Abstract
Data concerning 212 turtles emerging on the southwest beaches of Mahe Island in the Seychelles were collected in 2017 and 2018. These data were used to model the probability of eggs being laid in relation to several variables. The probability of successful laying after emergence was highest on certain beaches and in areas of short vegetation, between open sand and trees. We found successful laying was related to the physical properties of the soil, indicating that survivability of embryos and hatchlings is higher in certain areas. The turtles appeared to choose zones where soil had low salinity, good drainage but ability to retain water, and absence of spring tides and extreme temperatures.
Highlights
The Seychelles comprise around 150 granitic and coralline islands, believed to have been formed from the breakup of the supercontinent Gondwanaland in the Pre–cambric (Salm, 1978)
The two types of prevailing soil are the ferrolithic of granitic weathering origin with clay rich A and B horizons and a fine texture, and the calcareous coarse sands areas close to the sea (Government of Seychelles, 2006)
Overexploitation of turtle and chelonian products in the Seychelle Islands contributed to the decline of sea turtles
Summary
The Seychelles comprise around 150 granitic and coralline islands, believed to have been formed from the breakup of the supercontinent Gondwanaland in the Pre–cambric (Salm, 1978). Mahe is the main island, located in the centre of a granitic group and characterised by a very narrow coastal plateau of calcareous reef materials building up as sand dunes and pocket beaches known as 'anse'. The two types of prevailing soil are the ferrolithic of granitic weathering origin with clay rich A and B horizons and a fine texture, and the calcareous coarse sands areas close to the sea (Government of Seychelles, 2006). Since the early 1970s, positive measures of protection have led to the recovery of the main species of sea turtles in the archipelago: the green turtle (Chelonia mydas L.) and the hawksbill turtle (Eretmochelys imbricata L.) (Frazier, 1974). Worldwide, green and hawksbill turtles are listed as endangered and critically endangered, respectively, by the International Union for Conservation of Nature Red List of Threatened Species since 1996 (IUCN, 2015)
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