An Octopus Nursery Discovered on a Deep Underwater Mountain

A yellow sponge (Staurocalyptus sp. nov.) new to science, an orange basket star (Gorgonocephalus sp.) crawling on it, several white ruffle sponges (Farrea occa), and a new species of white-branched sponge (Asbestopluma sp. nov.) on the Davidson Seamount at a depth of 1316 meters. (Credit: NOAA/MBARI 2006)

Far below the surface of the Pacific Ocean, three quarters of a mile deep, lies the peak of an underwater mountain.  Rising 1.4 miles off the abyssal plains, Davidson Seamount, nearly 26 miles long and 8 miles wide, is one of the largest known seamounts in U.S. waters. Davidson contains an abundance of life including massive groves of large bubblegum corals and reefs of glass sponges.  Life is so abundant at the seamount, we proposed nearly a decade ago that Davidson Seamount with its dense aggregations of invertebrates may serve as source of many species to nearby canyons and rocky outcrops off the California coast.  Davidson may be a perfect habitat for many species allowing their populations to explode.  This Davidson Seamount cradle then may serve as source of migrating individuals into other less perfect habitats nearby.  This idea of Davidson as a biodiversity source was instrumental in getting Davidson added to the Monterey Bay National Marine Sanctuary (MBNMS) in 2009.

Octopuses observed at the Davidson Seamount, an ocean habitat about 80 miles to the southwest of Monterey. (Ocean Exploration Trust/NOAA)

A recent expedition by NOAA, MBNMS, and Nautilus, returned to Davidson Seamount.  And is typical of Davidson delivered with a spectacular display of life.   Over 1,000 individuals of the small sized octopus Muusoctopus robustus were caught on video hugging the rocks in a brooding position.  It is unclear why these octopuses are using the seamount as a nursery.  Higher currents around seamounts may bring more oxygenated waters.  The dense aggregations of other animals may provide abundant prey.  The crevasse, cracks, and rocky rubble of this old volcano may provide shelter from predators.

Dr. M (1801 Posts)

Craig McClain is the Executive Director of the Lousiana University Marine Consortium. He has conducted deep-sea research for 20 years and published over 50 papers in the area. He has participated in and led dozens of oceanographic expeditions taken him to the Antarctic and the most remote regions of the Pacific and Atlantic. Craig’s research focuses on how energy drives the biology of marine invertebrates from individuals to ecosystems, specifically, seeking to uncover how organisms are adapted to different levels of carbon availability, i.e. food, and how this determines the kinds and number of species in different parts of the oceans. Additionally, Craig is obsessed with the size of things. Sometimes this translated into actually scientific research. Craig’s research has been featured on National Public Radio, Discovery Channel, Fox News, National Geographic and ABC News. In addition to his scientific research, Craig also advocates the need for scientists to connect with the public and is the founder and chief editor of the acclaimed Deep-Sea News (, a popular ocean-themed blog that has won numerous awards. His writing has been featured in Cosmos, Science Illustrated, American Scientist, Wired, Mental Floss, and the Open Lab: The Best Science Writing on the Web.