Kemp's Ridley Sea Turtle (Lepidochelys kempii) Age at First Nesting

Caillouet, Charles W.; Shaver, Donna J.; Landry, André M.; Owens, David W.; Pritchard, Peter C. H.

doi:10.2744/ccb-0836.1

Cited by 28 publications

(45 citation statements)

References 8 publications

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“…Within-species variation in SSM in wild individuals is greater than that observed in captive species (Witzell 1983, Dodd 1988, Marquez 1994, Hirth 1997, Tiwari & Bjorndal 2000, Caillouet et al 2011, 2017see Table 2), potentially due to greater variation in juvenile growth rates within and between populations and species , Kubis et al 2009, Bell & Pike 2012, Avens et al 2017. Carry-over effects resulting from early environmental conditions, such as those associated with differences in habitat use or productivity at foraging grounds, have been speculated to be linked to differences in juvenile growth rates within and among populations and thus differences in SSM (Eder et al 2012).…”

Section: Age−size Trade-offmentioning

confidence: 94%

“…Bell et al 2005, Caillouet et al 2011, Tucek et al 2014, Rees et al 2016. To overcome this problem, a number of studies have investigated growth rates using captive individuals of known age (e.g.…”

Section: Age−size Trade-offmentioning

confidence: 99%

“…Although some resear chers consider ASM, age at first mating and age at first reproduction identical, it is possible for fe males to start reproducing 2−4 yr after reaching sexual maturity (Limpus 1990, Rostal 2005, Caillouet et al 2011; some individuals in Bjorndal et al 2013aBjorndal et al , 2014. However, for the purpose of this review, ASM and age at first observed nesting are considered to be the same.…”

Section: Introductionmentioning

confidence: 99%

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Growth rates of adult sea turtles

Omeyer¹,

Godley²,

Broderick³

2017

Endang. Species. Res.

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Indeterminate growth, i.e. growth that persists throughout life, is common in longlived reptiles. Because fecundity and body size tend to be correlated in such species, individuals face a life-history trade-off at sexual maturity. Saturation tagging and intensive monitoring at nesting grounds can potentially provide opportunities to accumulate data on individual measurements and reproductive output. Until recently, however, shortcomings from these methods have prevented the testing of theories on resource allocation between growth and reproduction at sexual maturity in wild populations of sea turtles. Here, we review the state of knowledge of growth rates in adult sea turtles and potential life-history trade-offs. We found that post-maturity growth rates varied among ocean basins. They appeared highest in the Atlantic Ocean for both green turtles Chelonia mydas and hawksbill turtles Eretmochelys imbricata, and highest in the Mediterranean Sea for loggerhead turtles Caretta caretta. For other species, there are too few studies at present to allow for intraspecific comparison. Additionally, we found no significant difference in mean female compound annual growth rates among species and ocean basins. Although captive studies have provided great insight into changes in energy allocation at sexual maturity and life-history trade-offs, this review highlights the lack of data on wild animals regarding changes in post-maturity growth rates and reproductive output over time. Such data are desirable to further our understanding of energy allocation, growth and ageing in wild sea turtles. They are further required to assess the status of species and to understand population dynamics for both conservation and management.

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Section: Age−size Trade-offmentioning

confidence: 94%

Section: Age−size Trade-offmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Growth rates of adult sea turtles

Omeyer¹,

Godley²,

Broderick³

2017

Endang. Species. Res.

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“…We are confident that the first nesting event of each turtle was detected. We used age at first oviposition as AgeSM, although, as Caillouet et al (2011) have pointed out, these values are not necessarily the same.…”

Section: Methodsmentioning

confidence: 99%

Variation in age and size at sexual maturity in Kemp’s ridley sea turtles

Bjorndal¹,

Parsons²,

Mustin³

et al. 2014

Endang. Species. Res.

