Point of View: Managing a sustainable deep-sea ‘blue economy’ requires knowledge of what actually lives there
Figures

Highlighting the absence of faunistic data in deep-sea mining exploration regions using the Ocean Biogeographic Information System.
(a) A 5° (300,000 km2) search box centered on the shallow North Sea with over 80,000 records from 1,500 annelid worm taxa. (b) The same size search box centered on the eastern Clarion-Clipperton Zone with just nine records from five taxa. (c) An expanded search box for the entire six million km2 CCZ showing only 12 records (OBIS, 2018). Criteria used: Phylum: Annelida, Sample Depth >500 m.

Two examples of a taxon-focused approach to conservation in the deep sea that identify both new discoveries of ecosystem services and new approaches to management based on hard evidence.
(a) The ‘scaly-foot gastropod’ Chrysomallon squamiferum is the ‘signature’ taxon discovered at Indian Ocean hydrothermal vents. As the only known animal to use iron in its skeleton, its discovery opens up new biological knowledge and the ability to ‘value’ environments such as hydrothermal vents (Chen et al., 2015c). Shell length 4 cm. (b) The small sponge Plenaster craigi is probably the most common animal living on nodules in the Clarion-Clipperton Zone, and was only described in 2017 (Lim et al., 2017). It is also a potentially useful monitoring taxon given our new knowledge of its distribution and functional role in filter-feeding on the small potato-sized nodules targeted for deep-sea mining. Scale bar 5 cm.