Seasonal changes in serum gonadal steroids associated with migration, mating, and nesting in the loggerhead sea turtle (Caretta caretta)

Wibbels, Thane; Owens, David; Limpus, Colin J.; Reed, Philip C.; Amoss, Max S.

doi:10.1016/0016-6480(90)90099-8

Cited by 132 publications

(101 citation statements)

References 21 publications

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“…Similar results have been found in green sea turtles in Queensland, Australia, where 21% of adult males were inactive (Jessop et al 2004), suggesting that adult male sea turtles, like females, may have multiannual reproductive cycles, possibly driven by food availability and individual health status. However, in Wibbels et al (1990), all male loggerheads captured at Heron Island, Australia, exhibited high testosterone levels during winter and spring. In addition, the 1 male turtle we captured both in 2006 and 2007 was reproductively active both years, suggesting males might reproduce annually much of the time and only 'skip' a year a small percentage of the time.…”

Section: Discussionmentioning

confidence: 92%

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Comparing methods for the assessment of reproductive activity in adult male loggerhead sea turtles Caretta caretta at Cape Canaveral, Florida

Blanvillain¹,

Pease²,

Segars³

et al. 2008

Endang. Species Res.

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In an attempt to better understand the reproductive cycle of adult male loggerhead sea turtles, several techniques were used to assess their reproductive activity, including plastron-softness analysis, ultrasonography, laparoscopy, testicular biopsy samples, and measuring testosterone levels. Stress levels were evaluated on a subset of turtles by measuring testosterone and corticosterone concentrations after capture and before release. A total of 40 adult males were captured in the Port Canaveral shipping channel in April of 2006 and 2007. Four turtles were classified as reproductively inactive based on laparoscopic examination, histology of the testes, and testosterone levels. The relative area of plastron softness was significantly lower for the inactive males compared to the active males. Ultrasonography proved to be a promising tool, as we were able to visualize both the testes and epididymides on the turtles examined. Furthermore, we found no statistical difference in epididymal duct diameters measured by ultrasonography and during laparoscopy, suggesting that ultrasonography could be used successfully as a substitute for laparoscopic surgery. Finally, testosterone levels separated into 2 distinct groups, with concentrations of the inactive males below 5 ng ml -1 , and concentrations of the active males reaching 188 ng ml -1. We conclude that in order to reduce stress levels due to capture and handling, especially during laparoscopy, ultrasonography and plastron analysis could be used together as a way to determine the reproductive activity of adult males in the field. The results from this study also suggest that not all adult males participate in mating activity each year.

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Section: Discussionmentioning

confidence: 92%

“…Wibbels et al 1990, Plotkin et al 1996, Jessop et al 2004. Laparoscopy, in particular, has the advantage of directly visualizing the gonads, allowing the investigator to make a straightforward diagnosis of reproductive and maturity status.…”

Section: Discussionmentioning

confidence: 99%

Comparing methods for the assessment of reproductive activity in adult male loggerhead sea turtles Caretta caretta at Cape Canaveral, Florida

Blanvillain¹,

Pease²,

Segars³

et al. 2008

Endang. Species Res.

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“…To date, relatively limited investigations have been conducted on the reproductive hormonal dynamics in green turtles (Chelonia mydas) relative to different phases of nesting. Circulating gonadotropins, gonadal steroids, and corticosterone levels associated with behavior and physiology of nesting activities have been investigated relative to breeding in some species of sea turtles (Licht et al 1979, 1980, Wibbles et al 1992, Jessop et al 1999 on C. mydas; Rostal 1991 on Lepidochelys kempi; Licht 1982 on Lepidochelys olivasea; Wibbles et al 1990, 1992, Guillette et al 1991and Rostal et al 1996 on Dermochelys coriacea). In addition, adrenocortical responsiveness to stress during nesting activities was examined in C. mydas (Jessop et al 1999), in L. olivacea (Valverde et al 1999) and in C. caretta (Gregory et al 1996).…”

Section: Introductionmentioning

confidence: 99%

Plasma hormone levels in the green turtles Chelonia mydas during peak period of nesting at Ras Al-Hadd-Oman

