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The image depicts a remotely operated underwater vehicle (ROV) illuminating a section of the ocean floor. The ROV’s bright lights cast a blue glow on the textured seabed, highlighting its rough surface. The surrounding water is a deep blue, fading into darker shades as it extends away from the light source, creating a sense of depth.

2026 American Samoa ROV + Mapping Exploration

Dive 07: East Muliāva Seamount

September 6, 2026

Location: Lat: -14.71175°; Long: -167.5644684°  
Dive Depth Range: 3,852-3,880 meters (2.39-2.41 miles)
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Dive 07 of the 2026 American Samoa ROV + Mapping Exploration expedition took place on a ridge on the northern flank of East Muliāva Seamount, an unexplored, undated deep seamount in the Muliāva Unit of the National Marine Sanctuary of American Samoa and Rose Atoll Marine National Monument, approximately 40 miles east of Rose Atoll. The base of the seamount lies in about 5,400 meters (3.4 miles) of water and the seamount is surrounded by complex topography including smaller mounts, hills, and pinnacles. The dive started at a depth of 3,876 meters (2.4 miles) and looked only at the upper slope of the main seamount.

During the dive, we documented a variety of marine life, including several sponge species and sea stars. Dead sponge stalks were observed to be providing habitat for organisms such as anemones, barnacles, crinoids, and sponges. The seafloor substrate shifted from sheet flow lavas with little sediment cover to bumpy surfaces and eventually transitioned to a large area of sediment with ripples. During remotely operated vehicle (ROV) deployment, oceanic white tip sharks and a large mahi mahi were observed at the surface while sharks, a rainbow runner, and a barracuda were seen during ROV recovery.

A dead sponge skeleton attached to deep-sea rocks has two pink anemones growing on its structure.

Throughout the seventh dive of the 2026 American Samoa ROV + Mapping Exploration expedition, numerous dead holdfasts and stalks of dead stalked sponges were observed. Standing stalks were often colonized by Poliopogon sp. sponges, anemones, barnacles, and some also had crinoids. Image courtesy of NOAA Ocean Exploration, 2026 American Samoa ROV + Mapping Exploration. Download largest version (jpg, 599 KB).

A white, cushion-shaped sea star rests on a dark, rocky ocean floor.

During Dive 07 of the 2026 American Samoa ROV + Mapping Exploration expedition, while exploring along the western side of a ridge feature with bumpy terrain, we observed several sea stars of the genus Ahuastera and several brittle stars. The Ahuastera sp. sea star pictured here was collected, as it may represent a previously unknown species. Image courtesy of NOAA Ocean Exploration, 2026 American Samoa ROV + Mapping Exploration. Download largest version (jpg, 613 KB).

Textured, dark grey rocky formations stretch across an uneven ocean floor.

Part way through Dive 07 of the 2026 American Samoa ROV + Mapping Exploration expedition, seafloor geology shifted from terraces and sheets to possible pillows and ferromanganese-encrusted flows and cobbles intermixed. The shift in structure did not seem to significantly impact the biological community, as we continued to see a variety of sponges and sea stars. Image courtesy of NOAA Ocean Exploration, 2026 American Samoa ROV + Mapping Exploration. Download largest version (jpg, 545 KB).

A pale, round, porous sponge on a thin white stalk grows from a dark, rocky ocean floor.

During Dive 07 of the 2026 American Samoa ROV + Mapping Exploration expedition, we observed this large Caulophacus sp. sponge that measured approximately 2 meters (6.5 feet) high and 50 centimeters (1.6 feet) across. This species is likely the main contributor to the dead stalks observed down slope during the dive. Image courtesy of NOAA Ocean Exploration, 2026 American Samoa ROV + Mapping Exploration. Download largest version (jpg, 687 KB).

A shark with white-tipped fins swims in blue water with a small striped fish beneath it.

Oceanic white tip sharks were observed at the surface on both remotely operated vehicle deployment and recovery during Dive 07 of the 2026 American Samoa ROV + Mapping Exploration expedition. Image courtesy of NOAA Ocean Exploration, 2026 American Samoa ROV + Mapping Exploration. Download largest version (jpg, 167 KB).