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Ecologically or Biologically Significant Areas (EBSAs)

  published:09 Feb 2017

Dorsal de Nazca y de Salas y Gómez (Salas y Gómez and Nazca Ridges)

General Information
The area is a biological hotspot, with one of the highest levels of marine biological endemism (41.2% in fishes and 46.3% in invertebrates) in the world. It is considered a stepping stone for some marine mammals (e.g., blue whale), and it has been identified as a foraging area for leatherback turtle. In addition, it has been described as a recruitment and nursery area for swordfish and a breeding zone for Chilean jack mackerel, an overexploited species. **Peru plans to undertake additional scientific and technical analysis of this area with a view to identifying this area as meeting the EBSA criteria and as applicable, to make this information available once the analysis is completed and subject to the adoption of a national position in this respect.**
The area proposed covers pelagic through hadal depth zones in the Salas y Gómez and Nazca submarine ridges, which are two sequential chains of submarine mountains of volcanic origin located in the Southeastern Pacific Ocean, jointly extending over 2,900 km. The Salas y Gómez ridge lies in a west-east orientation. Its western end intersects the East Pacific Rise inside the Chilean Exclusive Economic Zone (EEZ) of the Easter Islands and its eastern end adjoins the western end of Nazca ridge. The Nazca ridge spreads in a southwest-northeastern direction. Its southern end includes part of the Chilean EEZ of San Felix Island, while its northern end meets the Peru-Chile subduction zone inside the Peruvian EEZ. The area beyond national jurisdiction covers about 415,638 km2, which represent approximately 1.68% of the international waters surface in the FAO area No. 87. Further, it contains about 110 seamounts with summits between the sea surface level and 2,000 m depth (fishable depths), which represent some 41% of the seamounts in the Southeastern Pacific Ocean. The area is a biological hotspot with one of the highest levels of marine biological endemism (41.2% in fishes and 46.3% in invertebrates) in the World. It is considered a stepping stone for some marine mammals (e.g., blue whale, Rodrigo Hucke-Gaete personal communication). And it has been identified as part of the forage area for Leatherback turtle. In addition, it has been described as recruitment and nursery area for swordfish and it is part of the breeding zone described for Chilean jack mackerel, overexploited specie. Until now the area has been subject of minor, localized and sporadic activities, like bottom fishing and geological surveys and, therefore, a high degree of naturalness is expected for many seamounts into the area.
Description of the location
Eastern Tropical and Temperate Pacific
Salas y Gomez ridge is located between 23°42’ S and 29°12’ S, and between 111°30’ W and 86°30’ W. Nazca ridge is located between 15°00’ S and 26°09’ S, and between 86°30’ W and 76°06’ W.
DISCLAIMER: The designations employed and the presentation of material in this map do not imply the expression of any opinion whatsoever on the part of the Secretariat concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries.
Area Details
The Nazca area is influenced slightly by the eastern boundary currents of the South Pacific anticyclonic gyre. The Chile current carries subantarctic water north, along the coast of Chile towards the equator, along the coast of Chile. At approximately 20° S, influenced by the southeast trade winds and coastal configuration, the current turns westward, away from the coast influencing Nazca area with nutrient-rich waters (Galvez, 2009). The Salas y Gómez and Nazca ridges are a long chain of tall seamounts and guyots that vary greatly in depth, and are isolated from the nearest continental margin by a deep trench (Parin etal., 1997). The ridge area beyond national jurisdiction contains about 110 seamounts with summits at fishable depths down to 2’000 m, representing 41% of the seamounts in the south-eastern Pacific Ocean. The benthic and benthopelagic invertebrates and fishes of the area are much more closely related to the Indo-West Pacific than to the eastern Pacific fauna. Currently, 226 species of benthic and benthopelagic invertebrates and 171 fish species of 64 genera are known to inhabit the 22 explored seamounts of the ridges (Parin et al., 1997). Considering the overall number of seamounts