Dietary preferences of juvenile green turtles (Chelonia mydas) on a tropical reef flat

We offer the first published description of the feeding choices made by juvenile green turtles on a tropical feeding ground, in this case a reef flat environment. We collected 85 lavage samples from 76 turtles and compared the food eaten to the food resources available. Resampling of some individuals enabled us to gain preliminary insights into diet switching by juvenile turtles. The area of the reef flat at Green Island, Queensland, Australia, had similar proportions of coverage by seagrasses (52%) and by algae (48%). Seven species of seagrass and at least 26 species of algae were identified. The dominant seagrasses, on an area basis, were Cymodocea sp. (29.7%), Halodule sp. (11.1%), Thalassia sp. (6.4%) and Syringodium sp. (4.5%). The most dominant algae were Halimeda spp. (10.2%). and Galaxaura sp. (7.25%). Most juvenile green turtles ate primarily seagrass, but some individuals ate predominantly algae. The turtles showed clear preferences for the seagrass Thalassia hemprichii and the algae Gracilaria spp., Gelidiella sp., Hypnea spp. despite their low abundance in many cases. Ways to improve our understanding of preferences and possible diet switching, and potential factors affecting them, are discussed.

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Factors Affecting the Long-Term Population Dynamics of Green Turtles (Chelonia mydas) in Ogasawara, Japan: Influence of Natural and Artificial Production of Hatchlings and Harvest Pressure

Chelonian Conservation and Biology ◽

10.2744/ccb-1222.1 ◽

2017 ◽

Vol 16 (1) ◽

pp. 83-92 ◽

Cited By ~ 7

Author(s):

Satomi Kondo ◽

Yukari Morimoto ◽

Takayuki Sato ◽

Hiroyuki Suganuma

Keyword(s):

Population Dynamics ◽

Chelonia Mydas ◽

Factors Affecting ◽

Green Turtles ◽

Harvest Pressure

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Comparison of the diets of sympatric dugongs and green turtles on the Orman Reefs, Torres Strait, Australia

Wildlife Research ◽

10.1071/wr04015 ◽

2005 ◽

Vol 32 (1) ◽

pp. 53 ◽

Cited By ~ 31

Author(s):

Jessica André ◽

Emma Gyuris ◽

Ivan R. Lawler

Keyword(s):

Stomach Contents ◽

Chelonia Mydas ◽

Food Resources ◽

Thalassia Hemprichii ◽

Green Turtles ◽

Large Numbers ◽

Full Explanation ◽

Feeding Area ◽

Torres Strait ◽

Syringodium Isoetifolium

This study investigated the diet of dugongs (Dugong dugon, Dugongidae) and green turtles (Chelonia mydas, Cheloniidae) on the Orman Reefs in Torres Strait, between Australia and Papua New Guinea, where large numbers of these animals live sympatrically. The stomach contents of dugongs and green turtles caught in an indigenous fishery were examined. Dugongs fed exclusively on seagrasses (mainly Thalassia hemprichii, Cymodocea spp. and Syringodium isoetifolium) whereas turtles consumed both seagrasses (especially T. hemprichii and Enhalus acoroides) and algae (mainly Hypnea spp., Laurencia spp. and Caulerpa spp.). The two herbivores showed no overlap in resource use except for the seagrass T. hemprichii, which was abundant in the feeding area. Both species appeared to feed selectively and did not just consume the most available food items. These results are suggestive of partitioning of food resources between dugongs and green turtles but a full explanation requires more detailed, and concurrent, study of the food resources and the animals’ movements.

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Stock composition of green turtles Chelonia mydas foraging in the Ryukyu Archipelago differs with size class

Marine Ecology Progress Series ◽

10.3354/meps12657 ◽

2018 ◽

Vol 600 ◽

pp. 151-163 ◽

Cited By ~ 6

Author(s):

T Hamabata ◽

H Nishizawa ◽

I Kawazu ◽

K Kameda ◽

N Kamezaki ◽

...

