MTN 117:9 First Records of Olive Ridley Turtles (<i>Lepidochelys</i> <i>olivacea</i>) in Seychelles

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First Records of Olive Ridley Turtles (Lepidochelys olivacea) in Seychelles

Selby Remie¹ & Jeanne A. Mortimer^2,3
¹Director of Conservation, Department of Environment, Seychelles MENR, P.O. Box 445, Victoria, Mahe, Seychelles
²Island Conservation Society - ICS, P.O. Box 775, Victoria, Mahe, Seychelles
³Department of Zoology, University of Florida, Gainesville, Florida, USA (E-mail: mortimer@ufl.edu)

The first ever recorded occurrence of the olive ridley turtle (Lepidochelys olivacea) in Seychelles waters was made on 12 September 2006, followed by a second record less than eight months later on 4 May 2007. Both were juveniles. The first was documented by a team from the Conservation Division of the Seychelles Ministry of Environment and Natural Resources (MENR) who were called in to examine a dead turtle floating in the Victoria harbour of north east Mahe at the Inter-Island Quay, in the vicinity of the Industrial Fishing Port where tuna fishing vessels come to unload their catch. Its carapace measured 33.2 cm notch-to-tip (CCLn-t) and it was badly decomposed making it difficult to identify. Based on photographs, JAM identified it as an olive ridley, and this was confirmed by Pam Plotkin, Alberto Abreu-Grobois, and Peter Pritchard (pers. comm. to JAM). Photos of this turtle can be seen here: <https://seaturtle.org/cgi-bin/imagelib/index.pl?cat=500&si=remie&stype=1&thumb=1>

The second record was reported on 4 May 2007 by Elke Talma of the Marine Conservation Society of Seychelles (MCSS) who was called out to rescue a live turtle that had washed ashore in north west Mahe tangled in marine debris and with a gangrenous front flipper (MCSS 2007). It measured 34 cm (CCLn-t) carapace length, and was photographed and later identified as an olive ridley by Michael Coyne and Brendan Godley (pers. comm. to MCSS). It unfortunately lost its flipper on the spot; but after being disentangled, was released in apparently otherwise good condition (MCSS 2007).

The obvious question is why two records of this species would be reported within such a relatively short time after never having been recorded previously (Frazier 1984; Mortimer 1984), despite a very active turtle monitoring and conservation programme ongoing in Seychelles since 1995 (Mortimer 2000). When the first specimen was retrieved dead in the harbour, we considered the possibility that it represented by-catch discarded by purse seiners, which are known to occasionally capture small turtles (Domingue & Mortimer 2001). The second turtle, found alive, albeit entangled in debris, implicates marine pollution.

The olive ridley nests along the African and Indian coastlines (Frazier 1984), so its occurrence in Seychelles waters is not unexpected. Maybe under normal circumstances its pelagic lifestyle and relatively small size make it inconspicuous to human observers. But, both individuals reported here appear to have suffered traumatic events, perhaps associated with some combination of by-catch, ghost fishing, and extreme weather systems. This begs the question as to whether such events have increased in frequency. One might also consider the theory that climate change is affecting the current systems of the Indian Ocean, causing them to carry members of this species into waters where they previously did not occur (MCSS 2007). But the lack of supporting evidence for that theory indicates a need for further investigation.

DOMINGUE, J. & J.A. MORTIMER. 2001. The impact of commercial fisheries on turtles in Seychelles. Pp. 80-81. In: Ciccione, S., D. Roos & J-Y. Le Gall (Eds) Proceedings of Connaissance et Conservation des Tortues Marines du Sud-Ouest de l’Ocean Indien. Etudes et Colloques du CEDTM No 01.

FRAZIER, J. 1984. Marine turtles in the Seychelles and adjacent territories. In: Stoddart, D.R. (Ed.). Biogeography and Ecology of the Seychelles Islands. Monographiae Biologicae 55: 417-468.

MCSS. 2007. Rare species of marine turtle found in Seychelles. Marine Conservation News 5: 1.

MORTIMER, J.A. 1984. Marine Turtles in the Republic of Seychelles: Status and Management. IUCN, Gland, Switzerland. 80 pp.

MORTIMER, J.A. 2000. Sea turtles in the Republic of Seychelles: an emerging conservation success story. In Abreu-Grobois, F.A., R. Briseño-Dueñas, R. Marquez & L. Sarti (Comps.). Proceedings of the 18th Annual Sea Turtle Symposium. NOAA Tech. Memo. NMFS-SEFSC-436, pp. 24-27.