Deep-sea biodiversity at the extremes of the Salas y Gómez and Nazca ridges with implications for conservation

marine biodiversity [27, 29, 40, 41] (Fig 1). Despite its significance, there have been limited explorations of this region, especially in the deep sea, a pattern that is also evident for isolated islands globally [42–44] and in Pacific deep waters [45, 46]. The few deep-sea explorations along the Salas y Go´mez Ridge have documented many species new to science (e.g., [47–49]). One campaign surveyed different seamounts across the ridge and found that the fauna on every seamount has a unique community composition, with nearly complete species turnover between opposite ends of the ridge [50]. Because of the high rate of species discoveries and uniqueness within and among seamounts, the marine fauna of this region likely contains numerous undiscovered species, providing an enormous opportunity for marine biodiversity research and high conservation value [51–53]. An expedition to Rapa Nui (i.e., Easter Island) and Salas y Go´mez Island was conducted by the National Geographic Society’s Pristine Seas in February–March 2011 to provide a baseline assessment of the marine ecosystem at 75–2,363 m (Fig 1, [54]). In February and March 2013, National Geographic Society’s Pristine Seas also led an expedition to the Desventuradas Fig 1. Deep-sea camera system deployments on the Salas y Go´mez and Nazca ridges. Dotted lines depict exclusive economic zones (EEZs). Red dots depict camera deployment sites. Bathymetric data source: GEBCO Compilation Group (2020) GEBCO 2020 Grid (doi:10.5285/a29c5465-b138-234de053-6c86abc040b9). https://doi.org/10.1371/journal.pone.0253213.g001 PLOS ONE

Deep-sea biodiversity along the Salas y Go´ mez and Nazca ridges PLOS ONE | https://doi.org/10.1371/journal.pone.0253213 June 30, 2021 3 / 27