Seasonal fluctuations in sand temperature: effects on the incubation period and mortality of loggerhead sea turtle ( Caretta caretta ) pre-emergent hatchlings in Minabe, Japan

Matsuzawa, Yoshimasa; Sato, Katsufumi; Sakamoto, Wataru; Bjorndal, Karen A.

doi:10.1007/s00227-001-0724-2

Cited by 164 publications

(34 citation statements)

References 18 publications

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“…Seasonal changes in sand temperature resulting in temperatures outside of the viable range can induce seasonal changes in mortality. Embryos die from hyperthermia in nests with temperatures > 33°C for an extended period of time (Matsuzawa et al 2002). High nest temperatures can reduce emergence success by limiting the ability of hatchlings to reach the surface (Matsuzawa et al 2002).…”

Section: Unknown Sources Of Mortalitymentioning

confidence: 99%

“…Embryos die from hyperthermia in nests with temperatures > 33°C for an extended period of time (Matsuzawa et al 2002). High nest temperatures can reduce emergence success by limiting the ability of hatchlings to reach the surface (Matsuzawa et al 2002). Amount of rainfall affects hatching success of green turtles at Raine Island, Australia, where drier years have lower rates of hatching and nesting success (Limpus et al 2003).…”

Section: Unknown Sources Of Mortalitymentioning

confidence: 99%

“…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.…”

Section: Introductionmentioning

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: Unknown Sources Of Mortalitymentioning

confidence: 99%

Section: Unknown Sources Of Mortalitymentioning

confidence: 99%

Section: Introductionmentioning

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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“…Hatching success of 77.9 ± 27.0% and emergence success of 69.6 ± 30.3% are within the ranges for the region (Trono, 1991;Limpus et al, 2003;Balazs et al, 2015), but potentially on the low end. Future studies could test whether these parameters are negatively impacted by (i) higher frequency and intensity of tropical storms and typhoons inundating nests in the CNMI (Shaw, 2013), (ii) warm temperatures experienced at low latitudes (Matsuzawa et al, 2002), and (iii) habitat factors, such as high instances of coral rubble and roots from non-native vegetation trapping hatchlings in nests (Zárate et al, 2013). This population of nesting turtles exhibits a relatively low somatic growth rate.…”

Section: Nesting Ecologymentioning

confidence: 99%

Endangered Green Turtles (Chelonia mydas) of the Northern Mariana Islands: Nesting Ecology, Poaching, and Climate Concerns

Martin

Hapdei²,

Ruak³

et al. 2018

Front. Mar. Sci.

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Marine turtles in the western Pacific remain threatened by anthropogenic impacts, but the region lacks long-term biological data for assessing conservation status and trends. The Central West Pacific (CWP) population of green turtles (Chelonia mydas) was listed as Endangered by the U.S. in 2016, highlighting a need to fill existing data gaps. This study focuses on the subset of this population nesting in the Commonwealth of the Northern Mariana Islands (CNMI). Using 11 years of nesting data, we (i) estimate reproductive demographic parameters, (ii) quantify abundance and trends, and (iii) estimate the impacts of anthropogenic threats, such as poaching of nesting females and increasing sand temperatures. In 2006-2016, nesting beach surveys, identification tagging, and nest excavations were conducted on Saipan, and rapid assessments of nesting activity were conducted on Tinian and Rota. On Saipan, temperature data-loggers were deployed inside nests and evidence of poaching (adults and eggs) was recorded. This study documents year-round nesting with a peak in March-July. Nester abundance for the three islands combined was 11.9 ± 5.7 (mean ± standard deviation) females annually, with at least 62.8 ± 35.1 nests observed per year. For 39 tagged individuals, straight carapace length was 95.6 ± 4.5 cm, remigration interval was 4.6 ± 1.3 years, and somatic growth was 0.3 ± 0.2 cm/yr. Reproductive parameter estimates included clutch frequency of 7.0 ± 1.3 nests per female, inter-nesting interval of 11.4 ± 1.0 days, clutch size of 93.5 ± 21.4 eggs, incubation period of 56.7 ± 6.4 days, hatching success of 77.9 ± 27.0%, and emergence success of 69.6 ± 30.3%. Mean nest temperature of 30.9 ± 1.5 • C was above the pivotal threshold of 29.0 • C for temperature dependent sex determination, suggesting a female bias may already exist. Model results suggest (i) hatching success decreases and embryonic death increases when nests experience maximum temperatures beyond 34.4 • C and 33.8 • C, respectively, and (ii) embryonic death increases in nests with mean temperatures beyond 31.1 • C. On Saipan, 32% of nesters were poached, reducing the annual population growth rate from 11.4 to 7.4%. This study provides the first comprehensive assessment of a nesting green turtle population in the Mariana Summers et al. Nesting Ecology of Micronesian Green TurtlesArchipelago, as well as Micronesia, providing baseline data for the endangered CWP population. Our reproductive demographic data, abundance trends, and anthropogenic threat impact analyses are critical for endangered species management, including assessments of population status and fisheries impacts.

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“…Contrary to threats on the beach (e.g. Matsuzawa et al 2002, Kudo et al 2003, little is known about threats in the water (but see Hatase et al 2002b, Omuta 2011, Ishihara et al 2014. Threats resulting in higher mortalities should be identified and addressed to ensure recovery of loggerhead stocks in the North Pacific.…”

Section: Conservation Implicationsmentioning

confidence: 99%

Fine-scale genetic population structure of loggerhead turtles in the Northwest Pacific

Matsuzawa¹,

Kamezaki²,

Ishihara³

et al. 2016

Endang. Species. Res.

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Effective conservation of globally distributed marine species relies on identification of demographically independent populations to ensure that management actions are directed at the appropriate scale. This identification is particularly challenging for species with complex life histories when local breeding populations have not been adequately sampled. We used mtDNA to analyze the population structure of loggerhead turtles from a total of 555 samples collected from 12 nesting sites in Japan in the Northwest Pacific, including previously unsampled rookeries in the Ryukyu Archipelago, for a comprehensive coverage of the nesting distribution. We identified a total of 9 haplotypes based on 820 bp of the mtDNA control region, including 5 variants of a single previously described 380 bp haplotype. We discovered that 1 haplotype (CcP1.1) previously rare in the North Pacific is common in the Ryukyu Archipelago. Based on analysis of haplotype frequencies, we found significant differentiation among regionally grouped nesting populations (analysis of molecular variance p < 0.0001, df = 8; pairwise F ST ranging from 0.033 to 0.145). Our results provide evidence to support the recognition of 3 management units (MU) within the NW Pacific Regional Management Unit (RMU). These include (1) the Ryukyu MU that includes Okinawa, Okinoerabu and Amami, (2) Yakushima Island MU and (3) a Mainland MU that includes Bousou, Enshu-nada, Shikoku, Kii and Eastern Kyushu. These new data from Japan will provide important baseline data for global genetic stock assessments and contribute to our understanding of the population structure, ecology and life history of this migratory marine species in the northern Pacific.

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Seasonal fluctuations in sand temperature: effects on the incubation period and mortality of loggerhead sea turtle ( Caretta caretta ) pre-emergent hatchlings in Minabe, Japan

Cited by 164 publications

References 18 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

Endangered Green Turtles (Chelonia mydas) of the Northern Mariana Islands: Nesting Ecology, Poaching, and Climate Concerns

Fine-scale genetic population structure of loggerhead turtles in the Northwest Pacific

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