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.
This fish is endemic to the corals that surround Rapa Nui, where it can be found at a depth range between 1 to 18 meters. During the day, they hide from predators in caverns and coral reefs.
A sunset at Tahai archaeological complex in Rapa Nui is the island’s signature postcard. This is one of the oldest settlements near the town of Hanga Roa. The beautiful afternoon colors contrast with the dark silhouettes of the moais.
This fish in particular can blow up its body, raising long spines, when it feels threatened. It is nocturnal and can be found in coral reefs at a depth of up to 100 meters.
This carnivorous fish has a long, compact body, and it feeds on fish, crustaceans and mollusks. It can be seen in shallow waters, hiding in the cracks of rock formations. Its sharp teeth can be seen in the picture.
A lot of intertidal pools can be seen surrounding the island. Although not perceivable in plain sight, these pools form habitats for many species.
Beautiful coral reefs could be seen during diving expeditions; divers expected to find them teeming with fish, but that was not the case. The number of fish found in deep water diving was very low.
This is an endangered species according to the International Union for Conservation of Nature (IUCN), due to the degradation of its habitat, bycatch and because its meat and eggs have been used for human consumption. Therefore, registering a specimen always brings great joy.
This crab is endemic to Rapa Nui; its body size is three centimeters. It can be seen crawling on corals and rocky substrate.
This curious fish lives at a depth range of 8 and 50 meters. It is easily recognizable due to small horns over each eye. Males can measure up to 38 centimeters long. This fish is not edible because its flesh is poisonous to humans.
Not only the size of these corals impresses divers, but also that many of them are in very good conservation condition. However, the number of fish living in them is very low; like having large empty homes.
These fish can commonly be seen swimming in groups, coordinately dragging their chins over the sand, passing each other as in a formation. They can measure up to 38 centimeters and inhabit a depth range of 1 and 130 meters.
This turtle species shell measures up to 120 centimeters long and weighs up to 230 kilos. It’s mainly herbivorous, feeding on algae and grass. It is estimated that it lives in 140 countries and can be seen swimming alongside boats and bathers in the area of Hanga Roa Otai cove.
This is the first record of this species in Rapa Nui and its surroundings. It was sighted in the Pukao seamount at a depth of 280 meters.
Aggregations of can form dense forests, which play a very important role as refuge for young coastal fish of the island. The image, taken at a depth of 200 meters, shows a sea cucumber and a sea urchin in the background, both frequent inhabitants of these sandy floors.
This is the first record of feather stars in the Rapa Nui ecoregion. This is an echinoderm of the class Crinoidea, shot at a depth of 240 meters in the Pukao seamount.
This image shows a prawn living inside a rock, besides a sea anemone. Both species benefit each other: the sea anemone’s venomous tentacles protect the prawn from predators, while the prawn feeds itself by cleaning the sea anemone’s tentacles. The photograph was taken by the ROV main camera’s zoom, while filming 240 deep in the Pukao seamount.
This species, similar to a manta ray, is known as a jelly nose fishfor its nearly transparent head. It belongs to the Ateleopodidae family, of which only 12 species exist in the world. This specimen was documented at a depth of more than 200 meters and is probably a new species.
This image of a pregnant female shark is the first record of this shark species in the island, whose distinctive feature is that it has six gills, unlike other sharks who have five. This image was taken at a depth of 345 meters.