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Recent Advances in Lagoon-basedFarming Practices for Eight Speciesof Commercially Valuable Hard and

Soft Corals - A Technical Report

Simon EllisEileen Ellis

CTSA Publication No. 147

Recent Advances in Lagoon-basedFarming Practices for Eight Speciesof Commercially Valuable Hard and

Soft Corals - A Technical Report

Simon EllisEileen Ellis

Center for Tropical and Subtropical AquaculturePublication No. 147

March 2002

Table of Contents

Table of ContentsAcknowledgments .......................................................................... 1

Foreword .......................................................................................... 2

Introduction...................................................................................... 3About this publication ................................................................... 3The world market for live corals ................................................... 4Coral species used in the study ................................................... 5

Site selection ................................................................................... 9Test sites ...................................................................................... 9

Advances in farm structure ......................................................... 11A modular approach ................................................................... 11Use of cages .............................................................................. 14

Broodstock .................................................................................... 15Advances in broodstock collection and transport ...................... 15Recommendations for the test species ..................................... 16Placing broodstock at the farm sites .......................................... 17Broodstock regeneration and the case for in situ collectionversus on-site holding of broodstock ......................................... 18

Culture techniques ....................................................................... 26Substrates and their manufacture .............................................. 26Cutting ........................................................................................ 31Attachment and planting methods .............................................. 33

Growout and husbandry .............................................................. 37Growth rates and patterns .......................................................... 37Positioning and stocking density ................................................. 44

Diseases and pests ...................................................................... 45Pests .......................................................................................... 45

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Recent Advances in Coral Farming

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Diseases .................................................................................... 45

Harvest and transport .................................................................. 46Holding in the land-based facility ................................................ 47

Shipping ......................................................................................... 48Specific packing instructions ...................................................... 48Permits, CITES and shipping documents.................................. 49

Industry feedback ........................................................................... 50General comments ..................................................................... 50Specific comments .................................................................... 50

A revised economic model for coral farming in Pohnpeiusing recommendations from this study................................... 52

Capital costs ............................................................................... 53Operating costs .......................................................................... 53

Species summaries ...................................................................... 55Lemnalia ..................................................................................... 55Green polyped Sarcophyton ...................................................... 55Long polyped Sarcophyton ........................................................ 56Pachyclavularia ........................................................................... 56Acropora ..................................................................................... 57Porites ........................................................................................ 57Turbinaria .................................................................................... 58Euphyllia ..................................................................................... 58

References ..................................................................................... 59

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Acknowledgments

AcknowledgmentsThis publication was prepared as part of the work under a project titled “AquacultureResearch, Extension and Training Support in the U.S. Affiliated Pacific Islands - Year12.” Funding was provided by the Center for Tropical and SubtropicalAquaculture (CTSA) through a grant from the Cooperative State Research,Education, and Extension Service of the U.S. Department of Agriculture (grant#99-38500-7399). The views expressed herein are those of the authors and do notnecessarily reflect the views of the U.S. Department of Agriculture, the Center for Tropi-cal and Subtropical Aquaculture or any staff of those agencies.

Thanks go to the following for their assistance and input to this project:

The staff of the Marine and Environmental Research Institute of Pohnpei (MERIP) forproviding facilities and staff assistance for this work. In particular, Gregory MuckenhauptS.J., Tyler McAdam, Stacy Maenner, Susan O’Connor and John Tomczuk.

Private sector individuals, Roderick Bourke of Robert Reimers Enterprises, Joy Mead-ows of Harbor Aquatics and Butch Almberg of Reef Rascals, for their advice andfeedback.

The Australian Embassy Pohnpei for use of their boat to collect specimens from PakinAtoll.

Dr. Philip Alderslade for coral identifications.

Kai Lee Awaya of CTSA for editing this manual and for printing assistance.

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ForewordThe information presented in this publication was derived directly from a collaborativeresearch project on lagoon-based farming of corals. Collaborators were CTSA, MERIPand the College of Micronesia - Land Grant Program. While farming practices for thespecies covered are not fully complete, information provided herein is designed toprovide the reader with as much field derived data as possible for establishing acommercially viable coral farm. In addition, many of the farming techniques describedcan have direct application to other coral species with similar morphology and growthcharacteristics. This report assumes the reader to have some general knowledge ofthe benefits and basic aspects of coral farming as outlined in CTSA Publication #137“The Culture of Soft Corals (Order: Alcyonacea) for the Marine Aquarium Trade.” It isadvisable to be familiar with this publication in order to fully utilize the informationcontained herein. Publication #137 can be downloaded from the CTSA website (http://library.kcc.hawaii.edu/CTSA) or ordered from the address below.

