Global Environment Research Fund of the Ministry of the Environment“Study on the disturbance and restoration of the coral reef”

Manual for restoration and remediation of coral reefs

Manual for
restoration and remediation of coral reefs

Edited by Makoto Omori and Shuichi Fujiwara
March 2004

Ministry of the Environment

Nature Conservation Bureau
Ministry of the Environment, Japan

Forward
Coral reefs have been called “tropical forests of the sea”, with high productivity andbiodiversity underpinning their strong economic and social values as sources of food, places
for recreation and with recognition also of their importance as a reservoir of genetic
resources. The protection that reefs provide tropical coastlines is evident during storms andtsunamis, where reefs dissipate wave energy quickly and efficiently. However, because
environmental conditions affecting reefs in many tropical and subtropical regions has
deteriorated significantly during the past four decades, due to causes such as outbreaks ofthe predatory crown-of-thorns starfish (Acanthaster planci), sedimentation by terrestrial
run-off, and destructive fishing by dynamite or poison, conservation of the reef has become
an urgent international issue. Consequently, Japan, USA, Australia and other countries
concerned about coral reefs collaborated to establish, in 1995, the International Coral Reef
Initiative, which Japan has driven forward proactively.
Japan has approximately 96,000 ha of coral reefs, distributed mainly around the Ryukyu
Islands. Since Japan also is one of the few developed countries with significant reef areas,
we have a major role to play in the fields of reef research and conservation to provide a
positive contribution in tropical and subtropical waters. In pursuing such objectives, theMinistry of the Environment conducted studies on the disturbance and restoration of coral
reefs via the Global Environment Research Fund project during fiscal years 2000 to 2002.
The Ministry actively promoted new research on sedimentation impacts and also the processof coral settlement and recruitment with regard to the coral transplantation, to obtainfundamental knowledge of transplantation. In addition to the Ministry’s activities, otherresearch bodies such as Akajima Marine Science Laboratory and Japan Marine Science andTechnology Center (JAMSTEC) have made efforts, including various investigations andexperiments for the purpose of the coral reef restoration, to significantly advance ourknowledge.
This document has been prepared in recognition of an increasing need for information on
restoration of degraded coral reefs, through means such as transplantation, in order toprovide information that may be helpful for coral reef restoration activities worldwide. It is acooperative effort of the Japanese scientists who are playing principal roles in the research,
who have summarized their accomplishments and knowledge for this manual.
We express our heartfelt gratitude to those who have been fully cooperative with us for the
preparation of this document, and desire earnestly that it is utilized widely to be helpful forthe regeneration and restoration of the coral reefs.
Nature Conservation Bureau
Ministry of the Environment, Japan

Editors
Makoto Omori
Akajima Marine Science Laboratory
Shuichi Fujiwara
Metocean Environment Inc.

Authors
Shuichi Fujiwara
Metocean Environment Inc.
Masayuki Hatta
Ochanomizu University
Seiichi Hosoya
Metocean Environment Inc.
Kenji Iwao
Akajima Marine Science Laboratory
Satoshi Nojima
Amakusa Marine Biological Laboratory, Kyushu University
Mineo Okamoto
Tokyo University of Marine Science & Technology
Nami Okubo
Tokyo Institute of Technology
Makoto Omori
Akajima Marine Science Laboratory
Hiroki Taniguchi
Akajima Marine Science Laboratory

Contents
ForwardNature Conservation Bureau, Ministry of the Environment

1. Conservation, restoration and remediation of coral reefs: Background and significance2. Previous research and undertaking of coral reefs restoration

Omori M

1

Omori M & Okubo N

3

3. Restoration technology using sexual reproduction

14

3-1. Seed production

14

Hatta M, Iwao K, Taniguchi H & Omori M(1) Sampling of eggs and embryos from the sea

14(2) Spawning induction18(3) Maintenance and culture19(4) Mass production of larvae

21(5) Transportation

22(6) Inducement of settlement and metamorphosis

22(7) Substrates

23(8) Introduction larvae to substrate

24(9) Culture of polyps on substrate25

3-2. Manufacturing and placement of artificial substrates for coral settlement

Fujiwara S

4. Restoration technology using asexual reproduction
4-1. Transplantation of coral fragments

29

34
Okubo N

34(1)Sampling of fragments from donor coral34(2) Size of suitable fragments

34(3) Transportation

35(4) Fixation methods and choice of fragment

35(5) Choice of place

36(6) Preferable substrate

38(7) Preferable season38

4-2. Transplantation of juvenile corals

Okamoto M & Nojima S

41(1) Sampling

41(2) Method of transplantation

42(3) Evaluation of the method42

5. Transplantation of whole coral colonies and of coral reefs
Fujiwara S & Omori M

44

5-1. Transplantation of whole coral colonies

44

5-2. Replant of coral reefs

44(1) Selection of coral reef and choice of destination

45(2) Sampling

45(3) Transportation

46(4) Placement

46(5) Conclusion

47

6. Development of underwater techniques for coral reef restoration50

6-1. Experiment 1. Restoration using sexual reproduction
Okamoto M & Nojima S

50(1) Introduction50(2) Conception of methodology

51(3) Problem of use of substrate

52(4) Development of new artificial substrate

52(5) Design and construction of artificial substrate

53(6) Larval settlement and replant of substrate

56(7) Evaluation of methodology and perspective

57(8) Conclusion

58

6-2. Experiment 2. Transplantation of coral fragments: Acropora formosaOkubo N

62(1) Material and methods

62(2) Results

62(3) Conclusion

65

6-3. Experiment 3. Transplantation of whole coral colony: Porites lutea

Hosoya S

68(1) Method

68(2) Results

68(3) Conclusion

72

7. Maintenance of polyps on substrate, transplanted coral fragments and colony,
and replaced reef
Fujiwara S

74

(1) Removal of algae and predators

74(2) Announcement and enlightenment

74(3) Monitoring

75(4) Reproduction

77

8. Concluding observations

Fujiwara S & Omori M

79(1) Techniques of reef rehabilitation: Development and comparison

79(2) Future subjects to study81

1. Conservation, restoration and remediation of coral reefs: Background and significance

Deterioration and destruction of global coral reefs have caused increasing anxiety for several
decades. For the regeneration and restoration of coral reefs, the maintenance and recovery ofacceptable environmental conditions are essential, thus requiring social recognition for this serious
issue, including upgrading of popular support, and legal controls, recommendations and cooperationthat are supported by the administrations willing to protect the coral reefs. Natural death of corals
from typhoon or abnormal rise of water temperature can be corrected within several years or in a
decade if their rearing environmental conditions become acceptable. However, because reefs can bedegraded far faster than they can grow back, due to human caused stresses such as eutrophicationand terrestrial run off, we have seen a net reduction of reefs for decades.
In the environment marked by such circumstances, various techniques have been developed forrestoration of the coral reefs. But, the development of such techniques should not merely assume thatthe destruction of the coral reefs from the growth of human activities is inevitable. Restoration
techniques should always facilitate the improvement of the surrounding environment as well as thereefs. This is a point to be noted in the beginning. In Okinawa where restoration of the coral reef isthe most urgent demand, many reefs are still sacrificed and lost by human development activities.
As one of the coral reef restoration techniques, the transplantation of coral fragments has been
implemented in Japan from the 1990s in various locations. On one hand, when a coral reef wasremoved, due to the necessity of port and harbor or other underwater construction, thetransplantation (relocation) of whole colony or a part of the coral reef that is cut off to other location
was performed. However, many of the past transplantation projects were performed without
sufficient scientific verification and/or long term monitoring of the results. The projects did notalways lead to advance of the restoration techniques because their achievements were not analyzed.
Some restoration projects and development of techniques are in the stage of experiment or trial.
In this circumstance, we have decided to include the preparation of this manual for coral reef
restoration in the process of study of the promotion of restoration of the coral community, one of the
Ministry of the Environment’s Global Environment Research Fund Projects, to disclose theachievements and knowledge with regard to the restoration techniques that have been developed
mainly in Japan. This document includes the collection of the achievements that were alreadypublished and those considered disclosable by the author of each chapter. For the achievements thatare in the stage of trial or experiment, that is, state of the art, or those contained in patents, they aresimply outlined. Research and development for the coral reef restoration have been advanced byindividual institutes independently. The editors believes that the publication of this document thatcollects information about the present situation and outlook of the restoration of coral reefs will leadto greater mutual understanding of the relevant persons, and then, the exchange of the information1

can cause further development of their activities.
For the compilation of this document, the editors acquired advice and instructions from many
persons including Mr. S. Yamamoto, Ecoh Inc. and Dr. T. Hayashibara, Ishigaki Tropical Station,
Seikai National Fisheries Research Institute. We would like to acknowledge these persons for their
special favors. We would like to express our special thanks to Mr. G. Sweany, U.S. Foreign Service(ret.), and Dr. A. Heyward, Australian Institute of Marine Science, for their kind reading of the
English manuscript and for providing many useful suggestions.
(Omori M)

22. Previous research and undertaking of coral reefs restoration

This documents collects the methods, achievements, and problems of measures including 1)
seeding production and settlement induction by utilizing the coral sexual reproduction, 2)transplantation of coral fragments by utilizing asexual reproduction, 3) transplantation of colonies orentire reef, and 4) management of settled seeding, transplanted colonies and coral communities.
For the hermatypic corals, their larvae spawned by the sexual reproduction settle on the substrate
and metamorphose in due time, and when their polyps are nearly completed, they start to makeclonal polyps to form colonies. The colonies continue to bud to grow while increasing the polyps,
and a part of the colonies broken by the force of the wave from storm or other sources may settle on
the substrate again, where they grow by the asexual reproduction. An attempt to restore the coral
reefs through transplantation of the coral fragments using layman’s knowledge has been performed
from the 1980’s elsewhere than Japan, and from the 1990’s in Japan. Regarding transplantation of
the fragments, they can be fixed directly on the base rock in destination waters or settled on thesubstrate until they grow and then relocated to destination waters. There is another, patented atechnique that hangs a piece of rope with the fragments into the sea where they have grown(Japanese published application 06-303875). However, the past attempts so far have not sufficiently
investigated elements of fragment relocation such as suitable species, sites, methods and the size offragments, and no long term monitoring has been made much for the state of the corals after thetransplantation and ecological change in the periphery of the transplantation sites. Since it isexpected that the advance of the transplantation techniques will lead to the restoration of coral reefs,
creation of artificial coral reefs, and production and rearing of ornamental coral colonies that canpossibly cause reduction of collection of the natural corals, the information should be enriched. In
Japan, however many of the transplantations were carried out without sufficient scientific planningand the knowledge obtained from the activities is not collected, and thus, positive activities did notnecessarily contribute to the advance of the transplantation techniques. The method is accompanied
by big problems including criticisms against the method that obtains the fragments by breaking thelive coral colonies (hereafter called “donor”), difficulty of standardizing of the method, and highneed labor and other costs for large scale transplantation.
The followings are review of articles in the world with regard to transplantation of coral fragments
based on literatures regarding 71 species in 12 families (revised after Okubo and Omori 2001).
Those that were transplanted the most was the species of the genus Acropora of the Family
Acroporidae (see Table 2-1). In Japan, Acropora formosa, which is generally seen in the moats thatare affected by relatively strong waves, and branching corals such as A. nobilis which is seen in themoats and shallow places of reef slopes that are affected by weak waves are most commonlytransplanted. Results of the fragment transplantation (by species) that were conducted by the Marine

3Parks Center of Japan (1995) in the Sekisei Lagoon and Okinawa General Bureau (unpublished) at
Naha Harbor are shown in Figs. 2-1 and 2-2.

Number of survivals

100
Cyphastrea serailia

80

Porites cylindrica
Acropora cytherea

60

Acropora formosa
40

Acropora nobilis

20

Pocillopora eydouxi
Montipora digitata

0Jul-92 Nov-92 Jun-93 Nov-93 May-94 Nov-94

Fig. 2-1. Change in the number of survivors of seven species transplanted on the St. 9 off the northNo. of colonies

of Kuroshima Harbor, Okinawa (Marine Parks Center of Japan 1995).
80
70
60
50
40
30
20
10
0

St aghorn A cropora
Table- form Ac ropora
Gallax ea f as ci cularis
Seriat opora hy st rix
Mi llepora s p.

Nov
85

Nov
86

Nov
87

Nov
88

Nov
89

Fig. 2-2. Change in the number of survivors of different species transplanted at Naha Harbor,
Okinawa (Okinawa General Bureau, unpublished data)

Results are generally not very outstanding. Although records of long term monitoring are not
many, average survival rates (hereafter referred to as the rate) after 4 years are about 20 %. There ishigh rate for A. formosa, however. The fragments were transplanted two times and the rates were
69% at 43rd month after the first transplantation and 100% at 17th month after the second
transplantation (Okinawa General Bureau, Okinawa Development Agency 1997). It is reported thatthe rate of A. nobilis at 18th month after the transplantation was 82% (Japan Marine Science andTechnology Center 1991). In both species higher survival rates were those transplanted in shallow
waters with strong tidal current, good water quality, and little ocean waves. Lower rates wererecorded in turbid areas with weak tidal current that are separated from open sea at low tide (Marine

4Parks Center of Japan 1993, 1994, 1995). For the branching form A. microphthalma, the rate was
100％ at the 17th month, being the species with high aptness for transplantations (Okinawa General
Bureau, Okinawa Development Agency 1997). The rate of the corymbose form A. prominens was
51.8% at the first year (Auberson 1982); for A. humilis 79.9% at the second year (Clark and Edwards
1995). For A. tenuis that was transplanted by 1, 2 and 4 colonies separately in nearly the sameenvironment, the rate at second year varied to 100%, 50%, 25% respectively (Clark and Edwards
1995). The rates at three different locations using tabular coral A. hyacinthus were 24% at the firstyear (Japan Marine Science and Technology Center 1991), 44% at 17th month (Plucer-Rosario andRandall 1987), and 49％ at the second year (Clark 1997). The rate of A. divaricata was 80.6% at thesecond year with considerably high growth rate (Clark and Edwards 1995). The rate of A. cytherea
was 50% at the second year (Clark and Edwards 1995).
The rates of Montipora foliosa and M. stellata that were transplanted were both 100% at 15thmonth (Okinawa General Bureau, Okinawa Development Agency 1997). That of M. digitata wasover 80％ at the first year at a moat, but the rate was around 10％ in the locations affected bystrong ocean waves and tidal current (Marine Parks Center of Japan 1995).
Pavona frondifera of Agariciidae grew at higher rate and was tolerant against bleaching event(Yap et al. 1992). As compared to this, Leptoseris gardineri showed low rate at any experiment siteranging from shallow to deep waters (Plucer-Rosario and Randall 1987).
For Faviidae, the rate of Echinopora lammellos was 80% on coral rocks at the 3rd month (Kaly
1995). All Leptastrea purpurea and L. transversa died at 28th month later (Clark and Edwards 1995).
Galaxea fascicularis of Oculinidae and Pavona frondifera and others also showed relatively highrate (Japan Marine Science and Technology Center 1991；Clark and Edwards 1995；Plucer-Rosario
and Randall 1987).
For the rate of Pocilloporidae, Pocillopora damicornis were 100% at 7th month (Harriott and Fisk
1988) and 17th month (Okinawa General Bureau, Okinawa Development Agency 1997) respectively.
This species is distributed widely in a variety of habitat environments. As a result of transplantationof Seriatopora hystrix to harbor, the rate was 13% at 43rd month (Okinawa General Bureau,
Okinawa Development Agency 1997), and for Stylophora pistillata, the rate was 39% at 18th month(Japan Marine Science and Technology Center 1991). Both species are deemed to show low ratethough they are pioneer species that establish in the shattered coral reef easily (Bouchon et al. 1981).
So far, the one that showed significantly higher rates was Porites spp. of Poritidae. The rate of P.
lichen was 100％, P. lobata was 97%, and that of P. nigrescens was 84% (Clark and Edwards 1995).
The rate of P. lutea was 92% at the 28th month (Clark and Edwards 1995). As a case of P. cylindrical,
the transplantation to blocked water with more water flows showed good results (Marine Parks
Center of Japan 1993, 1994, 1995). Another experiment in such water, the rate was 75% at the 5thmonth (Japan Marine Science and Technology Center 1991).

5

In the hermatypic corals other than Scleractinia, fragments of Heliopora coerulea of Helioporidae
have been transplanted, and showed the rate of 100% at the first year (Auberson 1982). Millepora
dichtoma of Milleporina, showed 68% at the first year, where as M. platyphylla, 58% at the first year
(Auberson 1982).
In addition, a method has been proposed that electric current be applied to the wire which thefragments are attached for promoting deposition (mineralization) of the carbon ion and calcium ion
contained in the seawater to facilitate the growth of the corals. Although there are some positive
results in abroad (van Treek and Schuhmacher 1997, 1999; Schuhmacher et al. 2000), thisexperiment did not show outstanding results in Okinawa (Kudo and Yabiku 1988).
In the cases of the transplantation of whole colony and coral communities (entire reef),comprehensive survey on the depth, wave action and substrate of the transplantation site is essential,
too, before selecting the new locations. Current knowledge is insufficient however. It is expectedthat the results of observation on the state of coral colony after transplantation will be positive. There
are some report of coral colonies that were cut off together with the base rock and combined tocreate an artificial coral reef. In Japan, a coral reef is removed due to the necessity of port and harboror other underwater construction, and the activities are limited to the relocation of a part of a coral
reef that was cut off to a nearby site (Fukunishi et al. 1998).
The development of coral reef restoration techniques using sexual reproduction was brought up asa research theme at the Akajima Marine Science Laboratory at the beginning of the 1990’s, and the
supporting various fundamental biological observations and experiments were performed withcollaboration from Dr. A. Heyward and Dr. P. Harrison of Australia, Dr. D. Morse and ANC. Morseof the US, and Dr. T. Sugiyama and Dr. M. Hatta of Japan. In this study, the corals were spawned in
the laboratory, or embryos or larvae were collected from the slick or coral colonies on the sea thatare found immediately after the simultaneous spawning, and then bred intermediately in a floating
pond or water tank until the larvae start to settle on a suitable substrate, and then, they weretransplanted to a suitable site. The study was performed under the sympathetic understanding andsponsorship of Nippon Foundation and others. In Australia, the above-mentioned Dr. A. Heywardand others succeeded in seeding production similar to the Akajima case (Heyward et al. 2002).
The studies so far revealed that some species of red algae such as the crustose coraline algae
Hydrolithon reinholdi promote the settlement of larvae (Morse et al. 1996), and some species ofneuro-peptide provide an effect that induces metamorphosis.
The method of intermediate rearing and that of promoting the settlement attained certain
achievements. An attempt is made to raise the possibility of retention and to induce the settlement oflarvae on the substrate by using ocean structures such as breakwaters with finely indented surfaces.
The future research subjects include how to accelerate the growth of polyps after they settle on thesubstrate and to raise their survival. It is necessary to take measures for removing algae that grow on

6the substrate and protecting the polyps from coral eating fish.

