Hotsarihie (Helen Reef) Project Report

Thomas J. Goreau
Wolf Hilbertz
Sabino Sackarias
Huan Hosei
and the Hatohobei State Marine Park Rangers
September 30 2004

All atoll islands are imminently threatened by global warming and global sea level rise (see the Global Coral Reef Alliance Briefing to the UN Expert Meeting on Ocean Management in Small Island developing States:

This project is a first effort to save the most species-rich atoll in the Pacific threatened by global climate change: SIDS

Hotsarihie (Helen Reef) Atoll has been documented as having more kinds of corals and fishes than any other Pacific island (Maragos, J.E. 1993. Corals of the Palau Southwest Islands. In J. Margos (ed.) Natural and Cultural Resources Survey of the Southwest Palau Islands of Palau. Part 1: Rapid Ecological Assessment of Palau. Report Submitted to the Ministry of Resources and Development, Republic of Palau; Maragos, J.E., A.K. Kepler, R.L. Hunter-Anderson, T.J. Donaldson, S.H. Geermans, K.J. McDermid, N. Idechong, S. Patris, C. Cook, B. Smith, R. Smith, and K.Z. Meier. 1994. Synthesis Report: Rapid Ecological Assessment of Palau: Part 1 June 1992 Natural and Cultural Resources Survey of the Southwest Islands of Palau. Prepared for Bureau of Resources and Development, Republic of Palau. 62 p.; Donaldson, T.J. 1993. Fishes. In J. Margos (ed.) Natural and Cultural Resources Survey of the Southwest Palau Islands of Palau. Part 1: Rapid Ecological Assessment of Palau. Report Submitted to the Ministry of Resources and Development, Republic of Palau; Weng, K. and M. Guilbeaux. 2000. August 1999 Synoptic Ecological Survey of Helen Reef Atoll, Palau. Collaboration of Community Conservation Network, Honolulu, Hawaii and Hatohobei State Government, Koror, Republic of Palau. 9 p).

The name Hotsarihie means Reef of the Giant Clams in the local language, because of the record densities of Giant Clams as well as precious trochus shells the atoll was famous for (Hester, F.J., and E. Jones.1974. A Survey of Giant Clams, Tridacnidae, on Helen Reef, a Western Pacific Atoll. Mar. Fish. Rev. 36: 17-22: Bryan, P.G., and D.B. McConnell. 1976. Status of Giant Clam Stocks (Tridacnidae) on Helen Reef, Palau, Western Caroline Islands, April 1975. Marine Fisheries Review 38: 15-18; Hirschberger, W. 1980. Tridacnid Clam Stocks on Helen Reef, Palau, Western Caroline Islands. Mar. Fish. Rev 42 (2): 8).

Hotsarihie is very remote, around 700 kilometers from Koror, the capital of Palau, and can only be reached by boat. Hotsarihie lies 2 degrees north of the Equator, to the northwest of New Guinea. Although Hotsarihie has no permanent inhabitants, it has been owned and used since ancient times by the people of Hatohobei (Tobi) Island, about 70 kilometers to the west. The unparalleled richness of its marine resources, including large fish, have made it a magnet for poachers from Indonesia, the Philippines, Taiwan, and other countries, who have stripped the reef bare of most of its valuable marine resources. As a result Hatohobei State now stations its Marine Rangers on Hotsarihie to protect it.

Besides its exceptional marine diversity, Hotsarihie is a globally significant turtle nesting site and bird rookery. Fresh tracks of large nesting green turtles were seen every day, and baby turtles were seen emerging from nests almost every night. The Pisonia grandis trees in the forest that covers the island are packed with many thousands of nesting White-headed terns, while dense populations of Crested terns nest directly on the beach sand at the north end of the island. Blue footed boobies nest on the large shipwrecks around the perimeter of the atoll. Large numbers of Frigate birds patrol overhead.