Center for Tropical and Subtropical AquacultureThe Oceanic Institute41-202 Kalanianaole HighwayWaimanalo, HI 96795, USATel. 808-259-3168Fax. 808-259-8395e-mail: [email protected]

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Introduction

About this publicationThis publication reports directly on the results of an 18-month research study into thespecific farming practices of eight species of commercially valuable hard and softcorals in Pohnpei, Federated States of Micronesia (FSM). Four species of hard coraland four species of soft coral were selected for the trial using the following criteria:

1. The corals are attractive and are regularly kept as aquarium specimens (asdetermined by reference to aquarist texts such as Puterbaugh and Borneman,1996; Sprung and Delbeek, 1997; Delbeek and Sprung, 1994; Wilkens andBirkholz, 1992 and personal communication with aquarium wholesalers andaquarium hobbyists).

2. Corals that are hardy enough to be kept by aquarists with average experienceand standard equipment.

3. Corals that are abundant enough in and around Pohnpei lagoon and its associ-ated atolls to supply broodstock for an industry.

4. Corals that are photosynthetic.

Through a combination of field observations, growth and attachment trials, liaison withwholesalers and shipping and marketing trials this report strives to remove some ofthe unknown factors from coral farming, thereby making it easier for prospective farm-ers to enter this new field. Detailed for each species are the most efficient cutting andplanting methods, survival and growth data, broodstock regeneration times, refinedshipping methods, market acceptance information and a general price range derivedfrom actual sales of the product in the United States. While this information is basedon observations in Pohnpei, FSM it has wide ranging applicability to the rest of theIndo-Pacific region.

Throughout this report, reference will be made to CTSA publication #137 “The Cultureof Soft Corals (Order: Alcyonacea) for the Marine Aquarium Trade”. Publication #137provides much of the basic background and rationale for coral farming in general andis best used as a prefacing companion to this publication. Details of how to obtainCTSA publication #137 are given in the Foreword on page 2.

IMPORTANT NOTE: Before starting a coral cultivation project, it is criticallyimportant to become familiar with local and international laws regarding thecollection, cultivation and possession of live corals. Please contact local gov-ernment agencies to obtain information regarding current regulations.

Introduction

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The world market for live coralsMost of the live corals collected or farmed around the world supply the marine aquariumtrade. Over 90% of live corals are shipped to the United States which had an esti-mated 560,000 tropical marine aquaria in 1999, a figure that is growing at 20% perannum. The growth in the marine aquarium hobby has been triggered primarily byvast improvements in aquarium technology which allow an increasing number of ma-rine invertebrates to be kept alive in home aquaria. The percentage of live coral ex-ports as a proportion of the total global trade grew from approximately 5% in 1991 to53% in 1997 (Green and Shirley, 1999). It is currently estimated that there are some 1million pieces of hard coral and 6 million pieces of soft coral residing in US marineaquaria.

In recent years there has been increasing concern over the effect that wild collection ofcorals is having on reef health in developing nations. It is not so much the effect of thisone activity that is worrisome but rather that it is adding to manifold other pressures oncoral reefs such as destructive fishing and development practices. As a standaloneindustry, wild collection of corals for the aquarium industry could be a highly sustain-able practice, especially considering that it is a finite market and has one of the high-est economic returns for the environmental impact.

Mariculture or farming of corals has the potential to reduce the number of corals beingcollected from the wild. Many corals reproduce using a process called fragmentationwhere a small piece of coral breaks away from the main colony and forms a newcolony on its own (Highsmith, 1982). The majority of coral farming makes use of thissimple procedure. Despite the large potential for farming of corals only 0.03% of cor-als sold for marine aquarium use today are estimated to be farmed and with those thatare collected, demand currently outweighs supply (Green and Shirley, 1999).

