Long-Term Monitoring of Green Turtle Nesting on Tromelin Island Demonstrates Stable Reproduction and Population Parameters
|Author(s)||Derville Solene1, 2, Jean Claire2, Dalleau Mayeul2, Le Gal Jean-Yves3, Ciccione Stephane2, Bourjea Jerome4, 5|
|Affiliation(s)||1 : Univ Lyon, UCB Lyon1, Ecole Normale Super Lyon, Dept Biol, Lyon, France.
2 : Kelonia, Observ Tortues Marines La Reunion, St Leu 97436, Reunion.
3 : ENSAgro, F-35042 Rennes, France.
4 : IFREMER, Delegat Ocean Indien, Le Port 97822, Reunion.
5 : Univ Reunion Isl, CNRS, INEE FRE3560, St Denis 97715, Reunion.
|Source||Chelonian Conservation And Biology (1071-8443) (Chelonian Research Foundation), 2015-06 , Vol. 14 , N. 1 , P. 11-20|
|WOS© Times Cited||8|
|Keyword(s)||Reptilia, Testudines: Cheloniidae, Chelonia mydas, green turtle, nesting activity, population assessment, Indian Ocean, Tromelin Island|
|Abstract||Situated about 500 km off the Malagasy east coast, the island of Tromelin is a key nesting site for the endangered green turtle, Chelonia mydas, in the south Western Indian Ocean. Nesting turtles found in this isolated island have been closely monitored since the 1970s, but the most recent estimates of nesting parameters date from 1986. Using mark-recapture data, track counts, and nests monitoring data collected over the 2009/2010 nesting peak, reproductive characteristics, population size, and offspring production were updated and discussed in the light of the track survey undertaken from 1986 to 2010. Females showed a consistent reproductive behaviour compared with previous studies in terms of clutch frequency (2.75 +/- 1.46) and nesting success (0.65). Nest indices such as hatching success (0.76 +/- 0.25) and emergence success (0.61 +/- 0.33) were also included in the range of values calculated in the 1980s. Importantly, the estimated number of nesters and production in eggs and hatchlings were similar to older estimates, suggesting a relative demographic stability. For the 2009/2010 year-long nesting season, the size of the nesting population was estimated at about 1500 individuals, which produced around 480,900 eggs (+/- 103,900), resulting in 289,200 emerging hatchlings (+/- 152,000). These results are promising and support the effectiveness of conservation measures undertaken in the Iles Eparses, but further comparable monitoring is needed in the coming years to confirm the stability in Tromelin's green turtle nesting population.|