Diet selection by immature green turtles, Chelonia mydas, in subtropical Moreton Bay, south-east Queensland

1999 ◽  
Vol 47 (2) ◽  
pp. 181 ◽  
Author(s):  
S. J. Brand-Gardner ◽  
C. J. Limpus ◽  
J. M. Lanyon
Keyword(s):  
Algal Species ◽  
Chelonia Mydas ◽  
Diet Selection ◽  
Food Composition ◽  
Feeding Site ◽  
Nitrogen Levels ◽  
Green Turtles ◽  
Moreton Bay ◽  
Food Species ◽  
Preferred Species

Diet selection by immature green turtles (Chelonia mydas) in Flathead Gutter, Moreton Bay, was determined by examining food ingested in relation to food availability (measured as vegetation composition and abundance within the feeding site). Food composition was sampled by oesophageal lavage. Turtles were repeatedly located over a 10-week period by means of sonic telemetry and visual identification. The number of resightings indicated that these turtles remained within their feeding grounds for at least short periods of time. Immature green turtles fed on both seagrass and algal species. However, most fed selectively on algae, primarily Gracilaria sp. Food items consumed frequently by these turtles were analysed for total nitrogen, gross energy and neutral detergent fibre levels. There was a negative correlation between fibre level and the preferred food species, where the more frequently selected species had lower levels of fibre. The preferred species also had higher nitrogen levels

Using Animal-Borne Imaging to Assess Green Turtle (Chelonia mydas) Foraging Ecology in Moreton Bay, Australia

2007 ◽  
Vol 41 (4) ◽  
pp. 9-13 ◽  
Author(s):  
Karen E. Arthur ◽  
Judith M. O'Neil ◽  
Colin J. Limpus ◽  
Kyler Abernathy ◽  
Greg Marshall
Keyword(s):  
Feeding Ecology ◽  
Green Turtle ◽  
Foraging Ecology ◽  
Chelonia Mydas ◽  
Lyngbya Majuscula ◽  
Imaging Device ◽  
Green Turtles ◽  
Moreton Bay ◽  
Turtle Population ◽  
Insight Into

Traditional techniques for studying green turtle foraging ecology, such as the analysis of food availability and ingested dietary material, have concluded that green turtles are primarily herbivorous but selective foragers. However, green turtles that forage during Lyngbya majuscula blooms are exposed to toxins produced by the cyanobacterium overgrowing the seagrass. We used the Crittercam, an animal-borne imaging device, to observe green turtle foraging behavior in Moreton Bay, Australia, and to evaluate the system for assessing the impacts of Lyngbya blooms on green turtles. Eight large green turtles were captured while foraging on seagrass flats and each was fitted with a Crittercam. The deployments yielded over 28 hours of video and associated time-depth records. Turtles swam almost continuously and rarely stopped to feed on seagrass. Six turtles were observed feeding and all six consumed gelatinous animals from the water column. This prey source was previously undocumented in the Moreton Bay green turtle population but described in other green turtle populations using the Crittercam. Only one turtle was observed foraging on seagrass. The results of this study indicate that Crittercam technology can provide insight into turtle diet selection and that it will be a useful tool in identifying the impacts of Lyngbya blooms on green turtle feeding ecology. This study has also demonstrated that turtles in Moreton Bay may have a more flexible diet than previously described, indicating they could potentially supplement their diet with alternate prey items when seagrass quality or quantity is compromised. Longer deployment times, with an initial acclimation phase, are required to more fully understand questions pertaining to feeding ecology.

Diet selection by immature green turtles (Chelonia mydas) at Bahía Magdalena foraging ground in the Pacific Coast of the Baja California Peninsula, México

2008 ◽  
Vol 88 (3) ◽  
pp. 641-647 ◽  
Author(s):  
Milagros López-Mendilaharsu ◽  
Susan C. Gardner ◽  
Rafael Riosmena-Rodriguez ◽  
Jeffrey A. Seminoff
Keyword(s):  
Baja California ◽  
Gastric Lavage ◽  
Chelonia Mydas ◽  
Sea Turtle ◽  
Baja California Peninsula ◽  
Green Turtles ◽  
Turtle Conservation ◽  
The Pacific ◽  
Preferred Species ◽  
Conservation Plans

In order to determine if eastern Pacific green turtles (Chelonia mydas) exhibit feeding preferences samples of recently ingested food items were compared to the food resources available in the marine environment where C. mydas congregates. Stomach samples were collected by conducting gastric lavage and, at the same time, vegetation transects were conducted during spring and winter. Green turtles in our study selectively consumed seaweeds, with Codium amplivesiculatum and Gracialaria textorii as preferred species. Differences in the consumption of species were found across the two mentioned seasons and were consistent with changes in the availability of different algae species in the environment. Based on these results, it is recommended that sea turtle conservation plans along the Baja California Peninsula include Pacific coastal mangrove channels with a high diversity of algae species as priority areas for protection.

Evaluating different spatial scales of forage item availability to determine diet selection of juvenile green turtles (Chelonia mydas)

2020 ◽  
Vol 167 (11) ◽  
Author(s):  
Anthony J. Gillis ◽  
Natalie E. Wildermann ◽  
Simona A. Ceriani ◽  
Jeffrey A. Seminoff ◽  
Mariana M. P. B. Fuentes
Keyword(s):  
Spatial Scales ◽  
Chelonia Mydas ◽  
Diet Selection ◽  
Green Turtles ◽  
Item Availability ◽  
Selection Of

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

2018 ◽  
Vol 600 ◽  
pp. 151-163 ◽  
Author(s):  
T Hamabata ◽  
H Nishizawa ◽  
I Kawazu ◽  
K Kameda ◽  
N Kamezaki ◽  
...  
Keyword(s):  
Chelonia Mydas ◽  
Size Class ◽  
Ryukyu Archipelago ◽  
Green Turtles

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

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.

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.

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

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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