Table 2-1．List of coral species used for transplantation of coral fragments

Scientific name

References

Family Acroporidae
Acropora bruggemanni

Auberson (1982)

cervicornis

Becker and Mueller (1999); Bowden-Kerby (1997); Chilcoat et al. (2000)

conferta

Chen and Xiong (1995)

corymbosaChen and Xiong (1995)

cytherea

Clark and Edwards (1995); Marine Parks Center of Japan (1993, 1994, 1995)

digitifera

Clark and Edwards (1995)

divaricata

Clark and Edwards (1995)

echinata

Plucer-Rosario and Randall (1987)

formosa

Okinawa General Bureau, Okinawa Development Agency (1997); Marine
Parks Center of Japan (1993, 1994, 1995); Lindahl (2000); Thongtham(2000)

gemmifera

Clark and Edwards (1995); Kaly (1995); Japan Marine Science andTechnology Center (1991)

humilisClark and Edwards (1995)

hyacinthus

Ashizuri-Uwakai National Park (personal communication); Clark and
Edwards (1995); Japan Marine Science and Technology Center (1991);
Okinawa General Bureau, Okinawa Development Agency (1997); Yap et al.
(1992)

microphthalma

Okinawa General Bureau, Okinawa Development Agency (1997)

nasutaOkinawa General Bureau, Okinawa Development Agency (1997)

nobilisJapan Marine Science and Technology Center (1991); Okinawa
Commemorative National Government Park Office (1999); Nishihira (1994);
Okinawa General Bureau, Okinawa Development Agency (1997)

palmata

Becker and Mueller (1999); Iliff (1999); Bruckner and Bruckner (2001);
Garrison (2002)

prolifera

Bowden-Kerby (1997)

prominens

Auberson (1982)

prostrata

Chen and Xiong (1995)

pulchraYap and Gomez (1984)7

tenuisClark and Edwards (1995)

tumidaAwa Takegashima Marine Park (personal communication)

Montipora digitata

Marine Parks Center of Japan (1993, 1994, 1995)

foliosa

Okinawa General Bureau, Okinawa Development Agency (1997)

prolifera

Auberson (1982)

pulcherrima

Plucer-Rosario and Randall (1987)

Family Agariciidae
Pavona cactus

Plucer-Rosario and Randall (1987); Marine Parks Center of Japan (1993,
1994, 1995)

frondifera

Yap et al. (1992)

lata

Chen and Xiong (1995)

Leptoseris gardineri

Plucer-Rosario and Randall (1987)

Pachyseris rugosa

Chen and Xiong (1995)

Family Astrocoeniidae

Stephanocoenia bournoni

Dodge et al. (1999)

Family Faviidae
Cyphastrea serailia

Marine Parks Center of Japan (1993, 1994, 1995)

Diploria

clivosa

Dodge et al. (1999)

labyrinthiformis

Dodge et al. (1999)

lamellose

Kaly (1995)

Echinopora
Favia matthai

Chen and Xiong (1995); Marine Parks Center of Japan (1993, 1994, 1995)

speciosa

Clark (1997)

stelligera

Kaly (1995)

Goniastrea aspera

Chen and Xiong (1995); Clark (1997)

reticulosa

Clark and Edwards (1995)

Leptastrea purpurea

Clark and Edwards (1995)

transversa

Clark and Edwards (1995)

Montastrea annularis

Gil-Navia (1999); Sanchez et al. (2000)

cavernosa

Dodge et al. (1999)

faveolata

Becker and Mueller (1999); Dodge et al. (1999)

Platygyra rustica

Chen and Xiong (1995)

Family Meandrinidae
Meandrina meandrites

Dodge et al. (1999)

Family Mussidae
Symphyllia agaricia

Chen and Xiong (1995)

8

Family Oculinidae
Gallaxea fascicularis

Chen and Xiong (1995); Japan Marine Science and Technology Center(1991)

lamarcki

Chen and Xiong (1995)

Family Pocilloporidae
Madracis decactis

Dodge et al. (1999)

Pocillopora brevicornis

Chen and Xiong (1995)

elegance

Eakin (2000)

damicornis

Chen and Xiong (1995); Clark and Edwards (1995); Harriott and Fisk
(1988a); Okinawa General Bureau, Okinawa Development Agency (1997);
Yap et al. (1992); Eakin (2000)

danae

Chen and Xiong (1995)

eydouxi

Marine Parks Center of Japan (1993, 1994, 1995)

verrucosa

Japan Marine Science and Technology Center (1991); Chen and Xiong(1995); Clark and Edwards (1995)

Seriatopora hystrix

Okinawa General Bureau, Okinawa Development Agency (1997)

Stylophora pistillata

Japan Marine Science and Technology Center (1991); Kaly (1995)

Family Poritidae
Porites astreoides
cylindrica

Dodge et al. (1999); Gil-Navia (1999)
Japan Marine Science and Technology Center (1991); Marine Parks Centerof Japan (1993, 1994, 1995)

lichenClark and Edwards (1995)

lobataClark and Edwards (1995); Clark (1997)

lutea

Clark and Edwards (1995); Thongtham (2000)

nigrescens

Clark and Edwards (1995)

Family Siderastreidae
Siderastrea sidereal

Dodge et al. (1999)

Family Helioporidae
Heliopora coerulea

Auberson (1982); Clark and Edwards (1995)

Family Milleporidae
Millepora alcicornis

Clark and Edwards (1995)

dichotoma

Auberson (1982)

platyphylla

Auberson (1982)

9

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Becker LC and Mueller E (1999) The culture, transplantation, and storage of Montastraea faveolata,
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Bouchon C, Jaubert J and Bouchon-Navano Y (1981) Evolution of a semi-artificial reef built bytransplanting coral heads. Tethys 10 : 173-176.
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inOkinawa.

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Nishihira M (1994) Transplantation of hermatypic coral using fragments of colonies −Brief method
using bamboo stick−．Biol. Mag. Okinawa 32: 49-56. (in Japanese).
Okinawa General Bureau, Okinawa Development Agency (1997) Research of coral transplantationin the Ishigaki Port. 5pp. (in Japanese).
Okubo N and Omori M (2001) The review of coral transplantation around the world. Galaxea, JCRS
3: 31-40. (in Japanese).
Plucer-Rosario GP and Randall RH (1987) Preservation of rare coral species by transplantation: an
examination of their recruitment and growth. Bull. Mar. Sci. 41: 585-593.
Sanchez et al. (2002) Survivorship, regeneration, and grazing algae effects on transplanted colonies
of Montastraea annularis. Proc 9th Int Coral Reef Symp, Bali. Abstract. P. 229.
Shuhmacher H, Treek P, Eisinger M and Paster M (2000) Transplantation of coral fregments fromship groundings on elecreochemically formed reef structures. Proc. 9th Intl. Coral Reef
Sym. 2: 989-990.
Thongtham N, Panchaiyapum P and Somlap S (2000) Coral rehabilitation studies in the Andamancoast of Thailand. Proc. Intl. Coral Reefs Sym. Abstract: 231

11van Treek P and Schuhmacher H (1997) Initial survival of coral nubbins transplanted by a newtransplantation technology: options for reef rehabilitation. Mar. Ecol. Prog. Ser. 150:
287-292.
van Treek P and Schuhmacher H (1999) Artificial reefs created by electrolysis and coral transplantation: An approach ensuring the compatibility of environmental protection anddiving tourism.

East Coast. Shelf Sci. 49:75-81.

Yap HT and Gomez ED (1984) Growth of Acropora pulchra. Response of natural and transplantedcolonies to temperature and day length. Mar. Biol. 81: 209-215.
Yap HT, Alino PM and Gomez ED (1992) Trends in growth and mortality of three coral species(Anthozoa: Scleractinia), including effects of transplantation. Mar. Ecol. Prog. Ser. 83:
91-101.

Other useful references
Birkeland C, Randall RH and Grimm G (1979) Three methods of coral transplantation for the
purpose of reestablishing a coral community in the thermal effluent area at the Tanguisson
Power Plant. Univ. Guam Tech. Rep. 60pp.
Carlson BA (1987) Aquarium systems for living corals. Int. Zool. Yb. 26: 1-9.
Clark S and Edwards AJ (1995) Coral transplantation as an aid to rehabilitation: evaluation of casestudy in the Maldive Islands. Coral Reefs 14: 201-213.
Delbeek JC (2001) Coral farming: past, present and future trends. Aquarium Sciences andConservation 3: 171-181.
Edwards AJ and Clark S (1999) Coral transplantation: A useful management tool or misguided
meddling. Mar. Poll. Bull. 37: 474-487.
Franklin H, Muhando CA and Lindahl U (1998) Coral culturing and temporal recruitment patterns in
Zanzibar, Tanzania. Ambio 27: 645-650.
Heeger T, Cashman M and Sotto F (1999) Coral farming as alternative livelihood, for sustainable
natural resource management and coral reef rehabilitation.

Proc. Ocean. Intl. PacificRim, Singapore, 171-185.
Heeger T and Sotto F (2000) Coral Firming: A Tool for Reef Rehabilitation and Community
Ecotourism. German Ministy of Environment, German Technical Cooperation and theTropical Ecology Program (GTZ-TöB), 94pp.
Highsmith RC (1982)

Reproduction by fragmentation of corals. Mar. Ecol. Prog. Ser. 7: 207-226.

Lindahl U (1998) Low-tech rehabilitation of degraded coral reefs through transplantation of staghorn
corals. Ambio 27: 645-650.
Oren U and Benayahu Y (1997) Transplantation of juvenile corals: a new approach for enhancing
colonization of artificial reefs. Mar. Biol. 127: 499-505.

12

Rinkevich B (1995) Restoration strategies for coral reefs damaged by recreational activities: the useof sexual and asexual recruits. Res. Ecol. 3: 241-251.
Rinkevich B (2000) Steps towards the evaluation of coral reef restoration by using small branchfragments. Mar. Biol. 136: 807-812.
(Omori M & Okubo N)

13

3. Restoration technology using sexual reproduction

3-1. Seed production
This chapter discusses mainly Acropora coral. On the coral reefs of the West Pacific Ocean
including Okinawa, Acropora provides high species diversity and its existing amount is considerable.
Since the growth rate of Acropora is high, it is considered to be an important coral for coral reef
restoration. Since many Acropora corals spawn simultaneously, their initial loss is large, meaningthat many of the spawn and embryos disappear before they settle. However, since it is effective for
fertilizing corals to collect the eggs in the period immediately after the spawning to the next day andbreed them as the seeding animals.

(1) Sampling of eggs and embryos from the sea
a. Prediction of simultaneous spawning
In Okinawa Prefecture, the corals mainly of Acropora show the simultaneous, mass spawning.
The simultaneous spawning occurs during and around full moon, of each month mainly in May in
the Yaeyama Islands (Hayashibara, personal communication), in June in the Kerama Archipelago(Hayashibara et al. 1993) and also at the Main island of Okinawa (Heyward et al. 1987) (See Fig.
3-1).

genus Acropora

genus Montipora

family Faviidae

othersnew moon20
Number of spawned coral species

full moon

10

0
20

1991

10

0

1992
May

Jun

Jul

Aug

Sep

Fig. 3-1．Pattern of coral spawning at the Akajima Island, Kerama Archipelago(Shows the number of coral species spawned in each of flood tide, middle tide and neap tide)

The period may be moved by one month or separated into two times depending on the lunar cycle
and water temperature. When predicting the date, it is recommended to refer to the records of the14

past spawning dates of each location. Since the shift of the date from the full moon is also affectedby the water temperature, it is recommended to stand by for the spawning in the period from there
days before to seven days after the full moon. The spawning date also can vary among locations in
an island. To forecast the spawning date, break a branch of colony to examine the maturity of thespawn. The egg is colored as the spawning date comes nearer. The bundle appears in the mouth ofpolyps two or three hours before the spawning. Though the time of spawning varies a little
depending on the time of sunset, the species such as Acropora tenuis spawns the most in the period
from 19:00 hr to 19:30 hr, and for many other species, from 21:30 hr to 22:00 hr (Fukami et al.
2003). Some species spawn at around 20:00 hr or in August, however, the number of those species
and population are not many.

b. Sampling eggs immediately after spawning
For Acropora, each polyp emits eggs and sperms as a block (called a bundle). The bundles arebrought up to the sea surface by the buoyancy of the spawn. Then, the eggs and sperms dissociatefrom each other and meet the gametes that are emitted from other colonies to be fertilized. Therefore,
by setting a funnel form bundle collecting device (bundle collector) under water and above the coralcolony, the bundle can be collected easily (Kitada 2002). Schematic view of a typical bundle
collector is shown in Fig. 3-2.

plastic bottle
screw cap
polystyrene foam(buoy)

coral colony
concrete nails

Fig. 3-2．Schematic view of bundle collector

Following are instructions for making the collecting device. Make a cone rigid with fine nylon
mesh or vinyl sheet, and keep the conical form by holding the cone with stainless steel wires. Attacha plastic bottle (capacity of 500 ml to 1 liter) with a screwed cap and a foamed polystyrene float tothe top of the cone. The float holds the bottle at the top of the cone. Use a bottle made of transparent

15

material so that the inside can be seen. Connect the bottle and the funnel together to make the bottle
easy to attach / detach.
Put the bundle collecting device above the coral colony in every early evening in the predicted
spawning period, and fasten it by using strings and concrete nails as shown. Watch the device during
the predicted spawning time and, if no spawning is seen, set out the device again next day. Repeat
this process until the spawning occurs. Leaving the device set on the site can lead to damage to thecoral colony, and may cause loss of the device in case of worsening of the sea state. When the
spawning occurs, remove the bottle immediately after the spawning has ended, close it with the cap,and bring it back to the laboratory. The eggs may die from lack of oxygen if it is left in the bottle inhigh density for long time.
Transfer the collected bundle to other container such as a bucket. Mix the bundles that arecollected from 3 colonies or more per one species of coral to be fertilized. Acropora basically does
not self-fertilize, and the fertilization of gametes from 2 colonies may cause low fertility dependingon the combination of individuals. Also, it is possible that the bundle may be collected fromconcealed Acropora species that can hardly be identified based on the form. Thus, the collection of
the bundles from many colonies is recommended for the purpose of making the fertilization
successful.
The suitable density of gametes at insemination should be the density of sperms that makes thewhite turbidity visible (around 107/ml) and the floating eggs cover the water in the container
uniformly. It is desirable that the insemination work be completed within four hours after the
spawning. Mix the liquid at intervals. Leave it for one or two hours after mixing. Then, skim thespawn and transfer it to a larger rearing bowl (3〜5 liter). Avoid mixing in left over sperms which
can lead to deterioration of the water quality after death. The fertilized spawn (embryos) easily
become abnormal or die at this time of the process.
For the corymbose type coral Acropora tenuis, three colonies of around 30cｍ diam. allow
collection of approximately one million eggs (Shimomura et al. 2002).

c. Sampling eggs and embryos on the morning following simultaneous spawning
In many cases, aggregates of fertilized eggs (called “slicks”) of corals are formed on the morning
following simultaneous spawning, which drift on the sea surface forming a long and narrow strip,
though they are affected by the environmental factors such as the topography of the site, current andweather condition. In Okinawa where mainly fringing reefs exist, the slicks are washed on the shore
in many cases because the coral reefs are located near the land. Since they drift ashore at high tideand die, it is necessary to collect them before they are washed on the shore. The development stageof Acropora coral in this period of time is morula, the blastomere of which is easily dissociated todeath by wave impact on the pier or shore, thus selection of the sampling point(s) is also important.

16

The slick may drift ashore easier to some area of harbors. In this case, the slicks are preserved toaround 10:00 hr in the morning (Fig. 3-3).

Fig. 3-3．Slicks drifting ashore to inside of a harbor

Fig. 3-4．Offshore slicks

The slicks may be found by searching on the sea using a boat (Fig. 3-4). The slicks that areformed offshore (where contamination materials from the land are less) are suitable for raising. It
may be worth searching for slicks on other than the morning following simultaneous spawning at theinvestigation point, because the slicks from the simultaneous spawning at distant points may later17

drift ashore at the investigation points, or the slicks may come alongside the beach on morning of the
day after the next day of simultaneous spawning, which is rare. Conceivably, there will be years
when the slicks cannot be found at all because of the weather conditions.
When collecting the slicks, skim them by using a dipper and put them in a bucket to carry. Since
the simultaneous spawning consists mainly of Acropora, the embryos and larvae that are containedin the slicks are those of Acropora, but those of Montipora may be included. (The larvae ofMontipora can be distinguished from those of Acropora because they are smaller than the Acropora
larvae and contain zooxanthella.) It is necessary to verify the state of embryos by using astereoscopic microscope. The survival may be unsuccessful if many dissociations of blastomere orunfertilized spawn are seen. When much foreign matter is mixed in, it is recommended that live
embryos be selected using a pipette, which is a cumbersome work.

