Every summer in the Southern Hemisphere, during the full moon, female hammerhead sharks mysteriously gather around the coral islands of French Polynesia.
Scientists playfully refer to this as the “Female Hammerhead Conference”, which usually takes place from December to March in the area between the two coral islands of Tikehau and Rangiroa in French Polynesia.
Many female hammerhead sharks have mysteriously gathered in the area between the coral islands of Tikehau and Rangiroa, French Polynesia – (Photo: GETTY)
Each summer, scientists observe 54 large female hammerhead sharks in the coral islands, and they also note one individual whose sex cannot be definitively determined, according to Live Science.
At Rangiroa Atoll, these females concentrate in a location known as “Hammerhead Plateau”, at depths of around 45 to 60 meters. More than half of the sharks are seasonal residents, meaning they stay there for 6 days each month, and for up to 5 months overall.
According to scientists, they swim independently from each other and may not have any relationships among themselves; they seem to be attracted to the islands by external factors, seemingly related to the lunar cycle.
Hammerhead sharks – (Photo: The Sun/MPS/THOMAS PAVY).
Researchers believe that the number of female hammerhead sharks peaks during the full moon in summer, possibly because the bright moon enhances their hunting capabilities around the coral islands at night.
The timing of the hammerhead shark congregation coincides with a large influx of white-spotted eagle rays (Aetobatus ocellatus) entering the lagoon to spawn. The hammerheads prey on these rays.
Warm, protected lagoons and coastal waters are also breeding grounds for various shark species, and scientists are conducting further investigations to determine whether the coral islands of Rangiroa and Tikehau are breeding sites for great hammerhead sharks, a species that is at very high risk of extinction.
These findings have been published in the journal Frontiers in Marine Science.