Although the atoll is large, 25 kilometers long and nearly 10 kilometers wide, or around 200 square kilometers, the island is tiny, about 20-40 meters wide and 400 meters long, less than one part in ten thousand of the whole atoll. The island is the uppermost tip of a large sand dune that is migrating towards and falling into the lagoon. The island is only a few inches above the high tide mark. There are clear signs from sand waves and sea-borne detritus on top of the island that waves periodically go right over it. If the island were washed away, a critical part of Palau’s Exclusive Economic Zone, especially rich in tuna, would be lost.

The entire island itself is moving at about 3-4 meters a year towards the southeast. Several clear lines of evidence corroborate the long-term observations of the Hatohobei people. A boat that was wrecked on the east shore of the island 5 years ago is now located in the center of the island. The concrete base of a water tank built on the east shore of the island 10 years ago is now on the western shore. The Ray Ban outlet remains of the concrete foundations of a building built on the island by Japanese soldiers 70 years ago now lie about 150 meters offshore. Casuarina trees and coconut palms planted on the eastern side of the island fall into the sea on the western side before they can bear.

In 1998 record high ocean temperatures affected the area as the result of continued global warming (T. Goreau, T. McClanahan, R. Hayes, & A. Strong, 2000, Conservation of coral reefs after the 1998 global bleaching event, CONSERVATION BIOLOGY, 14: 5-15). Almost all the corals on the atoll died from heat stroke. Subsequent surveys found very low live coral cover (Helen Reef Resource Management Program, 2003, Helen Reef marine Resources in the Year 2000, 65pp.). Local fishermen noticed a marked decline in fish populations after their coral reef habitat died, confirmed by scientists (Donaldson, T.J. and Myers R.F. 2000. Change in Fish Biodiversity Following a Coral Bleaching Event at Helen Reef, Southwest Palau Islands. Proceedings of the 9th International Coral Reef Symposium. 20).

Background to the Project
Without a living reef, capable of growing and repairing the damage caused by storms and boring organisms, Hotsarihie risks losing the bulk of its protection from erosion, and will be unable to keep pace with global sea level rise. Therefore restoration of marine habitats and protecting the island from washing away are paramount concerns of the Hatohobei State Government’s management plan for Hotsarihie. Their goal is to see the atoll preserved and used for high-value low-impact diving by licensed fee-paying live-aboard dive boats.

At the International Coral reef Symposium in Bali the State Governor of Hatohobei asked Tom Goreau and Wolf Hilbertz of the Global Coral Reef Alliance to come and help restore the damaged reefs and protect the shoreline from erosion using Biorock technology. Proposals were prepared and sent to the major US public and private funding agencies claiming to support “Community-based Coral Reef Restoration”, but these all refused to help. Finally, after four years of trying, the Global Coral Reef Alliance and the Hatohobei State Government were awarded a grant from private sources for a pilot project.

The project was immediately scheduled for the best weather season for working on the exposed eroding side of the island. All needed imported materials were purchased and shipped to Koror, Palau, in advance. Unfortunately the only ship that goes to the southwest islands (including Hatohobei and Hotsarihie), the supply ship Atoll Way, broke down and had to be taken to dry dock in Manila for repairs. These took months longer than planned due to delays in getting the spare engine parts needed. A series of typhoons, unusually strong, unusually Occhiali Ray Ban outlet early in the season, and unusually far south of their normal tracks, caused further delays until near the end of the best period. Due to the short time frame for the project, it was decided to go ahead with the project, since waiting for the following year was not an option.

Due to the remoteness of the location, all needed materials had to be anticipated and bought in Koror before departure. The team conducting the project included the Hatohobei State Government Staff, led by Governor Sabino Sackarias, the Marine Park Rangers assigned to Hotsarihie, the Hatohobei community high school graduates and college students volunteering on their mid-year vacation, and several volunteers from Hatohobei. We were accompanied on the trip by the children of the Hatohobei community in Koror, who were going back to their home island to learn about their ancient cultural traditions. The boat was packed with people, it was really a floating village!

