The first IUCN Red List of cold-water corals highlights global declines

Abstract

The most well-known species-based conservation tool is the International Union for the Conservation of Nature (IUCN) Red List of Threatened Species. The current coverage of species in the Red List is known to under-represent benthic marine species. Cold-water corals (CWCs) are increasingly recognised as key to deep-water biodiversity and integral to protected vulnerable marine ecosystems (VMEs), but no deep-sea coral species were previously included in the Red List. We selected 22 cold-water coral species in the Northeast Atlantic, including 4 reef-forming stony corals and 18 octocorals including sea pens and gorgonians, and completed the first IUCN Red List global assessments for corals inhabiting the deep sea. Most of the species assessed herein are habitat-forming, including those that form coral reefs and marine animal forests such as coral gardens or sea pen fields. We assessed eight species as near threatened, and one species as globally vulnerable: Desmophyllum pertusum. Some of these species are distributed across an entire ocean basin, but the cumulative damage from human impacts have reduced populations by upwards of 30% from recent baselines . In addition, three species are listed as data deficient, and the remaining 10 species are assessed as least concern. All assessments in threatened categories were made using Red List criterion A, based on evidence of past population declines, and the main threats in most cases are related to bottom-contact fishing. We also present five case studies that illustrate the application of the Red List criteria to cold-water corals. Despite technological limitations to establishing baseline populations, documented large-scale declines of widespread species clearly demonstrate the magnitude of threats to deep-sea ecosystems and the need for large-scale conservation measures.

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