(2) Spawning induction
For small scale experimental research, the spawning can be conducted in the laboratory, or it ispossible to induce the spawning artificially. Though there hardly exist successful cases of theartificial induction of coral spawning, apparently it can only be accomplished with some corals of
Acropora and Montipora by using hydrogen peroxide. The method is as described below(Hayashibara et al. 1996; Ishigaki Tropical Station, Seikai National Fisheries Research Institute1999).
For corymbose type Acropora, after putting the coral colonies collected from the sea, add 2mM ofhydrogen peroxide for three hours or 5mM for two hours, and then, wait for the spawning while
sustaining in the clean flowing water (Fig. 3-5). The spawning by the induction occurs in the period
from 20:00 hr to 23:00 hr of the processing day under natural lighting, which is similar to the case ofnatural spawning in the open air. However, a period of at least 9 hours is needed from the induction
to the spawning (initiation of spawning at higher probability requires 16 hours). If the estimatedspawning time has come before the elapse of the 9 hour period, the spawning should not be
performed that day, and is postponed to the same time of the next day.
Although it is possible to induce the spawning at a desired day and time by using a series ofpractices described above, this spawning induction method may give considerable damage to thecoral colonies, which include secretion of mucus or emission of zooxanthella during the processingin the hydrogen peroxide, possibly leading to death. Since the degree of damage from the hydrogen
peroxide varies among the state and species of the colonies, it is recommended to observe the stateof colonies during the processing, and to adjust the density of the chemical and length exposure asnecessary. Also, mortality can be reduced by rinsing the fragments to remove the hydrogen peroxide
as soon as possible and then putting them in the clear flowing water. The spawning does not occur if
the eggs of the colonies are immature. However, it was confirmed that the gametes obtained from18

matured colonies are fertilized and become planula larvae, and then, metamorphose to be polyps(Hayashibara et al. 2003).
In addition to the above spawning induction method, the spawning time can be changed byadjusting the photo period. By making the environment dark by shielding the light with a camera
obscura or other means after the elapse of 9 hours from the induction, the spawning can be initiatedwithin 2 to 3.5 hours from the time (Iwao 2000).

1. Put the fragments from a coralcolony in the experimental segment,
and sustain them in the flowing water
until the experiment begins.

H2O2

D.W.
2. Stop the flowing water, and addhydrogen peroxide to the experimental
segment, and distilled water to control
site.

3. After the processing, start the water flowing
and breed under natural light condition.

Fig. 3-5．Method of spawning induction of coral using hydrogen peroxide(Ishigaki Tropical Station, Seikai National Fisheries Research Institute 1999)(3) Maintenance and culture
It is possible to rear the larvae by using a bowl if they are held only for small scale experimental
research. The larvae can be sustained in a good condition by transferring them to a new bowl using apipette at a rate of once or more per day. It is desirable that the density of larvae to be reared be lessthan 2000 individuals per one liter of seawater. The standard period needed for commencement ofsettling is 6 days after spawning at a water temperature of 26ºC, or 5 days at 27ºC. The larvae of19many species can sustain the settlement capability for approximately three weeks. The maturity of
the larvae can be known by scattering the cells of larvae on the slide glass using maceration andcounting the number of cnidae (Hayashibara et al. 2000). When performing large scale raising
growth of over 100 thousand individuals, because the larvae are sustained without changing thewater, the density must be lowered. The larvae that have been obtained using bundle collect could bediluted in large water tanks to raise easily, and it was possible to raise 500 thousand individuals per
one ton of seawater (Shimomura et al. 2000) (Fig. 3-6). The water quality can easily be deteriorated
by the foreign matter found among the larvae obtained from the slick and/or death of unfertilized
spawn, and thus, growth at lower density is required. Since the embryos drift on the water surface fortwo days after the fertilization, the exchange of water can be made. The rise of water temperaturefrom solar insolation is a problem when carrying out the rearing outdoors. It is necessary to keep thewater temperature always less than 30ºC, and 27ºC or lower is desirable.

Fig. 3-6．Large scale rearing of larvae indoors

The measurement of density and total number of larvae raised can be ascertained by sampling
approximately 0.1 liter of the seawater used for rearing and counting the number of larvae containedin the water. However, it is very difficult to obtain an accurate count, because the larvae are unevenly
distributed on the water surface in the initial period of the generation and the distribution is
influenced by the wind if outdoors. To prevent negative physical effects on embryos or initial larvae,
avoid stirring and mixing water as much as possible within one day from the spawning. For any
method, it is necessary to sample the water at least three to five times to evaluate the count in order20

to obtain reliable values.

(4) Mass production of larvae

2m
2m

water spray hosemesh screens

1mwater splay hose
pond forcoral larvae
culturebuoys

mesh screens
submersible water pump

Fig. 3-7．Large-scale rearing of coral larvae using floating pond

Rearing of more larvae can be made by using floating ponds on the sea surface (Aota et al. 2002,
Omori et al. 2003). The raft for segmented floating ponds on which the vinyl sheet used for eel
farming is adopted as the water reserve for rearing larvae. A hose with holes made at intervals is run
on the upper part of the reserve, using water taken by underwater pump from the sea around the raft.
The water is sprayed against the side walls to prevent the larvae from attaching to them. The reserve
is provided with water flowing through open screen on four sides and bottom to allow outflow ofseawater entering from the hose. It is necessary to clean the screens (using divers) when they are
clogged with micro algae or other matters. Aota et al. (2003) succeeded in rearing the larvae to over
six million individuals by using eight sets of 2m square floating ponds (1.0 m deep) shown in Fig.
3-7. It is possible to breed larvae to 200−400 inds/l of seawater.

21

(5) Transportation
When the scale of rearing is small, the larvae can be sent to remote places using a general parcel
delivery service or mailing by using a container such as a 1 liter plastic bottle. Akajima Marine
Science Laboratory succeeded in sending larvae alive to the aquaria of Germany and Holland byusing 50 ml tubes (Petersen and Tollrian 2001). When sending a large amount of larvae, a bucketwith a lid or a plastic tank with a small mouth is used for short range transportation. A density oflarvae similar to that for rearing causes no problem. For transportation that takes long time, however,lower the density, and seal the container with a little air space in it to reduce the stress from vibration
during the transportation. When divers release the larvae in the water, a collapsible polyethylene
container (10 liter or 20 liter) is suitable because the divers are able to discharge the water bysquashing it. The recommended time for transportation is fourth day or after from the fertilization
when the larvae ciliated and move actively, and have the tolerance against various stresses. In thistime, the larvae at the density of 3000 ind/l or less can be transported (2-3 days) with survival rate
higher than 90％.

(6) Inducement of settlement and metamorphosis
Though many of the mechanisms of settlement and metamorphosis of hermatypic corals are still
unrevealed, Morse and Morse (1991) demonstrated that the settlement and metamorphosis of thecoral Agaricia humilis larvae produced in Caribbean Sea are induced by eduction from Hydrolithonboergenseii, a kind of coralline algae. By further progressing the study, Morse et al. (1994) made asubstrate for inducing the settlement called “flypaper” from a settlement induction fraction ofcoraline algae, which requires considerable labor. To induce the settlement using the coraline algae,
employ the algal tissue itself or make the chips of algae and add them. The chips can be made byscraping the surface area of the algal tissue using a knife. They can be preserved for over one year ifthey are soaked in a beaker containing rifampicin water solution (2mg/l), washed, filtered to remove
water from the chip, and then deep-frozen. The settlement occurs in 6 to 72 hours after adding thethawed chips and larvae to filtered seawater. In many cases, the larvae settle on the bottom near thechips or corners, and in some case, on the chips. It is demonstrated that the settlement of JapaneseAcropora larvae can be induced when chips of Hydrolithon reinboldii are used (Morse et al. 1996).
Peyssonnelia sp. that belongs to red algae, but is not a species of the coraline algae, can also be
induced to settle at a level equivalent to the Acropora larvae or higher. In may cases, the settlement
rate is 90% or lower (Iwao 1997). Although the settlement induction method using the coraline algae
chips is relatively simple and easier, it may be difficult to obtain the algal tissue in some places, andscraping off chips from hard algal tissue may be laborious.
The use of neuro-peptide Hym-248 promotes higher and more stable settlement induction rate
(Iwao et al. 2002; Hatta and Iwao 2003). Hym-248 is the isolation from freshwater hydra Hydra

22

magnipapillata (Cnidaria, Hydrozoa), which can be artificially synthesized to make the desired
amount. When the larvae are added to the filtered seawater at the density of 1×10-6M, it immediately
reacts by contracting around body axis or rubbing the abactinal end on the substrate or container wall,and the settlement is completed within 12 hours from the addition of the peptide (Fig. 3-8). So far,Hym-248 has been effective only for Acropora larvae. The effect varies according to the age of thelarvae, and the settlement rate is low when the larvae are too juvenile (4 days-old or less). As they
get older, it is possible to achieve the settlement rate of 100%. It has been verified this possibility issustained for two weeks or longer (Iwao 2001).
Recently, bacteria that induce the settlement of Acropora juvenile corals were isolated from thecoraline algae (Negri et al. 2001). Though the settlement rate is around 52%, juvenile corals canpossibly be produced easily if the settlement induction method that uses incubated bacteria isestablished.

Fig. 3-8．The process of settlement metamorphosis induced with neuro-peptide(1) and (2) The planula larvae start to contract around the body axis on the wall of a container filled with seawater, towhich the neuro-peptide has been added. (3) In this stage, the adherence is weak, and thus, they sometimes come off
the container wall and swim while rotating. (4) The settled larvae become flatter in the body axis direction view fromthe above. (5) The barrier membrane is formed. (6) Tentacles and another barrier membrane are formed so that thelarvae are metamorphosed to polyps. “or” and “ab” represent an oral end and an abactinal end respectively.

(7) Substrates
As settlement substrates, materials such as concrete, unglazed tiles, shells, ceramic tiles, ceramic

23

works and slate plates have been utilized (various other materials are utilized by many researchers).
For any material, more larvae settle when substrates are placed in the seawater beforehand, to growsome other biota on the surface than when they are settled without such pre-processing. Brush androughly clean them immediately before using, because the marine life that grows on the substrate
include large sized algae, such as brown algae, grass-like algae, and/or colonial tunicate that preventthe juvenile corals from the settling or rot during the settlement in a static water tank, resulting inadversely affects to settlement and later metamorphosis. The larvae settles in as early as one day, orin five days at the latest (Fig. 3-9).
Although it is reported that the submergence of the substrate beforehand in the sea for one year orover provide good result, coral settles well after three weeks (Taniguchi 2002).

Fig. 3-9． Juvenile corals settled on the substrate, and the enlarged view (right)

Since more larvae settle inside irregular areas, the substrates with numerous declivities in structure
are considered effective for the settlement. However, the most suitable form has not been clearly
identified. Though many larvae also settle on the upper surface of substrates, sediments or
propagation of algae can easily cause depletion, and in many cases, they can be destroyedcompletely.

(8) Introduction of larvae to substrate
Set up a tent (use only the lining that can pass water well) on the sea bottom, put the settlement
substrate in it, and induce the larvae into it to obtain juvenile corals (polyps). With this method, thepolyps can be produced on a large scale because it is not necessary to control artificially the watertemperature and to be concerned about evaporation of water, both considerations when settling thelarvae indoors.
Production of the polyps can be done on a larger scale. In a collaboration between Tetra Inc. and
the Akajima Marine Science Laboratory, they made a nursery that had been surrounded by a vinyl
cloth or by a nylon mesh enclosure (5.5 m long, 5.5 m wide, and 6.0 m high), made of a sheet in the24sea of Naha Harbor. They discharged 1.64 million individuals of juvenile corals, brought with a boat
from Akajima, using divers to settle them on the blocks that had been set on the sea bottom of thenursery (Aota et al. 2003, Omori et al. 2003).
There is another method that puts the collected slick in a floating pond on the sea. It rears them;moves the floating pond to the destination; raises the water level of the floating pond by pumping
seawater into it, through the water circulating opening; and leads the larvae into the tent on the sea
bottom through a tube extended from the lower section, by using hydraulic pressure to induce themto the settlement substrates that are arranged on the sheet (Heyward et al. 2002) (Fig. 3-10).

Fig. 3-10．An example of a method that induces larvae to the tent on the sea bottom
from a floating pond (Heyward et al. 2002)(9) Culture of polyps on substrate
When polyps settled on the substrate are put in a water flowing tank or on the coral reef, it has
been verified that the zooxanthellae are brought into the body within one week. Since the polyps that
do not symbiose with zooxanthellae die before long, it is important to start the symbiosis well before
then. The newly settled polyps may be easily predated or scraped by sea-urchins and/or Gastropoda,
or covered with sediment, algae, colonial tunicate and/or Bryozoa, resulting in death by blockage.
Though it is desirable to breed them in an environment from which such causes of death have been25

removed, no certain method of removal has been established at this time. Some researchers haveraised initial polyps to large colonies (Misaki 1998, 2002), but no successful rearing of an initiallylarge population has been reported yet. Omori (pers. comm.) attempt to culture polyps with juvenilesof turban snail that remove micro-algae on substrate. When setting substrates that support polyps
outdoors, they should be set so that the surface with the polyps faces downward or sideways, toavoid of them to be buried in sediments or by overgrowth of algae. To reduce the labor for setting,and to set the polyps surface sideways, it is desirable to put multiple substrates with holes onto thestainless steel rods and set them on the sea bottom. At this time, to prevent predation of polyps byfish, and the invasion of

sea-urchin and/or Gastropoda place a spacer 5 to 10 mm long in between

the substrates, and increase the spacer distance as the polyps grow.
Fig. 3-11 shows the settled and grown Acropora florida of which the planula larvae were sentfrom Akajima Marine Science Laboratory to the Rotterdam Aquarium, Holland.

Fig. 3-11．Acropora florida at the Rotterdam Aquarium. Grown
from larvae sent by Akajima Marine Science Laboratory

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Morse DE, Morse ANC, Raimondi PT and Hooker N (1994) Morphogen-based chemical flypaperfor Agaricia humilis juvenile corals. Biol. Bull. 186: 172-181.
Negri AP, Webster NS, Hill RT and Heyward AJ (2001) Metamorphosis of broadcast spawning27

corals in response to bacteria isolated from crustose algae. Mar.Ecol. Prog. Ser. 223:
121-131.
Omori M, Aota T, Watanuki A and Taniguchi H (2003) Development of coral reef restoration methodby mass culture, transportation and settlement of coral larvae. Toward the Desirable
Future of Coral Reefs in Palau and Western Pacific, Proceedings. Palau International
Coral Reef Center Publication. No.04-001: 31-38.
Petersen D and Tollrian R (2001) Methods to enhance sexual recruitment for restoration of damaged
reefs. Bull. Mar. Sci. 69: 989-1000.
Shimomura Y, Hatta M, Watanuki A, Aota T and Iwao K (2002) Mass rearing of Acropora larvae forcoral seeding production. Abstracts of 5th Symposium of the Japanese Coral Reef
Society: 19. (in Japanese)
Taniguchi H (2002) Study on seeding production of hermatypic coral：examination of conditions forintermediate rearing. Abstracts of 5th Symposium of the Japanese Coral Reef Society:19. (in Japanese)(Hatta M, Iwao K, Taniguchi H and Omori M)

28

3-2. Manufacture and placement of artificial substrates for coral settlement

This is a method that makes irregularities of approximately 1 to 3 cm on the surface of marine
structures, such as breakwaters to facilitate the settlement of juvenile corals. It is expected that the
turbulence of microscale flows produced by the complex shape of the substrate surface can make thelarvae stay on the surface with a higher possibility of settlement when they come near. It is also
estimated that the surface irregularities can reduce the danger of predation and scraping fishes andsea-urchins after the settlement. Since many of the marine structures are made of concrete, it is easy
to make irregularities on the surface when manufacturing them. The irregularities can be made on
the wave-dissipating blocks that are placed in front of breakwaters and foot protection blocks thatare placed behind the structures (Fig. 3-12).

Caissoncaissonwave-abaiting
blocksmoundroot hardening blocks

Irregularities on blocks

processing bumps on blocks

Fig. 3-12. Breakwater areas with irregularities for coral substrates(Harbor & Marine Environment Laboratory 1999)

For making the irregularities on the blocks, the following methods have been considered (Harbor& Marine Environment Laboratory 1999):a) Chiseled: The concrete mould of the block form is made irregular by using chiseled interior
forms.
b) Drilled: Holes are made with a drill bit on the block after manufacture.
c) Streaked: Concrete is sprayed on the block surface to form the irregularities.
d) Square bar: Adhesive or bolts are used to fasten secondary products such as square bar, plates,or concrete cement on the block surface to form the irregularities.
According to research relating coral settlement success to various process to manufacture blocks
with requisite irregularities (Harbor & Marine Environment Laboratory 1999), there is an indicationthat the use of forms which have been affixed secondary products that produce a high degree ofroughness can produce more coral colonies (Fig. 3-13). As for the inclination of the substrate, there
was a an indication that both the coral coverage and the number of colonies are larger on the29horizontal surface or 45 degree surface than on the vertical surface at the depth of around 2 m, but nosuch difference was recognized at the depth of around 10 m.

Square bar
Streaked
DrilledChiseled
No. of coral colonies

Smoothed

’91

’92

’93

’94

’95

’96

’97

Year

Smoothed

Chiseled

DrilledSquare bar(control)(Grooves made(Holes(concrete squarewith a chisel)

made with abars are affixed)

drill bit)

Fig. 3-13. State of settlement of corals at the processed areas of substrate(Harbor & Marine Environment Laboratory 1999)

The only possible waters for the placing substrates are environments that the corals can readily30inhabit. Though it seems that any current coral area allows settlement corals, the settlement of larvae
cannot be expected in the areas where the transparency is low and the sediments are significant.
They may die out due to the luck of enough lighting or covering sediments even after the settlement.
As a result of experimental settlement of Acropora tenuis and Heliopora coerulea larvae undersuspended red soil or sediments, both species showed reduction of the settlement rate and secretionof mucus (Harii et al. 2002). As a red soil contamination guideline for maintaining the coral
communities healthy, Omija et al. (2003) defined the annual maximum permissible value of SPSS(Content of suspendible particles in seabed sediment) as 30 kg/cm3.
Yamamoto et al. (2002) researched the coral coverage and habitat environment on the artificial
structures in Naha Harbor, and classified areas unsuitable for the growth of coral and those thatallow growth. As a result, they identified suitable environmental conditions for the growth of corals,
on which numerical data are shown in Table 3-1.

