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

Murakawa, Shawn K. K.; Snover, Melissa L.

doi:10.3354/esr00885

Cited by 3 publications

(4 citation statements)

References 34 publications

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“…Green turtle non-monotonic growth has been reported for the Pacific (Limpus and Chaloupka 1997;Seminoff et al 2002;Balazs and Chaloupka 2004;Eguchi et al 2012;Murakawa and Snover 2018;Bell et al 2019) and a few sites in the Atlantic (Kubis et al 2009;Colman et al 2015); decreasing, monotonic growth has been more characteristic of the Caribbean (Bjorndal et al 2000;Patrício et al 2014). The green turtle growth spurts in this study, occurring in the larger size classes, were similar to those in the Pacific: growth spurt ca.…”

Section: Growth Ratessupporting

confidence: 72%

“…We recommend: (i) increasing the sample size on all size classes, particularly measurements of the smallest and largest size classes; (ii) reducing measurement errors by taking multiple measurements at the same encounter (e.g., Hawkes et al 2014); (iii) obtaining further information on fine-scale movement and habitat use (by tracking individuals) including use of the lagoon and surrounding reefs; (iv) improving models by investigating foraging ecology and resource availability with increasing body size; (v) determining the locations of foraging grounds of sub-adult and adult hawksbill turtles, and assess their foraging habitat and prey availability at those sites, to determine how food availability differs from that at habitat utilized predominantly by immature hawksbill turtles (< 65 cm CCL); (vi) investigating density dependence and carrying capacity with population estimates and habitat availability studies; (vii) improving understanding of when and where (and at what size) animals are recruiting in and out of the foraging population, together with improved knowledge of genetic connectivity; and (viii) assessing long-term growth trends of adult green turtles nesting at the atoll often, such as every 10 years. Furthermore, growth rates/age of sexual maturity are likely to differ between males and females, as has been suggested for both species (e.g., Chaloupka and Limpus 1997;Limpus and Chaloupka 1997;Bell et al 2005;Goshe et al 2010;Murakawa and Snover 2018;Turner Tomaszewicz et al 2022a. Nesting females were found to be larger than adult males at Aldabra (Mortimer et al 2022).…”

Section: Recommendationsmentioning

confidence: 72%

“…60 cm SCL, Florida, Kubis et al 2009). Growth spurts were found to peak in the 50-59.9 cm SCL size class for males and 70-79.9 cm SCL size class for females in Hawaii with skeletonochrology (Murakawa and Snover 2018), although when looking at average growth rates by 10-cm size class with the sexes combined, the highest growth rates were in the 50-59.9 cm SCL size class (Table S5).…”

Section: Growth Ratesmentioning

confidence: 99%

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Growth rate and projected age at sexual maturity for immature hawksbill turtles and green turtles foraging in the remote marine protected area of Aldabra Atoll, Seychelles

et al. 2023

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Changes in marine ecosystems from human stressors, and concerns over how species will respond to these changes have emphasized the importance of understanding and monitoring crucial demographic parameters for population models. Long-lived, migratory, marine vertebrates such as sea turtles are particularly vulnerable to changes. Life-history parameters like growth-in-body size can be largely influenced by environmental processes which can impact population growth. We analyzed a 40-year (1981–2021) capture-mark-recapture dataset from the protected UNESCO World Heritage Site, Aldabra Atoll, Seychelles, to estimate key population parameters, including body growth, for immature green turtles (Chelonia mydas) and hawksbill turtles (Eretmochelys imbricata). Curved carapace length (CCL) range was 34.3–110.9 cm (mean ± SD: 51.0 ± 11.4 cm, n = 1191) for green turtles and 28.7–89.4 cm (47.7 ± 14.4 cm, n = 538) for hawksbill turtles. Recapture events, with an 11-month minimum period, revealed a mean annual growth rate of 3.2 ± 1.5 cm year−1 for green turtles (n = 75) and 2.8 ± 1.4 cm year−1 for hawksbill turtles (n = 110). Hawksbill turtles exhibited a non-monotonic growth rate while no significant growth-size relationship was detected for green turtles. Green turtle mean annual growth per 10-cm size class was highest in the larger size classes (50‒69.9 cm). Hawksbill turtle growth rate was highest in the larger size classes (50‒69.9 cm) then declined in the largest size class (70‒79.9 cm). Green turtles and hawksbill turtles may spend > 8 and 18 years, respectively, using Aldabra, Seychelles, as a foraging ground.

