Age and growth rates of Hawaiian hawksbill turtles (Eretmochelys imbricata) using skeletochronology

Snover, Melissa L.; Balazs, George H.; Murakawa, Shawn K. K.; Hargrove, Stacy K.; Rice, Marc; Seitz, W. A.

doi:10.1007/s00227-012-2058-7

Cited by 40 publications

(44 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Owing to warmer ocean temperatures in the Caribbean [52], we might expect comparatively slower growth in Hawaii hawksbills, as occurs in similar comparisons for green turtles [15]. A recent analysis using skeletochronology estimated Hawaii hawksbills reach sexual maturity at 17 -22 years [46], similar to our fast growth scenario (15 -23 years). The authors of that study obtained all VBGF parameters (t 0 ¼ 21.44 and L 1 ¼ 95 cm) from model fitting, however, where we derived values (see Material and methods).…”

supporting

confidence: 85%

“…Age-length records from captive hawksbills are from PIFSC archives and published studies [40][41][42][43][44]. The VBGF relationship from captive hawksbill data sets the upper bound for k, and we fix the lower bound to 0.08 based on the literature [10,[45][46][47]. We generated a minimum, mean and maximum age estimate for each turtle from the D…”

mentioning

confidence: 99%

“…Otolith bones are widely used to age fishes, but are usually too small to construct a full time series within an individual [20,23]. Humeri bones are used to age sea turtles [11,46,49], but have an incomplete record as living tissue is reabsorbed. Vertebral and costal scute plates from hawksbill and other sea turtles [12,27,28,50] provide insights, but demonstrate significant abrasion and tissue loss.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Time in tortoiseshell: a bomb radiocarbon-validated chronology in sea turtle scutes

et al. 2016

Self Cite

View full text Add to dashboard Cite

Some of the most basic questions of sea turtle life history are also the most elusive. Many uncertainties surround lifespan, growth rates, maturity and spatial structure, yet these are critical factors in assessing population status. Here we examine the keratinized hard tissues of the hawksbill (Eretmochelys imbricata) carapace and use bomb radiocarbon dating to estimate growth and maturity. Scutes have an established dietary record, yet the large keratin deposits of hawksbills evoke a reliable chronology. We sectioned, polished and imaged posterior marginal scutes from 36 individual hawksbills representing all life stages, several Pacific populations and spanning eight decades. We counted the apparent growth lines, microsampled along growth contours and calibrated D 14 C values to reference coral series. We fit von Bertalanffy growth function (VBGF) models to the results, producing a range of age estimates for each turtle. We find Hawaii hawksbills deposit eight growth lines annually (range 5-14), with model ensembles producing a somatic growth parameter (k) of 0.13 (range 0.1-0.2) and first breeding at 29 years (range 23-36). Recent bomb radiocarbon values also suggest declining trophic status. Together, our results may reflect long-term changes in the benthic community structure of Hawaii reefs, and possibly shed light on the critical population status for Hawaii hawksbills.

show abstract

supporting

confidence: 85%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Time in tortoiseshell: a bomb radiocarbon-validated chronology in sea turtle scutes

et al. 2016

Self Cite

View full text Add to dashboard Cite

show abstract

“…Although a lack of humerus samples from individuals with fully documented reproductive histories has prevented direct validation of the relationship between onset of reproductive maturation and rapprochement in sea turtles, an abrupt decrease in LAG spacing has previously been observed in humeri of adult-sized turtles (Snover 2002;Goshe et al 2010;Snover et al 2013). As reproductively active loggerhead sea turtles exhibit very low growth rates (Frazer 1983a) and validation analyses of humeri from tagged turtles have demonstrated correspondence between bone and somatic measures (Snover et al 2007;current study), this decrease in increment spacing is consistent with attainment of reproductive maturity.…”

