Remigration and growth of loggerhead turtles ( Caretta caretta ) nesting on Senri Beach in Minabe, Japan: life-history polymorphism in a sea turtle population

Hatase, Hideo; Matsuzawa, Yoshimasa; Sato, Katsufumi; Bando, T.; Goto, Kiyoshi

doi:10.1007/s00227-003-1232-3

Cited by 51 publications

(47 citation statements)

References 15 publications

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“…The Sanriku coastal area is located at a latitude similar to that of the Virginia coast (Chesapeake Bay, 38°35' N) and is considered to be utilized by large juveniles during the summer (Narazaki 2009). In the present study, 39.3% of the turtles had an SCL shorter than 69.2 cm, which is the minimum SCL of Japanese nesting loggerhead turtles reported by Kamezaki et al (1995); 74.8% had an SCL shorter than 74.1 cm, which is the minimum SCL reported by Hatase et al (2002bHatase et al ( , 2004; and 98.1% had an SCL shorter than 82.1 cm, which is the mean SCL at maturity . Although the size of sea turtles at maturity is variable among individuals (Musick & Limpus 1997, Bjorndal et al 2013, the wide size range of the individuals in dicates that the feeding area in Sanriku may include both juveniles and adults.…”

Section: Discussionsupporting

confidence: 56%

“…Since only 1 sample was collected each year in 2005 and 2006, these years were excluded from the comparisons. A total of 42 and 80 of the 107 loggerhead turtles were smaller than the minimum size for nesting loggerhead turtles in Japan reported by (SCL ≤ 69.1 cm) and Hatase et al (2002bHatase et al ( , 2004) (SCL ≤ 74.0 cm), respectively. In order to assess these reported values for the minimum size at maturity during nesting, we tested differences in haplotype frequencies among the following 3 size classes by using the exact test (Raymond & Rousset 1995) with 817 bp fragments: (1) SCL ≤ 69.1 cm (defined as 'juveniles'; n = 42), (2) 69.2 cm ≤ SCL ≤ 74.0 cm (defined as 'recruits'; n = 38), and (3) 74.1 cm ≤ SCL (defined as 'adults'; n = 27).…”

Section: Dna Analysismentioning

confidence: 72%

“…Similar to other species of sea turtles, after reaching sexual maturity, the adult female loggerheads undertake seasonal breeding migrations between the feeding areas and the nesting beaches at intervals of 1 to 6 yr (Bolten 2003, Hatase et al 2004). …”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Genetic composition of loggerhead turtle feeding aggregations: migration patterns in the North Pacific

Nishizawa¹,

Narazaki²,

Fukuoka³

et al. 2014

Endang. Species. Res.

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Section: Discussionsupporting

confidence: 56%

Section: Dna Analysismentioning

confidence: 72%

See 1 more Smart Citation

Genetic composition of loggerhead turtle feeding aggregations: migration patterns in the North Pacific

Nishizawa¹,

Narazaki²,

Fukuoka³

et al. 2014

Endang. Species. Res.

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“…We constructed length frequency distributions for loggerhead turtles and estimated the percentage of adults. Length at maturity in females is close to average nesting length in loggerhead sea turtles (Frazer & Ehrhart 1985, Hatase et al 2004) and we used the average size of Japanese nesters as an approximation of length at maturity: 91 cm (CCL) , Hatase et al 2004.…”

Section: Methodsmentioning

confidence: 99%

High mortality of loggerhead turtles due to bycatch, human consumption and strandings at Baja California Sur, Mexico, 2003 to 2007

Peckham

Maldonado-Díaz²,

Koch³

et al. 2008

Endang. Species Res.

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Assessing mortality of long-lived organisms is fundamental for understanding population trends and for implementing conservation strategies, but doing so for marine megafauna is challenging. Here we assessed anthropogenic mortality of endangered North Pacific loggerhead turtles in the coastal waters of Baja California Sur, Mexico (BCS), through the synthesis of 3 sources: were stranded during summer fishing months over 5 yr, which is among the highest reported stranding rates worldwide. This stranding rate corroborates similarly high observed bycatch rates for local small-scale longline (29 loggerheads 1000 hooks -1 ) and gillnet (1.0 loggerhead km -1 of net) fisheries. A significant increase in mean length of 2636 carcasses measured at BCS occurred from 1995 to 2007. Given the endangered status of the North Pacific loggerhead population, conservation action to reduce bycatch and poaching at BCS is urgently needed.

