Cold-water corals on the NCS

**Overview**

As part of regular environmental monitoring, Equinor performs cold-water coral surveys on the Norwegian Continental Shelf (NCS). Cold-water corals are key species in the marine environment that are known to form two important habitat types: coral reefs and coral gardens. On the NCS, the coral reefs are predominantly made up of the scleractinian coral *Desmophyllum pertusum* (formerly known as *Lophelia pertusa*), whereas the coral gardens consist of several soft coral species (gorgonians) grouped together. Both coral reefs and gardens are covered by Equinor’s surveys.

The coral surveys are performed using visual ROV inspection according to the [Handbook Seabed habitats mapping, assessment and monitoring v01 (offshorenorge.no)](https://offshorenorge.no/contentassets/13d5d06ec9464156b2272551f0740db0/handbook-shec-mapping-assessment-and-monitoring-v0-final-signed.pdf). The surveyed coral locations are provided as georeferenced polygons that may be plotted in any GIS application. For each surveyed location, the corals are evaluated based on coverage and health. For coral reefs, the approximate living area (m2) and living coral coverage (%) are reported along with a corresponding health classification (poor, fair, good or excellent). For coral gardens, the number of specimens per 25 m2 is reported along with a health classification equivalent to that of coral reefs. Note that both reefs and gardens often are present at the same location.

The coral data are provided in the form of two .csv files that are formatted according to the Darwin Core terminology used by the Global Biodiversity Information Facility (GBIF). “EQ_corals_NCS_sampling_events” file lists the geographic attributes of the coral surveys performed. The “EQ_corals_NCS_associated_occurrences” file lists the performed coral evaluations, which can be linked to the “sampling_events” file through the “eventID” column present in both files. For further information on the Darwin Core terminology, use the following link: [Darwin Core quick reference guide - Darwin Core (tdwg.org)](https://dwc.tdwg.org/terms/).

Please note that this sharing solution is under development and that the coral dataset will be updated as new surveys become available.