A squat lobster perching on a undescribed genus of bamboo coral (family Isididae). This new genus of coral was first discovered in 2007 off of Twin Banks in the Northwest Hawaiian Islands/Papahānaumokuākea Marine National Monument. Image courtesy of the NOAA Office of Ocean Exploration and Research, 2015 Hohonu Moana. Download larger version (jpg, 1.3 MB).
Dive 16 was conducted today on what is believed to be an old reef terrace edge north of Gardner Pinnacles. The objective of this dive was to survey the terrace edge, which is now a 200-meter high narrow ridge, for corals and sponges to gather information on whether high-density communities can be found on ridge topography. The dive started at 1,560 meters on a flat surface consisting of manganese-crusted pavement with pockets of sediment and no animals at the landing site. As the ROV moved northwestward towards the base of the ridge, several fishes were observed, as well as a low number of sponges and unbranched bamboo corals. The density of animals remained low on the flank of the ridge and included sponges, corals, and anemones. Once the ROV arrived on the crest of the ridge, there was a higher sediment cover, as well as a higher density of sponges, which were all oriented with their surfaces perpendicular to the ridge. As the ROV moved northeastward along the crest of the ridge, the community was dominated by a single species of sponge and occasional tripod fishes. Towards the end of the dive, the ROV came upon very large boulders, which were 20 meters in height, and contained a higher density of sponges and corals. The ROV left the bottom at a depth of 1,412 meters after covering a linear distance of 1,150 meters.