Register      Login
Wildlife Research Wildlife Research Society
Ecology, management and conservation in natural and modified habitats
Shopping Cart: ( empty )
You are here: Home > Journals > WR > WR04015
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).


References

Anderson, P. K. (1986). Dugongs of Shark Bay, Australia – seasonal migration, water temperature, and forage. National Geographic Research 2, 473–490.
André J. (2002). Diet and resource partitioning between green turtles and dugongs in Torres Strait, Australia. M.Sc. Thesis, James Cook University, Townsville.

André, J. , and Lawler, I. R. (2003). Near infrared spectroscopy as a rapid and inexpensive means of dietary analysis for a marine herbivore, the dugong Dugong dugong. Marine Ecology Progress Series 257, 259–266.
Aragones L. (1996). Dugongs and green turtles: grazers in the tropical seagrass ecosystem. Ph.D. Thesis, James Cook University, Townsville.

Aragones, L. , and Marsh, H. (2000). Impact of dugong grazing and turtle cropping on tropical seagrass communities. Pacific Conservation Biology 5, 277–288.
Brand S. J. (1995). Diet selection by juvenile green turtles, Chelonia mydas, in sub-tropical Flathead Gutter, Moreton Bay. B.Sc.(Honours) Thesis, University of Queensland, Brisbane.

Brand-Gardner, S. J. , Lanyon, J. M. , and Limpus, C. J. (1999). Diet selection by immature green turtles, Chelonia mydas, in subtropical Moreton Bay, south-east Queensland. Australian Journal of Zoology 47, 181–191.
Channels P., and Morissey J. (1981). Technique for analysis of seagrass genera present in dugong stomachs, including a key to North Queensland seagrasses based on cell details. In ‘The Dugong’. (Ed. H. Marsh.) pp. 176–179. (James Cook University: Townsville.)

Erftemeijer, P. L. A. , Djunarlin, , and Moka, W. (1993). Stomach content analysis of a dugong (Dugong dugon) from south Sulawesi, Indonesia. Australian Journal of Marine and Freshwater Research 44, 229–233.
Forbes G. A. (1996). The diet and feeding ecology of the green sea turtle (Chelonia mydas) in an algal-based coral reef community. Ph.D. Thesis, James Cook University, Townsville.

Garnett, S. T. , Price, I. R. , and Scott, F. J. (1985). The diet of the green turtle, Chelonia mydas (L.), in Torres Strait. Australian Wildlife Research 12, 103–112.
Harris A. N. M. (1997). Torres Strait Turtles 1997. Fishery Assessment Report, Torres Strait Fisheries Assessment Group. Australian Fisheries Management Authority, Canberra.

Hasbún, C. R. , Lawrence, A. J. , Samour, J. H. , and Al-Ghais, S. M. (2000). Preliminary observations on the biology of green turtles, Chelonia mydas, from the United Arab Emirates. Aquatic Conservation: Marine and Freshwater Ecosystems 10, 311–322.
| Crossref | GoogleScholarGoogle Scholar | Hirth H. F. (1971). Synopsis of biological data on the green turtle, Chelonia mydas (Linnaeus) 1758. FAO Fisheries Synopsis No. 85.

Hirth, H. F. , and Carr, A. (1970). The green turtle in the Gulf of Aden and the Seychelles Islands. Verhandelingen der Koninklijke Nederlandse Akademie van Wetenschappen Afdeling Natuurkunde Tweede Reeks 58, 1–44.
Johanes R., and McFarlane W. (1991). ‘Traditional Fishing in Torres Strait Islands.’ (CSIRO Division of Fisheries: Hobart.)

Johnstone, I. M. , and Hudson, B. E. T. (1981). The dugong diet: mouth sample analysis. Bulletin of Marine Science 31, 681–690.
Kwan D. (2002). Towards a sustainable indigenous fishery for dugongs in Torres Strait: a contribution of empirical data and process. Ph.D. Thesis, James Cook University, Townsville.