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Age at sexual maturity (AgeSM) is one of the most serious demographic data gaps for sea turtle populations. Better estimates of AgeSM and associated variance would improve evaluation of population dynamics and responses of populations to disturbances and conservation measures. A population of Kemp's ridleys Lepidochelys kempii was raised in captivity under the same conditions from hatchlings to several years after maturity. Data collected from 14 female Kemp's ridleys at Cayman Turtle Farm over a 16 yr period allowed us to determine mean and variance in age, length, mass, and body condition at maturity, average pre-maturity growth rates, and post-maturity growth rates, as well as interactions among these parameters. Age, length, and mass at maturity exhibited considerable variance, with ranges of 5 to 12 yr, 47.0 to 61.0 cm, and 20.0 to 36.8 kg, respectively. Pre-maturity length growth rate is the best single predictor of AgeSM, accounting for 87% of the variation in AgeSM. Pre-maturity mass growth rate is the best single predictor of size at maturity, accounting for 51 and 65% of variation in length at maturity and mass at maturity, respectively. Although estimates of age and size at maturity from captive Kemp's ridleys cannot be applied to wild populations because of the effect of nutrition, the amount of variation around age and size at maturity in Kemp's ridleys from Cayman Turtle Farm is a good first approximation of inherent (or genetic) variation in these parameters for wild Kemp's ridleys. Population models for Kemp's ridleys that now employ a knife-edge estimate of AgeSM would be improved by incorporating a maturity schedule that reflects the variation in AgeSM.KEY WORDS: Age at sexual maturity · Size at sexual maturity · Indeterminate growth · Lepidochelys kempii · Sea turtle Resale or republication not permitted without written consent of the publisherEndang Species Res 25: 57-67, 2014 This variation is primarily a result of variation in LengthSM and not of growth after sexual maturity, because growth rates are largely negligible after maturity (Carr & Goodman 1970, Bjorndal et al. 1983, 2013a, Broderick et al. 2003, Price et al. 2004. Whether the variation in LengthSM is a result of inherent (or genetic) variation or environmental factors is not known. Whatever the cause, selection of an appropriate population-wide LengthSM for estimating AgeSM is problematic. Several measures have been used; minimum size and mean size of nesting females are the most common.A few records of AgeSM in sea turtles have resulted from marking hatchlings so they can be recognized at maturity or by tagging head-started turtles -turtles that have been reared in captivity usually for a year before release (Bell et al. 2005, Shaver & Wibbels 2007, Limpus 2009). Individual records of age at sexual maturity are very valuable and are not known for most populations. However, as these rare estimates trickle in, the extent to which they can be used to represent population estimates depends upon the amount of variation i...

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“…Determining ATM is difficult in marine turtles due to challenges related to both longevity and life history, and both empirical and indirect approaches have been pursued. For example, coded wire tags were injected into juvenile Kemp's ridley turtles (Lepidochelys kempii), and recovered via dead stranded animals years later to estimate a minimum ATM of 10-14 years (Shaver and Caillouet, 1998;Caillouet et al, 2011). This was similar to an ATM using capture-mark-recapture (CMR) and skeletochronology in headstarted Kemp's (10-17 years; Snover et al, 2007), but longer than an estimate from captive animals (5-12 years; Bjorndal et al, 2014), suggesting that growth and maturity may differ in the wild.…”

Section: Life Historymentioning

confidence: 99%

Advances in the Application of Genetics in Marine Turtle Biology and Conservation

et al. 2017

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Marine turtles migrate across long distances, exhibit complex life histories, and occupy habitats that are difficult to observe. These factors present substantial challenges to understanding fundamental aspects of their biology or assessing human impacts, many of which are important for the effective conservation of these threatened and endangered species. The early development and application of genetic tools made important contributions to understanding marine turtle population and evolutionary biology, such as providing evidence of regional natal homing by breeding adults, establishing connectivity between rookeries and foraging habitats, and determining phylogeography and broad scale stock structure for most marine turtle species. Recent innovations in molecular technologies, statistical methods, and creative application of genetic tools have significantly built upon this knowledge to address key questions in marine turtle biology and conservation management. Here, we evaluate the latest major advances and potential of marine turtle genetic applications, including improved resolution and large-scale syntheses of population structure, connectivity and phylogeography, estimation of key demographic rates such as age to maturity and operational or breeding sex ratios, insight into reproductive strategies and behavior, and assessment of differential human impacts among populations. We then discuss remaining challenges and emerging capabilities, such as rapid, multiplexed genotyping, and investigation of the genomic underpinnings of adaptive variation afforded by high-throughput sequencing technologies.

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Kemp's Ridley Sea Turtle (Lepidochelys kempii) Age at First Nesting

Cited by 28 publications

References 8 publications

Growth rates of adult sea turtles

Growth rates of adult sea turtles

Variation in age and size at sexual maturity in Kemp’s ridley sea turtles

Advances in the Application of Genetics in Marine Turtle Biology and Conservation

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