Over a century of study in American Samoa has built a foundation of coral reef ecology within the region. However, this work has been restricted to shallow coral reefs (SCRs; <30 m) until recently, where a few studies have started describing American Samoa’s mesophotic coral ecosystems (MCEs). MCEs are defined as coral reef communities with zooxanthellate corals and associated biotic assemblages between 30 and 150 m depth. Mapping efforts within the territory have documented habitat characteristics for SCRs, as well as MCEs.

The Phoenix Islands Protected Area, in the central Pacific waters of the Republic of Kiribati, is a model for large marine protected area (MPA) development and maintenance, but baseline records of the protected biodiversity in its largest environment, the deep sea (>200 m), have not yet been determined. Here, we present baseline deep-sea coral species distribution and community assembly patterns within the Scleractinia, Octocorallia, Antipatharia, and Zoantharia with respect to different seafloor features and abiotic environmental variables across bathyal depths (200–2500 m).

The Pourtalès Terrace is an exposed hard-bottom platform located south of the Florida Keys in 200–450 m depth with a diverse deep-sea coral ecosystem dominated by stylasterid hydrocorals, octocorals, and sponges that supports recreational and commercial fisheries.