Al-Habsi

Alkindi

Mahmoud

et al. 2006

Journal of Endocrinology

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Circulating estradiol (E 2 ), progesterone (Pro), testosterone, and corticosterone (B) levels were monitored in the green turtles Chelonia mydas during different nesting phases. Successful nesting includes emergence from sea, chamber and nest excavation, oviposition, burying the nest, and returning to sea. Unsuccessful nesting includes chamber and nest excavations but without oviposition. Blood samples were taken from the cervical sinus and collected within 5-min of capture to minimize stress. The samples were collected between 2000 and 0100 h during the peak season (MayOctober). High-performance liquid chromatography using a u.v. detection system coupled with tandem quadrupole mass spectrometry was used to measure B. Plasma B levels were significantly higher in successful and unsuccessful phases over emergence and excavation phases. However, B levels in successful versus unsuccessful or emergence versus excavation phases were not significantly different. Plasma steroid levels were measured by the Coat-A-Count RIA technique. Pro levels were significantly higher (P!0 . 005) in successful over unsuccessful turtles and also successful turtles over turtles in the other phases (P!0 . 01). The Pro levels immediately after nesting were found to be higher than that reported previously. Plasma testosterone values were higher in successful turtles but not significantly different from the turtles in other phases. Estrogen levels were undetected in all phases. Overall, the hormone values during different phases of nesting may play a major role in formulating the nesting behavior and physiology of the nesting activities in the green turtle.

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“…Nevertheless, the prenuptial pattern of spermatogenesis has been reported in the Loggerhead turtle, Caretta caretta (Wibbles et al 1990); the Kemp's Ridley sea turtle, Lepidochelys kempii (Rostal 1991) and the Green turtle, Chelonia mydas (Owens 1980). However, in tropical environments a prenuptial pattern of gonadal recrudescence should also be expected because it has been described as being primitive for turtles, and a postnuptial pattern of spermatogenesis must have arisen in most cases as a result of movement of turtles into temperate and subtropical regions of the world (Crews 1987;Meylan et al 2002).…”

Section: Discussionmentioning

confidence: 99%

“…The spermatogenic cycles of various marine and freshwater turtles have been documented, including the Stinkpot, Sternotherus odoratus (McPherson & Marion 1981); the Australian freshwater turtle Emydura krefftii (Georges 1983); the freshwater turtle Trionyx gangeticus (Rao & Shaad 1985); the Loggerhead turtle, Caretta caretta (Wibbles et al 1990); the Kemp's Ridley sea turtle, Lepidochelys kempi (Rostal 1991); the Australian freshwater turtles Chelodina rugosa and Elseya dentata (Kennett 1999) and the Florida Softshell Turtle, Apalone ferox (Meylan et al 2002). With the exception of the recent report of Olukole et al (2011), on the topographical anatomy of the male reproductive organs of the African sideneck turtle, little is known about the reproductive cycle in this family.…”

Section: Introductionmentioning

confidence: 99%

Spermatogenic cycle of the African sideneck turtlePelusios castaneus(Schweigger, 1812) (Reptilia: Testudines)

Olukole

Oyeyemi

Oke

2014

Italian Journal of Zoology

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We describe the spermatogenic cycle of the African sideneck turtle (Pelusios castaneus) (Reptilia: Testudines). We further classify the pattern of spermatogenesis in the species, generating new comparative baseline data on the spermatogenic cycle of freshwater turtles in the tropics. Seventy-two adult male P. castaneus collected at different times from various river drainages in Ibadan, Nigeria, were used for the study. The average body weight of the turtles was 723 ± 23.36 g while the curved carapace and plastron lengths of the turtles were 24.4 ± 1.47 cm and 15.7 ± 1.23 cm, respectively. Histology of the testis and epididymis, gonadosomatic index, epididymal mass index, seminiferous tubule diameter and epididymal ductal diameter all suggest the postnuptial pattern of spermatogenesis. Sperm production in P. castaneus starts in May and peaks in September. It is thereafter released into the epididymis, and the degree of sperm packing of the epididymis increases from October, reaching its peak in January. Spermatozoa were found in the epididymis of the turtles all through the year. The study shows that the postnuptial pattern of turtle spermatogenesis is not unique to turtles in the temperate regions of the world and that the spermatogenic cycle of P. castaneus is similar to those of other chelonians with minor variations. This report, the first of its kind for a pelomedusid turtle, therefore serves as baseline information for the family in comparative studies of the spermatogenic cycle of turtles.

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Seasonal changes in serum gonadal steroids associated with migration, mating, and nesting in the loggerhead sea turtle (Caretta caretta)

Cited by 132 publications

References 21 publications

Comparing methods for the assessment of reproductive activity in adult male loggerhead sea turtles Caretta caretta at Cape Canaveral, Florida

Comparing methods for the assessment of reproductive activity in adult male loggerhead sea turtles Caretta caretta at Cape Canaveral, Florida

Plasma hormone levels in the green turtles Chelonia mydas during peak period of nesting at Ras Al-Hadd-Oman

Spermatogenic cycle of the African sideneck turtlePelusios castaneus(Schweigger, 1812) (Reptilia: Testudines)

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