No island in the world is as distant from a great continent as Rapa Nui. Its former inhabitants were aware of this, which is why they called it Tepito o Te Henua, the world’s belly button. This characteristic, along with its ancestral culture, gives the place a mysterious aura attracting tourists and scientists. Between 2011 and 2018 Oceana participated in five expeditions where one of the objectives was to investigate whether this ecosystem, in spite of it being so isolated, held any connection to other Polynesian areas or the Salas and Gómez Island.

Oceana’s first expedition to Rapa Nui took place with a National Geographic team. The objective was to provide a baseline of the Motu Motiro Hiva Marine Park ecosystems and compare them to Rapa Nuis which were not protected. In Rapa Nui, scientists were able to observe coral in good conditions, but low fish biomass and an absence of sharks, an outright indication that the ecosystem had been overexploited. The footage collected in this expedition was used to make the documentary “Lost sharks of Eastern Island”, which was broadcast by National Geographic.

Three years later a second expedition took place whose objective was to determine if the previous disturbing situation was happening at greater depths. The research was part of the Ecology and Sustainable Management of Oceanic Islands project, (ESMOI in Spanish) which seeks to create the necessary scientific foundation to strengthen a sustainable management and biodiversity conservation strategy for seamounts and oceanic islands of Chile. Using the remote operations vehicle, ROV, scientists of the Universidad Católica del Norte explored the Apolo seamount, a traditional fishing area of the Rapa Nui people.

An interesting piece of information came about from this investigation; it was confirmed that the small volcanic stones the Rapa Nui people had been using for generations to fish on that seamount, turned out to be the perfect substrate for sea whip coral. Along with this discovery, a large number of encrusting sponges and coralina algae were found at a depth of about 300 meters, alongside several never-before documented species in the region, such as the boarfish or antigonia capros, which had only been seen during incidental fishing or in Hawaii. Four potentially new species to science were recorded as well (Tosanoides sp. nov., Chromis sp. nov., Suezichthys sp, Parapercis sp.).

With ESMOI project scientists, exploration of the area’s seamounts continued in 2016, only this time they went a bit further reaching the Pukao, whose peak is located at a depth of 155 meters. An abundance of lobster and slipper lobsters could be seen among the rocks, as well as a large diversity of echinoderm species such as sea stars and sea urchins; among them, 15 species never-before documented in this eco region and at least two that were recognized as new. The presence of sea lilies and a soldierfish were seen for the very first time.

This exploratory journey confirmed that fish biomass was much greater than what was first thought in 2011, and because the same species were found in both areas, a connection could be established between island and seamount species. Researchers were also able to document the first sighting of a fish that belongs to the Ateleopodidae family on the Eastern side of the island. Called the jelly nose fish for its nearly transparent head, this species is hard to find. Only a dozen of them have been documented in the entire world. In addition, the first images of the deep benthic zone were documented.

Deep water research continued in 2018, reaching a depth of 350 meters. The entire East side of the island was documented, and research started on the West side, which concluded with a new expedition in early 2019.  On this occasion a pregnant female Hexanchus griseus shark was filmed for the first time, a solitary species that has six gills on each side of its head. In addition, seven years after Oceana’s initial expedition to Rapa Nui, the increase of coral reef sharks around the island was evident, due to conservation measures implemented in recent years.

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A high-latitude, mesophotic Cycloseris field at 85 m depth off Rapa Nui