Nest Site Preference and Hatching Success of Green (Chelonia mydas) and Loggerhead (Caretta caretta) Sea Turtles at Akyatan Beach, Turkey

Türkozan, Oğuz; Yamamoto, Kristina H.; Yılmaz, Can

doi:10.2744/ccb-0861.1

Cited by 25 publications

(17 citation statements)

References 19 publications

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“…We could not determine whether fungus was a source of mortality, but it was present in > 50% of nests at each beach and year (Table S3) The mean hatching success and emergence success values found in this study were relatively low compared to other green turtle populations where most values have been shown to be > 70% (Table S4 in the Supplement). Low hatching success at other beaches is usually associated with intensive predation pressure (Brown & Macdonald 1995, Turkozan et al 2011 or very poorly sorted substrates (Mortimer 1990). The lowest hatching and emergence success for green turtles were recorded at Espumilla Beach on Santiago Island, Galápagos.…”

Section: Resultsmentioning

confidence: 99%

“…Low hatching success at other beaches is usually associated with intensive predation pressure (Brown & Macdonald 1995, Turkozan et al 2011 or very poorly sorted substrates (Mortimer 1990). The lowest hatching and emergence success for green turtles were recorded at Espumilla Beach on Santiago Island, Galápagos.…”

Section: Variation In Hatching Success and Comparisons With Other Seamentioning

confidence: 99%

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Hatching and emergence success in green turtle Chelonia mydas nests in the Galápagos Islands

Zárate¹,

Bjorndal²,

Parra³

et al. 2013

Aquat. Biol.

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The interactions of numerous abiotic and biotic factors experienced by sea turtle embryos during incubation affect their survival. In this study we determined the hatching and emergence success of green turtles Chelonia mydas from nests on 4 beaches on the Galápagos Islands, one of the most important rookeries for green turtles in the eastern Pacific Ocean. Mean (± SD) hatching and emergence success for the 1039 nests examined were 46.0 ± 33.4 and 45.6 ± 33.4%, respectively. These values are relatively low compared to other green turtle populations worldwide. We evaluated the effects of beach, year, day of oviposition, carapace length and width of female, nest position, nest habitat, and nest chamber depth on hatching and emergence success with binomial generalized additive models with fixed effects. We found variation in hatching and emergence success was significant among beaches, years, day of oviposition, and nest habitat. Predation by feral pigs and beetles and destruction of earlier nests by nesting females were the most important causes of embryo mortality. Efforts to keep threats at minimum levels, particularly controlling pigs near Isabela beaches, should be considered a major conservation objective. This study highlights important differences among beaches within a rookery and emphasizes the need to continue improving management strategies to protect green turtles and their critical habitats. Quantitative information provided here can be used as a basis for long-term studies in the Galá-pagos and for comparison to other sea turtles rookeries. KEY WORDS: Chelonia mydas · Sea turtle reproduction · Clutch success · Generalized additive models · Pacific Ocean · Predation · Feral pigs · Beetles · ReptilesResale or republication not permitted without written consent of the publisher Aquat Biol 19: 217-229, 2013 cess refer to artificial hatchery operations (Hirth 1997) or experimentally manipulated clutches of eggs (Ackerman 1980) that may not reflect natural survival rates (Wyneken et al. 1988, Abella et al. 2007).Hatching and emergence success depends upon the interaction of numerous abiotic and biotic factors and varies among species and populations of sea turtles (Hirth 1980, Van Buskirk & Crowder 1994. Temperature (Matsuzawa et al. 2002, Segura & Cajade 2010, moisture (Ackerman 1980, Mortimer 1982, sand structure and composition (Mortimer 1990), and salinity (Ackerman 1980) can affect embryonic development by altering nest conditions. Hatching success can be affected by the nest location and its microhabitat or surrounding environment (Whitmore & Dutton 1985, Bjorndal & Bolten 1992, Hays & Speak man 1993. Human activities on nesting beaches resulting in sand compaction can decrease hatching and emergence success (Kudo et al. 2003). Predation of sea turtle eggs and hatchlings by a wide taxo nomic range of predators can have major effects; both native and introduced animals can substantially reduce hatching and emergence success (Stancyk 1982).Clutches deposited earlier in the season can subs...

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Section: Resultsmentioning

confidence: 99%

Section: Variation In Hatching Success and Comparisons With Other Seamentioning

confidence: 99%

Hatching and emergence success in green turtle Chelonia mydas nests in the Galápagos Islands

Zárate¹,

Bjorndal²,

Parra³

et al. 2013

Aquat. Biol.

