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

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.

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

Oryx ◽

10.1017/s0030605300023607 ◽

1992 ◽

Vol 26 (3) ◽

pp. 165-171 ◽

Cited By ~ 1

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.

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

Oryx ◽

10.1017/s0030605317000771 ◽

2017 ◽

Vol 53 (1) ◽

pp. 71-80 ◽

Cited By ~ 4

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.

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Increase of sea turtles stranding records in Rhodes Island (eastern Mediterranean Sea): update of a long-term survey

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315413000556 ◽

2013 ◽

Vol 93 (7) ◽

pp. 1991-2002 ◽

Cited By ~ 3

Author(s):

Maria Corsini-Foka ◽

Gerasimos Kondylatos ◽

Elias Santorinios

Keyword(s):

Eastern Mediterranean ◽

Sea Turtles ◽

Loggerhead Turtle ◽

Aegean Sea ◽

Chelonia Mydas ◽

Caretta Caretta ◽

Fishing Ground ◽

Green Turtles ◽

Loggerhead Turtles

A total of 209 strandings of sea turtles (152 loggerhead turtles Caretta caretta, 42 green turtles Chelonia mydas, 15 unidentified) were recorded during the period 1984–2011 along the coasts of Rhodes (Aegean Sea, Greece). The proportion of dead to live individuals was different in the two species. Stranded Caretta caretta were larger than Chelonia mydas. The size range of stranded green turtles, usually juveniles, appeared to increase since 2000, including the largest specimens ever observed in Greek waters. For both species, a tendency to strand more frequently on the west coast of the island, along fishing ground areas, was noted. The higher incidence of loggerhead turtle strandings was observed in summer, while more green turtle strandings were documented in winter. Factors involved in the increased trend of stranding records of both species, along with the acceleration of this phenomenon in the last decade, are discussed. Data from Rhodes provide evidence that human activities detrimentally affect mainly larger-sized loggerhead turtles living in shallow waters.

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Estimating the number of green and loggerhead turtles nesting annually in the Mediterranean

Oryx ◽

10.1017/s0030605302000431 ◽

2002 ◽

Vol 36 (3) ◽

pp. 227-235 ◽

Cited By ~ 108

Author(s):

Annette C. Broderick ◽

Fiona Glen ◽

Brendan J. Godley ◽

Graeme C. Hays

Keyword(s):

Chelonia Mydas ◽

Marine Turtle ◽

Green Turtles ◽

Northern Cyprus ◽

Loggerhead Turtles ◽

The Status ◽

The Mediterranean ◽

Endangered Status ◽

Breeding Seasons ◽

Median Interval

Most species of marine turtle breed every two or more years and it is the norm for females to lay more than one clutch of eggs within a nesting season. Knowing the interval between breeding seasons and the clutch frequency (number of clutches laid by an individual in a breeding season) of females allows us to assess the status of a nesting population. At Alagadi Beach, Northern Cyprus, over a period of 6 years (1995–2000), we attributed 96% of green Chelonia mydas and 80% of loggerhead Caretta caretta turtle clutches to known individual females. This intensive level of monitoring enabled us to estimate the clutch frequency for both species. Using four different methods we estimated clutch frequency to be 2.9–3.1 clutches per female for green turtles and 1.8–2.2 clutches per female for loggerhead turtles. The median interval between nesting seasons for green turtles was 3 years, and for loggerhead turtles it was 2 years. Utilizing these parameters and available data from other beaches that are monitored regularly, we estimate that there are 2,280–2,787 logger-head and 339–360 green turtles nesting annually at these sites in the Mediterranean. This highlights the Critically Endangered status of this population of green turtles. Furthermore, as conventional beach patrols underestimate clutch frequency, these population estimates are likely to be optimistic.

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DNA BARCODE ANALYSIS OF THE ENDANGERED GREEN TURTLE (Chelonia mydas) IN MEXICO

Genome ◽

10.1139/gen-2019-0213 ◽

2021 ◽

Author(s):

Fátima Yedith Camacho-Sánchez ◽

A. Alonso Aguirre ◽

Jose Alberto Narvaez-Zapata ◽

Alan A. Zavala-Norzagaray ◽

Cesar P Ley-Quiñónez ◽

...

Keyword(s):

Green Turtle ◽

Dna Barcode ◽

Chelonia Mydas ◽

Sea Turtle ◽

Population Diversity ◽

Coi Gene ◽

Dna Barcodes ◽

Mexican Pacific ◽

Turtle Species ◽

Green Turtles

Technological and analytical advances to study evolutionary biology, ecology, and conservation of green turtles (Chelonia mydas) are realized through molecular approaches including DNA barcoding. We characterized the usefulness of COI DNA barcodes in green turtles in Mexico to better understand genetic divergence and other genetic parameters of this species. We analyzed 63 sequences, 25 from green turtle field specimens collected from the Gulf of Mexico and from the Mexican Pacific, and 38 already present in the Barcode of Life Data Systems (BOLD). A total of 13 haplotypes were identified with 4 novel haplotypes from the Pacific Ocean and 3 novel haplotypes from the Atlantic Ocean. Intraspecific distance values among COI gene sequences by two different models were 0.01, demonstrating that there is not a subdivision for green turtle species. Otherwise, the interspecific distance interval ranged from 0.07 to 0.13 supporting a clear subdivision among all sea turtle species. Haplotype and total nucleotide diversity values of the COI gene reflect a medium genetic diversity average. Green turtles of the Mexican Pacific showed common haplotypes to some Australian and Chinese turtles, but different from the haplotypes of the Mexican Atlantic. COI analysis revealed new haplotypes and confirmed that DNA barcodes were useful for evaluation of the population diversity of green turtles in Mexico.