Lanyon J. (1986). ‘Seagrasses of the Great Barrier Reef.’ (Great Barrier Reef Marine Park Authority: Townsville.)

Lanyon J. M., Limpus C. J., and Marsh H. (1989). Dugongs and turtles: grazers in the seagrass system. In ‘Aquatic Plant Studies 2: Biology of Seagrasses with Special Reference to the Australian Region’. (Ed. S. Shepherd.) pp. 610–634. (Elsevier Science Publishers: Amsterdam.)

Limpus C. J. (1978). The reef. In ‘Exploration North: Australia's Wildlife from Desert to Reef’. (Ed. H. J. Lavery.) pp. 187–222. (Richmond Hill Press: Melbourne.)

Long B., and Poiner I. (1997). Seagrass communities of Torres Strait, Northern Australia. Torres Strait Conservation and Planning Report, Annex 12. CSIRO.

Long B., Skewes T., Taranto T., Thomas M., Isdale P., Pitcher R., and Poiner I. (1997). ‘Seagrass dieback in North Western Torres Strait.’ (CSIRO Marine Research Division: Brisbane.)

Marsh H. (1999). Torres Strait Dugong 1998. Fisheries Assessment Report. Australian Fisheries Management Authority, Canberra.

Marsh, H. , Channells, P. W. , Heinsohn, G. E. , and Morrissey, J. (1982). Analysis of stomach contents of dugongs from Queensland. Australian Wildlife Research 9, 55–67.
Marsh H., Corkeron P., Limpus C. J., Shaughssy P., and Ward T. (1995). The reptiles and mammals in Australian seas: their status and management. In ‘State of the Marine Environment Report for Australia’. (Ed. R. Taylor.) pp. 151–166. (AGPS: Canberra.)

Marsh, H. , Beck, C. A. , and Vargo, T. (1999). Comparison of the capabilities of dugongs and West Indian manatees to masticate seagrasses. Marine Mammal Science 15, 250–255.
Mortimer J. A. (1982). Feeding ecology of sea turtles. In ‘Biology and Conservation of Sea Turtles’. (Ed. K. A. Bjorndal.) pp. 103–109. (Smithsonian Institution Press: Washington.)

Nietschmann, B. (1984). Hunting and ecology of dugongs and green turtles, Torres Strait, Australia. National Geographic Society Research Reports 17, 625–651.
Preen A. (1993). Interactions between dugongs and seagrasses in a subtropical environment. Ph.D. Thesis, James Cook University, Townsville.

Preen, A. (1995a). Diet of dugongs: are they omnivores? Journal of Mammalogy 76, 163–171.
Price I. R., and Scott F. J. (1992). ‘The Turf Algal Flora of the Great Barrier Reef. Part 1 Rhodophyta.’ (James Cook University: Townsville.)

Round F. E. (1981). ‘The Ecology of Algae.’ (Cambridge University Press: Cambridge.)

Russel, D. J. , and Balazs, G. H. (1994). Colonization by the alien marine algae Hypnea musciformis (Wulfen) J. Ag. (Rhodophyta: Gigartinales) in the Hawaiian Islands and its utilization by the green turtle, Chelonia mydas L. Aquatic Botany 47, 53–60.
| Crossref | GoogleScholarGoogle Scholar | Taranto T., Jacobs D., Skewes T., and Long B. (1997). Torres Strait reef resources: maps of percentage cover of algae and percentage cover of seagrasses. Torres Strait Conservation and Planning Report, Annex 8. CSIRO.

Thayer, G. W. , Bjorndal, K. A. , Ogden, J. C. , Williams, S. L. , and Zieman, J. C. (1984). Role of larger herbivores in seagrass communities. Estuaries 4, 351–376.
Williams G. (1994). ‘Fisheries and Marine Research in Torres Strait.’ (Australian Government Printing Service: Canberra.)