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

2005 ◽  
Vol 32 (1) ◽  
pp. 53 ◽  
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.

Mapping seagrass cost-effectively in the Coral Triangle: Sabah, Malaysia as a case study

2015 ◽  
Vol 21 (2) ◽  
pp. 113 ◽  
Author(s):  
Leela Rajamani ◽  
Helene Marsh
Keyword(s):  
Cost Effective ◽  
Human Populations ◽  
Coral Triangle ◽  
Thalassia Hemprichii ◽  
Seagrass Meadows ◽  
Green Turtles ◽  
Halophila Ovalis ◽  
Seagrass Mapping ◽  
Cymodocea Rotundata ◽  
Syringodium Isoetifolium

Knowledge of the distribution and relative abundance of seagrass communities in the Coral Triangle is limited, despite their global significance and the vital ecosystem services they perform for local human populations, threatened species such as dugongs and green turtles, as well as the role of being a globally significant carbon stock. To address this gap and investigate cost-effective methods in data-poor regions, we conducted seagrass mapping near two islands off the coast of Sabah in Malaysia: Banggi Island (7°15′N, 117°12′E) and Mantanani Island (6°43′N, 116°21′E). We used a staged approach that included: (1) interview surveys, (2) manta tow and spot surveys, and (3) comprehensive transect surveys. Approximately 415 ha and 112 ha of seagrass meadows were mapped off Banggi Island and Mantanani Island respectively. We found 10 species of seagrasses from two families: Halophila ovalis, Halodule uninervis (broad and thin leaf varieties), Thalassia hemprichii, Cymodocea rotundata, Halophila decipiens, Halophila spinulosa, Cymodocea serrulata, Syringodium isoetifolium, Enhalus acoroides and Halophila sp. nov. Our methodology proved cost-effective and the resultant information should be relevant to conservation planners.

scholarly journals Sea turtles in Lake Bardawil, Egypt - size distribution and population structure

2020 ◽  
pp. 32-36
Author(s):  
Basem Rabia
Keyword(s):  
Size Distribution ◽  
Narrow Range ◽  
Chelonia Mydas ◽  
Ratio And Proportion ◽  
Green Turtles ◽  
Loggerhead Turtles ◽  
Feeding Area ◽  
Development Area ◽  
Sexually Mature ◽  
The Mediterranean Basin

We investigated the size distribution, sex ratio, and proportion of sexually mature green (Chelonia mydas) and loggerhead (Caretta caretta) turtles in Lake Bardawil, a large coastal lagoon. During the study 30 green turtles (8 males, 4 females, and 18 juveniles / sub-adults) and 14 loggerheads (1 male, 8 females, and 5 sub-adults) were captured. Forty percent of the green and 64 % of loggerhead turtles were believed to be sexually mature. The green turtles had a mean curved carapace length of 65.23 cm (15 – 100 cm range) and the loggerhead turtles 68.79 cm but with a much narrow range (60 - 80 cm) reflecting the absence of juveniles. This study provides evidence that Lake Bardawil is an important feeding and development area for green turtles and feeding area for loggerhead turtles and expands our knowledge of such important sites in the Mediterranean basin.

The Diet of the Green Turtle, Chelonia Mydas (L.), In Torres Strait.

1985 ◽  
Vol 12 (1) ◽  
pp. 103 ◽  
Author(s):  
ST Garnett ◽  
IR Price ◽  
FJ Scott
Keyword(s):  
Red Algae ◽  
Green Turtle ◽  
Geographical Variation ◽  
Chelonia Mydas ◽  
Green Turtles ◽  
Herbivore Community ◽  
Nutritional Advantage ◽  
Torres Strait

The principal genera of plants consumed by green turtles in Torres Strait were Hypnea, Laurencia, Vadalia, Sargassum and Thalassia. Although some selectivity for soft red algae was detected, no evidence was found to support the theory that turtles feed on algae only when seagrasses are unavailable, but nor do algae appear to confer a nutritional advantage on those animals than eat them. Geographical variation in green turtle diets appears to be determined by the relative availability of seagrass and algae and the structure of the local herbivore community.

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

2006 ◽  
Vol 33 (8) ◽  
pp. 671 ◽  
Author(s):  
Mariana M. P. B. Fuentes ◽  
Ivan R. Lawler ◽  
Emma Gyuris
Keyword(s):  
Reef Flat ◽  
Chelonia Mydas ◽  
Thalassia Hemprichii ◽  
Factors Affecting ◽  
Green Turtles ◽  
Diet Switching ◽  
Dietary Preferences ◽  
Tropical Reef ◽  
Potential Factors ◽  
Feeding Choices

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.

Sea-Turtle Rookeries in North-Western Torres Strait

1989 ◽  
Vol 16 (5) ◽  
pp. 517 ◽  
Author(s):  
CJ Limpus ◽  
D Zeller ◽  
D Kwan ◽  
W Macfarlane
Keyword(s):  
Papua New Guinea ◽  
Chelonia Mydas ◽  
Sea Turtle ◽  
Barrier Reef ◽  
Eretmochelys Imbricata ◽  
Green Turtles ◽  
North Eastern ◽  
Nesting Sites ◽  
Torres Strait ◽  
North Western

Deliverance Island, Kerr Islet and Turu Cay in north-western Torres Strait support a major nesting population and the most northerly recorded rookery of the flatback turtle, Natator depressa. Nesting occurs there year round, with a peak in the early months of the year. The islands are insignificant nesting sites for the green turtle, Chelonia mydas, and the hawksbill turtle, Eretmochelys imbricata. The N. depressa turtles that nest in western Torres Strait-north-eastern Gulf of Carpentaria are smaller and lay smaller eggs on average than the N. depressa turtles that breed in the southern Great Barrier Reef. On Deliverance Island, the inhabitants of nearby Queensland islands and Papua New Guinea coastal villages infrequently harvest N. depressa eggs as well as the green turtles that feed over the surrounding reef flats.

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
Sign in / Sign up

Export Citation Format

Share Document