Table 3-1．Environmental conditions suitable for growth of coral communities
in Naha Harbor (Yamamoto et al. 2002)
Environmental item

Mean value ±sd

Wave height in front of breakwater (m)8.4±3.4

Salinity

34.7±0.1

Transparency (m)13.7±3.5SS(mg/l)

1.2±0.5

COD (mg/l)

0.8±0.1

TN (mg/l)

0.15±0.04

TP (mg/l)

0.012±0.005

Heeger & Sotto (2000), who studied coral transplantation, after the following set of the suitableenvironmental conditions for transplantation without indicating the relevant species (Table 3-2).

Table 3-2．Suitable environmental conditions for transplantation (Heeger & Sotto 2000)
Environmental item

Optimal value

Water temperature

22℃-30℃ (25℃ is desirable)

Salinity

32 to 36

Transparency

12ｍ or more

Tidal current

1ｍ/s or lessDepth

6 to 12ｍ

Sediment

Sand or algae community dotted

Remarks

Free from effects of rivers

Shallower areas are easily affected by drift sand.

with coral communities

31Since coral eggs and larvae drift for about five days near the surface, they are affected much by
the wind, which varies according to the weather conditions at the time. Therefore, the situation ofcoral recruitment for resettlement at a given place generally varies from year to year (Marine Parks
Center of Japan 1995). But, macroscopically, there may exist some places with a repeatedly highpossibility of retention of larvae, caused by middle scale turbulence and counterflow produced by
the bottom topography and constant flow of current. The frequency of the recruitment may be highin such places.
The depth for this purpose can be determined by noting to the depth of water peripheral to areasthat corals inhabit. The coral inhabitable depth varied depending on species, but in many cases canbe from the low tide level down to 30m as far as the transparency is good (Fig. 3-14).
Manufactured structures must be placed in the sea before the coral spawning, as a matter of course,which varies according to place and from year to year. In Okinawa’s coral reef areas, the spawning
begins in May, in the years that water temperature is higher range, and usually in July or August in
Honshu and Kyushu areas. The time of placement of structures should be determined by taking into
consideration the period needed to adapt the concrete for the seawater, and in addition, strategies toprevent algae attaching to the substrate and disturbing the coral settlement, or even can covering thesubstrate. However, it may be acceptable that the substrates are covered with some crustose red algae
because some of them encourage recruitment of coral larvae. As a result of experimental settlementof Acropora hyacinthus and A. tenuis larvae on artificial substrates (unglazed tiles) that were
submerged in the sea for three weeks, six months and one year respectively, it is reported that thesubmergence longer the more settled larvae. Larvae settled on the coralline algae that covered thesubstrates, which itself had varied lengths of time to become established (Taniguchi 2002). However,if the algae other than the coralline algae and/or sea squirts, sea sponge, Bryozoa or other competing
sessile animals cover the substrates, they must be removed.

Fig. 3-14．Pocillopora damicornis on breakwater wave-dissipating blocks (Ishigaki Harbor)32

Literature Cited
Harbor and Marine Environment Laboratory (1999) A Draft Manual on Harbor Construction
Harmonized with Coral Reef, 99+27pp. (in Japanese)
Harii S, Nadaoka K, Iwao K and Hayashibara T (2002)

Effect of red soil on settlement of juvenile

corals．Abstracts of 5th Symposium of the Japanese Coral Reef Society: 17. (inJapanese)
Heeger T and Sotto F(2000) Coral Farming: A Tool for Reef Rehabilitation and Community
Ecotourism. 9pp.
Marine Parks Center of Japan (1995) Study on recovery of coral reef ecological system．87pp. (inJapanese)
Taniguchi H (2002) Study on production of hermatypic coral larvae and polyps : examination of
conditions for intermediate rearing. Abstracts of 5th Symposium of the Japanese Coral
Reef Society: 19. (in Japanese)
Yamamoto, H. Takahashi Y, Sumida K, Hayashi T, Sugiura N, and T Maekawa T(2002)

Analysison growing process of coral community in the artificial structure．Proc. Coastal
Engineering, Japanese Soc. Civil Engineering 49：1186-1190. (in Japanese)(Fujiwara S)

33

4. Restoration technology by using asexual reproduction

4-1. Transplantation of coral fragments
It is desirable that the transplantation projects are developed by taking full advantage of theexperiences that have been obtained and enhancing more knowledge through experiments based on
the well planned methods and long time observations in the transplantation sites, time, locations,fixing method, substrates, and other factors.

(1) Sampling of fragments from donor coral
The most important matter here is that not to many fragments should be collected from a single
donor colony at a time, to minimize the effect of collection on the colony. There is little
physiological knowledge about the effects of the collection of the fragments on the reproduction ofdonor colony (Szmant-Foelich 1985, Smith and Hughes 1999, Koji and Quinn 1985, Zakai et al2000).
When collecting the fragments from a donor colony for transplantation, the colony and thefragments are not damaged severely if a wire cutter or underwater scissors are used for branchingcorals or a hammer and a chisel are used for tabular, corymbose, massive or other forms of corals, tobreak them at a blow. It may be possible to use the fragments broken by typhoon or other naturalcauses for the transplantation. Bruckner and Bruckner (2001) conducted transplantation of fragments
generated by ship groundings. The result is that surviving fragments (57%) were larger than deadfragments (26%).

(2) Size of suitable fragments
Generally, it is expected that the larger the transplantation fragments are, the higher the survival
rate is. However, because taking larger fragments can damage the donor colonies, the most important
point in the future experimental transplantation will be to define the minimum acceptable size whichallows a survival rate of 100%. To achieve this, the environmental conditions, such as the time fortransplantation, which are discussed later in this document, should be taken into consideration (caseexamples described in Chapter 6-2).
So far, fragments of 2 to 30 cm long or in diameter, or colonies of these sizes (entire donorcolonies) have been transplanted. As a result of transplantation of fragments of Montastrea faveolata,
which forms settling type massive colonies, with diameters ranging from 2.5 to 5.1 cm, the survival
rate at 9th month after the transplantation was 75%, and thus, Becker and Muller (1999) estimatethat even the colonies of diameters less than 2.5 cm can be transplanted.
However, for the transplantation of Acropora echinata and Pavona cactus colonies consisting of
three size groups, 5 to 10 cm, 10 to 15 cm, and 15 to 25 cm, and the fragments consisting of two size

34

groups, 2 to 4 cm, and 3 to 6 cm, no difference of mortality rate were seen among the three sizegroups of the colonies, but the mortality rate of many of the fragments groups were higher than thatof the colony groups (Plucer-Rosario and Randall 1987). As a result of the experiment that compared
three size groups of fragments Acropora prolifera, 3 to 5 cm, 8 to 12 cm, and 15 to 22 cm, smaller
fragments clearly showed higher mortality rate (Bowden-Kerby 1997). According to these results, it
can be said that the survival rate can be higher when the coral is transplanted in colonies than whentransplanted in fragments, and the rate can be higher when the coral is transplanted in large fragmentsize.

(3) Transportation
Regarding the method of transportation, not much difference can be seen among the researchers(Okubo and Omori 2001). The principal methods include the use of divers, who carry fragments incontainers without taking them out of the water if the destination is near (Dodge et al. 1999), or, if
the destination is far, a boat is used to carry the fragments in wire mesh bag or net bags hung in thewater from the boat (Dodge et al. 1999; Munoz-Chagin 1997). The fragments may be carried inwater-filled buckets on deck (Bowden-Kerby 1997), however, when using this method, it isnecessary to be careful that the water in the bucket is not warmed up during transportation in a hotseason.
Basically, it is desirable to transport the fragments without taking them from the sea. The
possibility that the transplantation fragments can survive transport in the air varies among the coral
species. Fragments of Acropora gemmifera and Favia stelligera can be transported out of the water
if the period is up to approximately 2 hours, but Stylophora pistillata or Rumphella sp. must betransported while submerged in water (Kaly 1995). Urabe et al. (2003) reported that the tolerance ofcoral communities to drying is higher for Fungia or massive corals and lower for branching corals,
and as a general tendency, watering is effective, but mere light shielding is not effective.

(4) Fixation methods and choice of fragments
Some methods of fastening coral fragments that have been used are listed below (Fig. 4-1).
1) In many cases, epoxy waterproof cement is used for fastening fragments on the substrate.
First, remove algae and other foreign matters from the substrate by using a wire brush or othermeans. Place the fragments on the substrate vertically or horizontally and adhere them withepoxy cement. In some past cases, regular industrial cement was used instead of thewaterproof cement. Since the transplanted corals can easily come off the substrate when only
this method is used, some supplemental methods are used additionally (Fig. 4-1-a).
2) Put a small plant pot in the hole made on the coral rocks used as the substrate, insert a coralfragment into each pot, and fix them by using cement that has already been mixed with35

freshwater on land beforehand (Auberson 1982)(Fig. 4-1-b).
3) Put the cement with retardant in a small polyethylene bag, and then put the bag on a concrete
mat. Then, insert the fragments or colonies into the cement in the bag and fix them. For the
fragment of 10 cm or longer, put concrete nails in the bag and fasten the fragment to the nails(Clark and Edwards 1995) (Fig. 4-1-c).
4) Put the cement with retardant in a nylon bag, insert the fragments into the bag, attach a hook
for securing the bag to the substrate, and then, keep the bag in the water tank until the cement
hardens. When the cement has hardened, fasten the bag to the base rock by using the hook anda rope (Clark 1997) (Fig. 4-1-d).
5) Put nails in the substrate for transplantation, and fasten the coral fragments to the substratewith wires or cable ties (Iliff et al. 1999; Okubo and Omori 2000; Okubo et al. 2001, 2002)(Fig. 4-1-e).
6) Skewering: Drill a hole at the center of each coral fragment, and run a bamboo skewer
through the hole. Make holes on the substrate for transplantation by using an underwater
drilling machine, and put the bamboo skewers with the fragments in the holes (Nishihira1994) (Fig. 4-1-f).

When fragments are attached to the nails that have been put on the substrate and fixed with cableties (Fig. 4-1-e), the fragments of some species that do not settle on the substrate easily because of
their mode of growth can increase the risk of the nails dislodging from the substrate as the years passafter the transplantation. Since the nails do not come off after the cable ties are cut, the loss of thefragments can be prevented more surely by fastening the nails to the substrate with epoxy cement.
Since the chemical effects of epoxy cement on transplanted fragments have not been assessed,
segments should be transplanted after the cement has hardened. Before applying the waterproof
cement, it is necessary to remove the algae and other foreign matter from the substrate by abrasion,using a wire brush. A vertical orientation of fragments, fixed to the substrate is recommended tominimize the deposit of sediment (Okubo and Omori 2000; Okubo et al. 2001, and Okubo et al.
2002).

(5) Choice of place
Since the optimal growing conditions of corals vary among the species, it is necessary toinvestigate the location that the donor colony inhabits, which is the source of the fragments, and thelocation to which the fragments are transplanted, with attention to their respective physical condition(wave, tidal current, turbidity, depth, light intensity, amount of sediments, salinity etc.) prior to thetransplantation. The survival rate of transplantation is higher when the environmental characteristicsof the two locations are similar, and it is lower when the fragments are transplanted to an unfamiliar

36

Fig. 4-1 Method of fastening coral fragments

environment (Auberson 1982; Marine Parks Center of Japan 1993, 1994, 1995).
It is also necessary to investigate the location to which the fragments are transplanted in order todiscover whether marine life such as crown-of-thorns starfish or coral-eating gastropods that predate
the corals are present. For the marine park zone in Ashizuri Uwakai National Park, Kochi Prefecture,
Japan, the survival rate at the first year after the transplantation was 0% in the past three attempts
because of mass populations of coral-eating gastropods in the location (Ashizuri Uwakai National
Park, personal communication).
One experiment placed fragments collected from three forms of Acropora, ie. Acropora intermedia(branching), A. millepora (corymbose form) and A. hyacinthus (tabular), on the reef flat, reef ridge
and reef slope, without fixing them (Smith and Hughes 1999). Their survival rates at the 17th month
later were 37% on the reef flat, 15% on the reef ridge, and 10% on the reef slope. Rates of settlementon the substrate were 39% on the reef flat, 31% on the reef ridge, and 4% on the reef slope. The
exposition of these results noted the following matters: the growth rate of the fragments placed on37

the reef flat is higher than that on the reef ridge, because the chance that the fragments placed on thereef flat are shielded from the sunshine by the surrounding tabular corals is less; the fragments caneasily settle on the reef flat, which consists of the coral rocks with the hard sediment; and thus, thenumber of fragments that are killed by the covering sediments is less.

(6) Preferable substrate
When it is necessary to transplant coral fragments on the underwater structures, it is very useful tounderstand what kind of substrate can permit make the corals to settle easily. There was anexperiment for comparing the suitability for settlement among five types of substrates, including
ferrite-containing concrete, unglazed tiles, concrete blocks and iron that are frequently used forunderwater structures, and natural coral rocks (Okubo 2003). As a result of this experiment, thefragments that showed the higher settlement rates were those transplanted on the concrete andferrite-containing concrete. Ikeda and Iwao (2001) transplanted 10cm fragments of Acropora.
formosa on the substrate for transplantation that was made of concrete mixed with coal ash, which isan industrial by-product, using the method just described. As a result, the settlement rate was nearly
equal to the fragments that were transplanted on regular concrete. Based on both of these results, it isestimated that the coral fragments can settle on concrete substrates easier than on other materials, foras yet reasons unknown.

(7) Preferable season
Most transplantations have been performed in warm periods when the monthly average airtemperature is in the range from 24 to 28 ℃. However, since the locations, coral species, their
fixing methods and other factors affecting past transplantations are different from each other, it is
impossible to compare them, in order to fix the most suitable time for the transplantation. Thus, thepresent author have performed experiments using the same materials and methods, and onlychanging the transplantation time, which are discussed in Chapter 6-2.
Four experiments were carried out in the subtropical region where the range of water temperatureis relatively large (the monthly average air temperature is in the range from 26.6 to 28.3 ℃) in a
warm season, using the fragments of nearly the same size and the similar methods. Though thespecies were different, the average survival rate at the 3rd month after the transplantation was 98.5%
in a total of 13 species including Dichocoenia stoksii, Montastrea cavernosa and Porites astreoides,
etc. (Dodge et al. 1999), and the survival rate at 43rd month after the transplantation of Acropora
formosa was 69% (Okinawa General Bureau, Okinawa Development Agency 1997). For Acropora
echinata, the rate at an unknown time after the transplantation was 46％ (Plucer-Rosario andRandall 1987). Thus, the results vary much among the species.
As a result of investigations of the relationship between the mortality and temperature an positive38

correlation was shown (Yap and Gomez 1984; Yap et al. 1992). The mortality is raised in a highwater temperature period by the stress from the transplantation and bleaching.

Literature Cited
Auberson B (1982) Coral transplantation; an approach to the re-establishment of damaged reefs.
Kalikasan 11: 158-172.
Becker LC and Mueller E (1999) The culture, transplantation, and storage of Montastraea faveolata,
Acropora cervicornis, and A. palmata: what we learned so far. Natl. Coral Reef Inst.
Abstract: 53.
Bowden-Kerby A (1997) Coral transplantation in sheltered habitats using unattached fragments andcultured colonies. Proc. 8th Intl. Coral Reef Sym. 2: 2063-2068.
Bruckner AW and Bruckner RJ (2001) Condition of restored Acropora palmata fragments off Mona
Island, Puerto Rico, 2 years after the Fortuna Reefer ship grounding. Coral Reefs 20:
235-243.
Clark S and Edwards AJ (1995) Coral transplantation as an aid to reef rehabilitation: evaluation of acase study in the Maldive Islands. Coral Reefs 14: 201-213.
Clark T (1997) Tissue regeneration rate of coral transplants in a wave exposed environment, Cape
D’Aguilar, Hong Kong. Proc. 8th Intl. Coral Reef Sym. 2: 2069-2074.
Dodge RE, Anderegg D, Fergen R, Cooke P (1999) Sewer outfall coral transplantation project. Natl.
Coral Reef Inst. Abstract: 80.
Harriott VJ and Fisk DA (1988) Coral transplantation as a reef management option. Proc. 6th Intl.
Coral Reef Symp. 2: 375-379.
Ikeda Y and K Iwao (2001) Coral transplantation to hardened coal ash. Abstract of 4th Symposiumof the Japanese Coral Reef Society: 38.
Iliff JW, Goodwin WB, Hudson JH, Miller MW and Timber J (1999) Emergency stabilization of
Acropora palmata with stainless steel wire and nails: impressions, lessons learned, andrecommendations from Mona Island, Puerto Rico. Natl. Coral Reef Inst. Abstract: 110.
Kaly UL (1995) Experimental test of the effect of methods of attachment and handling on the rapid
tranplantation of corals. CRC Reef Research Centre Tech Rep (1) 28pp.
Koji BL and Quinn NJ (1985) Puberty in Goniastrea favulus: age or size limited? Proc 5th Int Coral
Reef Congr, Tahiti, 4： 289-293.
Marine Parks Center of Japan (1993)

Study on Recovery of Coral Reef Ecological System. 42pp.

(in Japanese)
Marine Parks Center of Japan (1994)

Study on Recovery of Coral Reef Ecological System. 86pp.

(in Japanese)
Marine Parks Center of Japan (1995)

Study on Recovery of Coral Reef Ecological System. 87pp.

