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ESR prepress abstract   -  DOI: https://doi.org/10.3354/esr01061

Dugong (Dugong dugon) movements and habitat use in a coral reef lagoonal ecosystem

Christophe Cleguer*, Claire Garrigue, Helene Marsh

*Corresponding author:

ABSTRACT: Little is known about how the Vulnerable dugong Dugong dugon uses coral reef lagoons despite their being important habitats throughout much of its vast range. We used GPS-satellite tracking systems to explore the space use of 12 dugongs at 3 localities in the coral reef lagoons of the main island of New Caledonia in the southwest Pacific: Cap Goulvain, Ouano and Nouméa. The movements of the tracked dugongs were individualistic and all except one animal undertook large-scale movements (>15 km; mean 37.7 km ± SE = 5.2) from their capture location (maximum waterway distance range: 13.8 to 72.9 km). The straight-line distances across furthest GPS locations during each animal’s tracking period ranged between 21.3 and 74.5 km. We identified areas used intensively by 10 of the 12 tracked dugongs in all 3 study locations, some of which were areas where seagrass presence has not been verified, or where dugongs have not been observed during past aerial surveys. Dugongs spent most of their tracking time within the lagoons with 99.4% of GPS locations found inside the barrier reef. Nonetheless, where the lagoon is narrow and confined, 3 tracked dugongs used the fore reef shelf outside of the barrier reef in the open ocean to commute between bays. Our findings can inform conservation and management initiatives in New Caledonia as well as other countries within the dugong’s range with similar habitat geomorphology but where dugongs occur in numbers too low to be tracked and are considered Critically Endangered.