Section: Adult-stage Durationmentioning

confidence: 97%

Age and size at maturation- and adult-stage duration for loggerhead sea turtles in the western North Atlantic

et al. 2015

Self Cite

View full text Add to dashboard Cite

mark associated with maturation were 90.5 for females (range 75.0-101.3) and 95.8 for males (range 80.6-103.8). Ages at maturation estimated from (1) the rapprochement skeletal growth mark; (2) back-calculated SCL-at-age data; and (3) bootstrapping and fitting Fabens modified von Bertalanffy growth curve to back-calculated growth data were very similar between approaches, but demonstrated a wide possible range. Mean age predictions associated with minimum and mean maturation SCLs were 22.5-25 and 36-38 years for females and 26-28 and 37-42 years for males. Post-maturation longevity (i.e., adult-stage duration) was similar for males and females, ranging from 4 to 46 years (mean 19 years).

show abstract

“…If coupled with decreases in the mortality of adults and juveniles (as a result of conservation actions), we would expect the number of nesting females to increase with time. However, given that hawksbills are estimated to require 17+ years to reach sexual maturity (Boulon, 1994;Chaloupka & Musick, 1997;Crouse, 1999;Snover et al, 2013) and that the bulk of hawksbill conservation in the eastern Pacific was only initiated in 2008, it may be decades before we see an appreciable increase in the number of nesting females.…”

Section: Nesting Distribution and Abundancementioning

confidence: 99%

Living on the Edge: Hawksbill turtle nesting and conservation along the Eastern Pacific Rim

Gaos

Liles

Gadea

et al. 2017

lajar

View full text Add to dashboard Cite

ABSTRACT. Prior to 2007, efforts to monitor and conserve hawksbill turtles (Eretmochelys imbricata) in the eastern Pacific Ocean were opportunistic and records were virtually non-existent. The first abundance estimates were published in 2010, but contained limited data on the species. Ongoing research since that time has led to the identification of several rookeries, including sites containing large proportions of the overall hawksbill nesting currently known to occur in the region. Monitoring projects were established at several sites and have since provided substantial nesting data on the species. Here we summarize data collected between 1983 and March 2016 from all sites (n = 9) confirmed to host >10 nests in any given season to provide an update on hawksbill nesting in the eastern Pacific. We documented a total of 3,508 hawksbill nests, 265,024 hatchlings and 528 individual nesting females in the region. The vast majority of these records (99.4%, 99.9% and 99.6%, respectively) were generated subsequent to 2007, coinciding with the discovery of eight of the nine rookeries included in this study and the organization of monitoring efforts at those sites, which led to the increased documentation conferred here. Our findings should not be misconstrued as increases in actual nesting or signs of recovery, which could diminish the ongoing need for conservation actions, but rather as optimism, that there is still an opportunity to restore the species in the eastern Pacific. The top three sites in terms of average annual number of nests were Estero Padre Ramos (Nicaragua; 213.2 ± 47.6 nests), Bahia de Jiquilisco (El Salvador; 168.5 ± 46.7 nests) and Aserradores (Nicaragua; 100.0 ± 24.0 nests), and all three sites are located in mangrove estuaries in Central America, highlighting the importance of these rookeries/habitats for the survival and recovery of hawksbills in the region. The remaining six sites received between 6.9 ± 7.3 nests (Costa Careyes, Mexico) and 59.3 ± 17.7 nests (Los Cobanos, El Salvador) annually. By integrating data collected on nesting hawksbills with local conservation realities at the most important known hawksbill rookeries in the eastern 572 2 Latin American Journal of Aquatic Research Pacific, we provide a more holistic view of the conservation status and management needs of the species in this ocean region.

show abstract

Age and growth rates of Hawaiian hawksbill turtles (Eretmochelys imbricata) using skeletochronology

Cited by 40 publications

References 25 publications

Time in tortoiseshell: a bomb radiocarbon-validated chronology in sea turtle scutes

Time in tortoiseshell: a bomb radiocarbon-validated chronology in sea turtle scutes

Age and size at maturation- and adult-stage duration for loggerhead sea turtles in the western North Atlantic

Living on the Edge: Hawksbill turtle nesting and conservation along the Eastern Pacific Rim

Contact Info

Product

Resources

About