Influence of Beach Slope and Width on Hawksbill (Eretmochelys imbricata) and Green Turtle (Chelonia mydas) Nesting Activity in El Cuyo, Yucatán, Mexico

2010 ◽  
Vol 9 (2) ◽  
pp. 262-267 ◽  
Author(s):  
Eduardo Cuevas ◽  
María de los Ángeles Liceaga-Correa ◽  
Ismael Mariño-Tapia
Keyword(s):  
Green Turtle ◽  
Chelonia Mydas ◽  
Eretmochelys Imbricata ◽  
Beach Slope ◽  
Nesting Activity

Hawksbill turtle (Eretmochelys imbricata Linnaeus 1766) and green turtle (Chelonia mydas Linnaeus 1754) nesting activity (2002-2004) at El Cuyo beach, Mexico

2006 ◽  
Vol 27 (4) ◽  
pp. 539-547 ◽  
Author(s):  
Raquel Xavier ◽  
Andre Barata ◽  
Leopoldo Palomo Cortez ◽  
Nuno Queiroz ◽  
Eduardo Cuevas
Keyword(s):  
Green Turtle ◽  
Average Distance ◽  
Biosphere Reserve ◽  
Chelonia Mydas ◽  
Eretmochelys Imbricata ◽  
Nest Location ◽  
Hurricane Ivan ◽  
Green Turtles ◽  
Nest Site Fidelity ◽  
Nesting Activity

Abstract The Yucatan Peninsula nesting hawksbill turtles' population (Eretmochelys imbricata Linnaeus 1766) is the biggest in the Caribbean and fourth in the world; within the Ría Lagartos Biosphere Reserve, at El Cuyo beach both hawksbill and green turtle (Chelonia mydas Linnaeus 1754) nest. In the present study, the nesting trend and reproductive output of both species during three consecutive nesting seasons (2002-2004) was evaluated. Night patrols from mid April to September allowed the collection of data on number of nests, nest location and size of females. The number of hawksbill and green turtles' nests decreased along these seasons. No differences were found in mean length of female turtles of both species between nesting seasons. Both species showed high nest site fidelity with average distance between nests of 3 km for Hawksbill and 1.8 km for Green turtles. The regression analysis between size and fecundity was significant (p < 0.05) for both species. The spatial variation of laid nests was also analyzed revealing that both species nested mainly on the dune zone. Predation has risen on El Cuyo beach, affecting mostly hawksbills nests. Hurricane Ivan destroyed the majority of green turtles nests in 2004.

Trace elements distribution in hawksbill turtle (Eretmochelys imbricata) and green turtle (Chelonia mydas) tissues on the northern coast of Bahia, Brazil

2015 ◽  
Vol 94 (1-2) ◽  
pp. 284-289 ◽  
Author(s):  
Gustavo R. de Macêdo ◽  
Taiana B. Tarantino ◽  
Isa S. Barbosa ◽  
Thaís T. Pires ◽  
Gonzalo Rostan ◽  
...  
Keyword(s):  
Trace Elements ◽  
Green Turtle ◽  
Chelonia Mydas ◽  
Northern Coast ◽  
Eretmochelys Imbricata

Seafinding By Hatchling Sea Turtles: Role of Brightness, Silhouette and Beach Slope as Orientation Cues

Behaviour ◽  
1992 ◽  
Vol 122 (1-2) ◽  
pp. 56-77 ◽  
Author(s):  
Mark Lucas ◽  
Michael Salmon ◽  
Elizabeth Fritz ◽  
Jeanette Wyneken
Keyword(s):  
Green Turtle ◽  
Visual Cues ◽  
Chelonia Mydas ◽  
Sea Turtle ◽  
Infrared Light ◽  
Beach Slope ◽  
Green Turtles ◽  
Nest Sites ◽  
Orientation Cues

AbstractUpon emerging from underground nests, sea turtle hatchlings immediately crawl toward the ocean. The primary cues used in orientation are visual but the nature of the visual cues was a matter of speculation. Hatchlings might also respond to secondary cues, such as beach slope. Experiments were carried out in an arena where specific visual and slope cues, simulating those present at nest sites, could be precisely controlled and manipulated. Subjects were green turtle (Chelonia mydas L.) and loggerhead (Caretta caretta L.) hatchlings. Both species oriented toward the more intensely illuminated sections of the arena. They also oriented away from dark silhouettes which simulated an elevated horizon, typical of the view toward land. Turtles responded primarily to stimuli (both silhouettes and photic differences) at or near eye level. When presented simultaneously with a silhouette and a photic gradient located in different directions, hatchlings oriented away from the silhouette and ignored photic stimuli. Under infrared light, both species oriented down slopes. However in the presence of nocturnal levels of visible light loggerheads ignored slope cues and responses of green turtles to slope were weakened. The data suggest that loggerhead and green turtle hatchlings usually find the sea by orienting away from elevated silhouettes. This is a prominent and reliable cue for species which typically nest on continental beaches.

