Zoological Studies

Vol. 61, 2022

(update: 2022.9.29)

Transplantation Tests of Precious Coral Fragments Using Small-sized Artificial Substratum

Tatsuki Koido1,*, Sho Toshino1, Fujio Kumon2,3, Shu Nakachi4, Noriyoshi Yoshimoto5, and Takuma Mezaki1

1Kuroshio Biological Research Foundation, 560 Nishidomari, Otsuki, Kochi 788-0333, Japan. *Correspondence: E-mail: t.koido@kuroshio.or.jp (Koido).
E-mail: toshino@kuroshio.or.jp (Toshino); mezaki@kuroshio.or.jp (Mezaki)
2Faculty of Science, Shinshu University, 3-1-1 Asahi, Matsumoto 390-8621, Japan. E-mail: shkumon@shinshu-u.ac.jp (Kumon)
3Center for Advanced Marine Core Research, Kochi University, 200 Monobe-Otsu, Nankoku, Kochi, 783-8502, Japan. E-mail: shkumon@shinshu-u.ac.jp (Kumon)
4Natural History Lab, Suogata, Otsuki, Kochi 788-0313, Japan. E-mail: mail@umibelabo.com (Nakachi)
5Non-Government Organization of the Precious Coral Protection and Development Association, 5F, Kearney-Place Bldg., 1-3-20 Honmachi, Kochi 788-0870, Japan. E-mail: ipcf2012@yahoo.co.jp (Yoshimoto)

Received 15 February 2022 / Accepted 30 May 2022
Communicated by Yoko

Since the Roman era, precious corals have been used to make ornaments worldwide, and their demand has recently increased. As a basic study for artificial cultivation, we transplanted Corallium japonicum fragments. In 2016 and 2017, 132 fragments approximately 3–5 cm in length were attached to small-sized artificial substratums using marine epoxy on land. These artificial substratums, acting as transplant substrates, were then transported and sunk to a depth approximately 100 m off the coast of Otsuki Town and Tosashimizu City, Kochi Prefecture, where precious corals once flourished. From six months to three years post-submersion, we successfully recovered the transplanted substrates and found a total of 107 fragments (81%). We confirmed that 106 of these fragments were alive 177 to 936 days after transplantation. Although we could not measure growth rates due to the initial damage caused by the transplantation, we observed growth in coenenchyme tissues, new polyps and new branches in the 104 surviving fragments. This result suggests there is great potential to artificially multiply precious corals, which could aid in the development of a sustainable precious coral industry.

Key words: Coralliidae, Corallium japonicum, Mesophotic zone, Kochi, Japan.

Citation: Koido T, Toshino S, Kumon F, Nakachi S, Yoshimoto N, Mezaki T. 2022. Transplantation tests of precious coral fragments using small-sized artificial substratum. Zool Stud 61:46. doi:10.6620/ZS.2022.61-46.