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RESEARCH ARTICLE
Contents Vol 32(1)

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

Jessica André A , Emma Gyuris A B and Ivan R. Lawler A
+ Author Affiliations
- Author Affiliations

A Department of Tropical Environmental Studies and Geography, James Cook University, Townsville, Qld 4811, Australia.

B Corresponding author. Email: Emma.Gyuris@jcu.edu.au

Wildlife Research 32(1) 53-62 https://doi.org/10.1071/WR04015
Submitted: 17 February 2004  Accepted: 14 July 2004   Published: 25 February 2005

Abstract

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.


Acknowledgments

We thank Donna Kwan for allowing us to use her samples; Allan Cribb, Michelle Waycott and Oli Floerl for helping with the identification of algae, seagrasses and invertebrates respectively; Tim Hancock and Mike Steele for the statistical advice; and Helene Marsh and Colin Limpus for sharing their knowledge of dugongs and green turtles. This project was funded by the School of Tropical Environment Studies and Geography (James Cook University).


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