Paramphistomes (Digenea; Paramphistomidae) Parasitic in Marine Turtles (Reptilia: Chelonia).

1983 ◽  
Vol 31 (5) ◽  
pp. 851 ◽  
Author(s):  
D Blair
Keyword(s):  
Green Turtle ◽  
Sea Turtles ◽  
Chelonia Mydas ◽  
Original Material ◽  
Eretmochelys Imbricata ◽  
Marine Turtles ◽  
Australian Region ◽  
Species Inquirenda ◽  
Australian Specimen

Schizamphistomum scleroporum (Creplin, 1844) Groschaft, Otero & Tenora, 1977 nec Looss, 1912, and S. erratum, sp. nov. [=S. scleroporum sensu Looss, 1912 (nec Creplin, 1844)], are described from the green turtle, Chelonia mydas (L.), from Australia. One specimen of the former species was also recovered from an Australian specimen of the hawksbill turtle, Eretmochelys imbricata (L.). Paramphistomum papillostomum MacCallum, 1916 and Schizamphistomoides chelonei Gupta, 1961, are regarded as synonyms of Schizamphistomum scleroporum (Creplin). S. taiwanense Fischthal & Kunz, 1975 is regarded as a species inquirenda. The remaining species known from sea turtles, Schizamphistomoides spinulosum (Looss, 1901) Stunkard, 1925, is redescribed, mostly from original material collected by Looss. This species has not yet been found in the Australian region. The relationships between Schizamphistomum scleroporum, S. erratum and Schizamphntomoides spinulosum are discussed.

Green turtle (Chelonia mydas) nesting on Atol das Rocas, north-eastern Brazil, 1990–2008

2012 ◽  
Vol 93 (4) ◽  
pp. 1117-1132 ◽  
Author(s):  
Claudio Bellini ◽  
Armando J.B. Santos ◽  
Alice Grossman ◽  
Maria A. Marcovaldi ◽  
Paulo C. R. Barata
Keyword(s):  
Green Turtle ◽  
Carapace Length ◽  
Temporal Distribution ◽  
Chelonia Mydas ◽  
Sea Turtle ◽  
Annual Number ◽  
Eastern Brazil ◽  
North Eastern ◽  
The Mean ◽  
Nesting Activity

In this paper, information is presented on green turtle (Chelonia mydas) nesting on Atol das Rocas (Rocas Atoll), north-eastern Brazil. The temporal distribution of nesting events per season, annual number of nests, carapace length of nesting females, clutch size, hatching success, incubation period, internesting interval, clutch frequency, observed reproductive lifespan, and remigration period are reported. The study period included the nesting seasons from 1990 to 2008, but no regular beach monitoring was carried out in 1998 and 1999. Two sorts of methods were applied to the estimation of the annual number of nests in some seasons. Taking into account the estimated annual numbers of nests, the mean annual number of nests in the study period, excluding 1998–1999, was 335 (standard deviation = 139, range = 136–563, N = 17). An analysis of the available data indicates that the average nesting levels at the beginning of the study period (the first five seasons) and at its end (the last five seasons) were roughly the same. The mean curved carapace length of the nesting turtles decreased significantly during the study period, from 115.9 cm in 1990–1992 to 112.9 cm in 2006–2008. Atol das Rocas was established as a federal biological reserve in 1979, but regular sea turtle conservation activities actually started there in 1990. Since that year, the killing of nesting turtles has ceased, nesting activity by the turtles can proceed in an undisturbed fashion, and their clutches can incubate in a protected environment.

Green turtle ( Chelonia mydas (L.)) nesting activity at Aldabra Atoll

1979 ◽  
Vol 286 (1011) ◽  
pp. 255-263 ◽  
Keyword(s):  
Green Turtle ◽  
Chelonia Mydas ◽  
Human Settlements ◽  
Southwest Coast ◽  
Annual Variations ◽  
Recent Increase ◽  
Nesting Sites ◽  
Nesting Activity ◽  
Nesting Beaches

Green turtle ( Chelonia mydas ) nesting activity was indirectly monitored at the nesting sites at Aldabra by counting turtle tracks and nest pits during 11 months. Nesting activity took place throughout the year but a prolonged peak season was observed on southwest coast beaches between July and October, and less consistent peaks were observed for other beaches in February and March and from May to August. Estimations based on track and pit counts suggest that about 700 turtles nested at Aldabra during the year. Although annual variations may occur, this is similar to earlier estimates and does not suggest any recent increase. The distribution of turtle emergences among nesting beaches suggests that beaches fall into distinct nesting areas that are utilized to different extents. The distribution of turtle emergences on the largest beach suggests that human settlements may be reducing nesting there.

scholarly journals A Sea Turtle Population Assessment for Florida's Big Bend, Northeastern Gulf of Mexico