Keyword(s):

Chelonia Mydas ◽

Size Class ◽

Ryukyu Archipelago ◽

Green Turtles

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Effects of El Niño Southern Oscillation and local ocean temperature on the reproductive output of green turtles (Chelonia mydas) nesting at Tortuguero, Costa Rica

Marine Biology ◽

10.1007/s00227-020-03749-z ◽

2020 ◽

Vol 167 (9) ◽

Author(s):

Renato Saragoça Bruno ◽

Jaime Alberto Restrepo ◽

Roldán Arturo Valverde

Keyword(s):

Costa Rica ◽

El Niño ◽

Reproductive Output ◽

El Nino ◽

Southern Oscillation ◽

Chelonia Mydas ◽

El Niño Southern Oscillation ◽

El Nino Southern Oscillation ◽

Ocean Temperature ◽

Green Turtles

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Plasma proteomics of green turtles (Chelonia mydas) reveals pathway shifts and potential biomarker candidates associated with health and disease

Conservation Physiology ◽

10.1093/conphys/coab018 ◽

2021 ◽

Vol 9 (1) ◽

Author(s):

David P Marancik ◽

Justin R Perrault ◽

Lisa M Komoroske ◽

Jamie A Stoll ◽

Kristina N Kelley ◽

...

Keyword(s):

Chelonia Mydas ◽

Sea Turtle ◽

Protein Abundance ◽

Plasma Samples ◽

Important Species ◽

Green Turtles ◽

Rehabilitation Programs ◽

Potential Biomarker ◽

Health And Disease

Abstract Evaluating sea turtle health can be challenging due to an incomplete understanding of pathophysiologic responses in these species. Proteome characterization of clinical plasma samples can provide insights into disease progression and prospective biomarker targets. A TMT-10-plex-LC–MS/MS platform was used to characterize the plasma proteome of five, juvenile, green turtles (Chelonia mydas) and compare qualitative and quantitative protein changes during moribund and recovered states. The 10 plasma samples yielded a total of 670 unique proteins. Using ≥1.2-fold change in protein abundance as a benchmark for physiologic upregulation or downregulation, 233 (34.8%) were differentially regulated in at least one turtle between moribund and recovered states. Forty-six proteins (6.9%) were differentially regulated in all five turtles with two proteins (0.3%) demonstrating a statistically significant change. A principle component analysis showed protein abundance loosely clustered between moribund samples or recovered samples and for turtles that presented with trauma (n = 3) or as intestinal floaters (n = 2). Gene Ontology terms demonstrated that moribund samples were represented by a higher number of proteins associated with blood coagulation, adaptive immune responses and acute phase response, while recovered turtle samples included a relatively higher number of proteins associated with metabolic processes and response to nutrients. Abundance levels of 48 proteins (7.2%) in moribund samples significantly correlated with total protein, albumin and/or globulin levels quantified by biochemical analysis. Differentially regulated proteins identified with immunologic and physiologic functions are discussed for their possible role in the green turtle pathophysiologic response and for their potential use as diagnostic biomarkers. These findings enhance our ability to interpret sea turtle health and further progress conservation, research and rehabilitation programs for these ecologically important species.

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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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The impact of fibropapillomatosis on clinical characteristics, blood gas, plasma biochemistry, and hematological profiles in juvenile green turtles ( Chelonia mydas)

Bulletin of Marine Science ◽

10.5343/bms.2019.0120 ◽

2020 ◽

Vol 96 (4) ◽

pp. 723-734

Author(s):

Tsung-Hsien Li ◽

Chao-Chin Chang

Keyword(s):

White Blood Cells ◽

Extracellular Fluid ◽

Chelonia Mydas ◽

Sea Turtle ◽

Total Carbon ◽

Blood Gas ◽

Green Turtles ◽

Cell Counts ◽

Significant Difference ◽

The Impact

Fibropapillomatosis (FP) is a tumor- forming disease that afflicts all marine turtles and is the most common in green turtles (Chelonia mydas). In this study, the morphometric characteristics, blood gas, biochemistry, and hematological profiles of 28 (6 FP-positive and 22 FP-negative) green turtles from the coast of Taiwan were investigated. The results indicated that body weight ( P < 0.001) and curved carapace length (CCL; P < 0.001) in green turtles with FP were significantly higher than in turtles without FP. Furthermore, green turtles with FP had a significantly lower value of hemoglobin (HB; P = 0.010) and packed cell volume (PCV; P = 0.005) than turtles without FP. Blood cell counts of white blood cells (WBC; P = 0.008) and lymphocytes ( P = 0.022) were observed with significant difference; green turtles with FP had lower counts than turtles without FP. In addition, turtles with FP had significantly higher pH ( P = 0.036), base excess in extracellular fluid (BEecf; P = 0.012), bicarbonate (HCO3– ; P = 0.008), and total carbon dioxide (TCO2 ; P = 0.025) values than turtles without FP. The findings of this study provide valuable clinical parameters for the medical care of the species in sea turtle rehabilitation centers and help us to understand the physiological response of green turtles to different tumor-forming conditions.

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