Seragaki Island Clownfish Restoration Project

June 2021

You can read more from Hyatt Regency Seragaki Island Okinawa's project website.          link

This project, driven by Hyatt Regency Seragaki Island Okinawa in collaboration with the Marine Climate Change Unit at the Okinawa Institute of Science and Technology (OIST), aims to conserve and restore the clownfish population in Onna-son and develop a new eco-tourism program. A team of marine scientists from Marine Climate Change Unit is leading the overall logistics of this project and will conduct the following:

1) Selection of release location

The scientists will survey the natural habitats of endemic populations of clownfish around Seragaki Island and around Onna-son coastline, to select the most appropriate location for the release of juvenile clownfish.

2) Selection of the individuals to be released

There might be some concern that the introduction of new juveniles could cause unnatural genetic variations within the local clownfish population. To control this, the scientists from the Marine Climate Change Unit will analyze the genetics of both the wild and captive populations to verify which individuals should be introduced. Specifically, they will:

  • Collect a tiny piece of tail fin—a fin clip—from any wild clownfish that they find around Seragaki and Onna-son.
  • Collect fin clips from the juveniles raised at OIST’s marine station.
  • Extract DNA from these fin clips and sequence specific regions in the genome.
  • Evaluate the genetic diversity of both the wild population and the captive juveniles, using these regions as genetic markers.
  • Select the juveniles to be released, based on their genetic diversity and how closely it aligns with that of the wild population.

Because of this careful analysis, the scientists are confident that the natural genetic diversity of the clownfish populations in Okinawa will be maintained.

3) Monitoring after releasing

A maximum of 20 juvenile clownfish (10 breeding pairs) will be released. The hope is that they will contribute to a self-sustaining population by reproducing in the wild.

Every month, the scientists will monitor the condition of both the released clownfish and the local wild clownfish. Specifically, they’ll focus on the health, grow, mortality, breeding capability, and, for the released individuals, their overall adaptations to the new environment. When the released fish breed, the scientists will conduct the same genetic analysis on the offspring to verify the genetic diversity and the parental relationships. Through this monitoring program, the scientists aim to continue to improve the restoration project.