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.

scholarly journals Two hundred years after a commercial marine turtle fishery: the current status of marine turtles nesting in the Cayman Islands

Oryx ◽  
2001 ◽  
Vol 35 (2) ◽  
pp. 145-151 ◽  
Author(s):  
Jonathan J. Aiken ◽  
Brendan J. Godley ◽  
Annette C. Broderick ◽  
Timothy Austin ◽  
Gina Ebanks-Petrie ◽  
...  
Keyword(s):  
Chelonia Mydas ◽  
Marine Turtle ◽  
Current Status ◽  
Cayman Islands ◽  
Eretmochelys Imbricata ◽  
Marine Turtles ◽  
Mature Adults ◽  
Large Populations ◽  
Sexually Mature ◽  
Insight Into

AbstractLarge populations of marine turtles breeding in the Cayman Islands were drastically reduced in the early 1800s. However, marine turtle nesting still occurs in the islands. The present-day status of this nesting population provides insight into the conservation of marine turtles, a long-lived species. In 1998 and 1999, the first systematic survey of marine turtle nesting in the Cayman Islands found 38 nests on 22 beaches scattered through the three islands. Three species were found: the green Chelonia mydas, hawksbill Eretmochelys imbricata and loggerhead Caretta caretta turtles. Comparison with other rookeries suggests that the small number of sexually mature adults surviving Cayman's huge perturbations may be impeding population recovery. This shows the need to implement conservation measures prior to massive reductions in population size.

scholarly journals Using Aerial Photogrammetry to Assess Stock-Wide Marine Turtle Nesting Distribution, Abundance and Cumulative Exposure to Industrial Activity

2021 ◽  
Vol 13 (6) ◽  
pp. 1116
Author(s):  
Sabrina Fossette ◽  
Graham Loewenthal ◽  
Lauren R. Peel ◽  
Anna Vitenbergs ◽  
Melanie A. Hamel ◽  
...  
Keyword(s):  
Protected Areas ◽  
Large Scale ◽  
Chelonia Mydas ◽  
Marine Turtle ◽  
Cumulative Exposure ◽  
Cumulative Impact ◽  
Industrial Activity ◽  
Marine Turtles ◽  
Aerial Photogrammetry ◽  
Nesting Activity

The lack of accurate distribution maps and reliable abundance estimates for marine species can limit the ability of managers to design scale-appropriate management measures for a stock or population. Here, we tested the utility of aerial photogrammetry for conducting large-scale surveys of nesting marine turtles at remote locations, with a focus on the flatback turtle (Natator depressus) in the Pilbara region of Western Australia. Aerial surveys were conducted between 29 November and 6 December 2016 to overlap with the peak nesting season for flatback turtles and collected imagery was used to examine marine turtle distribution, abundance, and cumulative exposure to industrial activity relative to overlap with protected areas. Two observers independently reviewed aerial georeferenced photographs of 644 beaches and recorded turtle tracks and other evidence of turtle nesting activity. A total of 375 beaches showed signs of nesting activity by either flatback, green (Chelonia mydas) or hawksbill (Eretmochelys imbricata) turtles. Most of these beaches (85.3%) were located on islands, and the rest (14.7%) on the mainland. Half (n = 174) of the active beaches showed evidence of fresh (0–36 h. old) flatback nesting activity, with track abundance varying from 1.0 to 222.0 tracks·night−1. Six rookeries accounted for 62% of the Pilbara flatback stock. Remarkably, 77% of identified flatback rookeries occurred within protected areas. However, one-third (34%) of those were also located within 5 km of a major industrial site, including eight of the highest abundance beaches (50–250 tracks·night−1). Several key rookeries were also identified as being relatively unexposed to industry-related pressures but currently unprotected, highlighting the need for a cumulative impact assessment to be completed for this flatback stock. Finally, our aerial tallies and multiple ground-survey flatback track tallies were highly correlated and together with low intra- and inter-observer errors suggested that reliable data can be collected via aerial photogrammetry for nesting marine turtles. Such large-scale digitized surveys can therefore be used to assess the cumulative exposure of marine turtles to pressures, and to reveal new conservation opportunities.

scholarly journals OBSERVACIONES SOBRE LA ANIDACION DE TORTUGAS MARINAS EN LOS ROQUES (VENEZUELA) Y EVALUACION DE MEDIDAS PARA SU PROTECCION

2016 ◽  
Vol 17 ◽  
Author(s):  
Joaquín Buitrago B.
Keyword(s):  
Hatching Success ◽  
Chelonia Mydas ◽  
Hatching Rate ◽  
Eretmochelys Imbricata ◽  
Marine Turtles ◽  
Turtle Conservation ◽  
The Caribbean ◽  
Mortality Causes ◽  
Nesting Beaches ◽  
Hatching Rates

