ESR 3:1-9 (2007)  -  doi:10.3354/esr003001

Migration routes and foraging behaviour of olive ridley turtles Lepidochelys olivacea in northern Australia

S. D. Whiting1,5,*, J. L. Long2, M. Coyne3,4

1WWF-Australia, PO Box 1268, Darwin, Northern Territory 0801, Australia
2Tiwi Land Council, PO Box 38545, Winnellie, Northern Territory 0821, Australia
3Marine Geospatial Ecology Lab, Nicholas School of Environment, Duke University, Durham, North Carolina 27708, USA
4SEATURTLE.ORG, 1 Southampton Place, Durham, North Carolina 27705, USA
5Present address: Marine Biodiversity Group, Natural Resources, Environment and the Arts, PO Box 41775, Casuarina, Northern Territory 0810, Australia

ABSTRACT: The foraging ecology of endangered olive ridley Lepidochelys olivacea sea turtles is poorly known in Australia, with only a limited knowledge of their foraging distribution inferred from captures in trawl net fisheries. We attached satellite transmitters to 8 olive ridley turtles in 2004 and 2005 at a nesting beach in Australia’s Northern Territory to document their migratory routes and foraging behaviour. Three turtles moved up to 40 km from the nesting beach before renesting on the same beach within 12 to 23 d. The turtles made post-nesting migrations of 165 to 1050 km to 5 different foraging areas and used coastal, continental shelf and continental slope habitats. The use of one foraging area by 3 turtles, together with previous trawl data, indicate a predictable source of food in this area. Distinct foraging areas indicate that foraging behaviour differs from the meandering oceanic movements of turtles in the Pacific. During migration and foraging periods, turtles dived to the substrate with maximum depths of 150 to 200 m and maximum dive durations of 120 to 180 min. The locations of foraging areas overlapped with existing trawl fisheries and oil and gas exploration and mining.

KEY WORDS: Satellite tracking · Migration · Foraging · Olive ridley · Renesting · Inter-nesting ·Australia

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