Hammerhead Sharks in Mauritius

The scalloped hammerhead shark (Sphyrna lewini) is one of the most recognisable and awe-inspiring sharks in the ocean. Named after the distinctive hammer-shaped head — known as a cephalofoil — this species uses its unique anatomy to enhance sensory perception, detect prey buried in sand, and manoeuvre with surprising agility. In Mauritius, encounters with hammerheads rank among the most sought-after wildlife experiences in the Indian Ocean.

Why Mauritius Attracts Hammerhead Sharks

Mauritius sits within a highly productive zone of the Indian Ocean, surrounded by deep oceanic trenches, underwater ridges, and seamounts that serve as navigation waypoints for pelagic species. The island's offshore drop-offs — particularly those on the north and east coasts — funnel nutrient-rich currents upward, supporting the food chains that attract large predators including hammerheads. These sharks are often encountered at depth, circling seamounts or cruising along steep walls where reef fish and cephalopods are abundant.

Unlike many tropical destinations where hammerheads appear sporadically, Mauritius sees relatively consistent seasonal aggregations, particularly during the cooler months when water temperatures dip slightly and upwellings intensify. Scalloped hammerheads are known to form schools — sometimes numbering in the dozens — making group sightings possible for lucky divers on liveaboard or day boat excursions to the right sites.

Identifying Sphyrna lewini

The scalloped hammerhead is distinguished from other hammerhead species by the scalloped indentations along the front edge of its cephalofoil. Adults typically reach 2.5 to 3.5 metres in length, though larger individuals have been recorded. Their colouration ranges from olive-grey to brownish on the dorsal surface, fading to white on the underside. The tips of the pectoral fins often display a subtle dusky marking. In Mauritius, divers most frequently encounter juveniles and sub-adults at shallower sites, while larger adults tend to inhabit deeper offshore waters.

Best Dive Experiences

Hammerhead sightings in Mauritius are not guaranteed — this is wild ocean diving at its finest. The best encounters typically occur during early morning dives when sharks are most active and before boat traffic disturbs the water. Staying neutrally buoyant, minimising movement, and descending slowly without creating bubbles increases the likelihood of a prolonged sighting. Many operators recommend blue-water drift dives along offshore walls or seamount pinnacles where hammerheads patrol in the mid-water column.

Experienced dive guides play a crucial role in positioning divers correctly relative to current and depth. Hammerheads are notoriously skittish and will retreat from excessive noise, erratic movement, or large groups of divers. Small group sizes — ideally four to six divers — significantly improve encounter quality and duration.

Conservation Status and Threats

The scalloped hammerhead is classified as Critically Endangered on the IUCN Red List, having suffered dramatic population declines globally due to targeted fishing for the shark fin trade, bycatch in tuna longlines, and habitat degradation. Their slow reproductive rate — giving birth to live young after a gestation period of around nine to ten months — means populations recover extremely slowly from overfishing pressure. In Mauritius, while shark fishing regulations exist, enforcement at sea remains challenging, and the species continues to face pressure across the broader Indian Ocean.

Responsible dive operators in Mauritius actively support citizen science initiatives, encouraging divers to photograph and report hammerhead sightings to regional shark monitoring databases. Every image contributes to understanding migration patterns and population health. Choosing operators committed to no-touch, no-chase diving practices is not only ethically sound — it ensures the experience remains sustainable for future generations of divers.

Tips for Divers

• Book with operators specialising in pelagic and shark diving who know the offshore sites.
• Dive early morning for the best chances of undisturbed encounters.
• Wear dark or muted wetsuits — bright colours can startle wary sharks.
• Maintain depth control and avoid silhouetting yourself against the surface.
• Bring a wide-angle lens for underwater photography — hammerheads often appear at distance first.