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Marine Turtle Newsletter 116:25, © 2007

Marine Turtle Newsletter-Online

Discovery of a Gabonese Leatherback in South Africa

Jacques Fretey1, Alexis Billes2, Brent Baxter3 & Catherine Hughes3
1UICN-France, Muséum national d’Histoire naturelle, 26 rue Geoffroy Saint-Hilaire, 75005 Paris, France (E-mail: jfretey@imatech.fr)
2Programme Kudu, Cellule de coordination ECOFAC, BP 15115, Libreville, Gabon (E-mail: protomac_lbv@yahoo.ie)
3Golder Associates Africa Ltd, PO Box 6001, Halfway House, Midrand 1685, South Africa (E-mail: BBAxter@golder.co.za; chughes@golder.co.za)

An adult female leatherback (curved carapace length = 149.0 cm; curved carapace width = 113.0 cm) tagged with a monel flipper tag while nesting on February 23, 2005 at Pongara Point in Gabon (a few kilometers from the equator) was found stranded on August 21, 2005 along a rocky beach, approximately 3 km south of De Beers Namaqualand Mines village of Kleinzee (29° 42’ 44.4” S, 17° 03’ 33.1 E), on the west coast of South Africa. There was evidence of a deep cut just in front of the left rear flipper through which the turtle was partially disembowelled. There was no obvious evidence of scavenging on the carcass, and the cut may have been the result of a boat strike.

Billes et al. (2006) have described transatlantic movements of leatherbacks from nesting beaches in Gabon to South American waters (Argentina and Brazil). Georges et al. (in press) report that females nesting in southern Gabon move south towards the beaches of the National Park of Conkouati in the Congo during the inter-nesting period. This stranding is therefore the first evidence of a trans-African migration from a nesting beach near the equator towards the southern end of the continent where leatherbacks nesting on the Indian Ocean coast of South Africa are also some times known to migrate (Hughes 1998; Luschi et al. 2006). It should be noted that this movement from Gabon southwards goes against the flow of the cold Benguela current, so it is unlikely that the leatherback carcass drifted passively south with the currents to the South African coast. It is possible that a certain percentage of leatherbacks nesting on Central African beaches migrate towards South Africa to feed whereas others cross the Atlantic to South American waters to forage. More tracking studies are needed to elucidate post-nesting movements to develop appropriate management strategies away from the nesting beach where accidental captures in high seas fisheries (M. Honig & S. Peterson pers. comm., Billes et al. unpublished data) pose a major threat to their survival and to determine distinct migratory and foraging strategies within nesting populations.

Acknowledgements: Our thanks to Sharon Maree for having informed us about this stranded leatherback.

BILLES, A., J. FRETEY, B. VERHAGE, B. HUIJBREGTS, B. GIFFONI, L. PROSDOCIMI, D. A. ALBAREDA, J.-Y. GEORGES & M. TIWARI, 2006. First evidence of Leatherback Movement from Africa to South America. Marine Turtle Newsletter 111:13-14.

GEORGES, J.-Y., A. BILLES, S. FERRAROLI, J. FRETEY, D. GREMILLET, Y. LE MAHO, A.E. MYERS, H. TANAKA & G.C. HAYS. In press. Meta-analysis of movements in Atlantic leatherback turtles Dermochelys coriacea during nesting season. Marine Ecology Progress Series.

HUGHES, G.R., P. LUSCHI, R. MENCACCI & F. PAPI. 1998. The 7000-km oceanic journey of a leatherback turtle tracked by satellite. Journal of Experimental Marine Biology and Ecology 229: 209-217.

LUSCHI, P., J.R.E. LUTJEHARMS, P. LAMBARDI, R.MENCACCI, G.R. HUGHES & G.C. HAYS, 2006. A review of migratory behaviour of sea turtles off southeastern Africa. South African Journal of Science 102: 51-58.