The case for culturing corals rather than collecting them is one of conservation andsustainability versus economics. Wild collection offers an instantaneous return on in-vestment whereas farming requires some investment and a period of time beforeharvest can begin. However, in the long-term, farming can offer more stable income,the ability to grow large quantities of rarer, high value species, reduced operatingcosts and a more sustainable future for the industry in general.

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Coral species used in the studyUsing the criteria listed on page 3, four species of hard coral and four species of softcoral were chosen for the study. These species were chosen as the most likely candi-dates for successful farming and also as a diverse group of corals that would providea well rounded product line for a commercial farm based in Pohnpei. Because coraldiversity is not as high in Pohnpei as it is in the Philippines, Palau, Indonesia andother parts of the Indo-Pacific, the corals that might be chosen in each area are likleyto differ.

Species chosen were:

Soft corals1. Long polyped leather or mushroom coral (Sarcophyton spp.*). This speciesis abundant in Pohnpei lagoon and surrounds. It is found primarily in areas with highwater exchange such as channels and cuts. Color is brown/beige with large polypsthat when extended are also beige in color and move in the current (Figure 1, page 6).Long polyp Sarcophytons generally resemble a mushroom or toadstool. They arehardy and are recommended for standard marine aquaria and beginners. Level ofdifficulty of care is 2 on a scale of 1 to 10 with 1 being easiest (Puterbaugh andBorneman, 1996).* Soft corals in general, and members of the genus Sarcophyton and Lobophytum inparticular, are notoriously difficult to identify and distinguish between. Identification ofspecies to genus level for soft corals is usually acceptable for export permits andshipping documents.

2. Green polyped leather coral (Sarcophyton spp.). This species is much lessabundant in Pohnpei than the Long polyp Sarcophyton and occurs in deeper parts ofsimilar habitats. This species has a much shorter stalk and polyps than the Long polypSarcophyton but has bright green polyps that remain extended much of the time (Fig-ure 2, page 6). It can tolerate low light levels and poor water quality making it suitablefor beginners and expert hobbyists alike. Level of difficulty of care is 2 on a scale of 1to 10 with 1 being easiest (Puterbaugh and Borneman, 1996).

Introduction

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Figure 1. Long polyp Sarcophytonbroodstock

Figure 2. Green polyp Sarcophyton broodstock

Figure 4. Pachyclavularia broodstock

Figure 3. Lemnalia broodstock

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Figure 8. Turbinaria broodstock

Figure 5. Acropora broodstock

Figure 6. Porites broodstock

Figure 7. Euphyllia broodstock

Introduction

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3. Brown tree coral (Lemnalia spp.). This species is abundant in Pohnpei lagoonand surrounding areas. It has a brown/beige color and a branching or arborescentappearance (Figure 3, page 6). Abundance is greatest on shallow, well flushed reefflats although it also occurs at depth in cuts and channels. A poor shipper, this coralthrives once established in aquaria. Level of difficulty of care is 5 on a scale of 1 to 10with 1 being easiest (Puterbaugh and Borneman, 1996).

4. Green star polyps (Pachyclavularia violacea). This species is a stoloniferancoral in the family Tubiporidae (formerly classified as Clavularia). It is characterizedby green/brown polyps protruding from an encrusting purple mat (Figure 4, page 6).This coral was located off Pakin Atoll (25 miles NW of Pohnpei) at a depth of 15-20meters in very turbulent water. Although it has not been located in or around Pohnpeilagoon, it is quite abundant in the Pakin area. Pachyclavularia is a hardy species thatdoes well in aquaria provided there is a strong flow of water. Unlike most other corals,Pachyclavularia is unable to repel filamentous algae and detritus from its skeleton,which can be problematic. Because it is an encrusting species it can encroach onother living corals in an aquarium and may need to be controlled (Sprung and Delbeek,1997). Level of difficulty of care is 1 on a scale of 1 to 10 with 1 being easiest(Puterbaugh and Borneman, 1996).

Hard corals5. Blue tipped Acropora (Acropora nasuta). This species is found in abundanceon shallow reef flats and inner reef edges with high water movement and light intensity.It is characterized by a light brown color with bright blue growth areas on the tips andfringes of the base (Figure 5, page 7). In aquaria, it needs strong lighting and highwater flow. It is not recommended for beginners and has a level of difficulty of care of6-8 on a scale of 1 to 10 with 1 being easiest (Puterbaugh and Borneman, 1996).

