Precious coral biology
| Japanese red coral’s sexual maturation |
| An experiment to increase precious corals |
| Coral nets’ environmental impact |
| Sustainable use of precious coral |
| Publications |
| Research organization |
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Cnidarians
with skeletons are referred to collectively as “coral,” of which some
with skeletons fashioned into jewelry are classified as “precious
coral.” Precious corals and reef-building corals are taxonomically and
biologically different species of coral. Precious corals are a group of
corals in the subclass Octocorallia and live in waters from tens of
meters to 2,000 meters in depth. Meanwhile, most of reef-building
corals belong to the subclass Hexacorallia and live in waters from the
surface to tens of meters in depth. Precious
corals generally form a fan-shaped, tree-like structure called a colony
and live attached to a hard substrate such as rocks at the bottom of
the sea. The colony is supported by the axis, an internal skeleton,
covered with a layer of tissue called coenenchyme, in which polyps are
distributed. Each polyp is morphologically an individual creature and
has a cylindrical structure with a mouth at one end, which has eight
tentacles on the edge (Figs. 1 and 2). The tree-shaped colony of
precious corals consists of multiple polyps that are connected to each
other by a gastrovascular canal called solenia. The coenenchyme
contains numerous sclerites that serve as a protective function from
abrasion. Colonies are gonochoric and breed sexually, while polyps grow into the axis through asexual reproduction. The axis, synthesized by the overlying axial epithelium, develops with repeated branching off. However, the tip and the center of the axis are presumed to be formed through aggregation of sclerites deposited by bone-forming cells, or osteoblasts. (Nozomu Iwasaki of Rissho University) [Reference] |
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