in the region, many more species can be expected. Further, the bottom areas of Salas y Gómez and Nazca ridges have not been sampled biologically. The area is a biodiversity hotspot with one of the highest levels of marine biological endemism, amounting to 41.2% of fish species and 46.3% of benthic invertebrates (Parin et al., 1997; Mironov et al., 2006) even surpassing the rates for hydrothermal vent ecosystems (Richer de Forges et al., 2000). The ridges offer habitat to a number of low resilience and long-lived species like deep water sharks (Parin and Kotlyar, 2007), oreos, alfonsino, and reefbuilder corals (e.g., Madrepora oculata). They are likely to be speciation centers and provide the only extensive hard substrate available for propagation of benthic suspension feeders like black (Antipatharia) and stony corals (Scleractinia), of which at least 19 genera have been recorded, with many more species (Mironov et al., 2006). The seamounts of the ridges were found to host aggregations of vertically migrant, seamount-associated mesopelagic fishes and migratory pelagic fishes: Pelagic sharks, in particular schools of large (2 - 3 m TL) adult male blue sharks have been observed to aggregate over Nazca ridge. Also bigeye thresher sharks (Alopias superciliosus) were more abundant over seamounts than in the surroundings (Litvinov, 1989). The ridges function as recruitment and nursery areas for swordfish (Xiphias gladius) (Yañez et al., 2004, 2006, 2009) and are part of the breeding zone described for Chilean jack mackerel (Trachurus murphyi) (Arcos et al., 2001; Anon., 2007). The high pelagic productivity indicated by the formation of Taylor caps and local upwelling processes observed over the Nazca Ridge may support blue whales (Balaenoptera musculus), for which it is considered to be a likely reproductive zone and stepping stone during their extensive migrations (Hucke-Gaete and Mate, 2005). Salas y Gómez ridge is located at the center of the foraging area for leatherback sea turtles (Dermochelys coriacea) in the South Pacific Gyre (Shillinger, 2008) and, based on that, it has been postulated as ecologically or biologically significant marine area by Duke University and TOPP. Deepwater commercial species and the occurrence of vulnerable benthic species coincide to a large extent. There are indications of abundant mega- and macrofauna bycatch in trawls, including large branches of gorgonians. Between 1979/80 and 1987 significant changes in the benthic communities such as loss of antipatharian corals were observed in consequence of bottom trawling (Parin et al., 1997).
Based on satellite tracking of blue whales, Nazca ridge has been postulated as the likely reproductive zone for blue whale sub-population feeding in Corcovado Gulf (Southern Chile), but in situ research must be carried out to test such hypothesis. On Salas y Gómez ridge, most of the fishing activity carried out is pelagic (Vega etal., 2009). There has been historical fishing targeting jack mackerel, tunas and swordfish, but information from SPRFMO and IATTC should be available to conduct analyses in that sense. The area is likely to be on the route of cargo ships that transit between Asia Pacific countries and Chilean ports; therefore, strikes with whales may occur.
References
• Anon., 2007. Report from Chile on jack mackerel research and stock assessment. Paper SPRFMO-III-SWG-18 presented at Third Scientific Working Group of South pacific Regional Fisheries Organisation, 25-27 April 2007 in Reñaca, Chile. http://www.southpacificrfmo.org/third-swg-meeting/ • Arcos, D., L. Cubillos & S. Nuñez. 2001. The jack mackerel fishery and El Niño 1997-1998 effects off Chile. Progress in Ocenography, 49(1), 597-617. • BirdLife International (2012a) IUCN Red List for birds. Downloaded from www.birdlife.org/datazone/species/search on 29/08/2012 • BirdLife International (2012b) Important Bird Areas factsheet. Downloaded from www.birdlife.org/datazone/site/search on 29/08/2012 • Clark, J.G. & J. Dymond. 1977. Geochronology and petrochemistry of Easter and Sala y Gómez islands; implications for the origin of the Sala y Gómez Ridge. J. Volcanol. Geoth. Res., 2(1), 29-48. • Daneri, G., V. Dellarossa, R. Quiñones, B. Jacob, P. Montero & O. Ulloa. 2000. Primary production and community respiration in the Humboldt current system off Chile and associated oceanic areas. Mar. Ecol. Prog. Ser., 197, 41-49. • Dunstan, P.K., M.R. Clark, J. Guinotte, T. O’Hara, E. Niklitschek, A.A. Rowden, T. Schlacher, S. Tsuchida, L. Watling, & A. Williams. 