Drivers of Lophelia pertusa Distribution on the mid-US Atlantic Margin Revealed by Habitat Suitability Modeling at Multiple Scales

Ryan Gasbarro, Temple University, Philadelphia, United States, Jay J Lunden, Haverford College, Haverford, PA, United States and Erik E Cordes, Temple University, Philadelphia, PA, United States
Coral reefs support key ecosystem processes and harbor an abundant and diverse fauna, yet their ecological niche and distribution on the deep (> 200 m) seafloor remain poorly understood. A series of recent mapping expeditions and submersible dives on the Blake Plateau region of the U.S. Atlantic margin have confirmed the presence of numerous coral mounds that were not detected in coarser-resolution surveys. Previous predictive habitat models for scleractinians placed a low probability of corals in much of this area. Here, we use these newly acquired bathymetry and coral distribution data, in conjunction with regional mapping products, NOAA deep-sea coral records, and satellite oceanography data to create predictive habitat models for Lophelia pertusa, the primary reef-forming species. At the regional scale, the models indicate large swaths of seafloor surrounding the new observations that are likely to support scleractinians. Notably, this includes areas outside of the Mid-Atlantic Fisheries Management Council Deep-Sea Coral Habitat Areas of Particular Concern (HAPC). We also create local-scale, high-resolution predictive habitat models at two sites (one inside and one outside the HAPC). In order to test the relative influence of species interactions on scleractinian distributions at fine scales, we incorporate the distribution of other common Anthozoan taxa through Joint Species Distribution Modeling. In addition, we test the validity of the model by projecting it onto one of the sites surveyed on a subsequent ROV dive. These models represent an extension of the realized niche for this species, and may aid in conservation and exploration efforts through prediction of other areas of L. pertusa presence.