Our oceans play a fundamental role in our lives, from generating the oxygen we breathe, helping regulate the climate, feeding millions of people, and being “home” to a variety of living creatures.
With more than 2,45 miles (4,000 kilometers) of coastline, Chile has naturally become a leader in marine conservation. In fact, it posseses the largest marine protected area of Latin America; known as the Rapa Nui Marine Protected Area, it encompasses 286,000 square miles (740,000 square km) of Pacific Ocean surrounding what is also known as Easter Island (or Isla de Pascu in Spanish). Located 2,299 miles (3,700 km) from the coast of continental Chile and relatively close to the East Pacific Rise, this area is famous for the carved moai – colossal statues – representing ancestors. “This marine reserve will have a huge global significance for the conservation of oceans and of indigenous people’s ways of life,” said Matt Rand, Director of Pew Bertarelli which campaigned for the park, in a statement.
It’s true! Not only is it helping preserve centuries-old cultural traditions, the park provides protection for a minimum of 142 endemic marine species, including 27 that are endangered. This Marine Protected Area for Multiple Uses (MPA) includes the Motu Motiro Hiva Marine Park (a large no-take marine area surrounding Salas y Gómez Islet) and is recognized for the high overall endemism levels of its coastal marine fishes.
The bluntnose sixgill shark (Hexanchus griseus) is a large deep-water shark with global, yet patchy, … [+]
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Oftentimes, however, our deep sea conservation is forgotten. “Undoubtedly, there is much effort (both economic and human resources) behind deep-sea research in Chile and in Latin America in general,” said marine biologist Dr. Rodolfo Edward Vögler Santos of the Interdisciplinary Center of Marine Sciences, México. “At the same time, I believe that research using remote equipment (such as ROVs) generates greater interest when stimulating results are carried out, such as those found in our research.”
It was in the deep sea that during surveys of the benthic habitats (164-1,115 feet/50-340 m depth) off Rapa Nui using a remotely operated vehicle (ROV), a particular deep sea shark was recorded for the first time in this region. At 1,050 ft (320 m) deep, over a predominantly sandy substrate, a male bluntnose sixgill shark (Hexanchus griseus) glided in front of the underwater cameras to the delight of scientists. “It was a very exciting surprise [when my team and I realized that we were seeing an animal for the first time in situ in Chile]. You’re always looking to find something amazing at those depths, but when it actually shows up it is very exciting. Especially when it comes to a large but rare species of deep-sea shark, such as the Bluntnose sixgill shark (Hexanchus griseus),” said Santos.
The bluntnose sixgill shark is a large deep-water shark with a patchy distribution worldwide in tropical, temperate, and boreal waters. Seen on the continental slope, shelf, seamounts, mid-ocean ridges, and occasionally inshore, they can get down to 8,169 feet (2,490 m) deep. The finding is especially exciting, as this predatory shark is listed as Near Threatened (NT) by the International Union of Conservation of Nature (IUCN), and is actually close to meeting “Vulnerable” criteria.
Hexanchus griseus is mainly a deep water shark, rarely found at depths of less than 100 m.
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Like many shark species, the threats these sixgills face are numerous. This species is infrequently reported as either targeted or incidental catch from industrial and artisanal demersal trawl, longline, handline, traps, and gillnet fisheries, yet their bycatch numbers are frequently unreported. “In central Chile, the species represented ~5% of bycatch from squat lobster fisheries on the benthic ecosystem,” state the authors of what is currently known for these animals. “Thus, our in situ observations constitute essential evidence to support management strategies that guarantee the protection of marine apex predators of the deep-waters and coastal ecosystems, and contributes relevant information for the ongoing construction of a management plan for the Rapa Nui MPA.”
Santos believes their research highlights the importance of properly managing the marine protected area (MPA) around Rapa Nui, which includes the Motu Motiro Hiva Marine Park (a 150,000km2 no-take marine area surrounding Salas y Gómez islet). He hopes this new find highlights the urgent need to better understand deep-sea ecosystems and the species that inhabit it: “We need to know what we must protect. The greater the number of people who find out about these realities, the greater the awareness that we must act to keep the planet healthy and consequently protect our own species. We need to become more aware that all the effects generated in our immediate environment (such as plastics contamination, domestic waste) can affect remote and fragile ecosystems such as Rapa Nui.”
