More than a thousand kilometres east of Africa, nestled within the vast Indian Ocean, lies a scattered archipelago of granitic islands and coral atolls: the Seychelles. The first recorded landing on the islands was in 1609 by the East India Company, passing by on international trade routes. Back then, the islands must have felt prehistoric, a primordial crucible boiling with life and ruled by ancient leviathans. Giant tortoises ambled across the rugged, harsh terrain and crocodiles lurked in the turbid coastal waters. Even dugongs, the alleged inspiration for mermaids among weary sailors, frequented the mangrove-fringed shallows. Early anecdotes refer to an abundance of large sharks; fishermen were stalked by hammerheads in the harbour, the burgeoning local turtle population was persistently harassed by hungry tiger sharks, and even great whites patrolled the inky depths.
But such abundant life has proved ephemeral in the wake of human settlement. Demand for meat from locals and passing traders has reduced the Seychelles’ wildlife to a whispering shade of its former glory: crocodiles are now locally extinct, tortoises survive in only a few isolated spots and dugong sightings compete with a blue moon for frequency. Turtles were also hit hard, vanishing quickly as their meat and eggs were celebrated as local delicacies. But they were afforded full protection in 1994 and now the Seychelles once again hosts some of the largest turtle populations in the Indo-Pacific.
Sharks, however, have received no such reprieve. Traditional fisheries persist, supplying local demand for shark curries and chutneys, and their activities are exacerbated by increasing shark finning that supplies markets in the Far East. The information available suggests catastrophic declines in shark numbers, with larger species proving increasingly rare – the last recorded sighting of a white shark was more than 50 years ago. Without some sanctuary, the outlook is bleak for sharks in the Seychelles.
Yet all is not lost. Some refuges remain, providing piercing glimmers of hope for a broader recovery. One is the World Heritage Site of Aldabra, a large, isolated atoll that is protected from all fishing. It harbours an abundance of sharks, turtles, tortoises – and the last remaining dugongs in the Seychelles. Another is the comparatively small island of D’Arros and the associated atoll St Joseph in the Amirantes. St Joseph contains a shallow lagoon, no more than a few kilometres long, that can be accessed only at high tide. Although modest in size, such an access-restricted lagoon is rare and critical habitat in the Seychelles, providing sanctuary to a whole variety of sharks, turtles and rays, among other marine creatures.
Unfortunately, D’Arros and St Joseph do not enjoy the luxury of protection that Aldabra does, and they continue to suffer fishing pressure. Although the occurrences are uncommon, boats have been recorded finning sharks even within the inner sanctum of the lagoon. This is a grave concern, as predators like sharks are highly valuable not only for ecosystem stability, but also commercially, in fisheries and tourism. Losing predators from an ecosystem can have devastating, unpredictable consequences on community structure, as prey species are released from both the pressure and the risk of predation. In order to appreciate the true value of D’Arros and St Joseph and how to best manage their biological wealth, it is first necessary to understand the behaviour and ecology of their inhabitants.
A biological field station based on D’Arros Island in the Amirantes Group, Seychelles, the SOSF D’Arros Research Centre (SOSF–DRC) conducts research on the pristine D’Arros Island and St Joseph Atoll and the waters around them. In recognition of the islands’ outstanding natural values, the research centre was established in 2004 and tasked with becoming a regional centre of excellence for marine and tropical island conservation. Initially, collaborations were established with local and international institutions and baseline ecological surveys were conducted in the various habitats. Over the ensuing years an increasing number of research projects and monitoring programmes were implemented in response to questions raised by the baseline surveys and by visiting scientists. More recently, the centre expanded its activities to include ecosystem restoration and environmental education.
Today the SOSF–DRC boasts the longest-running nesting turtle monitoring programme in the Amirantes and the most detailed and technically advanced coral reef monitoring programme in the Seychelles, making use of techniques such as stereo-video photogrammetry, photoquadrats, remote underwater video systems (BRUVs) and visual census. The research centre also maintains the largest acoustic receiver array in the Seychelles, which monitors the local movements of sharks, manta rays, stingrays, turtles and fish. Since its inception in 2004, the centre has initiated no fewer than 36 research projects in collaboration with more than 26 conservation institutions. The projects have resulted in 10 peer-reviewed scientific papers, one PhD and one MSc dissertation, five conference presentations and 27 scientific reports.