scholarly journals Balanced primary sex ratios and resilience to climate change in a major sea turtle population

2017 ◽  
Vol 577 ◽  
pp. 189-203 ◽  
Author(s):  
AR Patrício ◽  
A Marques ◽  
C Barbosa ◽  
AC Broderick ◽  
BJ Godley ◽  
...  
Keyword(s):  
Climate Change ◽  
Sex Ratios ◽  
Sea Turtle ◽  
Turtle Population

Sedimentological characteristics of key sea turtle rookeries: potential implications under projected climate change

2010 ◽  
Vol 61 (4) ◽  
pp. 464 ◽  
Author(s):  
M. M. P. B. Fuentes ◽  
J. L. Dawson ◽  
S. G. Smithers ◽  
M. Hamann ◽  
C. J. Limpus
Keyword(s):  
Climate Change ◽  
Sea Turtles ◽  
Sea Turtle ◽  
Ecological Impacts ◽  
Coarse Grained ◽  
Sediment Characteristics ◽  
Emergence Success ◽  
Ecological Implications ◽  
Turtle Population ◽  
Reef Islands

Sea turtles rely on reef islands for key parts of their reproductive cycle and require specific sediment characteristics to incubate their eggs and dig their nests. However, little is known about the sedimentological characteristics of sea turtle rookeries, how these sediment characteristics affect the vulnerability of rookeries to climate change, and the ecological implications of different sediment or altered sediment characteristics to sea turtles. Therefore, we described the sediment and identified the reef-building organisms of the seven most important rookeries used by the northern Great Barrier Reef (nGBR) green turtle population. We then reviewed the literature on the vulnerability of each identified reef-building organism to climate change and how various sediment characteristics ecologically affect sea turtles. Sediments from the studied rookeries are predominantly composed of well-sorted medium-grained to coarse-grained sands and are either dominated by Foraminifera, molluscs or both. Dissimilarities in the contemporary sedimentology of the rookeries suggest that each may respond differently to projected climate change. Potential ecological impacts from climate change include: (1) changes in nesting and hatchling emergence success and (2) reduction of optimal nesting habitat. Each of these factors will decrease the annual reproductive output of sea turtles and thus have significant conservation ramifications.

scholarly journals The Impact of Temperature-Dependent Sex Determination on the Population Dynamics of Green Sea Turtles (Chelonia mydas)

Bionatura ◽  
2020 ◽  
Vol 5 (1) ◽  
pp. 1029-1038
Author(s):  
Candy Herrera ◽  
Evelyn Guerra ◽  
Andrea Rosas ◽  
Yingying Wei ◽  
Jack Pringle ◽  
...  
Keyword(s):  
Incubation Temperature ◽  
Sea Turtles ◽  
Sex Ratios ◽  
Chelonia Mydas ◽  
Continuous Model ◽  
Sea Turtle ◽  
Green Sea Turtle ◽  
Green Sea Turtles ◽  
Turtle Population ◽  
The Impact

The sex of the turtles is determined by the incubation temperature of the eggs during the mid-trimester of development. In green sea turtles (Chelonia mydas), recent studies show that sex ratios are changing, producing a female-biased sex ratio within the population. We developed a novel continuous model to analyze the dynamics of the green sea turtle population long-term. We determine the safe operating space for the proportion of eggs that become male at which the population of green sea turtle can exist without going to extinction. When the proportion of male eggs leaves this range the overall turtles’ population collapses. Additionally, we examined how temperature changes affect the sex ratios of the green sea turtle population.

Structural description of sea turtle fibropapilloma

2020 ◽  
Vol 13 (3) ◽  
pp. 585-591
Author(s):  
Luana Melo ◽  
Isabel Velasco ◽  
Julia Aquino ◽  
Rosangela Rodrigues ◽  
Edris Lopes ◽  
...  
Keyword(s):  
Green Turtle ◽  
Chelonia Mydas ◽  
Sea Turtle ◽  
Tumor Formation ◽  
Neoplastic Disease ◽  
Structural Description ◽  
Chemical Carcinogens ◽  
Epidermal Proliferation ◽  
Turtle Population ◽  
Bulky Mass

