The Hawksbill Turtle Season Begins…

When Denis De Trobriand discovered Denis in 1773 he described turtles as abundant in the waters around the island. Two species of turtle are still to be found nesting on Denis today – if in much reduced numbers from the abundant days of De Trobriand.

The Green turtle (Chelonia mydas) nests on Denis in small numbers year round with a peak of activity in April through June. The Hawksbill turtle (Eretmochelys imbricata) has a much more distinct nesting season (October – February) which is now commencing on Denis.

The hawksbill is classified as critically endangered by the World Conservation Union and Seychelles is one of the best five remaining locations in the world for the species (Meylan & Donnelly 1999).

Threatened by hunting for its shell (known as tortoiseshell) and loss of habitat – most critically nesting habitat – the hawksbill has received full protection under the law in Seychelles since 1994. Despite the success of certain protected area nesting sites the overall population has continued to decline (Mortimer 2004) with loss of nesting habitat to tourism development and activity being considered the primary ongoing problem.

Denis Island is member of the “Turtle Action Group Seychelles” (TAGS) which is a newly-formed association of some 14 agencies that manage turtle rookeries (nesting areas). As a requirement of its membership Denis must collect information on its nesting turtle populations and submit it to a national stakeholder database operated by TAGS. Data has been collected in the past on nesting turtles but limited human capacity has and continues to be the primary constraint to the consistent collection of standardised data. During the peak of the season thorough monitoring on Denis would entail at least two people working full-time. It is hoped that for season commencing in 2009 that designated accommodation will be available on the island to enable basic but thorough data collection to be undertaken by volunteers.

In the meantime however efforts will be made to gather the most basic form of data through the counting of tracks on the beach. Although turtles by no means nest successfully every time they come ashore the body of work by Dr Jeanne Mortimer has enabled a ratio of beachings per nest to be established for the Seychelles hawksbill population and this can be used to estimate the number of females actually nesting on Denis.

I will in due course periodically report on the progress of the season and set this in the context of management measures. This information will help guide management activity on the island and identify issues to be mitigated in order to optimise the breeding success of the hawksbill rookery on Denis. So check back regularly for news on the season as it progresses!

Meylan, A.B. & Donnelly, M. (1999). Status and justification for listing the hawksbill turtle (Eretmochelys imbricata) as Critically Endanagered on the 1996 IUCN Red List of Threatened animals. Chelonian Conserbvation and Biology 3 (2): 200 – 224.
Mortimer, J.A. 2004. Seychelles Marine Ecosystem Management Project (SEYMEMP): Turtle Component. Final Report. Vol 1: Text, 243 pages. Vol 2: Appendix 1-11, 158 pages.