scholarly journals Marine Sponges, Other Animal Food, and Nonfood Items Found in Digestive Tracts of the Herbivorous Marine Turtle Chelonia mydas in Hawai'i

2011 ◽  
Vol 65 (3) ◽  
pp. 375-381 ◽  
Author(s):  
Dennis J. Russell ◽  
Stacy Hargrove ◽  
George H. Balazs
Keyword(s):  
Chelonia Mydas ◽  
Marine Sponges ◽  
Marine Turtle ◽  
Animal Food

scholarly journals Dietary analysis of two sympatric marine turtle species in the eastern Mediterranean

2021 ◽  
Vol 168 (6) ◽  
Author(s):  
Josie L. Palmer ◽  
Damla Beton ◽  
Burak A. Çiçek ◽  
Sophie Davey ◽  
Emily M. Duncan ◽  
...  
Keyword(s):  
Green Turtle ◽  
Eastern Mediterranean ◽  
Chelonia Mydas ◽  
Marine Turtle ◽  
Dietary Analysis ◽  
Low Frequencies ◽  
Turtle Species ◽  
Dietary Shift ◽  
Green Turtles ◽  
Loggerhead Turtles

AbstractDietary studies provide key insights into threats and changes within ecosystems and subsequent impacts on focal species. Diet is particularly challenging to study within marine environments and therefore is often poorly understood. Here, we examined the diet of stranded and bycaught loggerhead (Caretta caretta) and green turtles (Chelonia mydas) in North Cyprus (35.33° N, 33.47° E) between 2011 and 2019. A total of 129 taxa were recorded in the diet of loggerhead turtles (n = 45), which were predominantly carnivorous (on average 72.1% of dietary biomass), foraging on a large variety of invertebrates, macroalgae, seagrasses and bony fish in low frequencies. Despite this opportunistic foraging strategy, one species was particularly dominant, the sponge Chondrosia reniformis (21.5%). Consumption of this sponge decreased with increasing turtle size. A greater degree of herbivory was found in green turtles (n = 40) which predominantly consumed seagrasses and macroalgae (88.8%) with a total of 101 taxa recorded. The most dominant species was a Lessepsian invasive seagrass, Halophila stipulacea (31.1%). This is the highest percentage recorded for this species in green turtle diet in the Mediterranean thus far. With increasing turtle size, the percentage of seagrass consumed increased with a concomitant decrease in macroalgae. Seagrass was consumed year-round. Omnivory occurred in all green turtle size classes but reduced in larger turtles (> 75 cm CCL) suggesting a slow ontogenetic dietary shift. Macroplastic ingestion was more common in green (31.6% of individuals) than loggerhead turtles (5.7%). This study provides the most complete dietary list for marine turtles in the eastern Mediterranean.

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 Fine-scale thermal adaptation in a green turtle nesting population

2011 ◽  
Vol 279 (1731) ◽  
pp. 1077-1084 ◽  
Author(s):  
Sam B. Weber ◽  
Annette C. Broderick ◽  
Ton G. G. Groothuis ◽  
Jacqui Ellick ◽  
Brendan J. Godley ◽  
...  
Keyword(s):  
Green Turtle ◽  
Spatial Scales ◽  
Thermal Adaptation ◽  
Chelonia Mydas ◽  
Breeding Population ◽  
Thermal Reaction ◽  
Marine Turtle ◽  
Conservation Units ◽  
Sand Beach ◽  
Incubation Temperatures

The effect of climate warming on the reproductive success of ectothermic animals is currently a subject of major conservation concern. However, for many threatened species, we still know surprisingly little about the extent of naturally occurring adaptive variation in heat-tolerance. Here, we show that the thermal tolerances of green turtle ( Chelonia mydas ) embryos in a single, island-breeding population have diverged in response to the contrasting incubation temperatures of nesting beaches just a few kilometres apart. In natural nests and in a common-garden rearing experiment, the offspring of females nesting on a naturally hot (black sand) beach survived better and grew larger at hot incubation temperatures compared with the offspring of females nesting on a cooler (pale sand) beach nearby. These differences were owing to shallower thermal reaction norms in the hot beach population, rather than shifts in thermal optima, and could not be explained by egg-mediated maternal effects. Our results suggest that marine turtle nesting behaviour can drive adaptive differentiation at remarkably fine spatial scales, and have important implications for how we define conservation units for protection. In particular, previous studies may have underestimated the extent of adaptive structuring in marine turtle populations that may significantly affect their capacity to respond to environmental change.

