Abstract


DEVELOPMENT OF A DEVICE FOR IN SITU COLLECTING, REARING, AND SEEDING CORAL LARVAE

Generally, a shortage of larval supply has been thought a major factor causing delayed coral recovery. In fact, coral eggs and larvae have been found to easily flow out to the outside lagoon among degraded reefs around Okinotorishima, an isolated oceanic island of Japan. Thus, Japan Fisheries Agency developed a device that enables both the in situ seeding and mass culture of coral larvae (hereafter, the device), to promote coral reproduction inside the lagoon. Although this idea had been suggested previously, few studies have addressed the design of such a device at a practical level. We conducted a basic examination for the device's functions using the lattice plate, which enhances the initial survival rate of juvenile corals in Ishigakijima of Okinawa. We also demonstrated the device's durability and effectiveness in Okinotorishima, an isolated oceanic island. We show below the abridged results. a.Appropriate mesh size of the net material of the device: we compared mesh size of the net, an important factor for enhancing survival rate of the enclosed larvae, from 30 to 250 μm. The 30 μm mesh size showed the highest survival rate. b.Quantity of larval collecting and rearing: We assessed the rearing capacity of the device. The maximum number of larvae was 3 million at 4d-old, which they can settle. c.Monitoring the survival of the juvenile corals: We confirmed that the settled corals on lattice plate survived until 18 mo after settlement. d.Demonstration tests in Okinotorishima: We could install the device in Okinotorishima of severe maritime conditions during 7 days.

Authors

Okada, W., ECOH Corporation, Japan, w-okada@ecoh.co.jp

Yasutake, Y., ECOH Corporation, Japan, yasutake@ecoh.co.jp

Suzuki, G., Seikai National Fisheries Research Institute, Fisheries Research Agency, Japan, gosuzu@fra.affrc.go.jp

Hayashibara, T., Seikai National Fisheries Research Institute, Fisheries Research Agency, Japan, hayat@fra.affrc.go.jp

Ando, W., Fisheries Infrastructure Development Center, Japan, w-ando@fidec.or.jp

Uchida, S., Fishery Agency, Ministry of Agriculture, Forestry and Fisheries, Japan, satoshi_uchida@nm.maff.go.jp

Nakamura, K., Fishery Agency, Ministry of Agriculture, Forestry and Fisheries, Japan, kousuke nakamura@nm.maff.go.jp

Details

Oral presentation

Session #:42B
Date: 06/23/2016
Time: 15:00
Location: 301 B

Presentation is given by student: No