To save the beautiful ocean in Okinawa
The fourth Phase
Transplanting
PlanFrom April 2024 to April 2025
2020 marked the 50th anniversary of Busena Marine Park. As a commemorative project for the milestone and one of the SDGs activities implemented by the Okinawa Convention & Visitors Bureau (OCVB), Busena Marine Park decided to formulate and implement a farmed coral transplanting plan in cooperation with the nonprofit organization Coral Okinawa, which works on coral preservation.
Busena Marine Park is a tourist facility managed and operated by OCVB, which was registered as an “Okinawa SDGs Partner” on February 1, 2021. OCVB clearly stated in the SDGs Plan submitted to the prefecture that it puts maximum effort to preserve the natural environment of Busena Marine Park.
OCVB was registered as the Okinawa SDGs Partner.
Since 2022, we and The Terrace Hotels Co., Ltd. have cooperatively conducted a coral transplantation project with the financial support of Aramco Asia Japan K.K. through the Okinawa Coral Reef Conservation Consortium.
In implementing this grant support, a project start-up report meeting was held in June 2022.
memo
Currently, many different organizations implement coral transplantation, but a standardized method or technique has yet to be established. It is not uncommon for monitoring research after transplantation to reveal a survival rate of 0%. However, there are cases where corals transplanted over 20 years ago have successfully grown and even reproduced. Busena Marine Park referred to past examples when deciding how, where, and what type of coral to transplant.Coral is a highly sensitive creature; therefore, it cannot grow well under unsuitable conditions. The transplanting location must be selected carefully, considering multiple factors such as depth, water quality, water temperature, current direction, seafloor conditions, the presence of natural enemies, and more.
Additionally, the location must be easily accessible so that visitors can observe the corals in the future.
We have selected a transplanting location near the pier of the glass-bottom boat that meets the following conditions:
The location is approximately 3 meters deep, close to the pier, and easy to access for transplantation and monitoring.
The seafloor is flat and rocky, which is ideal for coral transplantation.
There are nearby living coral reefs in good condition that demonstrate suitable conditions.
The presence of a current prevents coral bleaching due to high water temperatures during the summer.
There are few natural enemies of coral, such as Crown-of-thorn starfish, Coral-eating gastropods, and Parrotfish.
The Okinawa Fisheries Adjustment Regulations prohibit the gathering, possessing, buying, and selling of reef-building corals. Therefore, legally cultured coral must be used for coral transplantation.
There are multiple facilities that culture coral in Okinawa, but we asked Sango Batake, which has excellent experience in coral preservation, to provide the mother coral of Plate Coral.
In addition to Plate Coral, we also transplanted Branched Montipora Coral for the fourth phase.
Since Branched Montipora Coral is abundant in Busena Marine Park, we collected a portion of it and used it for transplantation. However, it was necessary to obtain Approval of Special Collection from Okinawa Prefecture to gather these pieces. After continuous consultation with the Fisheries Division of Okinawa Prefecture, permission was granted in July 2024.
It is a common species and has easily obtainable donor (mother) corals.
It can be obtained from the west shore of Okinawa main island to ensure genetic proximity to the corals already inhabiting the area.
It is cultured by a reliable farm.
There are past examples of successful transplantation of the species, and it has a high potential to survive after being transplanted to Busena Marine Park.
memo
The coral transplantation guideline of the Coral Reef Society states that "one should take maximum care to avoid genetic pollution of the coral reef ecosystem."Similar to the third phase, we conducted intermediate cultivation of coral seedlings in Busena Marine Park (near the boat dock) after obtaining special permission from the relevant Okinawa Prefecture departments.
The intermediate cultivation of Plate Coral, which was attached to simple, easy-to-use coral implantation devices, took place for about 3 months (from November 26, 2024, to March 2, 2025).
For the fourth phase of transplantation (November 26, 2024), the transplant project personnel and participants from the Coral Preservation Experience Program conducted by Busena Terrace prepared 30 seedlings of Plate Coral.
Secure a few-centimeter pieces of coral, cut from the donors, onto simply installable coral implantation devices using an underwater glue specially designed for coral. Apply sand over the protruding glue, then harden it by soaking in seawater to attach them firmly. After being nurtured in this condition for a few months, the coral pieces will adhere to the bases.
