2026 Cook Islands ROV Exploration

Location: Lat: -21.889433956°; Long: -158.998798521°
Dive Depth Range: 3,533-3,628 meters (2.2-2.3 miles)
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The last dive of the 2026 Cook Islands ROV Exploration cruise did not disappoint! The dive took place on Pepe Seamount, southeast of Rarotonga. We wanted to look for evidence that Pepe was formed by the same volcanic hotspot as Rarotonga – we found that it almost certainly is not, and is a much older volcano. The dive aimed to explore the seamount’s summit, traversing between a likely fissure lava-dike and a small summit crater to the south, collecting geological samples to analyze to help determine the age of observed lava flows. Upon arrival on the seafloor, we were met with extensive ferro-manganese coatings on volcanic rubble and possibly a few polymetallic nodules of various shapes and sizes. We also imaged a variety of marine life, including glass sponges and several coral species. Further along on the ridge top and crater rim we found common small polymetallic nodules in soft clay-ooze sediment that also showed an array of different types of burrows from infauna. A highlight of the dive was collecting a fossilized whale beak and partial skull, around 1 metre (3 feet) long. It was encrusted with ferro-manganese as well, suggesting that it is probably quite old, maybe over 1 million years old.

Remotely operated vehicle Deep Discoverer is recovered at the end of Dive 14, the final dive of the 2026 Cook Islands ROV Exploration cruise. Image courtesy of NOAA Ocean Exploration, 2026 Cook Islands ROV Exploration. Download largest version (jpg, 1.7 MB).

This dense field of small polymetallic nodules was seen while exploring Pepe Seamount during Dive 14 of the 2026 Cook Islands ROV Exploration cruise. Image courtesy of NOAA Ocean Exploration, 2026 Cook Islands ROV Exploration. Download largest version (jpg, 794 KB).

A glass sponge amongst the polymetallic nodules. It was one of several varieties of sponges seen during the final dive of the 2026 Cook Islands ROV Exploration cruise. Image courtesy of NOAA Ocean Exploration, 2026 Cook Islands ROV Exploration. Download largest version (jpg, 1.1 MB).

During Dive 14 of the 2026 Cook Islands ROV Exploration cruise, the team found and collected this fossilized whale beak, encrusted in polymetallic material. This is the first whale beak ever collected with remotely operated vehicle Deep Discoverer and may be the deepest beak ever recovered from the Pacific. Image courtesy of NOAA Ocean Exploration, 2026 Cook Islands ROV Exploration. Download largest version (jpg, 860 KB).