39

(in Japanese)
Munoz-Chagin RF (1997) Coral transplantation program in the Paraiso Coral Reef, Cozmel Island,
Mexico. Proc. 8th Intl. Coral Reef Sym. 2: 2075-2078.
Nishihira M (1994) Transplantation of hermatypic coral using fragments of colonies −Brief method
using bamboo stick−．Biol. Mag. Okinawa 32: 49-56. (in Japanese)
Okinawa General Bureau, Okinawa Development Agency (1997) Research of coral transplantationin the Ishigaki Port. 5pp. (in Japanese)
Okubo N and Omori M (2000) Optimal transplantation method of Acropora muricata (formosa).
Abstract of 3rd Symposium of Japanese Coral Reef Society: 18. (in Japanese)
Okubo N and Omori M (2001) The review of coral transplantation around the world. Galaxea, JCRS
3: 31-40. (in Japanese)
Okubo N Omori M and Motokawa T (2001) Optimal transplantation method of Acropora muricata(formosa). Abstract of 4th Symposium of Japan Coral Reef Society: 5. (in Japanese)
Okubo N, Taniguchi H, Omori M and Motokawa T (2002) Optimal transplantation method of threehetero-morphological Acropora species. Abstract of 5th Symposium of Japanese Coral
Reef Society: 20. (in Japanese)
Okubo N (2003)

Moderate substratum for coral transplantation. Midoriishi 14: 32-34.(in Japanese)

Plucer-Rosario GP and Randall RH (1987) Preservation of rare coral species by transplantation: an
examination of their recruitment and growth. Bull. Mar. Sci. 41: 585-593.
Smith LD and Hughes TP (1999) An experimental assessment of survival, re-attachment andfecundity of coral fragments. J. Exp. Mar. Biol. Ecol. 235: 147-164.
Szmant-Foelich A (1985) The effect of colony size on the reproductive ability of the Caribbean coral
Montastrea annularis (Ellis and Solander). Proc 5th Int Coral Reef Congr, Tahiti, 4：
295-300.
Urabe S, Kobayakawa H, Maehara H, Hayashi T, Takahashi Y and Tamura K (2003) Dry-tolerance
field experiment on transport of corals.

Abstract of 6th Symposium of Japanese Coral

Reef Society: 60. (in Japanese)
Yap HT and Gomez ED (1984) Growth of Acropora pulchra . Responses of natural andtransplanted colonies to temperature and day length. Mar. Biol. 81: 209-215.
Yap HT, Alino PM and Gomez ED (1992) Trends in growth and mortality of three coral
species (Anthozoa: Scleractinia), including effects of transplantation. Mar.
Ecol. Prog. Ser. 83: 91-101.
Zakai D, Levy O and Chadwick-Furman NE (2000) Experimental fragmentation reduces sexual
reproductive output by the reef-building coral Pocillopora damicornis. Coral Reefs
19:185-188.
(Okubo N)40

4-2. Transplantation of juvenile corals

During the investigation of corals in the Sekisei Lagoon, the present authors found that the densityof juvenile corals (at the first and second year after the settlement) per unit area varied significantly
among the locations. Although this is a phenomenon that has been known generally, it can be a
problem when a number of larvae of, for example, Acropora that becomes tabular or branchingcorals settle on the shallow area of a reef washed by rough waves. These juvenile corals are easily
broken by the waves as they grow, and thus, they can rarely grow to maturity. So, we decided tocollect such juvenile corals to transplant them to an area suitable for growth and development.

(1) Sampling
The larvae of corals settle in cracks or depressions found on coral reefs. Many of them also settleon the surface of corals that have just died and not yet covered by other marine life. It is assumed
that larvae settle largely in such patterned and indented surfaces because they tend to survive better
after settlement. The larvae start to grow outward from the declivities approximately one year fromsettlement, and become around 1 cm in size, which is clearly visible. Many of these juvenile corals
can be seen in shallow waters on the reefs that are washed by rough waves, and the density
frequently reaches several tens of individuals per one square meter or more. Individuals needed fortransplantation can be obtained by collecting these juvenile corals together with the substrate.
Then, we attempted to collect juvenile corals for the transplantation by using a dry land pneumatic
drill. They can be taken relatively easily by using a core sampling bit, with sufficiently big bore forthe size of the colony (juvenile coral). This method takes not only the juvenile corals, but also thesubstrate coral reef as a short core 3 to 4 cm long, which is easy to transport (Figs. 4-2 and 4-3).

Fig. 4-2．Natural juvenile corals and core sampling bit

41

Fig. 4-3．Core sample of juvenile corals

Fig. 4-4．Transplanted core sample of juvenile corals (fixed with adhesive)(2) Method of transplantation
When juvenile corals collected with substrate are kept in the sea for a long time during
intermediate rearing before transplantation, it is necessary to cover the substrate with vinyl tape toprevent sessile organisms from attaching to the surface of the core base. At the destination where thecoral is to be transplanted, use the core sampling (the same size as the one used for removing thecore ) to make a hole for fixing. Put a little underwater adhesive in the hole, and then insert thejuvenile coral, applying additional adhesive to complete the fixing. In the case of an environment inwhich silt be easily deposited, it is desirable to make the hole shallower than the height of the core sothat the juvenile corals protrude from the bottom a little (Fig. 4-4).

(3) Evaluation of the method
Conventional transplantation methods over the past few decades have used a part or entire colony,
and the biggest concern has been fixing the coral securely to the substrate. The primary difficulty has
42been that corals have various forms, and thus no single fastening method has been adequate for all ofthem. In addition, it is well known that survival after transplantation is affected by variable that canhardly be controlled, such as the risk of human error in the fixing work and the handling of corals
during the work.
The core sampling drill technique described above appears to deal with these risks and variables
most satisfactorily. During transit in the sea or on a boat, the juvenile corals are not normaly
damaged even if a large number of cores are put vertically in container. Also, the core samplingtechnique allows the use of a simple and assured mechanism that drills a hole in the substrate for theremoval and transplantation. It fastens the core using adhesive. Therefore, the removal andneimplantation phases can be better standardized and the risks during travel reduced.
As discussed above, it is technically possible to collect the naturally settled and grown juvenile
corals to utilize them for the transplantation. Corals can be severely damaged by the bleaching
events and the predation of the Crown-of-Thorns starfish, so sometimes it is advisable to perform
mass collection of the juvenile corals, which is a key to regenerating corals. But this should be done
under substantial regulation. It is a fact that the places where the juvenile corals settle naturally are
not always suitable for growth and development. If they are to be moved, then the decision must be
made by experts of this field.

In conclusion, an attempt to collect juvenile corals to utilize them for the transplantation can be
implemented under the lead of the experts if it is performed on a small scale (several thousand
juvenile corals). Several tens of thousand or more may have to be collected, for large scale
restoration project, but it is harder to find sufficient numbers in Okiawa for movement to new sites.
(Okamoto M & Nojima S)

43

5. Transplantation of whole coral colonies and coral reefs

5-1. Transplantation of whole coral colonies
Depending on species and size, there are several methods to recover and transplant coral
communities, if coral communities are threatened by a development work on the shore (and there isno other choice but to save them than transplantation). Chapter 6-3 introduces the example case of
Porites lutea colonies. Massive Porites exceed 1m in diameter, which is unsuitable for the usualtransplantation method that uses fragments of colonies. Therefore, whole colonies have to betransplanted together. The example is a case of colonies which range from 20 to 30 cm in diameter,
which are relatively easy to handle.
As the first step of Porites transplantation, the colony base is separated from the bottom using achisel, taking care not to damage to the corals, and the base is put into a container under water,transported to the destination, and then adhered to the substrate using waterproof cement. As thesettlement substrate, two types, an artificial substrate made of concrete plate and a natural base rockwere used. For the case of the natural base rock, a method that drives anchor bolts into the colonybase to fix them was used, which was demonstrated to be effective.
As a result of a follow-up survey four years following the transplantation, both the survival andgrowth of the corals on the natural base rock were better than on the artificial substrate. For themassive Porites, which is usually distributed in reef moats, it is recommended that they betransplanted to moats. However, moats generally provide no suitable substrates for settlement,
because they frequently have sandy or gravel bottom areas. Nevertheless, if there is no other choicethan transplanting on the sandy or gravel bottom, use the iron stakes driven in the bottom by apneumatic hammer as the settlement surface, after finely adjusting their positions. For this example
case of transplantation, colonies in the range from 20 to 30 cm in diameter were moved. However, it
is still difficult to transplant colonies larger than this size if only human power is used. The
relocation method discussed in the next section should be used for massive removals.

5-2. Replant of coral reefs

Fukunishi et al. (1998) and Waterfront Vitalization & Environment Research Center (1999)
introduced techniques for relocation of coral communities, as one of the methods for planning aharbor construction project that harmonizes with the coral reef. They describe this technique thatmoves the coral communities together with the base rock if there is a threat that the coral reef will beeliminated by reclamation or construction of a breakwater.
Utilizing this technique, a new experimental project has been implemented continuously since1998 in Hirara Harbor, Miyako Island, Okinawa, for carrying forward the harbor construction

44

project harmonized with coral community. Project achievements were partly reported by Ishii et al.
(2000, 2001) and introduced by the booklet issued by the Hirara Harbor Construction Office,Okinawa General Bureau, Okinawa Development Agency (2002).
The process of the coral community relocation is shown in Fig. 5-1, and the process andexperimental results of the coral community relocation in Hirara Harbor are outlined below.

Selection of coral reef and choice of destination

Preliminary experiment

Sampling

Transportation

Placement

Fig. 5-1 Process of coral community relocation(Waterfront Vitalization & Environment Research Center 1999)(1) Selection of coral reef and choice of destination
Prior to the beginning of the coral community relocation project, examine the areas that are
affected by it directly and indirectly, survey the actual state of the coral communities that exist in theareas, and select the coral communities that require the relocation.
Since it is desirable that the destination of the coral community relocation is environmentally
similar to the source, confirm beforehand the selection of the suitable site by performing a survey ofthe destination, selecting a concrete candidate site and then performing a preliminary experiment.

(2) Sampling
It is necessary to break the base rock to collect the base rock fragments on which coral
communities settle. When breaking the base rock, it is necessary to examine the fracture method andthe size of base rocks to be relocated so as to minimize the damage to the coral communities. Whenrelocating the coral communities, because there were no previous cases of relocation, an underwater
backhoe was used in FY1998 and 1999, and water jet, air lift and other means in FY2000 to breakout the settlement substrates (Fig. 5-2).

45

Fig. 5-2． Collection of base rock fragments on which the coral communities are settled(Hirara Harbor Construction Office 2002)(3) Transportation
The transport of the base rocks in Hirara Harbor was performed by using a method that prevents
the corals from contacting the air, which stress them, as shown in Fig. 5-3. This method is effective
for the relocation to places near the source, but the safety and efficiency of the transport lowers thefarther is the destination from the source. So, transportation aboard a boat should be considered
because some components of the species of the coral communities can be tolerant to a certain levelof drying. Doing that requires measures for minimizing damage to the corals, such as spraying sea
water on the coral communities continuously and/or covering with a light shielding sheet. It is
desirable to confirm the effect of the measures by performing the drying tolerance experiment
beforehand.

Fig. 5-3．Transport of base rock collected (Hirara Harbor Construction Office 2002)(4) Placement
When setting the base rock, it is desirable to make it stable by taking into consideration the size,
wave conditions of the location, and other factors. At Hirara Harbor, an underwater backhoe wasused in FY1998 and 1999, and a water jet was used in FY2000 to dig out the settlement substrate. To
46

avoid giving stress to the corals, the use of a pneumatic lift allowed the transportation of big coral
communities, keeping them below the water surface to relocate them to the periphery of the moundin the harbor.

(5) Conclusion
The results of the experimental but massive coral community relocation in Hirara Harbor are as
described below. Figure 5-4 shows the temporal change of coverage of the coral communities thatwere relocated to 12 points in January, 1999 (Ishii et al. 2001). The relocated coral communities
mainly included Poritidae, Siderastreidae and Faviidae. For the coral communities relocated in
January, 1999, the mass of rock was small, and some of them were washed away by the ocean waves
from a typhoon. However, most of the coral communities on the new stable substrate have survived.
Also, no affects of the settlement due to the environmental conditions of the relocation destination
could be seen, and we observed that the most of them survived the stress of relocation andenvironmental change before and after the relocation. At the survey in October, 2000 (21st monthafter the relocation), some points showed new growth of the coral.
100

Coral coverage(%)

8060Inside of theOutsideharborharborUpper layer□○

Lower layer

◇

▽

40

20

0

直後

Relocation(1999.1)
Jan. 1999

1st month

１ｹ月後

9th month

１年９ｹ月後21st monthFeb. 1999

Oct. 1999

Oct. 2000(1999.2)

９ｹ月後(1999.10) (2000.10)

Fig. 5-4．Change of coverage of corals relocated at Hirara harbor in FY1998 (Ishii et al. 2001)

In 1998, a coral bleaching event occurred worldwide due to high water temperature, and the coral
communities relocated to Hirara Harbor were also affected by the bleaching event. However, as
shown in Fig. 5-5, they were confirmed to have been recovered at the investigation in October, 1999
(9th month after the bleaching event), and no effect of the bleaching event was recognized in
October, 2000. These results may show that the stress the coral communities received from therelocation was small.

47
Bleaching

Recovered

of

the

白

回

化

復

Fig. 5-5．State of recovery from the 1998 bleaching event (Ishii et al. 2001)
Left: Immediately after relocation (Jan. 1999), Middle: 9th month after relocation (Oct. 1999), Right: 1
year and 9th month after relocation (Oct. 2000)

Table 5-1 shows the state of appearance of reef animals larger than corals observed on the mass ofrock supporting the coral communities immediately after the relocation in November 2000. The
number of species of large size benthic animals ranges from 0 to 11, and the number of individuals
ranges from 0 to 25. The sponges, colonial sea-squirts and other species of which individuals cannot
be counted also settled. These large size benthic animals were the same types that had lived on therock before the relocation and had been carried together with the base rock by the relocation. It is
worth noting that the coral community relocation technique allows conservation not only of the coral,
but also other animals and plants that adhere to them.
The principal advantages of the coral community relocation technique as compared with othercoral transplantation techniques, are that it allows conservation of whole coral communities
relocated and that handling of massive corals such as Porites is feasible. A patent is being applied forthis technique.

Table 5-1． State of appearance of large animals observed on the mass of rock, including the coral
communities (Ishii et al. 2001)

No. of species /m2
2

No. of individuals/m

MeanStandard deviation

Minimum

Maximum

5.0

2.7

0

11

7.3

8.5

0

25

In Hirara Harbor, the construction of a “environmental breakwater” that uses components such as“water pass caissons”, “wave-abating blocks with slots” and “root hardening blocks with various

48

structures” is underway in addition to the “coral community relocation” (Fig. 5-6).

root hardening blocks
with various structures

wave-abaiting
blocks with slots
water
pass
caissonArea

forconstructing

breakwater

Relocation

destination site for breakwater constructionofreef communities

coral

relocation of coral
community

Fig. 5-6．Schematic view of environmental breakwater at Hirara Harbor (Ishii et al. 2001)

Literature Cited
Fukunishi K, Yonaha K, Morita S, Yamamoto H and Takahashi Y (1998) A planning method on
harbor construction harmonizing with coral reef. Techno-Ocean '98 Intl. Symp. Proc.
181-184. (in Japanese)
Ishii M, Maekouchi N, Omura M, Yamamoto H, Takahashi Y and Tamura K (2000) An experimenton environmental concern by coral community relocation at the Hirara Harbor．
Abstracts of 3rd Symposium of the Japanese Coral Reef Society: 19. (in Japanese)
Ishii, M, Maekouchi N, Omura M, Yamamoto H, Takahashi Y and Tamura K(2001)

Remediation

techniques of environment concerning with coral community at the Hirara Harbor, Proc.
Coastal Engineering, JSCE. 48: 1301-1305. (in Japanese)
Hirara Harbor Construction Office (2002)

For realizing breakwater harmonization with theenvironment (brochure). (in Japanese)
Waterfront Vitalization & Environment Research Center (1999) A Draft Manual on Harbor
Construction Harmonizing with Coral Reef, 99+27pp. (in Japanese)(Fujiwara S & Omori M)

49

6. Development of underwater techniques for coral reef restoration

6-1. Experiment 1. Restoration using sexual reproduction(1) Introduction
In the period from FY1998 to FY2000, Japan Marine Science and Technology Center developed
various investigations and studies for the whole area of Sekisei Lagoon (the waters between Ishigaki
Island and Iriomote Island, Okinawa) in its research project (Okamoto 1998). Unfortunately, aworldwide bleaching event occurred in 1998, when the project was initiated, which cataclysmicallychanged the state of Sekisei Lagoon’s corals (Okamoto et al. 2000; Yamazato 1999). Moreover, in
2001, Sekisei Lagoon’s corals were damaged by a bleaching event again, causing growing concerns
about the survival of the corals.
The present authors commenced basic studies in Sekisei Lagoon from FY2001 as an effort toregenerate the coral reefs. This is an activity derived from our recognition that “Sekisei Lagoon does
require the actions that strengthen the regeneration capability of the corals, and the lagoon is water
having such potentiality”, based on: the ecological knowledge of the corals that were obtained
through conventional investigations and researches; and the fact that the corals of the wide Sekisei
Lagoon are on the road to death from the repeated bleaching events. Underwater working techniques
mainly include a diving.
The attempted coral reef regeneration that is discussed in this paper was planned and implemented
as one that can deal with “the fact that the corals are dying out due to the effect of the warming of
the earth”, based on the conventional coral transplantation method. We would like to introduce the
new technique as one underway for the coral reef restoration, asking the reader to understand that
final results cannot be shown because the activity is still in process.
We have performed the experiment by using settlement tiles (10 × 10 × 1.3 cm, with a hole in thecenter for securing) made of Amakusa porcelain. This tile substrate tests the settlement potential of
the juvenile corals that were generated at the simultaneous spawning. The settlement tiles wereplaced on architectural blocks. On each block, three pieces of the tiles were arranged at evenintervals in two layers, 6 pieces in total. The setting of the settlement tiles was performed fromabout one week before the date of simultaneous spawning to the spawning date. This way of setting
the tiles prevents the surface from being covered by competitors of the coral larvae at the time of thesettlement or by substances that can disturb the settlement.
Investigating the settlement potential of the larvae on the tiles, we collected the settlement boards
at the 3rd month after the simultaneous spawning, brought them back to laboratory after drying them,and counted the settled corals. For some of the tiles, we investigated the depletion rate of the settledcorals by collecting them at the first year after the spawning and counting them.
The corals that settled on the settlement tiles concentrated near the outer edge of the lower side of50

the tiles when they were collected at the 3rd month after the settlement. When the tiles are left in thesea as they are, the corals grow outward, and then gradually appear on the upper side. The corals,
once appearing on the upper side, grow faster to a size that limits injury to them from sea urchinsand fish (Fig. 6-1). The juvenile corals that have grown on the settlement tiles can be utilized for thetransplantation as they are.