To minimize damage to the coral, the securing process using underwater glue was performed quickly. By making grooves on the implantation devices in advance, applying the glue becomes easier and the process becomes smoother.
Method
While there are several methods for coral transplantation, we used the 'simple coral implantation device method' and the 'mesh pot method,' both of which were adopted during the third phase, in the fourth phase as well.
Two transplantation events took place using ‘mesh pots’ on December 23, 2024, and ‘simply installable coral implantation devices’ on March 3, 2025, during the fourth phase.
Before entering the water, participants received a briefing on the coral transplantation. For safety reasons and to comply with time limitations, the transplantation positions and procedures were carefully confirmed before the work began.
Step1
Enter the water from a pier at Busena Marine Park and carefully transport the coral seedlings to the transplantation site 90 meters offshore.
Step2
Confirm that no organisms are inhabiting the seafloor around the transplantation site.
Place the simply installable coral implantation devices into the crevices of the rock surface or hollows in the gravel, taking enough care to properly fix the Plate Coral.
Step3
Confirm there is no tilting or wobbling of the devices after installation. Make fine adjustments to the position to ensure that the devices are settled well.
Step1
Collect pieces of the Branched Montipora Coral from the location 80 meters offshore where Branched Montipora Coral develops.
Step2
Place pieces of Branched Montipora Coral in mesh pots, ensuring the coral pieces are intertwined with the mesh to prevent displacement by waves.
Carefully transfer the prepared mesh pots to the designated transplantation sites.
Step3
The transplantation is carried out at sandy locations where seagrass, such as sickle seagrass, thrives, near the vicinity of the third phase's transplantation site.
Create indentations on the surface of the sandy seafloor and place the mesh pots in them to prevent displacement by waves.
Monitoring the growth and survival rate of transplanted corals is critical.
To achieve this, Busena Marine Park conducts research at one week, one month, three months, six months, and one year intervals after the transplantation. Here are the results of this research.
We transplanted a total of 49 coral seedlings as part of the fourth coral transplanting operation, which included 19 Plate Coral (on March 3, 2025) and 30 Branched Montipora Coral (on December 23, 2024).
Plate Coral
Branched Montipora Coral
One week laterSurvival rate 100%
March 14, 2025 【Weather: Rain】
One week laterSurvival rate 96%
January 17, 2025 【Weather: Cloudy】
One month laterSurvival rate 96%
February 12, 2025 【Weather: Cloudy】
One week laterSurvival rate 100%
March 29, 2023 【Weather: Fine】
One month laterSurvival rate 86%
April 21, 2023 【Weather: Cloudy】
To monitor water temperatures at the transplantation site, we installed a thermometer and tracked the change. The graph above compares the summer (June to September) water temperatures recorded in 2023 and 2024.
In the summer of 2023, the average water temperature was approximately 28.6°C, while in 2024, it reached approximately 29.2°C, marking a 0.6°C rise. The highest recorded temperature in the summer of 2023 was approximately 30.6°C, whereas in 2024, it peaked at approximately 31.9°C, marking a 1.3°C rise.
During the summer of 2023, a sudden drop in temperature was observed from late July to early August following the approach of Typhoon #6, which mixed the seawater and reduced temperatures.
During the summer of 2024, coral bleaching was observed in both natural and transplanted corals at Busena Marine Park and the surrounding area. This phenomenon is believed to be linked to prolonged high water temperatures, which persisted due to fewer typhoons approaching the region.
The coral transplantation project at Busena Marine Park was launched to commemorate the park's 50th anniversary. Starting from the second phase (FY2022), we have been conducting the project in cooperation with The Terrace Hotels Co., Ltd. and with financial support from Aramco Asia Japan K.K. through the Okinawa Coral Reef Conservation Consortium.
To preserve the rich oceanic environment at Busena Marine Park, we will continue cooperation with businesses nearby and research institutes.
General Incorporated Foundation - Okinawa Convention & Visitors Bureau
Besena Marine Park Office
1744-1 Kise, Nago city, Okinawa, JapanTEL.0980-52-3379FAX.0980-53-0675