The nesting beaches and seasons of three species of marine turtles Chelonia mydas, Caretta caretta y Eretmochelys imbricata at Los Roques (Venezuela) were studied. E. imbricata was the most common, while C. mydas and C. caretta were rare. The data about the position of the nest on the beach, clutch size and hatching rate were examined. Five methods for the protection of nests against egg collectors were used camouflage, incubation in boxes from three different development times, and moving the eggs to a protected beach. The hatching success and mortality causes in each method are evaluated, finding that it is possible to move the eggs after 35 days of incubation with good hatching rates. The possibilities of these methods for turtle conservation programs at Los Roques and the Caribbean in general are discused.

scholarly journals Status of Marine Turtles in British Columbia Waters: A Reassessment

2004 ◽  
Vol 118 (1) ◽  
pp. 72 ◽  
Author(s):  
Donald F. McAlpine ◽  
Stan A. Orchard ◽  
Kelly A. Sendall ◽  
Rod Palm
Keyword(s):  
British Columbia ◽  
Marine Environment ◽  
Chelonia Mydas ◽  
Marine Turtle ◽  
Dermochelys Coriacea ◽  
Concerted Effort ◽  
Leatherback Turtles ◽  
Marine Turtles ◽  
Green Turtles

Marine turtles in British Columbia have previously been considered off course stragglers. Here we document 20 new reports for Green Turtles, Chelonia mydas, and Leatherback Turtles, Dermochelys coriacea, for the province. Until recently there had been no concerted effort to acquire data on marine turtle abundance or frequency off British Columbia. Observations presented here allow a reassessment of marine turtle status in British Columbia waters. We suggest Green Turtles and Leatherbacks should be considered rare vagrants and uncommon seasonal residents, respectively, off British Columbia and that they are a natural part of the British Columbia marine environment.

scholarly journals Natal foraging philopatry in eastern Pacific hawksbill turtles

2017 ◽  
Vol 4 (8) ◽  
pp. 170153 ◽  
Author(s):  
Alexander R. Gaos ◽  
Rebecca L. Lewison ◽  
Michael P. Jensen ◽  
Michael J. Liles ◽  
Ana Henriquez ◽  
...  
Keyword(s):  
Genetic Research ◽  
Eastern Pacific ◽  
Marine Turtle ◽  
Natal Philopatry ◽  
Eretmochelys Imbricata ◽  
Turtle Species ◽  
Marine Turtles ◽  
Complex Processes ◽  
Natal Homing ◽  
Hawksbill Turtles

The complex processes involved with animal migration have long been a subject of biological interest, and broad-scale movement patterns of many marine turtle populations still remain unresolved. While it is widely accepted that once marine turtles reach sexual maturity they home to natal areas for nesting or reproduction, the role of philopatry to natal areas during other life stages has received less scrutiny, despite widespread evidence across the taxa. Here we report on genetic research that indicates that juvenile hawksbill turtles ( Eretmochelys imbricata ) in the eastern Pacific Ocean use foraging grounds in the region of their natal beaches, a pattern we term natal foraging philopatry. Our findings confirm that traditional views of natal homing solely for reproduction are incomplete and that many marine turtle species exhibit philopatry to natal areas to forage. Our results have important implications for life-history research and conservation of marine turtles and may extend to other wide-ranging marine vertebrates that demonstrate natal philopatry.

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.

scholarly journals Impact of jaguar Panthera onca (Carnivora: Felidae) predation on marine turtle populations in Tortuguero, Caribbean coast of Costa Rica

2015 ◽  
Vol 63 (3) ◽  
pp. 815 ◽  
Author(s):  
Stephanny Arroyo-Arce ◽  
Roberto Salom-Pérez
Keyword(s):  
Costa Rica ◽  
Chelonia Mydas ◽  
Marine Turtle ◽  
Dermochelys Coriacea ◽  
Panthera Onca ◽  
Caribbean Coast ◽  
Eretmochelys Imbricata