Fig. 6-1．Juvenile corals that appear on the side of the settlement tileafter they settled on the other side(2) Conception of methodology
The method utilizes an indefinitely large number of coral larvae generated by simultaneous
spawning to breed the juvenile corals for transplantation. It requires a longer period of preparationcompared with the conventional fragment transplantation. Simultaneous spawning is a fundamental
natural strategy for the survival of corals. The largest advantage of this approach is that it does notdisadvantage any of transported species, and thus, juvenile coral communities consisting of various
species present in the spawning areas can be obtained. That is, we take advantage of population
patterns to aid the coral reef regeneration while maintaining the coral community, not the mere
regeneration of the singular species of corals.
The fundamental idea of this regeneration includes the steps described below.
a) Putting the larvae settlement apparatus on the suitable larval settlement site immediately before
the simultaneous spawning of the corals, and letting the larvae generated by simultaneous
spawning settle on their natural site;b) Moving the settlement apparatus to the rearing water just after larvae have settled, because
conditions at the settlement site are not as conductive to growth always the best destination site;c) Removing predators and cleaning the apparatus occasionally to raise the survival rate until the51

larvae grow to juvenile corals;d) Utilizing the grown juvenile corals for the transplantation because they have survived through thestage of mass depletion.

(3) Problem of use of substrate
The conventional tiles that have been used for the study of larvae settlement potential offered thefollowing problems:a) The tiles were larger than necessary.
Though many corals settled on the under side of the tile, the settlement is limited to the area near
the outer edge where they could easily spread to the top side as they grow. After the transplantation,
only one coral individual may be able to grow per one piece of tile as a result of their competionfor survival.
b) The work of setting out many boards was hard.
Since the coral larvae attached to the under side of the tile, they had to be arranged at evenintervals horizontally in layers. One tile that we employed weighs approximately 300g in the airand, thus, arranging many tiles required a specially made frame. Also, when taking into
consideration the packing and transportation in the sea, it was desirable to keep the total weight
including the settlement tiles and frame at around several tens of kilograms. Thus, only about 50
tiles could be arranged on one frame.
c) The work of fixing the tiles at the destination place was complex.
The juvenile corals which have reached the transplantable stage often had grown on both sides of
the tile. To prevent the corals from being damaged when fixing tile on the bottom, therefore it wasnecessary to use a variety of fastening methods and materials such as nails with a spacer put below
the tile.

(4) Development of new artificial substrate
When using the slabs (tiles) for the settlement, rearing and transplantation of the juvenile corals, it
was necessary to improve this artificial substrate surfaces to solve the fundamental problems
described above. In the initial stage of the examination, we attempted to use slabs and stone blocks
as the settlement surfaces after processing them into various forms. As we progressed, we performeda series of experiments with regard to the underwater fastening methods, the settlement state of thecorals, the transplantation methods etc.
With regard to the materials for settlement surfaces, we examined materials such as Amakusa
porcelain clay and Ryukyu limestone, together with materials that naturally grown juvenile corals
are attached. As a result, we determined that factors such as the roughness of the surface of thematerial and minute pores are crucial to make the settlement successful.

52

Then, we determined that it is necessary to abandon the use of flat slabs for corals settlement, and,then, to design and develop settlement devices with new design characteristics, taking into
consideration all requirements ranging from the settlement of corals to the transplantation works. For
the forms of the settlement devices, we took account of their relative easiness of use during
underwater works and ecological affects based on the mechanisms of settlement, growth andsurvival of the corals.
With regard to the easiness of use in the sea, the following three points were noted.
a) Suitable for the transplantation work (especially, the method of fastening on the substrate)b) Easiness of handling many settlement devices in the sea (small and light)c) Lower manufacturing cost (suited to mass-production)
From the ecological viewpoint, the following three points were considered important.
a) Allowing easy settlement of coral larvaeb) Protecting corals from predation at their initial stage of settlementc) No disturbing the growth of juvenile corals

When manufacturing the settlement devices that meet the above requirements, we noted that theuse of existing materials after processing them is technically difficult, and may cost significantly
even if they can be used. Then, we considered the utilization of ceramics, and came to conclusionthat the settlement devices could be mass-produced by utilizing the ceramic work techniques foundin Seto, Aichi Prefecture, Japan. Settlement device No.1 (ONF-1) was manufactured in April, 2002,
by molding the porcelain clay with pressure casting, utilizing a plaster former and then baking inoxidizing fire at 1,250 ℃. Since the ceramic devices have sufficient strength and minute pores allow
water into approximately 5% of the volume, we expected that this feature would be advantageous forbeing saturated with seawater in a short period after they are set in the sea. As the raw material,
regular porcelain clay was used here, however, the use of this baking method also allows
manufacture of settlement devices with similar characteristics using the coal ash that is produced bythermal power plants (Fig. 6-2).
The settlement devices are given a form that allows easy implantation of juvenile corals and aremade small and light to make the transplantation simpler. By laying the settlement devices insideeach other and arranging them on the frame, many settlement devices can be easily transported andthen individually set in the sea. Also we made a consideration to prevent the invasion of the predator
after the settlement of the larvae by adjusting the spaces between stacks of units.

(5) Design and construction of artificial substrate
The settlement devices are given a conical form similar to a toy wooden top. The unit consists of a53

Fig. 6-2．Coral settlement devices

settlement section, spacer and connecting-inserting section. The settlement section is given a wide
settlement area on the bottom side and provided with stacking holes on the top side, based on theform of Amakusa porcelain clay plates that have been used previously. Multiple grooves arearranged on the bottom side as a feature for increasing the settlement area. The spacer section is
given a role of keeping a certain gap between the settlement sections when stacking the settlement
devices on each other after implantation. The connecting-inserting section functions as a guide thatmakes it easier to lay many settlement devices on each other (Figs. 6-3 and 6-4).
Unit view

Stacked view

Contained in a frame for easier handling

Settlement
sectionSpacer section
Connecting-inserting
sectionFig. 6-3．Coral settlement device and assembling method
54

Fig. 6-4．Settlement devices assembled in a frame

Multiple settlement devices are stacked and arranged in a frame at close intervals. The gaps
between the settlement devices formed by the spacer section protects the settled corals from being
affected by the predation of invading sea-urchins. The stacks of settlement devices should bearranged in the frame at closer intervals to make it difficult for shells and fish to enter the gaps,
preventing the predation from these life. Of course, it is assumed that some of the stacks of thesettlement devices are thinned out to keep suitable intervals as the corals and sessile organisms grow.
After the juvenile corals have grown so that they appear on the side of the devices, up from thebottom side of the settlement section, make small holes on the bottom, put some adhesive in theholes, and them press the connecting settlement section of the device down into the adhesive. The
connecting-inserting section is in the hole made on the upper surface of the settlement device, so thatany life can hardly grow on it. The spacer section functions as a feature that prevents the juvenile
corals from the bottom side of the settlement device from being damaged at the transplantation (Fig.
6-5).
1

4

2

3

Fig. 6-5．Settlement device inserting and adhering procedure

1. Juvenile coral at 1st year after settlement. 2. Make hole on the substrate. 3. Fill the hole withadhesive. 4. Put the device into the hole to fix.

55

(6) Larval settlement and replant of substrate
In the natural world, many of the corals settle in relatively shallow waters, where it is hard for thecorals to form the colonies because they are affected by strong waves (Fig. 6-6). When setting thesettlement devices contained in a frame in such areas, it is safer to move them to calmer waters inearly time, after the settlement. Such calm waters also provide advantages for maintenance workers
such as; removal of predators, investigation of the state of growth and development of the corals;
reduction of settlement devices performed as corals grow (to adjust the intervals between settlement
device stacks); and easy access to such working areas. In the case of the Sekisei Lagoon, there arewide and calm moats to the south of Taketomi-jima, where suitable sites for rearing can be found invarious places with depth of water ranging from 7 to 10m.

Fig. 6-6．Settlement devices contained in frames on the bottom

The settlement of larvae is completed generally in 10 days from the simultaneous spawning.
Therefore, the settlement devices are moved to calmer rearing waters after about one month, after
the larvae have surely settled and become stable. The movement to a nearby place can be made in
the water with divers, but when moving to remote areas, an air lifter (a balloon-like bag which hangs
an object under the water by using lifter buoyancy) can be used to float the corals easily under thesea surface (Fig. 6-7). In the future, when several hundred larvae are moved as a project base, theutilization of towing type table for underwater movement or enclosed floating pond fortransportation can be expected.
Larvae settlement using this system has been performed experimentally, but has not reached thestage of routine transplantation work yet. However, the transplantation techniques are very simple,
consisting of two steps: putting adhesive in the holes made on the substrate to which the larvae aretransplanted, and inserting settlement devices in the holes and pushing them. As described in Chapter
564-2 “Transplantation of juvenile corals”, the steps can use conventional underwater working methods.
We expect that the transplantation can be done by volunteer divers, not necessarily by professional
divers, after these essential techniques are practiced.

Fig. 6-7．Moving the frames containing settlement devices to rearing waterby suspension from air lifters(7) Evaluation of methodology and perspective
Let us assume that juvenile corals are transplanted, to reefs located in the south of Sekisei Lagoon.
This area is considered a good source of supply of coral larvae in Sekisei Lagoon because of
relatively rich corals and high openness, and their high flow circulation environment. We consider
that it is important for Sekisei Lagoon to maintain its coral regeneration capacity, and in the longterm we view Sekisei Lagoon as the most important water for preventing Japanese corals found in
the Kuroshio areas from extinction. As to the causes of extinction of transplanted corals in this water,
two main factors are supposed: the rise of water temperature and predation by the crown-of-thorns
starfish. Even with these factors assumed, the conditions for the transplantation in Sekisei Lagoon
are far better than those of the Okinawa main island and Ishigaki Island where the corals near the
shore are exposed to terrestrial run-off and other marine pollution.
This experiment has been performed to verify that a series of the coral regeneration projectutilizing sexual reproduction can be implemented in waters where corals currently grow. That is, theverification is for the methodology for “strengthening the recovery capacity by performing a little
manipulation of natural life without giving any damage to the coral community of a body of water”
and “performing every intervention in the sea that the corals inhabit”. The undersea experiments are
performed generally based on the results of many land experiments. The reason why we performed
the sea area experiments hastily was that the number of the naturally settled corals is few, even in the57

present situation, and we expected that comprehensive verification of this idea in the sea become
more difficult in the future. Of source, this experiment was commenced based on the assumption thatit can be implemented completely. However, the results of measurements of the number of settled
larvae by using the settlement tile were, even in the southern sea area of Sekisei lagoon, muchsmaller than the values obtained in the periphery of Sesoko Island before 1998. Also, estimate thatthe number of the juvenile corals that can be obtained by the new settlement devices set in 2002 may
be few due to the effect of the bleaching event in 2001.
We expect that the method can be applied practically and relatively easily by adopting easier andsurer methods in the process of verification of the general idea of the coral reef regeneration throughthis experiment, if the verification is successful. For example, even if the number of settled corals ina body of water reduces significantly in the future, surer settlement may be achieved by setting many
settlement devices in the land water tank or in the sea enclosed by a partition net, and rearing many
larvae that are generated by the simultaneous spawning in it. The studies of such ideas has alreadybeing carried out (see Chap. 3-1). Figures 6-8 and 6-9 shows these ideas.
The advantage of this method is that the coral regeneration can be made in various places byboring into the existing substrate and then inserting juvenile coral-bearing devices into the holes. In
the natural environment, the chance that the corals can settle on the artificial substrates or reefs islimited significantly with regard to the season. For example, possibility of natural settlement is low
if the surface of the substrate has not been washed cleanly by waves in spawning time. Utilization of
the settlement devices to which the juvenile corals are attached may compensate such inadequate
condition.
It is inevitable that some corals die as the time elapses even if they are the naturally settled ones or
those transplanted using the settlement devices. In such case, continuous transplantation of corals
that are bred with the settlement devices can achieve coral reef regeneration surer (Table 6-1).

(8) Conclusion
This section has introduced an attempt to obtain juvenile corals for transplantation in the sea byutilizing the simultaneous spawning of corals. For the settlement and rearing of juvenile corals in thesea, it is necessary to understand the phenomenon of scattering of fertilized eggs that are generated
by the simultaneous spawning and to collect valid information about the waters where the larvae
settle. The southern reach of the wide Sekisei Lagoon has coral communities which are generally
healthy and wide enough for the fertilized eggs to stay until they grow to larvae. Therefore, the area
is considered one of the most suitable waters for rearing the juvenile corals. It can be said that
Sekisei Lagoon has been able to sustain the wide coral reef area up to now due to such good natural
conditions.

58

Table 6-1．Envisioned coral transplantation waters
1. Waters that are deemed supply sources of coral larvae (strengthening regeneration capacity)
Open waters south of Sekisei Lagoon and Kerama Archipelago, etc.
2. Locations where the corals are damaged by a transient cause (regeneration)
Damages from bleaching event (areas where seawater is exchanged well);
Destruction of corals by predation of crown-of-thorns starfish, typhoon, and stranding of ships, etc.
3. Creation of coral reef using artificial substrates (garden making)Utilizing existing installations (reutilization);
Utilizing new installations of structures (mitigation)

Fig. 6-8．How to obtain juvenile corals for transplantation

59

1
Rearing water

Settlement watertransportation

2
Coral eggs and larvae

Removal of enclosuresenclosureand transport to rearingt

3
Coral eggs and larvae
Water
Transport to rearing
tank
water

Fig. 6-9．Schematic view of process from settlement to rearing
1. Natural setting in the sea, 2. Integrated setting in the sea, 3. Integrated settlement in water tank

The settlement devices that were used for the experiment have features, such as strength suited tothe transplantation that prevents damage from predators from implantation to the rearing by stacking
the units. The use of ceramics allows flexibility for the forming, and utilization of the coal ash as theraw material instead of regular clay allows mass-production at lower cost. Needless to say, it isnecessary to advance the practical application of this system through various elementary experiments
and development of techniques, including not only the experiments in the sea but also those on theland.

Acknowledgment
The attempt to breed juvenile corals through sexual reproduction was implemented from 2001
based on the knowledge that was obtained when we engaged in a study of coral reefs conducted by
Japan Marine Science and Technology Center. This experiment was made possible because it was60based on the many insights and basic understandings obtained through the intensive studies of thecoral reefs conducted by the Center. We express our hearty thanks to the relevant persons of Japan
Marine Science and Technology Center, who kept a close eye on our studies of the coral reefs andthose who participated in and provided cooperation in the experiment in the sea and development of
the techniques since FY2001

Literature Cited
Okamoto M, Sato T and Morita S. (2000) Basic coral distribution data for long term monitoring at
Sekisei Lagoon. OCEANS 2000: 1383-1387.
Okamoto M (1998) Fundamental study for quantitative measurement of coral biomass. J. Recherche
Oceanogr. 23: 57-65.
Yamazato K (1999) Coral bleaching in Okinawa, 1980 vs 1998. Galaxea, JCRS 1: 83-87.

(Okamoto M & Nojima S)61

6-2. Experiment 2. Transplantation of coral fragments: Acropora formosa(1) Material and methods
The location of the transplantation was Majanohama, Akajima, Kerama Archipelago, Okinawa.
Because of its indented coast line, the current is slow except in typhoon. The average speed of thecurrent in 2001 was 4.08 cm/sec (Taniguchi 2001). The amount of sediments is relatively large, andsome turbid water flows out from the overhanging areas around the island. The water temperature in
the period from 1999 to 2002 was in the range from 21.3 to 30.3℃ (Iwao 2001, Taniguchi 2002),
and the monthly mean light intensity in the period from 1974 to 1990 ranged from 8.4 MJ/m2(January) to 20.5 MJ/m2 (July) (Scientific Data Year Book 2000). The water for the transplantation is
inhabited preferentially by Acropora on the reef flat, and the coral coverage by branching Acropora
is 44%, the one by corymbose type Acropora is 21.7%, the one by tabular type Acropora is 7.0%,
the one by sub-massive Acropora is 6.0%, and the one by other than Family Acroporidae is 21.4%(Taniguchi et al. 1999).
The species used for this experiment was branching Acropora formosa. In Okinawa, they begin to
make oocyte in the period from the end of September to October, and spawn in May and June of thenext year. Transplantation was performed on November 7, 1999, March 15, 2000, and August 11,
2000.
Fragments in three sizes, 5cm, 10cm and 20cm long, were taken from large donor colonies(approximately 1 m high, and surface area of approximately 4.5m2), with a total of 470 pieces, bymeans of a wire cutter, and the lengths were measured using a vernier calipers having a measurement
accuracy of 0.1mm. The fragments collected were put in a basket, and carried in the water to thedestination for the transplantation 10 to 20 m from the donor colonies. The depth of the place where
the fragments were collected and transplanted ranges from 2 to 3 m.
Concrete nails 8 cm long was driven into the substrate (coral rocks) approximately 3 cm, and then,the fragments were fixed vertically to the nail with cable ties (Fig. 6-10). The fragments of 5cm longand 10cm long were fixed to each nail with one piece of cable tie, and 20cm fragments were fixedusing two pieces. The species normally grows vertically but for the experimental transplantation in
November half of the fragments of each size were fixed horizontally to compare the results between
that and the normal direction. After the transplantation, the survival rate of the transplanted
fragments was measured every two months by SCUBA divers.

