaki, Tomoko; Fukuoka, Tatsunari; Sato, Katsufumi; Hamabata, Tomoko; Kinoshita, Masato; Arai, Nobuaki

doi:10.3354/esr00588

Cited by 14 publications

(15 citation statements)

References 40 publications

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“…and (ii) are the timing of ontogenetic habitat shifts of loggerheads in the western Pacific, as observed by Nishizawa et al . (), linked to the variable timing of similar ontogenetic shifts during the juvenile stage, as described in this study?…”

Section: Discussionmentioning

confidence: 76%

“…For example, are the larger nesting adults that forage neritically in Japan the same as those that foraged neritically in the BCP region as juveniles? and (ii) are the timing of ontogenetic habitat shifts of loggerheads in the western Pacific, as observed by Nishizawa et al (2014), linked to the variable timing of similar ontogenetic shifts during the juvenile stage, as described in this study?…”

Section: Implications Of Variable Timing Of Ontogenetic Shiftsmentioning

confidence: 67%

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Intrapopulation variability in the timing of ontogenetic habitat shifts in sea turtles revealed using δ¹⁵N values from bone growth rings

Tomaszewicz

Seminoff

Peckham

et al. 2017

Journal of Animal Ecology

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Summary Determining location and timing of ontogenetic shifts in the habitat use of highly migratory species, along with possible intrapopulation variation in these shifts, is essential for understanding mechanisms driving alternate life histories and assessing overall population trends. Measuring variations in multi-year habitat use patterns is especially difficult for remote oceanic species.To investigate the potential for differential habitat use among migratory marine vertebrates, we measured the naturally occurring stable nitrogen isotope (δ15N) patterns that differentiate distinct ocean regions to create a “regional isotope characterization”, analyzed the δ15N values from annual bone growth layer rings from dead-stranded animals, then combined the bone and regional isotope data to track individual animal movement patterns over multiple years.We used humeri from juvenile North Pacific loggerhead turtles (Caretta caretta), animals that undergo long migrations across the North Pacific Ocean (NPO), using multiple discrete regions as they develop to adulthood. Typical of many migratory marine species, ontogenetic changes in habitat use throughout their decades-long juvenile stage is poorly understood, but each potential habitat has unique foraging opportunities and spatially explicit natural and anthropogenic threats that could affect key life history parameters.We found a bimodal size/age distribution in the timing that juveniles underwent an ontogenetic habitat shift from the oceanic central North Pacific (CNP) to the neritic east Pacific region near the Baja California Peninsula (BCP) (42.7±7.2 vs. 68.3±3.4 cm carapace length, 7.5±2.7 vs. 15.6±1.7 years). Important to the survival of this population, these disparate habitats differ considerably in their food availability, energy requirements, and threats, and these differences can influence life history parameters such as growth, survival, and future fecundity. This is the first evidence of alternative ontogenetic shifts and habitat use patterns for juveniles foraging in the eastern NPO.We combine two techniques, skeletochronology and stable isotope analysis, to reconstruct multi-year habitat use patterns of a remote migratory species, linked to estimated ages and body sizes of individuals, to reveal variable ontogeny during the juvenile life stage that could drive alternate life histories and that has the potential to illuminate the migration patterns for other species with accretionary tissues.

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Section: Discussionmentioning

confidence: 76%

Section: Implications Of Variable Timing Of Ontogenetic Shiftsmentioning

confidence: 67%

Intrapopulation variability in the timing of ontogenetic habitat shifts in sea turtles revealed using δ¹⁵N values from bone growth rings

Tomaszewicz

Seminoff

Peckham

et al. 2017

Journal of Animal Ecology

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“…To investigate the relationship of different lineages and to represent part of the worldwide genetic diversity within species, mitochondrial control region haplotypes were compiled from literature and depicted in a network analysis. For C. caretta , the haplotypes (776 bp) were obtained from Shamblin et al (2014), Nishizawa et al (2014) and from the database of The Archie Carr Center for Sea Turtle Research (http://accstr.ufl.edu/resources/mtdna-sequences). For E. imbricata , the control region haplotypes (739 bp) were obtained from LeRoux et al (2012), Vilaça et al (2012), Vargas et al (2016) and Gaos et al (2018).…”

Section: Methodsmentioning

confidence: 99%

New genetic insights about hybridization and population structure of hawksbill and loggerhead turtles from Brazil