Materials and Methods
As insufficient power to operate a welding machine was available on Hotsarihie, it was necessary to construct all breakwater/reef structures by hand on the island. While a welding machine was available on board Atoll Way, there was only a small deck on which welding could be done and only a small boat to transport any welded structure. Therefore we could only weld the racks to mount the solar panels. These had to big enough and strong enough to hold the solar panels above the highest expected waves, and were constructed from welded steel pipe. The solar panel racks were very heavy and much wider than the boat used to transport them. Transport of the racks to the island for mounting and wiring the solar panels was carried out unavoidably in high waves. This was a very risky operation because if the top-heavy boat had capsized the islands would have lost their only means of transporting people and supplies to the Atoll Way. Fortunately, despite the bad weather, this was done successfully due to the skills of the entire crew.

The challenges on the island were equally large. Due to remoteness and logistic difficulties there had been no way to assess the site beforehand and accurately estimate what would be needed, and many guesses had to be made. The vast size of the shallow sand bank on which the island sits, and its remoteness from coral habitat, except in one extreme tip where a small but rich reef is being buried by rapidly migrating sand, made a coral and fish nursery project impractical with the limited time and materials available. Because of the rapid movement of the island, and the severe erosion that was toppling trees into the sea, we decided on site to focus on protecting the most severely eroding part of the island in order to stabilize it.

Because of the extreme shallowness of the water and the high tidal range, we were forced to mount the solar panel racks in the sea about 80 meters from the island, and to build breakwater/reefs on inter-tidal sand flats on which corals would not be able to survive due to periods of air exposure at low tide. A 150 meter (500 feet) long breakwater was constructed to protect the entire length of the shore along which trees were falling into the sea.

The breakwater consists of two parallel adjacent 150 meter long half cylinders made of steel square mesh, 1/8 inch thick with 6 inch spacing. This material was cut into curved lengths and the entire cylinder made by overlapping adjacent segments and tightening every single node (thousands of them) with steel binding wire crimped tight with pliers. The two half cylinders were then connected along the entire length of the top with similarly attached steel mesh, so that the entire structure, 150 m long, about 3 meters wide, and a bit over 1 meter tall formed a single electrically interconnected unit. This structure was assembled in sections on the beach, and joined on the final site. The breakwater was placed parallel to the shore, approximately 90 meters from the high tide water line, spanning the entire area of worst erosion. The structure was entirely submerged at high tide, and entirely exposed at spring low tide.

The breakwater structure was wired to the cathode terminals of 32 6-Volt solar panels, which were wired in parallel. The anode terminals were connected to 8 titanium anodes coated with rare-earth alloy, placed on the sand on both sides of the structure, and weighted down with rocks. The panels produce 75 watts each in full sunshine, so the total power is 2.4 Kilowatts of power. The solar panels were mounted on two welded steel tube racks placed next to the breakwater on the island side.

This work was carried out under very difficult weather conditions. Only the first and last days were clear and sunny. Throughout most of the work there were very strong winds, almost continual horizontal driving rain, and pounding surf in the area where we were working. When the work was finished we were trapped in the lagoon for many days with almost no food supplies left since the waves were too big to safely navigate the winding passage out of the atoll. Once the winds died down the waves were still too strong to take the children off Hatohobei onto the boat, and then large waves to the north caused the closure of all ports in Palau. We later learned that this was due to Super Typhoon Dianmu, which caused much devastation further north.

Immediate Results and Anticipated Long Term Results
Within minutes of the electrical connections being made to the panels, bubbles began to form all along the base of the structure, indicating that it was working and well inter-connected electrically. Within a day the first growth of white minerals on the framework could be seen. It was clear, just before we had to leave, that the project was working exactly as planned.