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 Some of them came home: the Cayman Turtle Farm headstarting project for the green turtle Chelonia mydas

Oryx ◽  
2005 ◽  
Vol 39 (2) ◽  
pp. 137-148 ◽  
Author(s):  
Catherine D.L. Bell ◽  
Joe Parsons ◽  
Timothy J. Austin ◽  
Annette C. Broderick ◽  
Gina Ebanks-Petrie ◽  
...  
Keyword(s):  
Chelonia Mydas ◽  
Breeding Population ◽  
Marine Turtle ◽  
Management Technique ◽  
Cayman Islands ◽  
Age At Maturity ◽  
Green Turtles ◽  
Local Breeding ◽  
The Caribbean ◽  
Cayman Turtle Farm

Headstarting is a management technique employed to enhance recruitment of turtles into diminished or extirpated marine turtle populations. Although there have been numerous projects worldwide, there has been a paucity of detailed investigations into its efficacy. Between 1980 and 2001, 16,422 captive-raised hatchlings and 14,347 yearling green marine turtles Chelonia mydas were released from the Cayman Turtle Farm. Approximately 80% of all turtles released were subject to some form of tagging, including living tags. A total of 392 tagged animals have been recaptured at intervals of up to 19 years. Of this total, 160 individuals were captured in the Cayman Islands and 232 were recorded from other locations within the wider Caribbean and southeastern USA. There was significant variation in the release-recapture intervals at the three countries with most returns (Cayman, Cuba and Nicaragua). A positive relationship exists between time at large and size at recapture and data suggest growth rates comparable to those of wild green turtles in the region. There have been at least six living tag returns, four involving turtles released as yearlings and two involving turtles released as hatchlings. This demonstrates an age at maturity that may be as short as 15–19 years, depending on stage of release. Results show that some headstarted turtles are moving around the Caribbean, surviving for long periods of time, contributing to the local breeding population, and are possibly displaying shifts in habitat utilization with age similar to those recorded by wild individuals.

scholarly journals The nesting success of green turtles on beaches at Kazanli, Turkey

Oryx ◽  
1992 ◽  
Vol 26 (3) ◽  
pp. 165-171 ◽  
Author(s):  
Stephanie J. Coley ◽  
Andrew C. Smart
Keyword(s):  
Nest Site ◽  
Chelonia Mydas ◽  
Nesting Success ◽  
Beach Erosion ◽  
Marine Turtle ◽  
Chemical Pollution ◽  
Turtle Species ◽  
Green Turtles ◽  
Nesting Beaches ◽  
Turkish Society

The green turtle Chelonia mydas is one of two marine turtle species to nest in Turkey. Its three main nesting beaches are in eastern Turkey, with possibly the densest congregation of nesting turtles in the Mediterranean being found at Kazanli. However, beach erosion, hatchling predation, agricultural encroachment and chemical pollution mean that the future of the Kazanli nest site is uncertain. The Turkish Society for the Protection of Nature (Dogal Hayati Koruma Dernegi) is making valiant efforts to protect all the turtle nesting beaches in Turkey but lacks detailed information on the numbers of nesting turtles on many beaches. This paper describes a short study of nesting turtles at Kazanli during 1990 and makes recommendations for the conservation of the nesting beach.

scholarly journals The value of long-term, community-based monitoring of marine turtle nesting: a study in the Lamu archipelago, Kenya

Oryx ◽  
2017 ◽  
Vol 53 (1) ◽  
pp. 71-80 ◽  
Author(s):  
Mike I. Olendo ◽  
Gladys M. Okemwa ◽  
Cosmas N. Munga ◽  
Lilian K. Mulupi ◽  
Lily D. Mwasi ◽  
...  
Keyword(s):  
Green Turtle ◽  
Low Cost ◽  
Western Indian Ocean ◽  
Chelonia Mydas ◽  
Sea Turtle ◽  
Marine Turtle ◽  
Olive Ridley ◽  
Community Based ◽  
Green Turtles ◽  
Incubation Duration

AbstractMonitoring of nesting beaches is often the only feasible and low-cost approach for assessing sea turtle populations. We investigated spatio-temporal patterns of sea turtle nesting activity monitored over 17 successive years in the Lamu archipelago, Kenya. Community-based patrols were conducted on 26 stretches of beach clustered in five major locations. A total of 2,021 nests were recorded: 1,971 (97.5%) green turtleChelonia mydasnests, 31 (1.5%) hawksbillEretmochelys imbricatanests, 8 (0.4%) olive ridleyLepidochelys olivaceanests and 11 (0.5%) unidentified nests. Nesting occurred year-round, increasing during March–July, when 74% of nests were recorded. A stable trend in mean annual nesting densities was observed in all locations. Mean clutch sizes were 117.7 ± SE 1 eggs (range 20–189) for green turtles, 103±SE 6 eggs (range 37–150) for hawksbill turtles, and 103±SE 6 eggs (range 80–133) for olive ridley turtles. Curved carapace length for green turtles was 65–125 cm, and mean annual incubation duration was 55.5±SE 0.05 days. The mean incubation duration for green turtle nests differed significantly between months and seasons but not locations. The hatching success (pooled data) was 81.3% (n = 1,841) and was higher for in situ nests (81.0±SE 1.5%) compared to relocated nests (77.8±SE 1.4%). The results highlight the important contribution of community-based monitoring in Kenya to sustaining the sea turtle populations of the Western Indian Ocean region.

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>

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