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“…When eggshells were fragmented, pieces were combined together to represent one egg (accurate to ±4 eggs (Turkozan et al 2011)). Hatching success does not consider success in emergence from the nest or reaching the ocean.…”

Section: Data Collectionmentioning

confidence: 99%

“…Many factors have been observed to influence female nest site selection, including beach width, distance to the water or back of the beach, sand grain size, elevation, slope, sand moisture, sand compaction, sand grain size, presence of vegetation, artificial lighting, sand temperature, and nest site fidelity, among others (e.g., Horrocks and Scott 1991;Hays et al 1995;Wood and Bjorndal 2000;Lopez-Castro et al 2004;Santos et al 2006;Turkozan et al 2011). However, in other studies, nest site selection was determined to be random and vary between individuals, species, and populations, or no significant relationship was identified between nest site selection and hatching success (e.g., Johannes and Rimmer 1984;Eckert 1987;Bjorndal and Bolten 1992;Woody et al 1998;Kamel and Mrosovsky 2005).…”

Section: Introductionmentioning

confidence: 96%

Climate change implications for the nest site selection process and subsequent hatching success of a green turtle population

Santos

Livesey

Fish

et al. 2015

Mitig Adapt Strateg Glob Change

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Sandy beach habitat where sea turtles nest will be affected by multiple climate change impacts. Before these impacts occur, knowledge of how nest site selection and hatching success vary with beach microhabitats is needed to inform managers on how to protect suitable habitats and prepare for scientifically valid mitigation measures at beaches around the world. At a highly successful green turtle (Chelonia mydas) rookery at Akumal, Quintana Roo, Mexico, we measured microhabitat characteristics along the beach crawl (rejected sites) and related nest site conditions (selected sites) to subsequent hatching success rates for 64 nesting events. To our knowledge, this is the first study to report environmental data along the nesting crawl for a green turtle population and the first to use natural breaks in the data to describe their preferred habitat ranges. Our results indicate that turtles were likely using a combination of cues to find nest sites, mainly higher elevations and lower sand surface temperatures (Kruskal-Wallis test, H=19.84, p<0.001; H=10.78, p<0.001). Hatching success was significantly and negatively correlated to sand temperature at cloaca depth (Spearman's Mitig Adapt Strateg Glob Change ρ=−0.27, p=0.04). Indeed, the preferred range for cloaca sand temperatures at the nest site (26.3-27.5°C) had significantly higher hatching success rates compared to the highest temperature range (Tukey HSD=0.47, p=0.05). Sand temperatures at various depths were intercorrelated, and surface and cloaca depth sand temperatures were correlated to air temperature (ρ=0.70, p=0.00; ρ=0.26, p=0.04). Therefore, rising air temperatures could alter sand temperature cues for suitable nest sites, preferred nest site ranges, and produce uneven sex ratios or lethal incubating temperatures. Elevation cues and preferred ranges (1.4-2.5 m) may also be affected by sea level rise, risking inundation of nests.

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“…Based on our observation, we concluded that turtles prefer to nest under dense vegetation compare to other area where Pandanus tectorius growth is less dense. Nuitja (1992) stated the Green turtles favored a nesting ground on a beach which is dominated by vegetation of Pandanus tectorius species and Turkozan et al (2011) which states that vegetated area has the highest success ratio of eggs hatching.…”

Section: Spatial Analysis Of Green Turtle Habitatmentioning

confidence: 99%

HABITAT SUITABILITY AND ZONING ANALYSIS FOR GREEN TURTLE Chelonia mydas IN THE MARINE CONSERVATION AREAS OF PANGUMBAHAN TURTLE PARK, SUKABUMI

Afandy¹,

Yulianda

Agus

et al. 2017

J. Ilmu dan Teknologi Kelautan Tropis

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ABSTRAK Penelitian ini mengkaji tentang kesesuaian habitat penyu hijau di Kawasan Konservasi Perairan Kata kunci: Chelonia mydas, penyu hijau, kesesuaian, konservasi, Pangumbahan ABSTRACTThis study reviews the suitability of habitat for the green turtle in the Pangumbahan Turtle Park. The purpose of this study is to evaluate the existing zoning system and to provide recommendations of alternative zoning approach based on ecological suitability turtle habitat. Observations and fieldwork were undertaken throughout the coastal area of Pangumbahan from January to June 2015 by collecting data which include nesting site for turtles, sand temperature and moisture content, width of the beach, surface slope of the beach, vegetation cover, seagrass and secondary data. Methods of data analysis consists of suitability analysis with the spatial approach using Geographic Information System. The results of the analysis of overlay method were classified into three classes of suitability, which include very suitable covering 6.91 hectares, suitable covering 14.60 hectares and less suitable covering 37.21 hectares. The current existing zones needs to be revised using the recommended zoning system. As an implementation of the findings from this study as well as to effectively manage the conservation area based on the green turtle ecology, it is highly recommended to do a zoning system which is based on the principal of the green turtles habitat suitability to ensure the sustainability of the green turtle within the conservation area. This will ensure the zoning system suits the green turtles' characteristics hence enabling each of the zones to effectively functioning.

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Nest Site Preference and Hatching Success of Green (Chelonia mydas) and Loggerhead (Caretta caretta) Sea Turtles at Akyatan Beach, Turkey

Cited by 25 publications

References 19 publications

Hatching and emergence success in green turtle Chelonia mydas nests in the Galápagos Islands

Hatching and emergence success in green turtle Chelonia mydas nests in the Galápagos Islands

Climate change implications for the nest site selection process and subsequent hatching success of a green turtle population

HABITAT SUITABILITY AND ZONING ANALYSIS FOR GREEN TURTLE Chelonia mydas IN THE MARINE CONSERVATION AREAS OF PANGUMBAHAN TURTLE PARK, SUKABUMI

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