As long as there is no interruption to the solar power supply, hard solid limestone rock will grow on all breakwater surfaces at a rate of a few centimeters a year. At first waves will pass unimpeded right through the breakwater. But as it grows more massive and strong the waves will increasingly slow down as they pass through it, dropping out part of their suspended sand, and creating a sand bar under the structure. This will extend parallel to and towards the shore, and will gradually grow and bury the breakwater from the bottom up. As this stabilized sand bar grows, the wave energy, and erosive forces at the shore will decrease. The beach should stop eroding and start growing within about 1- 2 years, as has happened in similar projects in the Maldives: Growing A Beach, 2004

The major threat to this project could not have been anticipated prior to seeing the site. An astonishing number of large tree trunks lay along the shore. Although almost all were found on the eroding westward shore, from their size and species only a small proportion was derived from Hotsarihie trees that fell into the sea from erosion. Most of these trees were of Dipterocarp species not found on the island, which were transported by the west Monsoon from the Philippines, Indonesia, or New Guinea. One giant trunk on the shore looked like Douglas Fir, and contained rounded red granite cobbles trapped in its roots identical to those found on beaches in British Columbia, suggesting that it had come all the way across the Pacific. Almost every day new large tree trunks washed ashore.

Originally this project had been planned for construction during the season while the breakwater was on the lee side of the island, which would have allowed it to gain strength before being exposed on the windward side during the other season. Unfortunately, due to the unanticipated delays the project had to be postponed to the end of the favorable season. However the abnormal weather patterns experienced, which may be linked to global warming, caused unusually large waves and an exceptionally early start to the west monsoon season, which carried large trees towards the breakwater before the structure had gained strength to withstand them. One day after the breakwater was connected, a large log passed right over it, denting a portion of the structure. The minor damage was immediately repaired, by bending and stretching it back into its original shape. However such repairs will require continual vigilance of the rangers during the West Monsoon, which may not always be possible.

Such events are capable of breaking mineral growth layers off the breakwater, and slowing its increase of strength. However as long as the connections are good, damaged areas will preferentially fill in with new growth. While we feel that the solar panel racks are strong enough to withstand the impact of logs, damage to anodes or cables could take place. If these connections are all broken, the project will stop until they are repaired. Once any broken connections are repaired, all the damaged areas will preferentially fill in with new growth.

A remarkable job was accomplished in completing the breakwater on time despite hazardous weather, insufficient time, difficult logistics, and inadequate materials, tools, and equipment. This was due to the exceptional hard work, dedication, and skill at improvising of the entire group. The project is the longest such single Biorock structure in the world. The Hatohobei people can be proud that they are the first low-lying islanders in the world to take serious steps to save their island from global climate change, and have done so under as difficult conditions as can be imagined for such a project. However it must be recognized that this pilot project is only the first step, and it may not be sufficient by itself to save the island without sufficient follow through. The following section lists recommendations to ensure this project has a lasting effect on the scale that is needed.

A long-term solution to the protection and sustainable management of Hotsarihie will require expanding on the foundation already laid in this project, and learning from its limitations. Significantly more time, people, materials, equipment, and funding will be needed.

1) While the existing breakwater/reef covers the entire most severely eroding section, it extends less than half the length of the island. A longer structure may be needed in the long run.

2) The structure was made at the wrong time of year to be strong enough to avoid damage from large logs. Subsequent efforts should be done at the start of the good season.

3) While the structure is strong enough to deal with wave forces, it may not be strong enough to avoid all damage from large logs in its early stages. The breakwater should be made with welded rebar frames to withstand the impact of large logs.

4) This requires more materials, more time, more solar panels and cables, and a portable welding machine on the island, which would require a more powerful electrical generator than the small one that exists there now.

5) Due to lack of time and insufficient materials we were not able to build the coral and fish nurseries planned on both Hotsarihie and Hatohobei. This remains a top priority because of the severe decline of coral, fish, and shellfish populations, not only in Hatohobei State but also in all the Southwest Islands, all States of Palau, and all tropical island nations, and all coral reef countries.

6) There are extremely strong and predictable tidal currents in the only channel through the encircling reef, which becomes very shallow at low tide. Vast amounts of energy could be generated there using Gorlov helical vertical-axis turbines. This could be used to grow a new and much larger island on the large barren reef flat adjacent to it. This could provide a new home for the Hatohobei people that would be much more accessible, more productive, and better located to protect the atoll’s marine resources.

