Estuarine crocodiles ride surface currents to facilitate long-distance travel

Campbell, Hamish A., Watts, Matthew E., Sullivan, Scott, Read, Mark A., Choukroun, Severine, Irwin, Steve R., and Franklin, Craig E. (2010) Estuarine crocodiles ride surface currents to facilitate long-distance travel. Journal of Animal Ecology, 79 (5). pp. 955-964.

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Abstract

1. The estuarine crocodile (Crocodylus porosus) is the world’s largest living reptile. It predominately inhabits freshwater and estuarine habitats, but widespread geographic distribution throughout oceanic islands of the South-east Pacific suggests that individuals undertake sizeable ocean voyages.

2. Here we show that adult C. porosus adopt behavioural strategies to utilise surface water currents during long-distance travel, enabling them to move quickly and efficiently over considerable distances.

3. We used acoustic telemetry to monitor crocodile movement throughout 63 km of river, and found that when individuals engaged in a long-distance, constant direction journey (>10 km day−1), they would only travel when current flow direction was favourable. Depth and temperature measurements from implanted transmitters showed that they remained at the water surface during travel but would dive to the river substratum or climb out on the river bank if current flow direction became unfavourable.

4. Satellite positional fixes from tagged crocodiles engaged in ocean travel were overlaid with residual surface current (RSC) estimates. The data showed a strong correlation existed between the bearing of the RSC and that of the travelling crocodile (r2 = 0·92, P < 0·0001).

5. The study demonstrates that C. porosus dramatically increase their travel potential by riding surface currents, providing an effective dispersal strategy for this species.

Item ID: 17325
Item Type: Article (Refereed Research - C1)
Keywords: behaviour; Crocodylus porosus; migration; telemetry; zoogeography
ISSN: 1365-2656
Date Deposited: 30 May 2011 01:46
FoR Codes: 06 BIOLOGICAL SCIENCES > 0602 Ecology > 060205 Marine and Estuarine Ecology (incl Marine Ichthyology) @ 100%
SEO Codes: 96 ENVIRONMENT > 9608 Flora, Fauna and Biodiversity > 960802 Coastal and Estuarine Flora, Fauna and Biodiversity @ 100%
Citation Count from Web of Science Web of Science 2
Downloads: Total: 2
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