2021 ◽  
Vol 32 ◽  
pp. 19-33
Author(s):  
Ryan Chabot ◽  
Ryan Welsh ◽  
Cody Mott ◽  
Jeffrey Guertin ◽  
Brian Shamblin ◽  
...  
Keyword(s):  
Gulf Of Mexico ◽  
Green Turtle ◽  
Sea Turtles ◽  
Distance Sampling ◽  
Chelonia Mydas ◽  
The United States ◽  
Sea Turtle ◽  
Eretmochelys Imbricata ◽  
Green Turtles ◽  
Big Bend

Coastal waters of Florida’s Big Bend, Gulf of Mexico (GOM) once supported one of the largest sea turtle fisheries in the United States. To fill an information gap in this region on abundance and distribution of sea turtles, we used vessel—based distance sampling and active capture methods to characterize current foraging aggregations near the St. Martins Marsh Aquatic Preserve. Over 10 sampling periods between 2012—2018, we completed 513 km of transects and recorded 819 turtles among 4 species—green turtle (Chelonia mydas, n = 624), Kemp’s ridley (Lepidochelys kempii, n = 147), loggerhead (Caretta caretta, n = 47), and a single hawksbill (Eretmochelys imbricata). Turtle densities in 4 study plots within the 200 km2 study site ranged from 57—221 immature green turtles/km2, 16—56 immature Kemp’s ridleys/km2, and 1—14 juvenile—to—adult loggerheads/km2. Of 200 green turtles captured, 67.5% showed skin tumors consistent with fibropapillomatosis, a frequency similar to that from urbanized estuaries of Florida’s east coast. The largest green turtles (> 60 cm straight standard carapace length), abundant in the southern portion of our study area, are of note because this size class is uncommonly recorded within US territorial waters. Analyses of green turtle mtDNA haplotypes found contributions from rookeries in the western GOM, Mexican Caribbean, and Costa Rica. Although Big Bend protected areas were principally designed to conserve marine and coastal habitats, these regulatory zones have also effectively encompassed a hotspot for foraging sea turtles.

scholarly journals DETERMINACIÓN DE DDT Y DDE EN HUEVOS DE TORTUGA BLANCA (Chelonia mydas) Y DE TORTUGA CAREY (Eretmochelys imbricata), EN LA COSTA DE YUCATÁN, MÉXICO.

2003 ◽  
Vol 18 (2) ◽  
pp. 87
Author(s):  
E. Cuevas ◽  
A. Maldonado ◽  
V. Cobos
Keyword(s):  
Gas Chromatography ◽  
Green Turtle ◽  
Ecological Impact ◽  
Chelonia Mydas ◽  
Eretmochelys Imbricata ◽  
Chronic Effects ◽  
Low Concentrations ◽  
Biologic Effects

Evidence exists linking organochlorines to adverse biologic effects, like mating disfunctions and inmunosupression. The pesticide DDT is an organochlorine used in Mexico for combating malaria. In October 4th 2000, eight unviable green turtle and hawksbill turtle eggs were collected in El Cuyo and Celestún, Yucatán, México, respectively, and they were analyzed, using gas chromatography, to detect quantifiable organochlorine concentrations. DDE residual were not detected in any of the sea turt le eggs. Only two green turtle eggs had quantifiable DDT concentrations (0.059 ppm and 0.0550 ppm), both of which were considered lower in comparison to other studies, even though threshold limits of or ganochlorine concentrations for reptiles have not been established. These low concentrations should not be expected to bring immediate consequences and their chronic effects would be minimal. However, it is necessary to make more indepth studies to determine the potential ecological impact of these concentrations in this area. Yucatan State (México) fisheries: history and management during the period 1976- 1997

scholarly journals The importance of north-west Madagascar for marine turtle conservation

Oryx ◽  
2007 ◽  
Vol 41 (2) ◽  
pp. 232-238 ◽  
Author(s):  
Jessica Metcalf ◽  
Katie Hampson ◽  
Alain Andriamizava ◽  
Rivo Andrianirina ◽  
Claudine Ramiarisoa ◽  
...  
Keyword(s):  
Environmental Education ◽  
Chelonia Mydas ◽  
Marine Turtle ◽  
Conservation Priority ◽  
Eretmochelys Imbricata ◽  
North West ◽  
Marine Turtles ◽  
Incidental Capture ◽  
Turtle Conservation ◽  
Nesting Activity

AbstractThe coast of north-west Madagascar is an important nesting and feeding ground for marine turtles, but little is known about populations in this area. From July to December 2000 we documented nesting activity of, and investigated threats to, green Chelonia mydas and hawksbill Eretmochelys imbricata turtles at three sites along this coast: Nosy Iranja, the Radama Islands, and the Nosy Hara archipelago. Levels of nesting activity varied between sites, with green and hawksbill turtle nesting concentrated in different areas. The principal threats identified were opportunistic exploitation of nesting females and incidental capture in fishing nets. Commercial importance of marine turtles was negligible, suggesting conservation measures such as targeted environmental education could have beneficial impacts on these populations. Evidence for high levels of nesting activity reported here indicate that education efforts in these areas should be a conservation priority.

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