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Section: Growth Ratessupporting

confidence: 72%

Section: Recommendationsmentioning

confidence: 72%

Section: Growth Ratesmentioning

confidence: 99%

See 1 more Smart Citation

Growth rate and projected age at sexual maturity for immature hawksbill turtles and green turtles foraging in the remote marine protected area of Aldabra Atoll, Seychelles

et al. 2023

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“…In addition, knowledge on how individuals and populations use space over time can be fundamental to identify critical habitats, resources, migratory pathways (Musick & Limpus 1997, Bolten 2003, Meylan et al 2011, baseline and shifts in growth rates (Diez & van Dam 2002, Bjorndal et al 2013, 2016, Murakawa & Snover 2018, as well as the cumulative impacts of threats (Bolten et al 2011) and areas of refuge (Maxwell et al 2013, Halpern et al 2015. For example, cumulative survival can be influenced by life stage duration, with varying exposure to stage-and habitat-specific threats (Frazer 1986, Sasso & Epperly 2007, Turner-Tomaszewicz et al 2015, Vélez-Rubio et al 2018.…”

Section: Establishing Research Priorities For Immature Stagesmentioning

confidence: 99%

Informing research priorities for immature sea turtles through expert elicitation

Wildermann¹,

Gredzens²,

Avens³

et al. 2018

Endang. Species. Res.

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Although sea turtles have received substantial focus worldwide, research on the immature life stages is still relatively limited. The latter is of particular importance, given that a large proportion of sea turtle populations comprises immature individuals. We set out to identify knowledge gaps and identify the main barriers hindering research in this field. We analyzed the perceptions of sea turtle experts through an online survey which gathered their opinions on the current state of affairs on immature sea turtle research, including species and regions in need of further study, priority research questions, and barriers that have interfered with the advancement of research. Our gap analysis indicates that studies on immature leatherback Dermochelys coriacea and hawksbill Eretmochelys imbricata turtles are lacking, as are studies on all species based in the Indian, South Pacific, and South Atlantic Oceans. Experts also perceived that studies in population ecology, namely on survivorship and demography, and habitat use/behavior, are needed to advance the state of knowledge on immature sea turtles. Our survey findings indicate the need for more interdisciplinary research, collaborative efforts (e.g. data-sharing, joint field activities), and improved communication among researchers, funding bodies, stakeholders, and decision-makers.

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Growth rates and age at maturity of Mediterranean loggerhead sea turtles estimated from a single-population foraging ground

et al. 2023

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In sea turtles, somatic growth rates and Age at Sexual Maturity (ASM) are important parameters for investigating population dynamics. Moreover, ASM informs on the time lag needed to observe the effects of past environmental variables, threats and conservation measures acting at nesting beaches on future numbers of clutches or nesting females, that are the most monitored indices. Assessing ASM of mixed populations that share the same foraging areas is difficult, as in the case of the Mediterranean Sea that is frequented by turtles originating from both the Mediterranean and the Atlantic. Here we investigated growth rates of loggerhead sea turtles (Caretta caretta) foraging in the Adriatic Sea, known to be frequented only by individuals of Mediterranean origin. Capture–mark–recapture records of 79 turtles provided growth rates ranging from – 1.1 to 9.6 cm yr−1 which were analyzed through Generalized Additive Models. When integrated with previous data on growth rates in the first years of life, results indicate a non-monotonic growth curve, likely due to an ontogenetic shift from oceanic to neritic areas. Using an integration equation, we estimated mean ASM to be 29.5 or 25.0 year based on mean nester size in Greece (83.4 cm curved carapace length, CCL) or across the Mediterranean (79.7 cm CCL), respectively. Growth rates and size-at-age are similar to the Atlantic population, but Mediterranean turtles mature earlier at a smaller size. The heterogenous growth rates and ASM reported so far in the Mediterranean are probably due, at least in part, to different foraging areas.

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

Cited by 3 publications

References 34 publications

Growth rate and projected age at sexual maturity for immature hawksbill turtles and green turtles foraging in the remote marine protected area of Aldabra Atoll, Seychelles

Growth rate and projected age at sexual maturity for immature hawksbill turtles and green turtles foraging in the remote marine protected area of Aldabra Atoll, Seychelles

Informing research priorities for immature sea turtles through expert elicitation

Growth rates and age at maturity of Mediterranean loggerhead sea turtles estimated from a single-population foraging ground

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