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March 22, 2021: Sea Pen

This sea pen was seen during the second dive of the Océano Profundo 2018: Exploring Deep-sea Habitats off Puerto Rico and the U.S. Virgin Islands expedition, while exploring to the east of Vieques Island and to the south of St. Thomas, at depths between 460-772 meters (~1,520-2,530 feet).

Image courtesy of the NOAA Office of Ocean Exploration and Research, Exploring Deep-sea Habitats off Puerto Rico and the U.S. Virgin Islands. Download larger version (jpg, 1.2 MB).

This sea pen was seen during the second dive of the Océano Profundo 2018: Exploring Deep-sea Habitats off Puerto Rico and the U.S. Virgin Islands expedition, while exploring to the east of Vieques Island and to the south of St. Thomas, at depths between 460-772 meters (~1,520-2,530 feet). Sea pens are a kind of octocoral, meaning that each sea pen polyp has eight (octo means eight) hollow tentacles fringed with little branches called pinnules. This feature distinguishes octocorals from hard corals, which have simple tentacles in multiples of six.