Growth rates of juvenile green turtles Chelonia mydas from three ecologically distinct foraging habitats along the east central coast of Florida, USA

Kubis, Stacy; Chaloupka, Milani; Ehrhart, Llewellyn M.; Bresette, Michael J.

doi:10.3354/meps08206

Cited by 56 publications

(63 citation statements)

References 26 publications

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“…Since recapture rates of turtles are highly variable (Piovano et al 2011), using just 1−2 yr of growth provides an incomplete life history and is likely to miss rare growth spurts. Therefore, long-term datasets are more accurate in estimating life-stage durations as they are more likely to capture the variability in and full distribution of growth rates, but such studies are quite laborious and time-consuming, requiring multiple recaptures of animals (Bjorndal et al 2000, Balazs & Chaloupka 2004b, Kubis et al 2009, Eguchi et al 2012, Avens & Snover 2013, Sampson et al 2015, Goshe et al 2016.…”

Section: Discussionmentioning

confidence: 99%

Impact of exceptional growth rates on estimations of life-stage duration in Hawaiian green sea turtles

Murakawa¹,

Snover²

2018

Endang. Species. Res.

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Section: Discussionmentioning

confidence: 99%

Impact of exceptional growth rates on estimations of life-stage duration in Hawaiian green sea turtles

Murakawa¹,

Snover²

2018

Endang. Species. Res.

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“…This longer duration at vulnerable sizes could decrease the probability of older values of AgeSM resulting from slow length growth or larger values of size at maturity from slow mass growth. In contrast, density-dependent effects could yield older AgeSM and smaller LengthSM and MassSM, as populations recover , Chaloupka et al 2008) and somatic growth rates slow (Bjorndal et al 2000, Balazs & Chaloupka 2004, Kubis et al 2009). In addition, sea turtles are subjected to a large number of threats (Lutcavage et al 1997, Bolten et al 2011), many of which produce sublethal effects that can decrease juvenile growth rates (McCauley & Bjorndal 1999, Roark et al 2009) and thus could result in older values of AgeSM and smaller size at maturity.…”

Section: Comparisons With Wild Populationsmentioning

confidence: 99%

“…Somatic growth rates in sea turtles vary spatially and temporally (Diez & van Dam 2002, Balazs & Chaloupka 2004, Kubis et al 2009, Bjorndal et al 2013b However, variation in age and size of wild turtles could be decreased -although not below the level of variation in CTF turtles -by increased mortality of slow-growing turtles that remain in vulnerable size classes for a longer time. This longer duration at vulnerable sizes could decrease the probability of older values of AgeSM resulting from slow length growth or larger values of size at maturity from slow mass growth.…”

Section: Comparisons With Wild Populationsmentioning

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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“…At a local scale, previous studies have found foraging site specific growth rates, likely as a consequence of habitat quality and availability of food resources (Balazs & Chaloupka 2004, Kubis et al 2009). The differences observed here between foraging aggregations are also likely attributable to habitat rather than to genetic stock or to size distributions, as neither of these aspects differ significantly among sites.…”

Section: Foraging Site Specific Growth and Abundance Trendsmentioning

confidence: 99%

“…Spatial and temporal variability in somatic growth dynamics, particularly when coupled with abundance estimates, make good indicators of the quality of foraging sites, as lower growth rates may imply less food availability (Balazs & Chaloupka 2004, Kubis et al 2009, and declines in somatic growth rates coupled with higher abundance suggest a density-dependent effect (Bjorndal et al 2000a, Kubis et al 2009). …”

Section: Introductionmentioning

confidence: 99%

Spatial and temporal variability of immature green turtle abundance and somatic growth in Puerto Rico

Patrício¹,

Díez²,

Dam³

2014

Endang. Species. Res.

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Understanding conservation needs relies on robust estimates of key population parameters, such as survival, abundance and somatic growth. We investigated the somatic growth and abundance dynamics of 2 aggregations of immature green turtles, at Tortuga Bay and Puerto Manglar (Culebra, Puerto Rico), throughout 15 yr of capture-mark-recaptures. We used nonlinear models to investigate the effects of carapace length, sampling year, growth interval and the presence of fibropapillomas on growth rates, and used the size-specific growth rate function to estimate how long turtles remain at each bay. Abundances were estimated and compared with timespecific growth rate functions, to infer density-dependency effects on somatic growth rates, and trends in abundance were evaluated by fitting generalized linear models. We found foraging site specific growth rates and report the highest mean somatic growth rate for green turtles in the wild (6.1 ± 1.7 cm yr −1 , at Puerto Manglar). The size-specific growth rate function was monotonic at both sites, with growth rates declining continuously with increasing carapace length. We inferred minimum ages at maturity of 14 and 22 yr, for Puerto Manglar and Tortuga Bay turtles, respectively. Throughout the 15 yr of this study there was a positive trend in aggregation size at Puerto Manglar (mean annual increase of 10.9%), which was not observed at Tortuga Bay. Our study highlights the influence of geography and habitat quality on somatic growth rates, and delivers robust demographic estimates valuable for local and regional assessments of the conservation status of the green turtle.

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Growth rates of juvenile green turtles Chelonia mydas from three ecologically distinct foraging habitats along the east central coast of Florida, USA

Cited by 56 publications

References 26 publications

Impact of exceptional growth rates on estimations of life-stage duration in Hawaiian green sea turtles

Impact of exceptional growth rates on estimations of life-stage duration in Hawaiian green sea turtles

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

Spatial and temporal variability of immature green turtle abundance and somatic growth in Puerto Rico

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