2011. Identifying Ecologically and Biologically Significant Areas on Seamounts. Gland, Switzerland: IUCN. 14 pp. http://data.iucn.org/dbtw-wpd/edocs/2011-056.pdf • Gálvez, M. 2009. Seamounts of Nazca and Salas y Gómez: a review for management and conservation purposes. Lat. Am. J. Aquat. Res., 37(3), 479-500. http://www.scielo.cl/pdf/lajar/v37n3/art16.pdf • Hucke-Gaete, R. & B. Mate. 2005. Feeding season movements and fall migration to wintering areas for Chilean blue whales. Abstracts of the 16th Biennial Conference on the Biology of Marine Mammals, 12-16 December 2005, San Diego, CA, USA. • Koslow, T. 2007. The silent deep: the discovery, ecology and conservation of the deep sea. Chicago. The University of Chicago Press, Chicago, 270 pp. • Litvinov, F.F. 1989. Struktura epipelagicheskogo taksocena Elasmobranchii v Atlanticheskom i Tikhom okeanakh i ee izmeneniya v noveyshee geologicheskoe vremya. Voprosy Ikhtyologii, 29, 973–984. • Mironov, A.N., T.N. Molodtsova & N.V. Parin. 2006. Soviet and Russian studies on seamount biology. Presentation at the International Seabed Authority workshop on Cobalt-Rich Crusts and the Diversity and Distribution Patterns of Seamount Fauna. http://www.isa.org.jm/en/scientific/workshops/2006/Mar06. • National Geographic & Oceana. 2011. Expedición a Isla de Pascua y Salas y Gómez, Febrero – Marzo 2011.Informe Científico. http://oceana.org/sites/default/files/reports/Informe_IPySG_final.pdf • Parin, N.V., A.N. Mironov & K.N. Nesis. 1997. Biology of the Nazca and Sala y Gómez submarine ridges, an outpost of the Indo-West Pacific fauna in the Eastern Pacific Ocean: composition and distribution of the fauna, its communities and history. In: A.V. Gebruk et al. (ed.). The biogeography of the oceans. Adv. Mar. Biol., 32, 145-242. • Parin, N.V. and A. N. Kotlyar. 2007. On Finding of Shark of the Genus Somniosus (Squalidae) at the Submarine Ridge of Nazca (Southeastern Pacific). Journal of Ichthyology, 47(8), 669–672. • Rayner, M. J.; Taylor, G. A.; Gummer, H. D.; Phillips, R. A.; Sagar, P. M.; Shaffer, S. A.; Thompson, D. R. 2012. The breeding cycle, year-round distribution and activity patterns of the endangered Chatham Petrel (Pterodroma axillaris). Emu. • Richer de Forges, B.; J.A. Koslow & G.C.B. Poore. 2000. Diversity and endemism of the benthic seamount fauna in the southwest Pacific. Nature, 405, 944–947. • Vega, R., R. Licandeo, G. Rosson & E. Yáñez. 2009. Species catch composition, length structure and reproductive indices of swordfish (Xiphias gladius) at Easter Island zone. Lat. Am. J. Aquat. Res., 37(1), 83-95. http://www.scielo.cl/pdf/lajar/v37n1/art07.pdf • Yáñez, E., C. Silva, J. Marabolí, F. Gómez, N. Silva, E. Morales, A. Bertrand, J. Campalans, A. Gamonal, J. Chong, P. Rojas, B. Menares & J.I. Sepúlveda. 2004. Caracterización ecológica y pesquera de la Cordillera de Nazca como área de crianza del pez espada. Informe Final Proyecto FIP N° 2002-04: 388 pp. • Yáñez, E., C. Silva, N. Silva, A. Ordenes, F. Leiva, P. Rojas, J. Chong, J. Campalans, S. Palma, G. Claramunt, C. Oyarzún, R. Meléndez & R. Vega. 2006. Caracterización ecológica y pesquera de Cordillera de Nazca como área de crianza del pez espada. Fase II. Informe Final Proyecto FIP 2004-34: 236 pp. • Yáñez, E., C. Silva, M. Barbieri1, A. Órdenes & R. Vega. 2009. Environmental conditions associated with swordfish size compositions and catches off the Chilean coast. Lat. Am. J. Aquat. Res., 37(1), 71-81. http://www.lajar.cl/pdf/imar/v37n1/Articulo_37_1_6.pdf
Status of submission
Areas described as meeting EBSA criteria that were considered by the Conference of the Parties
  • dec-COP-12-DEC-22
Assessment of the area against CBD EBSA criteria
C1: Uniqueness or rarity Low
The seamounts of N&SG are unique in that they constitutes a biogeographical province much more closely related to the Indo-West Pacific than to the eastern Pacific. Findings in the area shown high endemism rates, reached to 41.2% in fishes and 46.3% in invertebrates associated to the bottom (Parin etal., 1997; Mironov etal., 2006). These endemism rates are the higher found in seamounts, and surpass rates of ecosystems associated with hydrothermal vents, one of the most isolated in the Ocean (Richer de Forges etal., 2000). These ridges have 15 out of 94 seamounts in shallow water and has a high proportion of the total number of shallow seamounts in the region and met the criteria for unique habitats (Dunstan etal., 2011).