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“…Therefore, food accessibility and the rate at which an organism can process food (West et al 2004, Molles 2010) regulate the metabolic investment of energy into reproduction or growth. Thus, the onset of sexual maturity -as indicated by a reduction in energy investment into somatic growth and a greater energy allocation into the growth and maturation of reproductive organs (Hatase et al 2004, Berner & Blanckenhorn 2007, Snover et al 2007, Bjorndal et al 2012) -is dependent on both population characteristics (intrinsic) and the environment (extrinsic).…”

Section: Introductionmentioning

confidence: 99%

Age-size relationship at reproduction of South African female loggerhead turtles Caretta caretta

Tucek¹,

Girondot²,

Hughes³

2014

Endang. Species. Res.

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Average age and size at first reproduction are important demographic parameters used in the management and conservation of populations. For sea turtles, absolute values for these parameters are still ambiguous, as most species are slow-growing, late-maturing migrants which are rarely encountered during the first 1 to 2 decades of their lives. Additionally, growth is significantly influenced by a variety of intrinsic and extrinsic factors which make it difficult to describe age−size relationships. Extensive notching (mutilation-tagging) of South African loggerhead turtles was used to determine age and size at reproduction (putative first nesting season), and thus to identify the trigger for sexual maturation. To date, 137 clearly identified notched adult females have been encountered at the nesting beach. A Gaussian and log-normal distribution were fitted to the age distribution data but only the Gaussian distribution can be used to safely estimate age at first observation, as the right part ('older ages') of the distribution is still unknown. The estimated age at first observation was corrected for the possibility that a female was not encountered during her first nesting season. Results indicate an average age of 36.2 ± SD 7.71 yr (95% CI 28.2 to 44.3 yr) with a straight carapace length (SCL min ) of 83.7 ± 4.15 cm (95% CI 83.0 to 84.4 cm). It was concluded that size is a more important threshold for the initiation of the maturation process than age and that the onset of sexual maturity is dependent on intrinsic and extrinsic factors. KEY WORDS: Age and size at reproduction · Loggerhead turtle · Mutilation tagging Resale or republication not permitted without written consent of the publisherEndang Species Res 23: [167][168][169][170][171][172][173][174][175] 2014 extrinsic factors. Intrinsic factors that affect the growth rate in sea turtles include species, genotype, health status and sex (Chaloupka & Limpus 1997, Van Dam 1999, Heppell et al. 2003. Extrinsic factors that regulate growth rate are, for example, water temperature, food quality and food availability (Parker 1929, Bjorndal et al. 2003, Balazs & Chaloupka 2004. These factors are easy to regulate in captive studies but are often highly variable and difficult to measure under natural conditions (Mendonca 1981) as sea turtles migrate over thousands of kilometres and experience large habitat variations that additionally affect their growth rate (Musick & Limpus 1997, Casale et al. 2007, Koch et al. 2007). The variability in growth rate has already been documented in different species and several populations. Green turtles from the Hawaiian archipelago (Balazs & Cha loupka 2004) and the southern Great Barrier Reef grow at different rates due to differences in food quality and availability, as well as in sea surface temperatures of their foraging grounds. Furthermore, Hughes (1974) and Bjorndal et al. (2003) found that compensatory growth (accelerated growth) appears in juvenile sea turtles when they move from a suboptimal environment to b...

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Remigration and growth of loggerhead turtles ( Caretta caretta ) nesting on Senri Beach in Minabe, Japan: life-history polymorphism in a sea turtle population

Cited by 51 publications

References 15 publications

Genetic composition of loggerhead turtle feeding aggregations: migration patterns in the North Pacific

Genetic composition of loggerhead turtle feeding aggregations: migration patterns in the North Pacific

High mortality of loggerhead turtles due to bycatch, human consumption and strandings at Baja California Sur, Mexico, 2003 to 2007

Age-size relationship at reproduction of South African female loggerhead turtles Caretta caretta

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