6. Yellow finger coral (Porites cylindrica). This species is extremely abundant inPohnpei lagoon occurring primarily in shallow areas of the inner fringing reefs. It istolerant of poor water quality and can be found in turbid and slow moving waters.Porites cylindrica is characterized by a branched, finger coral structure and a green/yellow color (Figure 6, page 7). Like the Acropora it requires strong light and is notrecommended for novices. Level of difficulty of care is 8 on a scale of 1 to 10 with 1being easiest (Puterbaugh and Borneman, 1996).

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7. Hammer or anchor coral (Euphyllia ancora). This species is only moderatelyabundant in Pohnpei and occurs in poorly lit, turbid areas of the inner lagoon in largecolonies. It is characterized by single large polyps with beige, hammer shaped ten-tacles on a skeletal stem (Figure 7, page 7). Because these corals favor lower lightand water flow they are easier to keep in aquaria. Level of difficulty of care is 5 on ascale of 1 to 10 with 1 being easiest (Puterbaugh and Borneman, 1996).

8. Yellow lettuce or scroll coral (Turbinaria reniformis). This coral is moderatelyabundant in Pohnpei and surrounding areas, occurring mainly on well flushed shallowreef flats and at depth of up to 20 m in fast flowing channels and cuts. It is character-ized by a bright yellow color and a curved or scroll like shape in larger colonies (Figure8, page 7). These corals require high light intensity and water flow in the aquariummaking them unsuitable for beginners. Level of difficulty of care is 8 on a scale of 1 to10 with 1 being easiest (Puterbaugh and Borneman, 1996).

Site selection

Test sitesIn order to evaluate how the eight test species would grow in conditions of varyinglight, current, turbidity and nutrient load, corals were grown under identical conditionsat three different sites. Recommendations for growout sites for the test species arebased on observations taken from these sites. Where species grew and survived wellat one or more sites, general recommendations from all those sites are made.

Site conditions were as follows:

Site 1 was close to the mouth of a shallow eutrophic bay lined with mangrove forest.The substrate was a dark silt/sand mixture and coral cover was sparse consistingprimarily of Porites heads, Goniopora and low light tolerant species such as Plerogyra,Physogyra and Lobophyllia. Of the species tested only Turbinaria reneformis wasfound in the general vicinity. Light penetration (mean 19,676 lux) was comparativelypoor, and turbidity and nutrient load comparatively high. Average depth for growoutwas 4.61 m. While unidirectional water flow only averaged 2.04 cm/sec, this site alsoreceived wave surge in rough weather leading to increased water movement aroundthe corals.

Introduction

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Site 2 was close to the barrier reef and received very high flows of fresh ocean wateron the flood tide. Located in an open sandy channel running down the side of a barrierreef island it was quite protected on three sides from severe weather. Average depthfor growout was 4.24 m. The substrate was a fine white sand. Light penetration wascomparatively higher (mean 29,553 lux) and unidirectional water flow the highest ofthe three sites (mean 10.53 cm/sec). Surrounding coral cover consisted mainly of firecorals (Millepora). Of the corals tested only Porites cylindrica was found in the gen-eral vicinity.

Site 3 was midway between the barrier reef and the island of Pohnpei. This site wascharacterized by limited water movement (mean 1.62 cm/sec) and comparatively highlight intensity (mean 50,484 lux). Average depth for growout was 3.84 m. Coral coverat this site was exceptionally high with large colonies of Porites, Lobophyllia,Montipora, Goniopora, Pachyseris and Pavona. Of the species tested only Poritescylindrica was found in the general vicinity.

DepthAll sites were in 3-5 m of water. A minimum depth of about 4 m helped in keeping thecorals away from excessive light intensity, rapid changes in temperature and highwave action. This depth also made it easy to work on the farm using either snorkel orSCUBA equipment. Species kept in water shallower than 4 m showed a lightening incolor or bleaching presumably caused by elevated temperature and light levels.

SCUBA or Hookah versus snorkeling

All facets of farm operation, with the exception of broodstock collections for deeperwater species were designed so that diving equipment such as hookah or SCUBA isno longer necessary. However, the investment in diving gear should be consideredcarefully as it can save a substantial amount of time because workers are not inter-rupted by constantly having to surface for air.

