Recent harvest records of commercially valuable precious corals in the Ryukyu Archipelago

Abstract

Data, including depth, temperature and substrate, are reported for 143 colonies of 3 species of precious corals (Subclass Octocorallia; Family Coralliidae) collected in the Ryukyu Archipelago from June 2005 to May 2008. Colonies were collected by a commercial harvesting company using a remotely-operated vehicle (ROV) and a manned submersible, and identified tentatively as Paracorallium japonicum, Corallium elatius and Corallium konojoi. The data suggest that these species live deeper in lower latitudes (Amami, Okinawa and Ishigaki regions) than in higher latitudes (southern Kagoshima). Colonies of C. elatius may be larger at lower latitudes than at higher latitudes, but with the data available so far this cannot be definitely determined. Size differences may reflect harvest history, not physical or biological factors. (The more southern regions have been exploited more recently than the northern region.) There has not yet been enough data made available to estimate the resource of precious corals remaining in the Ryukyu Archipelago. More studies of their taxonomy and biology, especially growth rates, age and size at fertility and timing of reproduction, and data on biomass are necessary in order to make meaningful estimates. © Inter-Research 2009.