C2: Special importance for life-history stages of speciesHigh
Nazca ridge and the eastern end of Salas y Gomez ridges are considered to be the main recruitment area for Chilean jack mackerel and a nursery zone for swordfish (Yañez etal., 2004, 2006). Almost half of all invertebrates recorded live in those seamounts; therefore, the habitat provided by these seamounts is required for invertebrate populations to survive and thrive. It provides the only extensive hard substrate available for propagation of benthic suspension feeders like Antipatharians and Scleractinians. On isla Sala y Gomez three species of seabird breed in internationally significant numbers and the site qualifies as an Important Bird Area (IBA) according to BirdLife criteria. Christmas Island Shearwater (Puffinus nativiatis), White-throated Storm-petrel (Nesofregetta fuliginosa) and Masked Booby (Sula dactylatra). BirdLife International (2012b). Isla San Felix and isla Ambrosio also hold internationally important seabird colonies, with both qualifying as IBA. Defilippi’s Petrel (Pterodroma defilippiana) is the species of greatest importance, with over 10,000 pairs known to occur, and is an endemic breeder to Chile, only occurring elsewhere on the Juan Fernandez Islands. BirdLife International (2012b). While no tracking data exists for these species, and many are highly pelagic potentially travelling up to 500 km on a single foraging trip, the area included in this area will include a large proportion of their feeding areas used during the breeding season. Data collected from tracking devices shows that the area north of Islas San Felix and Ambrosio is used by the Chatham Petrel (Pterodroma axillaris), which migrates here from New Zealand to feed in its non-breeding season during the months of June to September. (Rayner et al 2012)
C3: Importance for threatened, endangered or declining species and/or habitatsHigh
In particular deep water species and biogenic habitats such as formed by cold water corals and sponges are considered vulnerable (Koslow, 2007), as often fragile, and slow (if at all) to recover due to slow growth, retarded maturity and high generation length, as well as population characteristics of high diversity at low biomass. Please see below for illustration: “Significant changes were noted between 1979-1980 and 1987 in the structure of bottom communities. Antipatharians were destroyed by the bottom otter-trawl […], and [cirripedes] were lost with their substratum animals, [while] populations of sea urchin [, who feed over cirripedes,] declined following the destruction” (Parin etal., 1997: 178) All seabirds are long lived (several decades) and slow at reproducing (normally 1 chick a year, and often taking several years to reach maturity) making them vulnerable and slow to recover following declines.
C4: Vulnerability, fragility, sensitivity, or slow recoveryHigh
Much of the fauna recorded in Nazca and Salas y Gomez ridges is endemic to their seamounts. Therefore, due the scarce information most of benthic or benthopelagic species inhabiting these ridges are not evaluated in their status or are data deficient classified in the IUCN Red List. However, the ridges offer habitat for a number of low resilient and long-living species like deep water sharks (Parin and Kotlyar, 2007), oreos, alfonsino, and reef-builder coral (e.g., Madrepora oculata). If these species are adversely affected they may easily become threatened. Satellite tracking has recorded the presence and persistence of blue whales and leatherback turtles, both threatened species. The IUCN RedList includes Defilippi’s Petrel as Vulnerable, Chatham Petrel as Endangered and the White-throated Storm-petrel as Vulnerable (BirdLife International, 2012a).
C5: Biological productivity Medium
Daneri etal (2000) have shown strong evidence that may support the formation of Taylor columns over the seamounts of Nazca ridge, and the occurrence of local upwelling process in Nazca area, making this area particularly more productive than the surrounding South-eastern Pacific Ocean. The Nazca area is slightly influenced by the eastern boundary currents of the South Pacific anticyclonic gyre. The Chile Current arises in the Subantarctic region. Thus, it carries “equatorward”, along the coast of Chile, Subantarctic Water. When it reaches approximately 20° S, influenced by the southeast trade winds and coastal configuration, turns westward, away from the coast influencing Nazca area with rich nutrients waters (Galvez, 2009).
C6: Biological diversityHigh
Few comprehensive studies have been conducted on the N&SG ridges. Taking into account only the Russian research, we know that 192 species of benthopelagic and benthic invertebrates and 171 species of fishes inhabit the 22 explored seamounts of the Nazca and Salas y Gomez ridges (Parin etal., 1997). If we consider that the area comprise at least 110 seamounts, then we can expect to discover a much higher biodiversity. It is important to note that the bottom of Nazca and Salas y Gomez ridges has not been biologically sampled. Elevations and depths ranging from abyssal soft sediment plains and trenches to the hard bottom peaks of seamounts and hills on the ridges may provide for an extensive range of ecological niches. Preliminary information on research done in 2011 shows that new species and high biological diversity were found in Salas y Gomez ridge close to Salas y Gomez island (National Geographic and Oceana, 2011)
C7: Naturalness High
Only the former URSS scientific expeditions and Chilean bottom trawling fleet were known to bottom fish in this area (Galvez, 2009) There are indications that big branches of gorgonias were destroyed by trawlers (Parin etal., 1997). However, from beyond fishing depth, no significant human impacts are known. In sum, the area has been lightly fished with only 12 seamounts with reported fishing activity, so naturalness is reasonably high (Dunstan etal., 2011). In the case of Salas y Gomez ridge, most of the fishing activity carried out is on pelagic layer on tuna and swordfish (Vega etal., 2009).