Sex Ratio Estimation of the Most Eastern Main Loggerhead Sea Turtle Nesting Site: Anamur Beach, Mersin, Turkey

Uçar, Aşkın Hasan; Kaska, Yakup; Ergene, Serap; Aymak, Cemil; Kaçar, Yasemin; Kaska, Arzu; İli, Pınar

doi:10.1560/ijee.58.1.87

Cited by 10 publications

(7 citation statements)

References 28 publications

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“…This is contrary to the female-biased sex ratios produced at most Mediterranean nesting areas (Witt et al 2010a with additional data in Uçar et al 2012). This male bias is likely a consequence of several factors.…”

Section: Discussioncontrasting

confidence: 60%

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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Section: Discussioncontrasting

confidence: 60%

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

et al. 2017

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“…Few studies have been conducted on the sex ratio of hatchlings of this species, which will be affected by global warming. Despite multiple studies of loggerhead turtles that have been conducted on the beaches of Turkey (Kaska et al 1998(Kaska et al , 2006Oz et al 2004;Ucar et al 2012), the few published studies about green turtles deal with the identification of sex ratio through beach temperatures (Casale et al 2000), nest and sand temperatures (Candan and Kolankaya 2014), the temperatures and histology (Kılıç and Candan 2014).…”

Section: Discussionmentioning

confidence: 99%

Sex Ratio of Green Turtle (Chelonia mydas) Hatchlings at Sugözü, Turkey: Higher Accuracy with Pivotal Incubation Duration

Candan¹,

Kolankaya

2016

Chelonian Conservation and Biology

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“…No metabolic heat was detected before day 19 of incubation, but it then increased to a maximum of 0.84 Watts on day 34 when the nest was destroyed by a storm. Most studies reported that metabolic heat peaked in the final trimester, across all species (Figure 2: e.g., Howard et al, 2014;Sari and Kaska, 2016), and was generally followed by a decrease in nest temperature 0-9 days before emergence (Chan and Liew, 1995; Neville et al, 1998;Koch et al, 2007;Uçar et al, 2013;Sari and Kaska, 2016). However, one study of green sea turtle nests at Lanyu Island, Taiwan reported that average metabolic heat across 14 nests peaked during the middle trimester, although the difference in average metabolic heat between the second and third semester was not statistically significant (Cheng et al, 2015).…”

Section: Metabolic Heat Measured In Natural Nestsmentioning

confidence: 99%

“…Temperature variation within and between sea turtle nests also results in different development rates for individual eggs (Marco et al, 2017). For example, in loggerhead nests an approximately 1 • C difference in nest temperature was attributed to a 4-day (Uçar et al, 2013) or 7-day (Kaska and Sezgin, 2019) difference in incubation duration. Further, temperature varaition within the nest chamber increases the asynchrony of hatchling emergence (Houghton and Hays, 2001).…”

Section: Eggs Within the Same Nest Experience Different Temperatures mentioning

confidence: 99%

A Systematic Review of Metabolic Heat in Sea Turtle Nests and Methods to Model Its Impact on Hatching Success

et al. 2020

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Just as organisms do not passively exist in their environment, developing sea turtle embryos affect their own incubation microclimate by producing metabolic heat and other waste products. This metabolic heat ultimately contributes to successful development, but it is unclear how it influences embryonic traits such as hatchling sex, and whether trends exist in the magnitude of metabolic heat produced by different species. In this systematic review, we document all empirical measurements of metabolic heat in sea turtle species, its impact on their development, and explore the methods used to predict nest temperature and how these methods account for metabolic heat. Overall we found metabolic heat increases throughout incubation in all seven species. Typically, the temperature at the center of an egg clutch peaked during the final third of incubation, and exceeded the adjacent sand temperature by 2.5 • C. Metabolic heat was not influenced by species or clutch size (n = 16 studies), but this finding was likely influenced by inconsistency in the methods used to measure metabolic heat, and by localized differences in sand properties, such as moisture, albedo, and thermal conductivity. The influence of metabolic heat on embryo sex determination and survival was dependent on the sand temperature surrounding the nest chamber, and had an appreciable affect only when it caused nest temperatures to exceed key thresholds for sex determination and survival. Methods for modeling nest temperature were either correlative (70% of publications) or mechanistic (30% of publications). Correlative models describe relationships between empirical data to predict sand temperature, while mechanistic models are based on physical laws and do not require extrapolation when predicting novel situations, such as climate change. Most correlative models (74%) accounted for metabolic heat when predicting nest temperatures, but no mechanistic models did-largely because they were developed for predicting primary sex ratios, which are widely believed to be unaffected by metabolic heat. Consequently, developing a generalisable mechanistic model that incorporates metabolic heat will be critical for predicting incubation success as the sand temperatures at sea turtle beaches increase due to anthropogenic climate change.

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Sex Ratio Estimation of the Most Eastern Main Loggerhead Sea Turtle Nesting Site: Anamur Beach, Mersin, Turkey

Cited by 10 publications

References 28 publications

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

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

Sex Ratio of Green Turtle (Chelonia mydas) Hatchlings at Sugözü, Turkey: Higher Accuracy with Pivotal Incubation Duration

A Systematic Review of Metabolic Heat in Sea Turtle Nests and Methods to Model Its Impact on Hatching Success

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