These sensational sea slugs bring some pizzazz to the deep sea

When you think of slugs, the plant-chomping residents of your backyard or garden probably come to mind. But dive into the ocean, and you’ll meet a rainbow of sea slugs called nudibranchs. These living treasures come in over 3,000 species exhibiting a wide array of bright colors and patterns. Many are covered in frills and fluffy gills and can look like shag carpets or punk rockers with mohawk hair-dos. Nudibranchs and their kin live in various ocean habitats around the world, from tide pools down to the deep seafloor. Most inch their way along the bottom, but a few species spend their lives swimming in open water.

We still have much to learn about the sea slugs that dwell in the ocean’s depths. MBARI researchers and their collaborators have discovered some remarkable nudibranchs during our explorations of Monterey Bay and beyond. Our robotic submersibles are helping scientists better understand and document the amazing biodiversity of animals in the deep sea. This information is becoming increasingly critical as overfishing, pollution, and climate change threaten ocean health. Help spread the word about protecting the important but rarely seen animals and habitats deep below the ocean’s surface.

Learn more about the fascinating animals of the deep: https://mbari.co/AnimalsOfTheDeep

Producer/Editor: Megan Bassett
Production team: Larissa Lemon, Kyra Schlining, Nancy Jacobsen Stout, Susan von Thun
Music: KVmusicprod / Pond5

*A close relative to the nudibranchs, this mighty sea slug is in the order Pleurobranchida (side-gilled sea slugs).

Animals in order of appearance:
0:00 Rosy nudibranch (Tritonia tetraquetra) | 882 meters (2,893 feet)
0:22 Undescribed nudibranch | 3,975 meters (13,041 feet)
0:35 Black tiger nudibranch (Tochuina nigritigris) | 1,713 meters (5,620 feet)
0:46 Undertaker nudibranch (Aeolidia libitinaria) | 378 meters (1,240 feet)
0:57 White vent nudibranch (Dendronotus claguei) | 2,340 meters (7,677 feet)
1:04 California sea owl (*Pleurobranchaea californica) | 404 meters (1,325 feet)
1:11 Pelagic nudibranch (Cephalopyge trematoides) | 527 meters (1,729 feet)
1:25 Pink frond nudibranch (Dendronotus patricki) | 1,516 meters (4,973 feet)
1:36 Yellow-edge cadlina (Cadlina sp.) | 310 meters (1,017 feet)
1:49 Giant hedgehog nudibranch (Bathydoris aioca) | 3,126 meters (10,256 feet)
2:05 California sea owl (*Pleurobranchaea californica) | 353 meters (1,158 feet)
2:17 Rosy sea slug (Tritonia tetraquetra) | 879 meters (2,883 feet)

A close relative to the nudibranchs, this mighty sea slug is in the order Pleurobranchida (side-gilled sea slugs).