Last February, researchers found a new species of octopuslike creature crawling along the seafloor near Necker Island in the Northwestern Hawaiian Islands.

The tiny “octopod” had a ghostly appearance and was quickly dubbed Casper.

Now a team of Hawaii and German scientists has found that the species lays its eggs only on the dead stalks of sponges attached to manganese nodules. That means that their welfare would have to be weighed in any future seabed mining operation for the mineral, widely used in the manufacture of computers and cellphones.

Their findings are reported in the Dec. 19 issue of the journal Current Biology.

When she first saw pictures of Casper, Deborah Eason, a geology assistant researcher at the University of Hawaii at Manoa, had a sense of deja vu. She had seen a similar octopod in 2011 while studying Kaena Ridge, which extends into the ocean off Kaena Point, using a remotely operated vehicle, or submarine drone.

“During one of the ROV dives we stopped to collect a rock sample and saw an interesting octopod,” recalled Eason, a co-author of the study. “It was sitting on the side of an outcrop right next to our sampling site, and hung out there while we were sampling.”

Based on the observations of the Hawaiian Casper octopod and 28 additional observations of similar octopods made elsewhere in the Pacific, the study reveals new knowledge about life in the deep sea and the ecological role of manganese nodules.

For one thing, many deep-sea octopods lay very few eggs and have extremely long reproductive cycles. Disturbances like mining would likely have serious consequences for the octopod offspring, the scientists said.