7) Training, research, and development programs are critically needed to give island communities the tools to restore their coral reefs, fisheries, and protect their coastlines on a scale that will allow sustainable management of these resources for future generations. At present none exist.

8) Island Nations need to mobilize international support and funding for meaningful efforts to protect themselves against global climate change. Because of this project, Palau is well placed to lead such international efforts.

We are extremely grateful to the donor of the funds for this project, who has asked to remain anonymous, for kind and invaluable support. We gratefully acknowledge the support of the entire Hatohobei community on Koror, Hatohobei, and Hotsarihie, in particular the State Government Staff, Marine Park Rangers, the students, and the staff of Atoll Way.


1) Image Gallery
2) Palauan Star article
3) Open Democracy article by Caspar Henderson:
A Pacific Odyssey, Caspar Henderson, Open Democracy, 16 September 2004
4) Map
5) Follow up report and photographs by Huan Hosei and the Marine Park Rangers with list of all participants (to be submitted later when available)

Appendix 1

A selection of photographs about the Helen Reef Project:[easyrotator]erc_87_1390563526[/easyrotator]

Appendix 2

Palau Newspaper Article
500 -Ft Long Structures Put Up At Helen Reef
By Agnes  M. Abrau : Horizon News Staff

Last week two experts from the Global Coral Reef Aliance (GCRA) erected a 500-foot long structure on Helen Reef to grow limestone breakwaters to protect the island from erosion and rising sea levels.
Helen Reef, a marine protected area of Hatohobei State, is threatened by disappearance due to global climate change, said Dr. Thomas Goreau, president of GCRA, a small non-profit organization dedicated to growing, protecting, and maintaining the most threatened of all marine ecosystems – coral reefs, founded in 1990.
The structures, which are about 3 and a half feet high, are powered by 32 solar panels, Goreau said. The installation of the structures, one of the largest ever built by the experts, took four days to complete. With the help of 15 people, including the Helen Reef Rangers led by William Andrew, students, and community members, the team, along with Goreau and Hilbertz was able to complete the installation despite bad weather.
The project, requested by Gov. Sabino Sackarias in a meeting with Dr. Goreau and Prof. Hilbertz in Bali, Indonesia, in 2000 during an international coral reef conference, was made possible through a $30,000 funding made by a small private foundation from the United States, Goreau said in an interview.
“Gov Sackarias realized the kind of technology we have and thought of applying it in Palau, particularly on Helen Reef, just to stabilize the island. The beach is very shallow”, Goreau said.
He added that the structures get stronger when they age. This would enable Helen Reef to grow at least an inch a year, enough to protect the island, Goreau said.
He also said that due to the coral beaching phenomenon in 1998 and global warming almost all corals have died including the Southwest Islands. GCRA has successfully applied growing coral reefs – a bigger scale project – using the Biorock process in 15 countries worldwide. Some of them include Maldives, Seychelles, Thailand, Indonesia, Papua New Guinea, Mexico, Panama, among others.
The two experts employed a method of Biorock process, a technology that has been successfully applied to fish and shellfish mariculture as well as to grow limestone breakwaters to protect islands and coastal areas from erosion.
Sackrias said that this is a pilot project and they are aiming to build an island within the state in the near future so long as funding is available.
“We are aiming to create a new island and install a fish habitat to grow some corals because of the sea level crisis” Sackarais said.
“Restoring the damaged habitat is a government priority. This project may not be possible if not for Gov. Sackarias’ vision, even if it’s small scale, and before it’s too late”  Goreau said.
GCRA is a coalition of volunteer scientists, divers, environmentalists, and other individuals and organizations committed to coral reef preservation founded in 1990. They focus on coral reef restoration, marine diseases, and other issues caused by global climate change, environmental stress, and pollution.

Appendix  3

Open Democracy article by Caspar Henderson: A Pacific Odyssey, Caspar Henderson, Open Democracy, 16 September 2004

Appendix  4

Map Palau : Helen Reef