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Redescription of Charaxicephaloides polyorchis Groschaft and Tenora 1978 (Digenea: Pronocephalidae) from the green turtle Chelonia mydas in Costa Rica

Helminthologia ◽

10.2478/s11687-009-0019-6 ◽

2009 ◽

Vol 46 (2) ◽

pp. 97-99 ◽

Cited By ~ 1

Author(s):

M. Santoro ◽

P. Brandmayr ◽

E. Greiner ◽

J. Morales ◽

B. Rodríguez-Ortíz

Keyword(s):

Costa Rica ◽

Host Species ◽

Green Turtle ◽

Chelonia Mydas ◽

Original Description ◽

Northwest Coast ◽

Green Turtles ◽

New Information

AbstractCharaxicephaloides polyorchis Groschaft and Tenora, 1978 is redescribed on the basis of specimens collected from the stomach of green turtles Chelonia mydas in Costa Rica. Our specimens are consistent with the original description which was based on four flukes from the same host species from the northwest coast of Cuba. Our redescription provides a new range of variations and adds new information on this species. This represents only the second record of C. polyorchis in green turtles.

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Status of Marine Turtles in British Columbia Waters: A Reassessment

The Canadian Field-Naturalist ◽

10.22621/cfn.v118i1.885 ◽

2004 ◽

Vol 118 (1) ◽

pp. 72 ◽

Cited By ~ 3

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.

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ASPEK MORFOLOGI, REPRODUKSI, DAN PERILAKU PENYU HIJAU (Chelonia mydas) Di PANTAI PANGUMBAHAN, KABUPATEN SUKABUMI, JAWA BARAT

BAWAL Widya Riset Perikanan Tangkap ◽

10.15578/bawal.3.2.2010.93-101 ◽

2017 ◽

Vol 3 (2) ◽

pp. 93

Author(s):

Adriani Sri Nastiti Krismono ◽

Achmad Fitriyanto ◽

Ngurah Nyoman Wiadnyana

Keyword(s):

Green Turtle ◽

Carapace Width ◽

Chelonia Mydas ◽

Sea Turtle ◽

Stratified Sampling ◽

Hatching Rate ◽

Brood Stock ◽

Green Turtles ◽

And Behavior ◽

Nesting Season

Penyu hijau (Chelonia mydas) termasuk dalam phylum Chordata dan famili Cheloniideae. Jumlah penyu hijau yang singgah ke Pantai Pangumbahan untuk bertelur semakin menurun karena tidak terkendalinya masyarakat melakukan penangkapan induk penyu dan pengambilan telurnya. Penelitian tentang morfologi, reproduksi, dan perilaku penyu hijau sebagai salah satu dasar pengelolaan telah dilakukan di Pantai Pangumbahan pada bulan Agustus 2008. Metode penelitian yang digunakan pengambilan contoh berstrata. Penelitian ini dilaksanakan pada bulan Agustus 2008 (pada saat puncak peneluran). Parameter yang diamati antara lain ukuran penyu dari 89 ekor jumlah penyu bersarang, jumlah telur dan tingkat penetasan, serta perilaku pada saat penyu bertelur. Hasil penelitian menunjukan yang diamati diperoleh panjang karapas berkisar antara 97-15 cm dan lebar karapas 83,5-108 cm, jumlah penyu naik ke pantai 89 ekor dan penyu yang bertelur 39 ekor. Jumlah telur penyu hijau berhasil dihitung 80-105 butir per induk penyu. Bulan Agustus 2008 merupakan puncak musim peneluran. Kegiatan peneluran penyu hijau dibagi menjadi enam tahap. Upaya konservasi yang sudah dilakukan adalah penetasan telur penyu semi alami, restocking tukik, dan menjaga keamanan sarang telur penyu. Green turtles (Chelonia mydas), including the phylum Chordata and families Cheloniideae. The number of green turtles come to lay eggs Pangumbahan beach to decline because of increasingly unmanageable public do making arrests turtles brood stock and their eggs. Research on the morphology, reproduction, and behavior of green turtles as one of the basic management has been conducted on the Pangumbahan Beach in August 2008. The method used stratified sampling. The experiment was conducted in August 2008 (at the peak of nesting). Other parameters were observed between the size of the 89 tail number of turtles nesting turtles, the number of eggs and hatching rate and behavior during turtle nesting. Results obtained showed that the observed length ranges from 97- 15 cm carapace and carapace width from 83.5-108 cm, the number went up to the beach 89 sea turtle and sea turtle nesting tail as much as 39 tails. The number of green turtle eggs had counted as many as 80-105 eggs per turtles brood stock. Month August 2008 is the peak nesting season of green turtle nesting activities are divided into six stages. Conservation efforts that have been done is semi natural turtle hatchery, restocking hatchlings, and nest of turtle eggs to maintain security.

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Fine-scale thermal adaptation in a green turtle nesting population

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2011.1238 ◽

2011 ◽

Vol 279 (1731) ◽

pp. 1077-1084 ◽

Cited By ~ 47

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.

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