By Mary Collins, IUCN WCPA Connectivity Conservation Specialist Group’s Marine Connectivity Working Group (MCWG) Graduate Associate, hosted by the Center for Large Landscape Conservation

Context and challenge 

Figure 1. Representative and unique taxa observed with deep-sea camera systems in the eastern Salas y Gómez and Nazca Ridge zone in Chile’s national jurisdiction, with both species in frame A and the species in frame F identified as endemic (Friedlander et al., 2021).

The Salas y Gómez and Nazca Ridges are two connected seamount chains extending 3,000 kilometres (1,864 miles) off the west coast of South America in the Southeastern Pacific Ocean. The underwater ridgelines hold exceptional biological importance because they support the highest known concentration of endemic species in the marine environment (species that live in a specific area and nowhere else) (figure 1 and 2). Through geographic isolation by the surrounding Humboldt Current, the Atacama Trench, and an area of low oxygen, these marine species and their habitats adapted while secluded for about 2 million years in the shallow zones near Chile and Peru and up to 27 million years in the deep waters toward Easter Island. It is estimated that about half of the marine population is endemic. Additionally, the ridges host high assemblages of biodiversity and species richness in benthic and pelagic communities, with much still undiscovered (Pew Charitable Trusts; Wagner et al., 2021). In addition to isolation, the uniqueness of these systems is due in large part to the more than 110 seamounts formed along the ridge, representing 41 percent of all seamounts in the region and ranging in depth between just a few meters on the western end to over 3,000 meters towards the northeastern end. Notably for connectivity considerations, the seamount-dense ridges provide important habitat and ecological stepping stones for both resident and migratory species, including whales, sea turtles, swordfish, sharks, jack mackerel, deep-water corals, shallow-water corals, and a myriad of other ecologically important species (Wagner et al., 2021). 

Figure 2. Images taken of marine biodiversity in the Salas y Gómez and Nazca ridges, captured with a deep-sea camera system. Rhodolith beds, mesophotic coral ecosystems, black corals, shark species, and deep-water coral and sponge communities growing amongst seamounts (Wagner et al., 2021).

Much of the Salas y Gómez and Nazca ridges lie in the high seas, also called areas beyond national jurisdiction (ABNJ), with only small portions on either end located in Chilean and Peruvian national waters. The South Pacific Regional Fisheries Management Organisation governs conservation and sustainable use of fishery resources in the ridges’ ABNJ area, but there is currently no mechanism for coordinating across geographic areas and sectors for establishing area-based protections. This creates a legal and logistical challenge and leaves 75 percent of the Salas y Gómez and Nazca ridges unprotected and under threat of increased stressors, including fishing, pollution, and potential deep-sea mining (Pew Charitable Trusts; Wagner et al., 2021). Specifically, for the commercial fisheries present, increased commercial fishing would include purse seining, pelagic trawling, jigging, bottom trawling, and bottom longlining, in many cases causing destruction to seafloor communities (Pew Charitable Trusts). Globally, extractive seafloor mining is increasing due to rapid advances in technology and increasing demand for goods and trade, posing threats to zones previously untouched (like the Salas y Gómez and Nazca ridges), through habitat destruction, sediment plume dispersal, and introduced mixing (Pew Charitable Trusts; Wagner et al., 2021).

Approach

Weathering minimal impact from historical fishing, the Salas y Gómez and Nazca ridges remain relatively pristine, presenting an opportunity for protecting a valuable biodiversity hotspot, marine species migration route (swimway), and a place for research that helps us better understand deep-sea ecosystem dynamics (Georgian et al., 2021). Several international authorities made their stance on the need for protections clear. In 2020, the Pew Charitable Trusts included the Salas y Gómez and Nazca ridges as one of 10 sites in the high seas with outstanding conservation value. Their analysis included an algorithm that allowed for multiple oceanographic and biological factors, and they chose sites based on a spectrum and combination of important features such as species richness, productivity, and habitat diversity (Pew Charitable Trusts). The zone was also identified by the United Nations Convention on Biological Diversity (CBD) as an Ecologically and Biologically Significant Area (EBSA) in need of protection (United Nations). Ocean experts additionally grouped under the Coral Reefs of the High Seas Coalition to advocate for a marine protected area (MPA) (Wagner et al., 2021).

In recognition of the Salas y Gómez and Nazca ridges’ biological importance, in 2021 Chile proposed to advance with establishing protections. After designating waters as MPAs in both the east and west portions of the ridges that fall under national jurisdiction- the Nazca-Desventuradas Marine Park to the east and the Rapa Nui Marine Protected Area surrounding Easter Island to the west- Chile intends to connect protections my championing a high seas MPA over the 3,000 kilometre (1,864 mile) ridge zone (figure 3) (United Nations). While Chile already exceeded the United Nations’ deadline for protecting 30 percent of marine zones by 2030, it is ‘not enough’ and they intend to promote further protections. Consequently, the gaining pressures influenced Peru to open evaluations for a proposal to protect the farthest east-reaching portion of the Nazca Ridge.  

