Effects of a power plant closure on home ranges of green turtles in an urban foraging area

A natural experiment was conducted to determine effects of a fossil-fueled power plant on home ranges of east Pacific green turtles Chelonia mydas in an urban foraging ground. The power plant, located in south San Diego Bay, California, USA, co-existed with a resident foraging aggregation of ~60 green turtles for ~50 yr. It was decommissioned during a long-term green turtle monitoring study, thus providing a rare opportunity to evaluate how the cessation of warm-water effluent affected turtle movements and habitat use in the area. During pre- and post-decommissioning of the power plant, 7 and 23 green turtles, respectively, were equipped with GPS-enabled satellite transmitters. Useful data were obtained from 17 turtles (4 for pre- and 13 for post-decommissioning). Core use areas (50% utilization distribution [UD]) increased from 0.71 to 1.37 km2 after the power plant decommissioning. Increase in post-power plant 50% UD was greater during nighttime (0.52 to 1.44 km2) than daytime (1.32 to 1.43 km2). Furthermore, UDs moved from the effluent channel to an area closer to seagrass pastures, a presumed foraging habitat of the turtles. The observed expansion of green turtle home ranges may increase turtle-human interactions, such as boat strikes, within the foraging ground; this underscores how seemingly innocuous human actions contribute to inadvertent consequences to wildlife. Possible management and conservation actions include increasing awareness of the public regarding turtle presence in the area through signage and education as well as legislating for a reduction in boat speeds in select areas of the bay.

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

Marine Biology ◽

10.1007/s00227-021-03895-y ◽

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.

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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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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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Ascension Island as a mid-Atlantic developmental habitat for juvenile hawksbill turtles

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315414001258 ◽

2014 ◽

Vol 97 (4) ◽

pp. 813-820 ◽

Cited By ~ 3

Author(s):

Sam B. Weber ◽

Nicola Weber ◽

Brendan J. Godley ◽

Tara Pelembe ◽

Stedson Stroud ◽

...

Keyword(s):

Benthic Algae ◽

Chelonia Mydas ◽

Small Population ◽

Future Research ◽

Home Ranges ◽

Utilization Distribution ◽

Eretmochelys Imbricata ◽

Ascension Island ◽

Minimum Residence Time ◽

Hawksbill Turtles

Ascension Island in the South Atlantic Ocean is renowned for its globally-important nesting population of green turtles (Chelonia mydas) that has been the subject of long-term research. By comparison, very little is known about the apparently small population of hawksbill turtles (Eretmochelys imbricata) that have been recorded in its waters, thousands of kilometres from known nesting beaches. Here, we collate 10 years of in-water tagging data, opportunistic public sighting records and underwater observations to provide a baseline for future research, and present preliminary data on habitat use derived from two individuals fitted with GPS transmitters. Although public sightings were inevitably biased towards popular recreation areas, the resulting distribution suggests that hawksbill turtles occur year round in Ascension Island's waters along the entire 65 km of coastline. Hawksbills were observed feeding on benthic algae and encrusting sponges, and were frequently seen scavenging on fish discards around the Island's pier at night aided by anthropogenic lighting. Between 2003 and 2013, 35 turtles were captured, measured, tagged and then released. Curved carapace lengths ranged from 33.5 to 85 cm (mean = 48.8 cm) indicating that most (if not all) individuals encountered around Ascension are post-pelagic juveniles. Four individuals were recaptured at least once giving a mean minimum residence time of 4.2 yr (range: 2.8–7.3 yr) and a mean growth rate of 2.8 cm yr−1. Turtles fitted with Fastloc™ GPS devices remained at Ascension Island for the duration of the study (>90 days) and occupied restricted home ranges with an average area of 2.5 km2 and an average ‘core use area’ (50% utilization distribution) of 0.05 km2. Together, these results suggest that Ascension Island serves as a mid-Atlantic developmental habitat for benthic-feeding, juvenile hawksbill turtles on extended oceanic migrations before recruiting to their adult foraging grounds, likely to be located in Brazil or tropical West Africa.

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Characterization of fibropapillomatosis in green turtles Chelonia mydas (Cheloniidae) captured in a foraging area in southeastern Brazil

Diseases of Aquatic Organisms ◽

10.3354/dao03020 ◽

2016 ◽

Vol 121 (3) ◽

pp. 233-240 ◽

Cited By ~ 4

Author(s):

AB Tagliolatto ◽

SM Guimarães ◽

G Lobo-Hajdu ◽

C Monteiro-Neto

Keyword(s):

Chelonia Mydas ◽

Southeastern Brazil ◽

Green Turtles ◽

Foraging Area

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

Amphibia-Reptilia ◽

10.1163/156853806778877077 ◽

2006 ◽

Vol 27 (4) ◽

pp. 539-547 ◽

Cited By ~ 12

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.

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Inter- and Intra-Beach Thermal Variation for Green Turtle Nests on Ascension Island, South Atlantic

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315400018269 ◽

1995 ◽

Vol 75 (2) ◽

pp. 405-411 ◽

Cited By ~ 20

Author(s):

Graeme C. Hays ◽

Colin R. Adams ◽

Jeanne A. Mortimer ◽

J.R. Speakman

Keyword(s):

Green Turtle ◽

Chelonia Mydas ◽

South Atlantic ◽

Nest Temperature ◽

Long Beach ◽

Thermal Variation ◽

Green Turtles ◽

North East ◽

Ascension Island ◽

East Bay

Nest temperatures for green turtles (Chelonia mydas) nesting on Ascension Island, South Atlantic (7°57'S 14°22'W), were examined. Temperature probes were placed into nests on two beaches, Long Beach (26 nests) and North East Bay (8 nests). Within these beaches there was relatively little thermal variation (SD of nest temperature was 0.32°C for Long Beach and 0.30°C for North East Bay). To examine inter-beach thermal variation temperature probes were buried at 55 cm on 12 beaches. Inter-beach thermal variation was large and was related to the beach albedo with the darkest beach (albedo, 016) being 4.2°C warmer than the lightest coloured beach (albedo, 0.73).

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The green turtle, Chelonia mydas, in Queensland: breeding males in the southern Great Barrier Reef

Wildlife Research ◽

10.1071/wr9930513 ◽

1993 ◽

Vol 20 (4) ◽

pp. 513 ◽

Cited By ~ 63

Author(s):

CJ Limpus

Keyword(s):

Great Barrier Reef ◽

Green Turtle ◽

Carapace Length ◽

Chelonia Mydas ◽

Barrier Reef ◽

Adult Males ◽

Green Turtles ◽

Adult Females ◽

Breeding Seasons ◽

Slow Growing

Breeding male green turtles, Chelonia mydas, at any one courtship area in the southern Great Barrier Reef mate with females that will nest on rookeries spread throughout the region. In comparison with the breeding females from the same breeding unit, the males are smaller in curved carapace length, and a higher proportion of males remigrate for additional breeding seasons at 1-2-year intervals. Like the adult females, adult males are slow-growing, averaging 0.046 cm year-1. Each male appears to display a fidelity to a particular courtship area, to which it returns in successive breeding migrations. At the conclusion of the courtship period, the males disperse to widely scattered feeding areas.

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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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