FUJISAWA, Kanagawa -- An aquarium here has succeeded in successive breeding of a rare deep sea tube worm, often called the "zombie worm," which survives on the bones of dead whales fallen to the sea floor.
The particular zombie worms that are on display at Enoshima Aquarium were originally discovered in the sea at a depth of 225 meters -- off the coast of Cape Noma in Kagoshima Prefecture by the Japan Agency for Marine-Earth Science and Technology in 2012. Enoshima Aquarium has been breeding the organism with help from the agency on site since 2016 and has found ways to successfully carry out successive breeding of the zombie worm in joint research with the agency. According to the aquarium, the organism is "an extremely important living creature in helping us to understand the evolution of life."
The deep-sea worm secretes a special acid which is used to melt whale bones on the sea bed -- after which it feeds on these melted bones as nourishment. It belongs to the Polychaeta class of annelid worms, and interestingly, female zombie worms are on average considerably larger than their male counterparts -- with average sizes being 40 millimeters and 0.5 millimeters, respectively. In addition, the male zombie worm fertilizes the female worm by attaching itself to the latter's body.
Following the discovery that the zombie worm is capable of successive breeding, Enoshima Aquarium has decided to put the organism on public display. The aquarium is keen to continue research related to this organism, with an official saying, "We are pursuing research in areas such as how to improve breeding methods as well as the relationship between water temperature and survival periods."