Emperor Seamounts

Salas y Gómez and Nazca ridges

Imagine a mountain range the length of the southern Andes –110 volcanic peaks, stretching nearly 3,000 km end to end. Imagine these mountains are filled with rare, spectacular wildlife, that nearly half the species they shelter live nowhere else on Earth, and that scientists are discovering new life forms with every expedition.

Now stop imagining, because these mountains are real: they’re called the Salas y Gómez and Nazca ridges, and are deep in the waters of the South East Pacific.

These two unique chains of submarine slopes and summits areseparated from South America by the rich, cold waters of the Humboldt Currentand the yawning abyss of the Atacama Trench. Numerous studies have concluded they’reamong the most ecologically significant areas in the high seas – those areas ofthe ocean that lie beyond the jurisdiction of any country. Far below the waves intricategardens of slow-growing corals and gorgonians adorn the rocky slopes in some ofthe clearest waters on the planet, and in the plankton-abundant upwellings overthe ridges sharks, turtles, whales and seabirds gather to forage. This uniqueregion is a vital habitat for commercial species too, from swordfish to jackmackerel, underpinning sustainable food security for millions – but only if welook after it.

Threats and the future

The Salas y Gómez and Nazca ridges are still largely ecologically intact, but biodiversity and ecosystem resilience are never the less under threat. Deep-water trawling has destroyed coral and seabed habitats down to depths of 2,000 m, and has taken a heavy toll in bycatch of animals and plant life alike. Floating plastic debris drives the risk of ingestion and entanglement for nearly 100 species. Meanwhile climate change is making the seas warmer, less oxygenated and more acidic, all of which pose an existential threat to marine biodiversity .

Ominously, there’s cobalt in the crusts of the Salas y Gómezand Nazca ridges, which the deep-sea mining lobby may one day step up effortsto exploit – but doing so would be an ecological disaster.

We’ve got a time-sensitive window of opportunity. By permanently closing the area to fishing and mining and establishing a high seas MPA, we can save the Salas y Gómez and Nazca ridges for ourselves and for future generations. And with 80% of the mountains still unexplored, there’s surely so much more for them to discover…

Back to the surface

Currently, no legal mechanism exists to establish comprehensive marine protected areas (MPAs) in the high seas. It is critical that the new United Nations High Seas Treaty, currently under negotiation, sets up a global process for the establishment and effective management of a network of representative and well-connected MPAs in the high seas, including highly and fully protected areas where no harmful industrial activities are allowed.

People might not think of the Hawaiian Islands as part of a vast underwater mountain range, but in a manner of speaking that’s what they are – the unsubmerged parts of the mountain range. Extending across over 2,000 km of seafloor between the north westernmost point of the Hawaiian Islands and the Kuril-Kamchatka Trench lies a chain of more than 80 underwater mountains - the Emperor Seamounts. Nine of the peaks of the seamounts bear the names of revered Japanese rulers from the last two millennia, an appropriate symbol of their imperial majesty.

The nutrient-rich waters of the Emperor Seamounts support vast biodiversity. Tunas and whales swim above their summits, and the skies are filled with seabirds. The world’s oldest known wild bird, an albatross named Wisdom, has been foraging in the area for at least the last 70 years. Longevity is a theme below the waves too – a hugely varied array of cold-water corals have formed most of the complex sea-floor habitats along the mountain chain, slowly growing millimetres each year. Among these, black corals are some of the oldest animals on Earth – there are colonies on the Emperor Seamounts which date back an astonishing 4,200 years. Among the deep-water habitats, diverse corals and sponges make beautiful forests of fans, trees, whips and other forms, providing shelter for countless fish species and a high number of invertebrates.

In the North Pacific, the Emperor Seamounts are an artery of biodiversity cutting across the often featureless deep sea. Scientists believe that these underwater mountains act like stepping stones for a multitude of marine animals, with each unique seamount acting as a staging post that affects how species are distributed and allowing gene flow to occur across vastly separated populations.

Threats and the future

In ecological terms, the Emperor Seamounts have paid heavily for the rich life they support. Between the 1960s and the 1970s they provided the highest takes of any seamount fisheries in the world, with more than 200,000 tonnes of fish and coral alike removed in peak years. Today, precious coral skeletons can sell for up to $880/kg for use in jewelry and other industries.

The US has taken the lead by protecting the seamounts which fall within its EEZ, and there are already encouraging signs of recovery of coral colonies in previously trawled areas – but it’s the remaining areas that most need our immediate action to protect.

The World Congress on Protected Areas and many others have called for the Emperor Seamounts to receive priority protection. By permanently closing the area to fishing and establishing a high seas MPA through a new UN High Seas Treaty, we can save the Emperor Seamounts for ourselves and for future generations. Because this unique and special place is a global common, we can only effectively protect this area for ourselves and future generations through an international treaty.