Montgomery et al. 2019

scientific chapter |

American Samoa

Montgomery AD, Fenner D,Kosaki RK, Pyle RL, Wagner D, Toonen RJ


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. We estimate that American Samoa has 451.5 km2 of marine habitat between the shoreline and 150 m depth. Mesophotic depths represent 357.5 km2 (79%) of the total area. Approximately 56 km2 (12.4%) of the marine habitat above 150 m is under various levels of protection through a system of local, territorial, and federal marine protected areas. Of this, 21.7 km2 (6%) includes mesophotic depths. With only a handful of studies conducted and the majority of MCEs in American Samoa unexplored, there remain significant information gaps in understanding the basic biodiversity and ecology of the region. There are over 300 species of scleractinian corals known from American Samoa, and approximately 110 species at mesophotic depths, representing over one third of the total diversity. Approximately 1013 fish species have been recorded from American Samoa (0–150 m), including 5 new records and 4 potentially new species from MCEs. Other anthozoan corals are currently being studied, but most invertebrate and algal communities at mesophotic depths remain uninvestigated.