One obstacle to successful protection is a lack of knowledge. Therefore, scientists gather information that informs potentially effective zoning. One key method used for informing MPA design when there is limited information available, is habitat suitability modeling. By modeling the distribution of three habitat structure-producing taxa (demosponges, glass sponges, and stony corals) foundational to supporting large assemblages of associated fauna, scientists were able to predict areas highly suitable for each taxa throughout the Salas y Gómez and Nazca ridges. The most suitable habitat features included small patches within large terrain features such as seamounts, guyots, ridges, and escarpments (Georgian et al., 2021). Scientists have also been able to determine that faunal community structure is highly dissimilar between and within subregions of the Salas y Gómez and Nazca ridges, for invertebrates and fishes alike (Friedlander et al., 2021). Determining spatial distribution, habitat suitability, diversity, migratory species connectivity, and like-ness of these marine ecosystems is critical to informing effective spatial protection and management, as the proposal progresses toward negotiations.

Figure 3. Proposed zone for protecting the Salas y Gómez and Nazca ridges in the high seas, with current protected areas and exclusive economic zones (China Dialogue Ocean).

Results 

While Chile champions the proposal for MPA designation, the challenge remains that there is currently no mechanism for coordinating across jurisdictional areas and sectors for establishing area-based protections for the high seas. Therefore Chile depends on an important and forthcoming agreement being developed – the High Seas Treaty- under the U.N. Convention on the Law of the Sea, which defines country rights and responsibilities for use of the world’s oceans. The treaty, undergoing ongoing negotiations, offers an opportunity to address current gaps in high seas ocean governance to allow for comprehensive and connected protection of marine biodiversity (A/CONF.232/2020/3). The South Pacific Regional Fisheries Management Organisation remains engaged in the Salas y Gómez and Nazca ridgeline designation negotiations process (Pew Charitable Trusts). This forward-thinking approach to interconnecting protected systems across jurisdictions using an anticipated agreement may put the Salas y Gómez and Nazca ridges as one of the first and largest to be governed by the high seas treaty, if protected. 

As seen for other large protected areas that span into the high seas, like the Ross Sea Regional MPA in the Southern Ocean, there remains uncertainty as to whether negotiations for MPA designation can occur in a succinct and effective manner. A high-level scientific technical group will develop the proposal with the objective of protecting the ridgelines from destructive extractive activities and compounding threats and present it to relevant international organizations (United Nations). However, some have questioned the unilateral nature of the announcement, inquiring for reasons that Chile did not include its Peruvian and Ecuadorian neighbors in the initial announcement. It is likely that due to its cross-jurisdictional and pioneering nature, it will take intense diplomatic work between all countries and relevant governance bodies in the region. 

References

Friedlander AM, Goodell W, Giddens J, Easton EE, Wagner D. 2021. Deep-sea biodiversity at the extremes of the Salas y Gómez and Nazca ridges with implications for conservation. PLoS ONE 16(6): e0253213. https://doi.org/10.1371/journal.pone.0253213. 

Georgian S, Morgan L, Wagner D. 2021. The modeled distribution of corals and sponges surrounding the Salas y Gómez and Nazca ridges with implications for high seas conservation. PeerJ 9:e11972 https://doi.org/10.7717/peerj.11972. 

Intergovernmental conference on an international legally binding instrument under the United Nations Convention on the Law of the Sea on the conservation and sustainable use of marine biological diversity of areas beyond national jurisdiction. Fourth session, New York, 23 March–3 April 2020. https://undocs.org/en/a/conf.232/2020/3. 

The China Dialogue Ocean. https://chinadialogueocean.net/17423-chile-wants-to-protect-part-of-the-high-seas-ahead-of-global-treaty/. 

The Pew Charitable Trusts. 2020. A Path to Creating the First Generation of High Seas Protected Areas. https://www.pewtrusts.org/-/media/assets/2021/03/highseas_mpa.pdf 

United Nations (UN). 2021. President Piñera Announces Chile Will Advance A Proposal To Fully Protect An Area Of The High Seas In The Southeastern Pacific, The First Of Its Kind. https://sdgs.un.org/news/president-pinera-announces-chile-will-advance-proposal-fully-protect-area-high-seas. 

Wagner, D. et al. 2021. The Salas y Gómez and Nazca ridges: A review of the importance, opportunities and challenges for protecting a global diversity hotspot on the high seas. Marine Policy. Volume 126, 104377. https://doi.org/10.1016/j.marpol.2020.104377.