(2) Results
Among the fragments which were fastened using the cable ties and nails, no loss was found at thefirst year after the transplantation. Regarding most of the fragments that were fixed vertically, newpolyps budded from the top of the branch. Many of them were tossed by the waves so as to wobble

62

ａ

ｂ

Fig. 6-10．Fragments of Acropora formosa immediately after the transplantationa: 5cm fragment, horizontal

b: 5cm fragment, verticaleven 1.5 years after transplantation, but no sediments were seen. The fragments that were fixedhorizontally changed their orientation to vertical as the time elapsed after the transplantation. Amongthe fragments that were fixed horizontally, many of their surface areas contacted the substrate of thecoral rock, and thus, they were stable and hardly tossed by the waves, but they also did not show thesettlement to the substrate, and the surface of the fragments was covered with sediments consistingof fine particles. The bottom side of the fragments that did not get the sun died and were covered
with algae. As a result of comparison between the vertically fixed fragments and horizontal ones thatwere transplanted in November, those vertically fixed showed higher survival rate for all sizes. For
the fragments that were fixed horizontally, 90% of the large size ones survived, but 10cm and 5cm
ones showed low survival rates and died one after the other after the observation. 5 cm fragments
showed the survival rate as low as 10%.
The survival rates are summarized as follows. The vertically fixed fragments showed higher
survival rates without regard to the time for transplantation. The 20 cm fragments survived nearly
100%. Among the fragments that were transplanted in August, the 10 cm ones also survived nearly
100% (Figs. 6-11 and 6-12). The effect of timing on the transplantation survival rates is clear forsmaller fragments. For the 5 cm fragments that were transplanted in November and March, about
15% of them died within three months from the transplantation. In contrast, all of the 5 cm
fragments that were transplanted in August died. The fragments that were transplanted in March did
not die after that, but those transplanted in November had a reduced their survival rate, to as low as
28% within 1 year and a half after transplantation.

63

Fig. 6-11. Survival rate of vertically fixed A. formosa vs number of days after transplantation
a: 20cm fragments, b: 10cm fragments, c: 5cm fragments. : August transplantation; : Marchtransplantation; ×: November transplantation

64

Fig. 6-12. Survival rates of horizontal A. formosa fragments transplanted in November (solid line)
The rates of vertically fixed fragments are shown with dotted line for comparison.
: 20cm fragments, △: 10cm fragments, □: 5cm fragments(3) Discussion
a. Fastening methods
Acropora formosa showed a higher survival rate when they were attached vertically thanhorizontally, mainly because of greater sedimentation. Since the surface of horizontal fragments isnear the substrate, the sediments easily deposit and accumulate; the low profile of the fragments
receive little water flow, preventing the sediments on them from being removed by the flow. Also,
the predation of the polyps is disturbed, and photosynthesis does not occur to support zooxanthellae
because of luck of sunshine. Algae can easily invade. Therefore, with all species, the vertically fixedfragments show higher survival rates.

b. Timing of transplantation
For the larger fragments, the survival rates are higher regardless of the season. But, when thesurvival rates of 5cm fragments transplanted in November and those in March are compared witheach other, though the water temperature is higher in November than March, the survival rate of the
5cm fragments transplanted in November was 29％, which is low, but the rate of the 5cm fragments
which were transplanted in March, where the water temperature is lower, is 87%. The values of thelight intensity in November and March were nearly equal. Because the water temperature and lightintensity rises from March, but these are reduced from November, we are able to conclude thattransplantation can be successful even in water of 20℃ if the water temperature and light intensity
rise within 2 months after transplantation, when they easily survive the stress due to thetransplantation. With regard to the best season for transplantation, the fragments that weretransplanted in August showed the highest survival rate. But, in the summer of the next year, many
corals died from the bleaching event in the experimental region because of the continuous high water65

temperature over 30 ℃ (Taniguchi 2002). Yap and Gomez (1984) who transplanted branching
Acropora pulchra reported a reduction of the survival rate of corals that were transplanted in waterof 30℃ or higher. Kajiwara et al. (1995) reported that the total amount of photosynthesis increased
linearly in the range of from 20 to 30℃, and the calcification was maximized at 28℃ but reduced at
30℃. Since there is no doubt that the fragments are sensitive to the external stress in the period
immediately after the transplantation, it is estimated that the best season for the transplantation isspring, when the amount of photosynthesis increases and there is no danger of a bleaching event.

c. Size of fragments and their survival rate
The survival rate of the 20cm fragments was nearly 100%. The larger the size the higher thesurvival rate is, and this relationship became clearer as the degree of stress from external causes(fastening method and the time of transplantation) became greater.
Based on the result that the survival rate lowers as the size of the fragment become smaller, there
is an opinion that transplantation of an entire colony is more effective that fragmentation(Plucer-Rosario and Randall 1987). But, since the mortality rate does not exceed 3％ for the
fragments larger than a certain size (Connell 1973), taking a small number of fragments of sufficient
size for the transplantation may produce a satisfactory survival rate. Nevertheless, it is important toknow the size of fragments that can achieve the survival rate of 100%.
Also, since fragments of Acropora are fixed after the transplantation, and thus, are not turned overto damage the texture, the survival rate and growth rate of the transplanted fragments are higher thannaturally made fragments. It is reported that the survival rate of branching Acropora intermedia
fragments scattered loose on the reef flat at the 17th month after the transplantation was 31% for
those of 6 to 9 cm long, and 81% for those of 13 to 16 cm long (Smith and Hughes 1999). Therefore,
to do successful restoration of corals without damaging the donor colonies, it is considered that thebest way is to fasten down the coral fragments produced by storm immediately after the event.
Since the 20 cm fragments that are transplanted and vertically fixed at the suitable time survived
well, the size of fragments of A. formosa that is the most suitable for the transplantation wil be about
20cm.

Literature Cited
Connel J (1973) Population ecology of reef building corals. Jones OA, Endean R (eds) Biology andGeology of Coral Reefs 2, Biology 1. Academic Press, New York, 205-245.
Iwao K (2001) Oceanographic condition at Akajima Island from 1995 to 2000. Midoriishi 12: 21-25.
(in Japanese)
Kajiwara K, Nagai A, Ueno S and Yokochi H (1997) Examination of the effect of temperature, lightintensity and zooxanthellae concentration on calcification and photosynthesis of66

scleractinian coral Acropora pulchra. Bull. Inst. Oceanic Res. Develop. Tokai Univ
18: 1-10.
National Astronomical Observatory of Japan (2000) Scientific Data Year Book. Maruzen, Tokyo.
1064pp. (in Japanese)
Okubo N and Omori M(2001) The review of coral transplantation around the world. Galaxea,
JCRS 3: 31-40. (in Japanese)
Plucer-Rosario GP and Randall RH (1987) Preservation of rare coral species by transplantation: an
examination of their recruitment and growth. Bull. Mar. Sci. 41: 585-593.
Smith LD and Hughes TP (1999) An experimental assessment of survival, re-attachment andfecundity of coral fragments. J. Exp. Mar. Biol. Ecol. 235: 147-164.
Taniguchi H (2001) Measurement of time-averaged intensity of water motion around Akajima Island.
Midoriishi 12:18-20. (in Japanese)
Taniguchi H (2002) Bleaching event around Akajima Island in 2001:Comparison with 1998.
Midoriishi 13:26-29. (in Japanese)
Taniguchi H, Iwao K and Omori M(1999) Bleaching event of hermatypic coral around Akajima
Island, Kerama Archipelago :Survey result in September 1998．Galaxea, JCRS 1:
59-64. (in Japanese)
Yap HT and Gomez ED (1984) Growth of Acropora pulchra. Responses of natural and transplantedcolonies to temperature and day length. Mar. Biol. 87: 209-215.
(Okubo N)676-3. Experiment 3. Transplantation of a whole coral colony: Porites lutea

In recent years, occasional attempts to transplant whole coral colonies have been made in order toprevent possible extinction of coral communities due to events such coastal development works. In
one example case, corals threatened by the installation of a bridge were transplanted from the bridge
supports.
This section discuss the transplantation at Kouri-ohashi Bridge, that was built in the northern partof main island of Okinawa by the Okinawa Prefecture(Dept. of Civil Engineering andConstruction, Okinawa Prefecture and Metocean Environment Inc. 2002).

(1) Method
On the bridge support section in shallow water located on the main island side of Kouri-ohashi
Bridge, massive Porites of 5 to 80 cm diam. were distributed preferentially (Fig. 6-13). Of thosecorals, the communities of Porites lutea ranging from 20 to 30 cm in diameter were mainly collected
and transplanted in December 1998 in sandy bottom near the eastern part of the bridge. The depth of
the artificial substrate was approximately 2m below the reference water level, and that of the naturalbase rock was approximately 1m below the reference water level.
In all, 25 colonies were transplanted to five pieces of concrete substrates, and 5 colonies to thenatural base rock, and the follow-up investigations were performed for four years, five times a year.
The investigation items were the states of corals mainly including: survival and death, growth,
activity, and deposition of soil.
Each concrete substrate consisted of a concrete block plate (1.2ｍ×1.2ｍ×0.2ｍ) with five holes(10 cm diam. × 5 cm deep) in the surface for transplantation (Figs. 6-14 and 6-15).
The collection of P. lutea from the colony base was performed by using a chisel, taking care not todamage the corals. The corals removed from the bottom were put into a container in the water andtransported to the place where they were transplanted. To adhere the corals to the substrate,waterproof adhesive was used. To adhere them to the natural base rock, holes for the transplantation(similar to those made on the artificial substrate) were made on the rock beforehand by using a chisel
and a hammer. Later, a method to fasten the corals to anchor bolts driven into the colony basesubstrate was used; the colonies grew to wrap around the bolts, demonstrating that the method was
effective for the settlement.

(2) Resultsa. State of survival and death
One of the colonies transplanted to the concrete substrate was dead within 7 months, but otherones on both concrete and natural base rock survived for 45 months after the transplantation,

68

Fig. 6-13．Massive Porites for transplantation

Fig. 6-14．Artificial substrate placed on the sea bottom

especially the colonies transplanted to the natural base rock which scarcely showed even partial
death of the polyps. Regarding the colonies transplanted to the artificial substrates, while there waspartial death due high water temperature in summer, did not lead to overall extinction.

b. Growth
When the annual average growth (width and height) of the colonies transplanted on the concrete
substrate and the ones on the natural base rock are compared, the growth of corals on the concrete in1999 was higher for both height and width. But, for those 1st and 2nd years after transplantation thegrowth on the natural base rock was higher than on the concrete substrate, with the difference
ranging from 3 to 4 mm/year in width, and 2 to 5 mm/year in height. The growth of colonies which
had many polyps killed on the concrete might have been affected by that event (Fig. 6-16).

69

Lifting eye

・Lifting eye

Fig. 6-15．Dimensions of concrete substrate
Two types of the concrete substrates, one with holes for transplantation (5cm diam. ×
and another with holes (5 cm diam. × 10 cm deep), are prepared.

14
Artificial
substrata

12

NaturalRock

Growth（㎜）

10
8
6
4
2
0
Hor
1st year

Ver

Hor

Ver

2nd yearHorVer

3rd yearFig. 6-16．Annual average growth after transplantation in December 1998.
Hor-Horizontally fastened, Ver-Vertically fastened

70

5cm deep)c. Activity
The data on the annual variation of healthy coral colonies (not those bleached and those with thincolor) show that the colonies on the natural base rock tend to have higher health rate for each year
than the ones on the concrete substrates. In the 3rd year after transplantation, many coral colonies
were bleached due to the high water temperature in summer 2001, resulting in reduction of healthy
ones (Fig. 6-17).

No. of healthy colonies(%)

100

Artificial substrata
Natural rock

80

60

40

20

0
1st year

2nd year

3rd yearFig. 6-17．Percentage of healthy colonies to the whole after transplantation in December 1998

d. Number of mucus secreting colonies
The results of observation of the soil sedimentation show that the concrete substrate tends to havemore sediment than the natural base rock, and thus, the number of colonies that secrete mucus as anaction to eliminate soil sediment is greater on the concrete substrate for each year. In 2001, thenumber of colonies that secrete mucus increased, possibly due to the high water temperature insummer (Fig. 6-18). The phenomenon of colonies covered with the sediment and secretion
frequently to eliminate the soil was observed, and it is estimated that this activity may require
much energy.
Artificial substrata
Natural rockNo. of mucus secreting colonies(%)

60

40

20

0
1st year

2nd year

3rd yearFig. 6-18．Percentage of mucus secreting colonies to the whole after
transplantation in December 199871

According to conclusions drawn from observation of generative cells of P. lutea on the easternbeach of Ishigaki Island, the percentage of colonies that have generative cells was less on the areawith much red soil sediment than on the area with less red soil sediment, giving an indication thatthe formulation of generative cells diminishes when the corals have to consume energy to eliminatedsediment (Harii and Nadaoka 2002). This fact indicates that Porites lutea should be transplanted tonatural base rock to prevent the effect of the sediment on their regeneration.

(3) Conclusion
Since P. lutea is found much in the moats, it is recommended that they be transplanted tomoats.

According to the results of investigation of massive Porites distribution in the moats of Miyara Bay,
Ishigaki Island, colony density is higher in the areas with deeper bottoms, where many of thecolonies are distributed on the bottom at 2 to 3m deep (Sato et al. 2000). Based on these observations,
it is desirable to transplant colonies in the deepest possible bottom in the moats for stable settlement.
However, because the bottom of moats is mainly covered with sand, it may be difficult to find firm
natural substrate, and often sort of artificial substrate is needed. Since the use of anchor bolts has
provided acceptable results, as described before (Fig. 6-19), installation of reinforcing steel stakesthat can be used on sand bottom may be adequate. According to the results of experimental use ofreinforcing steel stakes on the sand bottom, stakes of 12 mm in diameter and 1m long are easy tohandle. A pneumatic hammer can drive the stakes easily, and it is recommended that stakes be
sharpened so that they can crush or push aside gravels that may be encountered during the driving.
Since the reinforcing steel stakes are relatively soft, their forms can be finely adjusted after the
installation by bending.
As for the size of the colonies to be transplanted, it is estimated that those of 20 to 30 cm indiameter are easy to handle by divers. However, massive Porites exceeding 1 m in diameter or
length is not uncommon, and when there is a need to transplant the colonies of such scale, it isnecessary to examine the colony size and the bottom topography of each location, so that they can be
firmly fixed on bottom.

Fig. 6-19．Coral wrapping around an anchor bolt

72

Literature Cited

Department of Civil Engineering and Construction, Okinawa Prefecture and Metocean Environment
Inc. (2002) Survey on transplantation and conservation of marine living organisim at
the Kouri-ohashi Bridge (4). 83+61pp. (in Japanese)
Harii S and Nadaoka K(2002) Effect on red soil to fertilization of Porites．Abstracts of 5th
Symposium of Japanese Coral Reef Society：35. (in Japanes)
Sato T, Hori N and Suzuki A (2000) Distribution of massive Porites at moat of fringing reef inMiyara Bay, Ishigaki Island. Galaxea, JCRS 2：43-50. (in Japanese)(Hosoya S)73

7. Maintenance of polyps on substrate, transplanted fragments and colony, and replaced reef

(1) Removal of algae and predators
Since algae can easily attach to the settling part of transplanted coral fragments, and the algae may
grow to cover the corals leading to possible death, it is necessary to monitor and remove the algaefrequently (Fig. 7-1). The monitoring is also necessary when organisms eating corals, such as crownof thorns starfish or coral-eating gastropods are distributed around the transplantation area.
Especially immediately after the transplantation, the corals frequently secrete mucus because they
were cut, which can attract crown-of-thorns starfish. They should be eliminated from the peripherybefore the transplantation.

Fig. 7-1．Acropora tenuis on the substrate for transplantation covered with algae (March, 2002)(2) Announcement and enlightenment
When the location of the transplantation is near a beach, surface-cast fishhooks can snag on thetransplanted corals. So, it is necessary to obtain cooperation from sportfishermen by setting a noticeboard calling on them to avoid the fishing near the location. The most serious cause of damage to thetransplanted corals is the anchoring by boats. So, it is necessary to set a buoy to indicate that corals
are transplanted in the area, and to set a mooring buoy in the areas where boats may otherwise
anchor frequently. It is also desirable to involve parties concerned with the transplantation byobtaining the cooperation from fishermen and diving services. For the fishermen and diving services,
the coral reefs are places of their business, and thus, the coral reef regeneration is their prime
concern. So their positive participation can be expected. The transplantation may also lead todeepening of the public awareness of the coral reefs, possibly promising an environment-educational
effect. However, for successful transplantation, it is necessary that sufficient technical instructions
are made, and Natural Parks Law and ordinances related to fisheries regulations are observed.
In Sekisei Lagoon, organizations that are related to the coral reefs such as International Coral Reef

74

Research and Monitoring Center of Ministry of the Environment, Okinawa Prefecture, Municipalityof Taketomi-cho, Yaeyama Marine Park Research Station, and Union of Diving Services set up
Yaeyama Coral Reef Conservation Conference for regeneration of the coral reefs of Iriomote
National Park. They performed transplantation of coral fragments as part of its project, which
continued for several years with support from various funds. The project contributed to theregeneration of the coral reefs, and led to other positive activities of the Conference (Fig. 7-2).
Activities like these are also performed around Akajima, Kerama Archipelago, where the local
fishermen's Cooperative and Aka-Geruma Diving Association participate in activities such as reef
checking, removal of crown-of-thorns starfish, and transplantation of corals with the cooperation of
the Akajima Marine Science Laboratory.

