The trophic and spatial ecology of stingrays at the St Joseph Atoll, Seychelles.

Globally very little information is available on the ecology of tropical stingrays. Several species, particularly, Himantura granulata, Urogymnus asperrimus and Pastinachus sephen are abundant in the St. Joseph Atoll (S 5°24.9'; E 53°17.9') on the Amirantes Bank, Republic of Seychelles, where it is hypothesized that they play a vital role in the ecosystem through linking trophic levels and affecting community structure through predation and bioturbation. This study aims to investigate aspects of the spatial and trophic ecology of stingrays at this remote atoll, where the proclamation of a no-take MPA is imminent. A combination of passive and active acoustic telemetry tracking will be employed to investigate both long-term and fine-scale movement patterns of these stingrays. To further understand the trophic role of these stingrays in the ecosystem, diet sampling will be conducted using gastric lavage to determine diet composition and tissue samples will be taken for stable isotopes analyses to determine long-term shifts in diet. Although the St. Joseph Atoll is relatively isolated from anthropogenic activities it is still impacted by global change and pollution. Anecdotal evidence suggests that stingray numbers have been subject to fluctuations and there has been an overall decline in abundance over the past two decades. It is thus important to better understand interactions between the dominant species and the role they play in atoll ecosystems. This project is funded by the Save Our Seas Foundation and supported by SAIAB and the D’Arros Research Centre

Supervisor: Prof Paul Cowley (SAIAB) Co-supervisor: Dr Rainer von Brandis (SOSF D’Arros) Research Centre)