Fibropapillomatosis is a neoplastic disease that affects sea turtles. It is characterized by multiple papillomas, fibropapillomas and cutaneous and/or visceral fibromas. Although its etiology has not been fully elucidated, it is known that there is a strong involvement of an alpha - herpesvirus, but the influence of other factors such as parasites, genetics, chemical carcinogens, contaminants, immunosuppression and ultraviolet radiation may be important in the disease, being pointed out as one of the main causes of a reduction in the green turtle population. Thus, the objective of this article was to describe the morphology of cutaneous fibropapillomas found in specimens of the green turtle (Chelonia mydas), using light and scanning electron microscopy in order to contribute to the mechanism of tumor formation. Microscopically, it presented hyperplastic stromal proliferation and epidermal proliferation with hyperkeratosis. The bulky mass was coated with keratin, with some keratinocyte invaginations, that allowed the keratin to infiltrate from the epidermis into the dermis, forming large keratinized circular spirals. Another fact that we observed was the influence of the inflammation of the tumors caused by ectoparasites.

scholarly journals Long-term decline of the western Pacific leatherback,Dermochelys coriacea: a globally important sea turtle population

Ecosphere ◽  
2013 ◽  
Vol 4 (2) ◽  
pp. art25 ◽  
Author(s):  
Ricardo F. Tapilatu ◽  
Peter H. Dutton ◽  
Manjula Tiwari ◽  
Thane Wibbels ◽  
Hadi V. Ferdinandus ◽  
...  
Keyword(s):  
Sea Turtle ◽  
Western Pacific ◽  
Dermochelys Coriacea ◽  
Turtle Population ◽  
The Western Pacific

scholarly journals Managing fisheries in a world with more sea turtles

2020 ◽  
Vol 287 (1930) ◽  
pp. 20200220
Author(s):  
Nathan F. Putman ◽  
Jesse Hawkins ◽  
Benny J. Gallaway
Keyword(s):  
Stock Assessment ◽  
Sea Turtles ◽  
Sea Turtle ◽  
Fishing Effort ◽  
Eastern United States ◽  
Green Turtles ◽  
Management Actions ◽  
Nesting Sites ◽  
Near Shore ◽  
Turtle Population

For decades, fisheries have been managed to limit the accidental capture of vulnerable species and many of these populations are now rebounding. While encouraging from a conservation perspective, as populations of protected species increase so will bycatch, triggering management actions that limit fishing. Here, we show that despite extensive regulations to limit sea turtle bycatch in a coastal gillnet fishery on the eastern United States, the catch per trip of Kemp's ridley has increased by more than 300% and green turtles by more than 650% (2001–2016). These bycatch rates closely track regional indices of turtle abundance, which are a function of increased reproductive output at distant nesting sites and the oceanic dispersal of juveniles to near shore habitats. The regulations imposed to help protect turtles have decreased fishing effort and harvest by more than 50%. Given uncertainty in the population status of sea turtles, however, simply removing protections is unwarranted. Stock-assessment models for sea turtles must be developed to determine what level of mortality can be sustained while balancing continued turtle population growth and fishing opportunity. Implementation of management targets should involve federal and state managers partnering with specific fisheries to develop bycatch reduction plans that are proportional to their impact on turtles.

Estimating past and present sex ratios of sea turtles in Suriname

1996 ◽  
Vol 74 (2) ◽  
pp. 267-277 ◽  
Author(s):  
Matthew H. Godfrey ◽  
N. Mrosovsky ◽  
R. Barreto
Keyword(s):  
Sea Turtles ◽  
Sex Ratios ◽  
Negative Relationship ◽  
Chelonia Mydas ◽  
Sea Turtle ◽  
Dermochelys Coriacea ◽  
Green Turtles ◽  
Sand Temperature ◽  
Turtle Conservation ◽  
Sea Turtle Conservation

Leatherback (Dermochelys coriacea) and green (Chelonia mydas) sea turtles in Suriname lay eggs over several months of the year. During this nesting season, changes in rainfall produce changes in sand temperature, which in turn influence the sexual differentiation of incubating sea turtle embryos. The overall sex ratio of leatherback and green sea turtle hatchlings produced at Matapica beach in Suriname was investigated. Estimates of the sex ratios of these turtles in 1993 (green turtles 63.8% female, leatherbacks 69.4% female) were roughly 10% more female-biased than those from an earlier study in 1982. For both species, a significant negative relationship was found between monthly rainfall and monthly sex ratios. Using this relationship and data on rainfall in the past, it was possible to estimate overall sex ratios for an additional 12 years. These estimates varied considerably among different years, ranging from 20 to 90% female in the case of green turtles. Nevertheless, males tended to be produced primarily in April and May, while some females were produced in all months. Such seasonal patterns of production of turtles of different sexes have implications for sea turtle conservation programs that involve manipulating or harvesting eggs.

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