The Sharks of Saint Brandon
A note before the list. Saint Brandon’s reef and the deeper waters of its outer slope support a healthy elasmobranch community — elasmobranch is the umbrella term for sharks, rays, and skates. The 1997 World Bank transect surveys documented two shark species directly by name: the silvertip and the blacktip reef shark. The wider scientific and observational record at the atoll adds at least five more species, ranging from the small inshore patrollers of the lagoon to the larger pelagic species that pass through the deeper outer waters of the spur-and-groove zones. During preparation I was warned by multiple friends who are also very experienced skippers and fisherman, that there are many sharks and I should not attempt to surf at all, and that I should be careful when swimming and diving. For the record, there has never been a recorded shark attack on a human at Saint Brandon. The fly-fishing guides on Raphael wade these flats every day of the season. What follows is the working list as it stands. Where I encountered a species directly during the trip, I say so. Where the species is documented from scientific surveys or the fishermen’s working knowledge but I did not personally encounter it, I note that.
A note on shark conservation at Saint Brandon
Sharks at the atoll face two principal pressures. The first is global: the trade in shark fins, which has driven declines in nearly every commercially viable species across the Indian Ocean.
The second is local: bycatch in the line-and-trap fishery, where larger sharks taking baited hooks are sometimes killed rather than released. The 1998 World Bank Management Plan acknowledged shark mortality as a concern even within an otherwise low-impact fishery, and the Raphael Fishing Company’s catch-and-release fly-fishing operation has, in the years since, shifted considerable pressure off the species by replacing extractive tourism with observational tourism. The Saint Brandon Conservation Trust lists healthy elasmobranch populations as one of the atoll’s defining ecological features and a priority for monitoring.
The sharks I saw at Saint Brandon were not many. But the sharks I did see were calm, patrolling their reef structure without urgency, behaving like animals that have not learned to fear what comes from above. That is one of the things you do not get on a reef that has been heavily fished. It is one of the markers of how much of Saint Brandon has been kept.
Blacktip reef shark — Carcharhinus melanopterus
The most common shark of the Saint Brandon lagoons and reef flats. I encountered one while examining a rock in the shallow reef. It quickly approached me and turned away when I started kicking into the sand. Slender, brown-grey, with vivid black tips on every fin — particularly the first dorsal, which often shows above the surface as the shark patrols in less than a metre of water. Reaches around 1.6 metres. Lagoon-resident, rarely venturing into deep water. Visible from above to drone footage on a clear day. They are the shark you most often see on the flats while wading.
Whitetip reef shark — Triaenodon obesus
A small, slim, slate-grey shark with bright white tips on the dorsal fin and tail. The most common shark of the Saint Brandon reef-terrace and the deeper sections of the lagoon. Patrols the spur-and-groove channels in small groups during the day, often resting on the bottom; hunts more actively at night. Not generally aggressive to people. Reaches around 1.6 metres. My field notes record several sightings on the bottom near the Tigoulou anchored in twelve metres off South Island.
Grey reef shark — Carcharhinus amblyrhynchos
Heavier-bodied than the white-tip, with a dark trailing edge on the tail and a more pronounced dorsal fin. Patrols the deeper reef structures, especially the western reef wall and the outer edges of the passes. Reaches around two metres. Encountered by us at Sharks Point, off the eastern reef edge near South Island. They are the species the fishermen most often refer to when they speak of reef shark in the singular.
Silvertip shark — Carcharhinus albimarginatus
Larger and more pelagic than the other Carcharhinids — a powerful reef-associated species with brilliant white edges along the trailing margins of all the fins. Documented in the 1997 World Bank transect surveys at Saint Brandon. Reaches three metres. Inhabits the deeper outer reef slope, dropping into open water below forty metres. More commonly seen by divers and by the deep-water fly-fishing boats. The species is in steep global decline and is listed as Vulnerable on the IUCN Red List.
Sicklefin lemon shark — Negaprion acutidens
A large, yellow-brown shark with a broad blunt snout, frequenting the shallow flats and lagoon entrances of Indo-Pacific atolls. Documented from the western Indian Ocean region including the Seychelles and Chagos archipelagos and reported by Saint Brandon fly-fishing guides as a flats species. Reaches 3.8 metres. Listed as Endangered on the IUCN Red List.
Tiger shark — Galeocerdo cuvier
A large, broadly distributed pelagic predator that ranges through the outer waters of the Saint Brandon atoll. The fishermen and the fly-fishing guides occasionally encounter tigers cruising the outer reef edges. The species is the largest shark routinely present at the atoll, reaching five and a half metres. They do not typically enter the shallow lagoons but are part of the deeper marine community surrounding the reef.
Bull shark — Carcharhinus leucas
A wide-ranging coastal shark documented from Mauritian waters generally. Encountered occasionally at the outer reef edges of Saint Brandon. Less common in the shallow lagoons than at the deeper passes. Capable of tolerating brackish water and known elsewhere for entering rivers and lagoon systems. Reaches around three metres.
Scalloped hammerhead — Sphyrna lewini
A seasonal visitor to the deeper offshore waters of the Mascarene region, occasionally observed at the outer reef slope of Saint Brandon during periods when their schooling migrations bring them through. Recognisable from any angle by the distinctive scalloped front edge of the broad head. Listed as Critically Endangered on the IUCN Red List. Their presence at Saint Brandon is not consistent enough to call them resident.
Whale shark — Rhincodon typus
The largest fish in the sea. A seasonal pelagic visitor to the deeper waters around the Mascarene Plateau. Occasionally sighted off the outer reef of Saint Brandon during the warmer months when plankton density rises. They do not enter the shallow lagoons. Reaches twelve metres and beyond. Listed as Endangered on the IUCN Red List. An encounter is rare. A confirmed sighting is the kind of story the fishermen still talk about.