Fig. 7-2．Volunteer diver performing transplantation of corals(3) Monitoring
It is important to monitor how the transplanted or relocated corals survive over time for evaluationof the techniques and results of transplantation or the relocation. For the details of the monitoring,
the following items should be noted.
a. State of survival and death of corals
Corals can be classified as follows according to the state of extinction of the transplanted coralcolonies;
Healthy corals: no extinction at all,Partly dead corals: extinction less than 30％,
Partly alive corals: more than than 30％ alive
Very small number of corals alive: extinction equal to 70% or over and less than 100%,Extinct：No corals alive,
Disappeared: coral colonies disappear.

75

b. State of activity of corals
Coral colonies can be classified as follows according to the state of transplantation;
Good: Color of polyps and coenosarc is normal, no abnormality in extension of tentacles, and notcovered with much mucous membrane.
Bad: polyps and coenosarc are bleached, the surface is covered with much mucous membrane, ordead area is expanded by the abnormal growth of algae and sea sponge.

Basically monitoring of transplanted corals is performed in each season, and it is necessary to add
a monitoring at the first month immediately after transplantation, where corals are unstable. Whenjuvenile corals made from settled larvae is on the bottom, it is assumed that colonies may takeapproximately four years until they present a scene close to the natural state. Therefore, it isnecessary to continue monitoring five years including the follow up investigation.
For scientific assessment of a transplantation, the transplanted communities should be comparedwith natural communities. However, there may be no normal colonies near by. Sometimes it is
impossible to find a comparison in an area previously cleared of healthy coral by bleaching or othernatural or human causes.

c. Monitoring of habitat environment
When monitoring corals, it is necessary to monitor their habitat environment at the same time tounderstand it as one of several factors affecting coral survival. The important environmental factorsthat can affect the survival of corals are water temperature, water movement, sedimentation andpredators. Long term rise of water temperature kills corals, which is why coral bleaching due to highwater temperature is a worldwide problem. By monitoring water temperature continuously for longtime, it is possible to discover water temperature trends in locations that affect survival of the corals.
Recently, compact and low cost self-recording water temperature thermometers have come on themarket. Some are now can measure the temperature hourly for six months used for temperature
measurement in the coral reef waters (Nature Conservation Bureau, Ministry of the Environment
2001).
Water movement is also a factor that can affect the survival of corals. Many species have greatneed for the transplantation to locations with more water movement (Marine Parks Center of Japan
1995). As a simple and easy method for discovering the movement characteristics of thetransplantation destination, there is a measuring method that uses calcium sulfate balls (Nabeshima
and Kida 1990; Komatsu 1992; Komatsu and Kawai 1992; Furushima et al. 2000, 2001). Since thismethod provides the state of the cumulative tidal flow in time series, it is suitable for knowing the
average characteristics of the site. This method allows repetition of measurement at low cost.
On some coral reefs, terrestrial run-off of soils occurs frequently, which affect mainly the76

environment of moats. It has a serious impact on the survival of corals. Among the methods fordiscovering the state of the sedimentation are visual observation to see the state qualitatively, the useof sediment traps, and the SPSS method that measures the optical penetration of object to be
examined (Ohmija and Mitsumoto 2001). These methods are easiest in the following order: visual,
SPSS and trap. It is recommended to pick one of them for scale of monitoring because any of themcan provide useful data for any purpose.
There are some other important factors such as light photon and nutrient salts, which should beselected as necessary because they require much cost for long term measurement.

(4) Reproduction
The speed of growth and survival rate should be thought of as more important than mere
regeneration with regard to the transplantation of coral fragments, but if the transplanted corals canspawn, that should contribute more to the recovery of total coral reefs because the coral supply
source is increased. Since the possibility of the spawning is increased as the transplanted colonies
grow, verify the spawning at the time of spawning. Though the time of spawning varies from year toyear and among the various waters, it is known that many species usually spawn around the fullmoon in early summer night (see Chapter 3-1). Therefore, it is desirable to verify the spawning bycontinuously monitoring the polyps (Fig. 7-3).

Fig. 7-3. Genital gland of matured Acropora (photo by K Shimoike)

Literature Cited
Furushima Y, Okamoto M, Oguro I, Kaya T and Matsuda T (2000) Evaluation of water movementin the neighborhood of coral reef (1) –Manufacture of the integrative current velocity
sensor-. JAMSTEC, 41:15-20. (in Japanese)77

Furushima Y, Okamoto M, Oguro I, Kaya T, Matsuda T and Komatsu T (2001) Measurement ofsmall scale water motion in the neighborhood of coral reef．JAMSTEC, 43:125-132. (inJapanese)
Marine Parks Center of Japan (1995) Study on recovery of coral reef ecological system, 87pp. (inJapanese)
Nature Conservation Bureau, Ministry of the Environment (2001) Water quality survey, Report of
Activities on Research and Monitoring in Coral Reef：153-157. (in Japanese)
Komatsu T (1992) Improvement and data example of measurement method on time –averaged
intensity of water motion by plaster ball, Kaiyo 24(8)：503-511. (in Japanese)
Komatsu T and Kawai H (1992) Measurements of time-averaged intensity of water motion withplaster balls. J. Oceanogr. 48: 353-365.
Nabeshima Y and Kida W (1990)

Measurement method of water movement by plaster ball.

Aquaculture 38(2): 127-133. (in Japanese)
Ohmija, T and Mitsumoto H (2001) Relationship between measured values of turbidity, horizontaltransparency and SPSS at coral reefs. Annual Report of Okinawa Prefectural Institute of
Health and Environment 35：103-110. (in Japanese)(Fujiwara S)

78

8. Concluding observations(1) Techniques of reef rehabilitation: development and comparison
The very first case of coral transplantation in Japan was possibly the one for the restoration ofundersea scenery around the undersea observatory that was constructed in 1970 in Kushimoto,
Wakayama Prefecture by the Marine Park Center. This water is a typical area of hermatypic coral
distribution in Honshu which is known for its wide community of tabular type Acropora hyacinthus.
As a result of experimental transplantation (fragment) using the similar form corals, it is reported
that the species transplanted at this time grew to a size that shows the feature of colonies within 1 to
2 years (Tatsuki 1977). Worldwide, the transplantation of coral fragments has been implemented as atechnique for recovery of coral reefs that suffered a large scale coral predation from an explosive
infestation of crown-of-thorns starfish from 1960’s to 1970’s. Then efforts made little progress in therecovery. Nowadays, several organizations (such as Reef Ball Development Group, Ltd:www.artificialreefs.org), that promote restoration of coral reefs deteriorated by human activities, aretaking an active part. Also an attempt to increase employment opportunities of fishermen indeveloping countries has been made through the restoration activities and production of ornamental
coral (for example, Heeger et al. 1999). If a full-scale coral farming (seed production and culture ortransplantation of coral fragments) can be set underway by Japanese research laboratories that havethe highest developed techniques in the world for fishery farming, they will be able to support
development of restoration techniques based on their actual performance and transfer them todeveloping countries in sub-tropical and tropical regions, resulting in better conservation of theworld’s marine environment.
If the coral reefs suffer widely from the predation by crown-of-thorns starfish, resulting in
extinction of most of the coral communities, the recovery takes very long time. Their case was an
extinction of almost all corals from the severe infestation in Sekisei Lagoon of Okinawa in 1981. It
took dozens years until the recovery could be fully recognized (Mori 1995). The progress of therecovery in this period has not been simple. Recovery is usually retarded in the moats, that haveclosed features, as compared with reef edges which are open. It is common that different and theplaces, even if they are closed, generally show a difference in the degree of the recovery linked tothe differences in their habitat environments. The effects of the physical environment of waters, suchas uncertainly of larvae recruitment and impact of wave motion or influx of water on the growth anddevelopment of corals and formation of the reefs have scarcely been studied. So now is the time toadvance studies of selection of suitable sites for the release of larvae or transplantation.
The sedimentation from terrestrial run-off became prominent from the 1980’s in Okinawa, which
disturbed the settlement of juvenile corals and prevented their growth, making the process of therecovery complex. The variation of the degree of the recovery of coral reefs among locations is79

greatly affected not only by the possibility of supporting juvenile corals and their survival rate, butby the deterioration of habitat environment. Under such circumstances, it is vital to attempt positive
restoration (not simply to wait for natural recovery).
The techniques for restoration of coral reefs was initiated by transplantation of fragments. They
have been evolved to the larval production techniques that utilize sexual reproduction, and then to
the larvae settlement induction techniques. This process seems to show that the techniques areadvancing toward measures that do not affect the existing coral communities. Since it is expectedthat coral reef restoration techniques will be evolved more through further studies in the future, thisdocument has made clear the status of past and present research and has collected themsystematically. Table 8-1 summarizes the restoration techniques for comparison.
The technique that can be implemented immediately is the transplantation of coral fragments if
one has a certain level of ecological knowledge and transplantation technique. Since it can be
implemented if the nails and wires are available, this is the method that was adopted earlier than theother techniques. After that, the adhesive that is effective in seawater became available, which has
become widely used as a typical method of the transplantation. The method that attempts to increase
the coral by utilizing the sexual reproduction while minimizing the effect on the donor colonies
mainly include production of larvae in the laboratory, collection of eggs in the field, and induction of
the settlement. Since each of the methods has specific features, it is desirable to select the mostsuitable method based on the situation. The seed production is carried by using an indoor water tankor outdoor floating ponds, thus involving higher material than the other methods, but it allows
relatively stable collection of the seed and allows selection of the species. The larvae-releasing
method can settle the seeding in wide range. The labor and material cost of the larvae settlement
induction method is lower than the other methods. The larvae settlement induction method, in which
the reach of larvae is affected by the weather and oceanographic condition, can restore the coralmore assuredly if the movement of the drifting larvae can be predicted more assuredly and a methodthat can detain the slick near the transplantation structure is developed.
For the growth of corals, Yamamoto et al. (2002) shows an approximate formula for obtaining the
growth at the depth of water of 1m and inclination angle of 10° based on the results of continuous
observation for six years in Naha Harbor.
Coral coverage y ＝0.0227e1.25t (R2＝0.69, n＝9 and t: year)
The approximate formula for obtaining the growth of corals at the depth of water of 0.5 m basedon the report of investigation of natural coral communities on Heron island of the Great Barrier Reef
is as shown below.
Coral coverage y ＝0.0261e1.10t (R2＝0.95, n＝4, and t: year)
According to the results of calculations using these formulas, the coral coverage increases rapidly
at 3rd to 5th year and enters the stable growing period at 6th year. This is why the “Time to80

Table 8-1．Comparison of coral reef restoration techniques
Fragment
transplantation

Juvenile coraltransplantation

Seedling production

Larvae releasing

Induction of larvae
settlement

Collection of larvae
collection and nurturingfrom tank or field,
Induce larvae
larvae is same as left.
nurture larvae, induce
settlement on settlement
Transport larvae andsettlement on plate, andtool or surface
releasing (establish
transplant plate to theprocessed structure
sheet on destination)
field

Outline of themethodColony fragmentationand fixation on
substrate

Collection of juvenilecolonies andtransplantation

Time required

ca. three years (fix inspring)Five years after
ca. five years after
ca. three years (can fix
transplantation (collect settlement (settle inyear-round)larvae in summer)
summer)Equipments andmaterials

Wire, nail, cable tie,
and adhesive

Adhesive

Nurturing devices,
settlement plate, andadhesivesame as left

ca. one week, every-day
Transplantation andcare for larvae
ca. one week, every-day
collection of settlement
nurturing, and 100
care for larvae
tools, and structure
platesnurturingprocessing
fixation/worker/day

Number of settlement
plate will be restricted same as left
by number of divers

Number of settlement
Amount of seedling and Relatively broad scale,tool and processed
fixation will be
although amout ofstructure will be
restricted by nurturing larvae will be restricted
restricted by number offacility and number of by scale of nurturing
divers and project's
divers, respectively
facility
scale

Required effort＊

Scale of restoration

100 fragments
fixation/worker/day

ca. five years after
settlement (settle insummer)Nurturing devices andSurface processedsurface processed
structure
structure*Required efforts after fixing on to the field substrate is common, thus will be abbreviated.

restoration” shown in Table 8-1 is “approximately 5 years”. Chapter 7-3 describes the required
monitoring period as 5 years.
In addition to the techniques shown in Table 8-1, there is a method that transplants all colonies of
Porites lutea discussed in Chapter 6-3. This technique is a little different from the restoration ofcoral reefs by transplantation, which is a kind of emergency evacuation of the communities that mayotherwise be

killed off. That is why it was introduced only as an example case and not listed in the

Table 8-1. The relocation of an entire coral reef is also not listed in the table for the same reason.

(2) Future subjects to study
It is expected that the mainstream of the future coral reef restoration techniques will be
improvements in the handling of larvae. In contrast with relatively closed waters where themovement of larvae can be predicted relatively easily, the open sea areas, it is essential to predict the
movement of larvae slicks because they are transferred long distance in a short period by the windcurrents. However, the current significant lack of oceanographic information makes it impossible topredict the movement of the drifting larvae and thus, it is crucial to develop the research in this field.

81

When planning the transplantation or release of corals, selection of the suitable destination is avery important matter. Needless to say, successful restoration requires the favorable growth of corals
introduced into a new environment, and expansion of their habitat through satisfactory generation of
the progenies. To achieve that, it is necessary to make clear the relationship between each stage ofthe overall life of corals and field factors, including biological causes, such as the effects ofinterspecies competitions and predation from coral feeding fish such as damselfish. As discussed
previously, our knowledge for microscopic or mesoscopic physical and topographic factors such as
flow of water and inclination in the coral reef areas are scarce. These also are important researchsubjects in the future.

Fig. 8-1．Transplanted branching Acropora
Finally, we would like to discuss the effects of genetic disturbances by hybridization on the coral
population and the deterioration of genetic diversity of the coral communities that can be caused by
the restoration projects. The transplantation of corals may cause no problem if the destination iswithin the range of natural diffusion of the spawn. But the long distance transportation of corals may
disturb the characteristics of the local genetic constitution.Since it is well known that hermatypiccorals have high genetic diversity and easily form hybrids (Hatta et al. 1999; Willis 1997), it isnecessary to obtain the eggs and coral fragments from many colonies that are distributed as wide as
possible, regardless whether they are used for the seed production or for the fragment transplantation.
If the number of donor colonies is limited or the diversity of their genetic pool is lacking, coral
communities that are very susceptible to environmental change or disease agents may be made. It is
known that Polites compressa, that is found in Hawaiian Islands, shows high genetic diversity in theplaces with relatively large environmental disturbance and low genetic diversity in the places withrelatively small environmental disturbance (Hunter 1993). Molecular biology, that is making
considerable progress today, should be applied to the estimation of the size of genetic diversity ofcurrent coral communities. The results could be used as a reference for larvae production inlaboratory and in the transplantation of coral fragments from the source sites.

82

Literature Cited
Hatta M, Fukami H, Wang W, Omori M, Shimoike K, Hayashibara T, Ina Y and Sugiyama T (1999)
Reproduction and genetic evidence for a reticulate evolutionary history ofmass-spawning corals. Mol. Biol. Evol. 16: 1607-1613.
Heeger T, Cashman M and Sotto F (1999) Coral farming as alternative livelifood for sustainable
natural resource management and colal rehabilitation. Proc. Ocean. Intl. Pacific Rim,
Singapore: 171-185.
Hunter CL (1993) Genotypie variation and colonal structure in coral populations with different
disturbance histories. Evolution 47: 1213-1228.
Mori M (1995) Change of stony coral and crown-of-thorns starfish in the Sekisei Lagoon, Marine
Parks Journal (107)：10-15. (in Japanese)
Tatsuki T (1977) Remediation of underwater scenery, Marine Parks Journal (41)：10-12. (inJapanese)
Yamamoto H, Takahash Y, Sumida K, Hayashi T, Sugiura N and Maekawa T (2002)

Analysis on

growing process of coral community in the artificial structure. Proc. Coastal
Engineering, JSCE 49: 1186-1190. (in Japanese)
Willis BL, Babcock RC, Harrison PL and Wallace CC (1997) Exprimental hybridization and rearing
in compatibilities within the mating systems of mass spawning reef corals. Coral Reefs
16 (Suppl.): S53-S65.
(Fujiwara S & Omori M)

83

Profile of Authors
Makoto Omori
Director
Akajima Marine Science Laboratory
Aka, Zamami-son, Okinawa-ken 901-3311
makomori@amsl.or.jp

Shuichi Fujiwara
Senior Researcher
Okinawa branch, Metocean Environment Inc.
2-6-19 Aja, Naha-shi, Okinawa-ken 900-0003
fshuichi@notes.metocean.co.jp

Masayuki Hatta
Associate Professor
College of Science
Ochanomizu University
2-1-1 Otsuka, Bunkyo-ku, Tokyo 112-8610
mhatta@cc.ocha.ac.jp

Seiichi Hosoya
Director
Okinawa branch, Metocean Environment Inc.
2-6-19 Aja, Naha-shi, Okinawa-ken 900-0003
seiiti@notes.metocean.co.jp

Kenji Iwao
Researcher
Akajima Marine Science Laboratory
Aka, Zamami-son, Okinawa-ken 901-3311
iwao@amsl.or.jp

Satoshi Nojima
Associate Professor
Amakusa Marine Biological Laboratory
Kyushu University
Tomioka, Reihoku-cho, Kumamoto-ken 863-2507
satoshi@mbox.ambl-unet.ocn.ne.jp

Mineo Okamoto
Associate Professor
College of Marine Science
Tokyo University of Marine Science and Technology
4-5-7 Konan, Minato-ku, Tokyo 108-8477
okamotom@s.kaiyodai.ac.jp

Nami Okubo
Graduate School
Department of Life Science
Tokyo Institute of Technology
2-12-1 Okayama, Meguro-ku, Tokyo 152-8551
namiokubo@nifty.com

Hiroki Taniguchi
Researcher
Akajima Marine Science Laboratory
Aka, Zamami-son, Okinawa-ken 901-3311
taniguchi@amsl.or.jp84