Arantes

Vilaça

Mazzoni

et al. 2020

Preprint

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19An extremely high incidence of hybridization among sea turtles is found along the 20 Brazilian coast. To understand this atypical phenomenon and its impact on sea turtle 21 conservation, research focused in the evolutionary history of sea turtles is fundamental. We 22 assessed high quality multilocus haplotypes of 143 samples of the five species of sea turtles 23 that occur along the Brazilian coast to investigate the hybridization process and the population 24 structure of hawksbill (Eretmochelys imbricata) and loggerhead turtles (Caretta caretta). The 25 multilocus data were initially used to characterize interspecific hybrids. Introgression (F2 26 hybrids) was only confirmed in hatchlings of F1 hybrid females (hawksbill x loggerhead), 27 indicating that introgression was either previously overestimated and F2 hybrids may not 28 survive to adulthood, or the first-generation hybrid females nesting in Brazil were born as recent 29 as few decades ago. Phylogenetic analyses using nuclear markers recovered the mtDNA-based 30 Indo-Pacific and Atlantic lineages for hawksbill turtles, demonstrating a deep genetic 31 divergence dating from the early Pliocene. In addition, loggerhead turtles that share a common 32 2 feeding area and belong to distinct Indo-Pacific and Atlantic mtDNA clades present no clear 33 genetic differentiation at the nuclear level. Finally, our results indicate that hawksbill and 34 loggerhead rookeries along the Brazilian coast are likely connected by male-mediated gene 35 flow. 36 37

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“…Breeding populations and regional management units (RMUs) for loggerhead turtles have been defined using behavioural and genetic data respectively (Bowen et al 2004; Wallace et al 2010) and seasonal and ontogenetic movements have been identified at several locations (Limpus and Limpus 2001; Hawkes et al 2007; McClellan and Read 2007; Casale et al 2008; Mansfield et al 2009; Hays et al 2010a; Marcovaldi et al 2010; Rees et al 2010; Nishizawa et al 2014b). The recent use of more variable genetic markers and extended coverage of nesting areas has increased the resolution of mitochondrial DNA (mtDNA) studies, aiding the identification of further sub-populations (Shamblin et al 2014).…”

Section: Introductionmentioning

confidence: 99%

Linking loggerhead locations: using multiple methods to determine the origin of sea turtles in feeding grounds

et al. 2017

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Many marine megavertebrate taxa, including sea turtles, disperse widely from their hatching or birthing locations but display natal homing as adults. We used flipper tagging, satellite tracking and genetics to identify the origin of loggerhead turtles living in Amvrakikos Gulf, Greece. This location has been identified as hosting regionally important numbers of large-juvenile to adult sized turtles that display long-term residency and/or association to the area, and also presents a male biased sex ratio for adults. A total of 20 individuals were linked to nesting areas in Greece through flipper tagging and satellite telemetry, with the majority (16) associated with Zakynthos Island. One additional female was tracked from Amvrakikos Gulf to Turkey where she likely nested. Mitochondrial DNA mixed stock analyses of turtles captured in Amvrakikos Gulf (n = 95) indicated 82% of individuals originated from Greek nesting stocks, mainly from Zakynthos Island (63%), with lesser contributions from central Turkey, Cyprus and Libya. These results suggest that the male-biased sex ratio found in Amvrakikos Gulf may be driven by the fact that males breed twice as frequently on Zakynthos, resulting in their using foraging grounds of greater proximity to the breeding site. Conservation measures in localised foraging habitats for the protection of marine vertebrates, such as sea turtles, may have positive impacts on several disparate breeding stocks and the use of multiple methods to determine source populations can indicate the relative effectiveness of these measures.Electronic supplementary materialThe online version of this article (doi:10.1007/s00227-016-3055-z) contains supplementary material, which is available to authorized users.

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Genetic composition of loggerhead turtle feeding aggregations: migration patterns in the North Pacific

Cited by 14 publications

References 40 publications

Intrapopulation variability in the timing of ontogenetic habitat shifts in sea turtles revealed using δ¹⁵N values from bone growth rings

Intrapopulation variability in the timing of ontogenetic habitat shifts in sea turtles revealed using δ¹⁵N values from bone growth rings

New genetic insights about hybridization and population structure of hawksbill and loggerhead turtles from Brazil

Linking loggerhead locations: using multiple methods to determine the origin of sea turtles in feeding grounds

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Genetic composition of loggerhead turtle feeding aggregations: migration patterns in the North Pacific

Cited by 14 publications

References 40 publications

Intrapopulation variability in the timing of ontogenetic habitat shifts in sea turtles revealed using δ15N values from bone growth rings

Intrapopulation variability in the timing of ontogenetic habitat shifts in sea turtles revealed using δ15N values from bone growth rings

New genetic insights about hybridization and population structure of hawksbill and loggerhead turtles from Brazil

Linking loggerhead locations: using multiple methods to determine the origin of sea turtles in feeding grounds

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Intrapopulation variability in the timing of ontogenetic habitat shifts in sea turtles revealed using δ¹⁵N values from bone growth rings

Intrapopulation variability in the timing of ontogenetic habitat shifts in sea turtles revealed using δ¹⁵N values from bone growth rings