Dietary preferences of juvenile green turtles (Chelonia mydas) on a tropical reef flat
Mariana M. P. B. Fuentes A B , Ivan R. Lawler A and Emma Gyuris AA School of Tropical Environment Studies and Geography, James Cook University, Douglas, Qld 4811, Australia.
B Corresponding author: Email: mariana.fuentes@jcu.edu.au
Wildlife Research 33(8) 671-678 https://doi.org/10.1071/WR05081
Submitted: 12 September 2005 Accepted: 20 October 2006 Published: 19 December 2006
Abstract
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.
Acknowledgments
This project was undertaken in collaboration with the broader research project of Mr Ian Bell of the Queensland Parks and Wildlife Service. Permission for the stomach lavages was granted under his permit (G03/9866.1). Further permits for this study included Marine Park Permit (G04/12081.1) and animal ethics approval (A881_04) from James Cook University. Mr Ian Osborn, the QPWS Ranger in Charge at Green Island, generously offered accommodation, access to the boat and personal assistance in the field-based component of the project. Dr Kirsten Heimann of the School of Tropical Biology, James Cook University, gave advice on the identification of algae.
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