<p>Existe poco conocimiento sobre el impacto que tienen los jaguares sobre las tortugas marinas que anidan en el Parque Nacional Tortuguero, Costa Rica. Este estudio evaluó el impacto de la depredación de jaguar sobre tres especies de tortugas marinas (<em>Chelonia mydas</em>, <em>Dermochelys coriácea</em> y <em>Eretmochelys imbricata</em>) que anidan en Tortuguero. Los reportes de depredación fueron obtenidos empleando dos metodologías, revisión literaria (eventos registrados antes del 2005) y monitoreos semanales a lo largo de la playa (durante el periodo 2005-2013). La depredación del jaguar se ha incrementado de una tortuga en 1981 a 198 tortugas en 2013. Asimismo, los jaguares consumieron anualmente un promedio de 120 (SD= 45) y 2 (SD= 3) tortugas verdes y tortugas baula en Tortuguero, respectivamente. Nuestros resultados indican que los jaguares no representan una amenaza para la población de tortugas verdes que anida en Tortuguero, y no son la causa principal de la disminución poblacional de la tortuga baula y carey. No obstante, se recomienda continuar con el monitoreo con el fin de entender cómo esta interacción depredador-presa evolucionará en el futuro.</p>

scholarly journals Chelonia mydas fibropapillomatosis in Baie Blanche, Tintamarre Island Saint Martin (FWI), an environmental sciences and veterinary cross-analysis

2021 ◽  
Author(s):  
Claire SALADIN
Keyword(s):  
Early Stage ◽  
Health Assessment ◽  
Environmental Parameters ◽  
Chelonia Mydas ◽  
Marine Turtle ◽  
Neoplastic Disease ◽  
Environmental Pressures ◽  
Marine Turtles ◽  
Key West ◽  
Saint Martin

Abstract Chelonia mydas’s fibropapillomatosis is a panzootic neoplastic disease that has been affecting the species since 1930’s, starting in Key West Florida USA. Most likely induced by the Chelonian HerpesVirus 5 (ChHV5), fibropapillomatosis has been recorded as affecting all species of marine turtles, provoking the growth of malignant external and internal round shaped tumors to marine turtles, that share numerous genomic similarities with human cancers. This research focuses on the two pristine bays of Tintamarre island in Saint Martin (French West Indies), Baie Blanche and Lagon, where the early stage of fibropapillomatosis has been observed affecting juvenile Chelonia mydas resident of Tintamarre. The results obtained when cross-analyzing the environmental monitoring and studies performed of Tintamarre island and a veterinary health assessment of Chelonia mydas juvenile and sub-adult marine turtles of Baie Blanche, bring a different perspective to the environmental pressures that may be responsible of the expression of the disease in Chelonia mydas. Macro-algae and Cadmium (Cd) contamination of marine turtles habitat and foraging grounds are environmental parameters that are found as possibly inducing fibropapillomatosis clinical expression in Tintamarre in this research, concurring with previous publications findings. Tintamarre island in Saint Martin (FWI) is a key site to study pertaining to marine turtle fibropapillomatosis.

scholarly journals Effectiveness of monitoring techniques employed to determine reproductive success of marine turtles in Cuba

2017 ◽  
Vol 43 (3) ◽  
pp. 548-556
Author(s):  
Julia Azanza-Ricardo ◽  
José Luis Gerhartz-Muro ◽  
Yanet Forneiro Martín-Viaña ◽  
Félix Moncada-Gavilán
Keyword(s):  
Cost Benefit ◽  
Chelonia Mydas ◽  
Eretmochelys Imbricata ◽  
Marine Turtles ◽  
Systematic Monitoring ◽  
Monitoring Frequency ◽  
Monitoring Strategies ◽  
Monitoring Effort ◽  
The Right ◽  
Nesting Beaches

Monitoring of nesting has been used globally to estimate the population size of marine turtles. Nevertheless, monitoring effort varies widely, for instance in Cuba, four different approaches are applied: nighttime systematic monitoring, daytime systematic monitoring, sporadic monitoring with nest verification, and sporadic monitoring with no verification. These variations imply that the amount and accuracy of data gathered and the quality of derived information, differ amongst the approaches. This paper assesses the effectiveness of the different methodologies used for determining the reproduction success of marine turtles in Cuba. Nighttime systematic monitoring is only carried out in one area, while sporadic monitoring with nest verification is the most used approach along the country. The proportion of the nesting season covered with monitoring personnel is low in most of the beaches and for all the three species (Chelonia mydas, Caretta caretta and Eretmochelys imbricata), although the species in the most critical situation is hawksbill. Significant differences were found between systematic and sporadic monitoring, which has important implications for the understanding of the nesting behavior, as the capacity to detect false and true crawls essentially depends on the monitoring frequency, according to our findings. Low detection capacity in sporadic monitoring hampered the development of efficiency assessments in all the nesting beaches. In summary, despite the effort carried out nationwide to monitor nesting populations that has even increased in the last three years, important gaps exists and new monitoring strategies are needed to guarantee the right information for the species is gathered, while adequate cost-benefit balance is achieved.

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