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A translucent jellyfish swims above a textured ocean floor covered in dark, round formations, set against a dark background.

2026 Cook Islands ROV Exploration

Dive 11: Northern Border Abyss 2

August 4, 2026

Dive 11 of the 2026 Cook Islands ROV Exploration cruise took place on an abyssal plain near the Cook Islands’ northern boundary with American Samoa, starting at a depth of approximately 5,600 meters (3.5 miles). Upon reaching the seafloor, we encountered a vast expanse of fluffy clay, with no polymetallic nodules in sight. This seafloor surface, or substrate, was in sharp contrast with what was seen during earlier cruise dives along the southern part of the Cook Islands exclusive economic zone. The sedimented seafloor seen on Dive 11 provided habitat for marine life living in the sediment (infauna) and marine life living off the sediment as detritivores. Animals encountered ranged from sponges, crinoids, and a sea urchin to a few fish. Small burrows were common.

A transparent ctenophore suspended in dark water, featuring long, thin tentacles and iridescent colors.

This ctenophore, or comb jelly, was seen swimming in the water column just above the seafloor during Dive 11 of the 2026 Cook Islands ROV Exploration cruise. Ctenophores are large planktonic predators, hunting prey while using hundreds of combs, or ctenes, to maneuver in the water column. These ctenes are made up of many fused flagella, which are visible in this image. Image courtesy of NOAA Ocean Exploration, 2026 Cook Islands ROV Exploration. Download largest version (jpg, 201 KB).

Underwater scene showing a robotic arm collecting a sample from the sandy seafloor, with a cylindrical container marked “#3” attached to it.

A push core being collected from the heavily sedimented seafloor encountered during Dive 11 of the 2026 Cook Islands ROV Exploration cruise. Image courtesy of NOAA Ocean Exploration, 2026 Cook Islands ROV Exploration. Download largest version (jpg, 847 KB).

A pale blue cephalopod with prominent tentacles is resting on the sandy ocean floor.

This sea cucumber with interesting and long appendages was seen on the seafloor during Dive 11 of the 2026 Cook Islands ROV Exploration cruise. Image courtesy of NOAA Ocean Exploration, 2026 Cook Islands ROV Exploration. Download largest version (jpg, 639 KB).

A spiral pattern made of light-colored materials on a sandy surface, with a coarse, light brown texture surrounding it.

We saw several of these coiled detritus trails on the seafloor during Dive 11 of the 2026 Cook Islands ROV Exploration cruise. The coils are fecal casts likely produced by deep-sea acorn worms. Image courtesy of NOAA Ocean Exploration, 2026 Cook Islands ROV Exploration. Download largest version (jpg, 982 KB).

Close-up of an eel-like fish with a pale gray body and large dark eyes against a teal background.

A beautiful shot of a cusk eel seen during Dive 11 of the 2026 Cook Islands ROV Exploration cruise. Image courtesy of NOAA Ocean Exploration, 2026 Cook Islands ROV Exploration. Download largest version (jpg, 343 KB).