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Advances in farm structure

A modular approach

Previous recommendations for constructing farms has centered around the use ofvarious forms of containment such as nursery trays, milk crates and PVC pipe placedon the substrate. This method has a number of pros and cons. The primary benefit tomaking farms in this way is that construction is quick and inexpensive.

However, in Pohnpei lagoon this method has a number of drawbacks that in the longrun can waste time and cause coral mortality. Pohnpei lagoon is characterized byshallow reef flats that drop sharply to the lagoon floor. Consequently there is little flatarea in the 4-5 m range to do coral farming. Those areas that are suitable are gener-ally sandy or silty and have large populations of burrowing shrimp and polychaeteworms. The mounds of sand produced by the burrows can either smother a tray or tiltit so that corals fall over or move to one side of the tray. In addition, trays placed on thesand in areas of high water flow quickly sink into the sand. Constant maintenance ofthese trays is troublesome and time consuming.

To overcome this problem and also to standardize the growout of the test species ateach site, tables or trestles were constructed out of locally available 13.5 mm diam-eter iron reinforcing bar (re-bar). These tables allowed the farming of corals on slop-ing reef faces (Figure 9) as well as sandy and silty areas (Figure 10).

Figure 9. Tables placed on a sloping reefface.

Figure 10. Tables placed on a flat sandybottom.

Advances in Farm Structure

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In sloping areas the legs were buried in thesand until the table surface was flat and insandy areas concrete “boots” (Figure 11) wereattached to the legs of the table to stop themfrom sinking. This proved highly effective evenin very high flow areas. Boots were made byplacing a piece of 10-cm diameter PVC pipeor the bottom of a plastic soft drink bottle ap-proximately 25 cm long over the bottom of theleg and filling it with concrete.

The cost of manufacturing the tables was ap-proximately US$25 each including labor andmaterials. Given a predicted 5-year life spanand that each table can hold up to 160 coralsthe cost of manufacture was not considered

excessive given the benefits of theiruse. The modular concept of usingtables also allows streamlining of thefarming process and less work tokeep track of inventory.

Up to 4 tables could be carried on thework boat (Figure 12) during any oneouting. Tables were easily deployedat the work site either by loweringthem to the substrate from the boat orusing floats to move them into placethen lowering them to the bottom. Thislatter technique was particularly effec-tive in areas of high coral growth.Tables could be lowered into smallsand patches on the reef slope with-out impacting the surrounding coral.

Figure 12. Standard workboat common inPohnpei.

Figure 11. Concrete “boot” on tableleg.

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Tables were constructed to fit 8 –25 x 50 cm standard nursery trayswhich were each filled with 4 litersof basalt gravel. Gravel was pre-washed and measured into poly-ethylene bags (Figure 12) prior todeployment in order to reduce un-derwater working time. Gravelwas placed in the trays even ifanother attachment substrate wasbeing used for the corals. Thisadded weight to the trays and al-lowed substrates to be nestleddown in the gravel providing morestability to the corals in high cur-rents or wave action. The tablesalso proved to be a comfortable and easy platform to work on, providing a stable areafor divers to cut, plant and attach corals thereby improving working efficiency (Figure13). A full table with trays, gravel and corals could also easily be picked up underwaterand moved by two workers.

Use of tables had a number of environmentally beneficial effects. Firstly, the use oftables allowed coral culture to take place in areas that would otherwise be impracticalfor farming due to a sloping or poor substrate. This effectively removed the farmingprocess from reef areas where it might impact the reef itself or otherwise interfere withcultural- or tourism-related reef activities such as fishing, snorkeling or diving. Sec-ondly these tables form their own mini-reefs recruiting large numbers of reef fish tosettle from the plankton and grow up in the area.

Table dimensions are as follows:Legs – 0.9 mWidth – 1.1 mLength – 1.1 mCenter struts – 27 cm apartCurved ends – 27 cm apart

Figure 13. Farm workers at a table.

Advances in Farm Structure

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Use of cagesWhile predation was rarely a problem dur-ing the study, seacucumbers, hermitcrabs and large fish often interfered withthe corals (Figure 14). Grazing activitiesof these animals tended to knock the cor-als over, causing blemishes, reducedgrowth and extra work to re-right them.To overcome this problem cages de-signed to house giant clams were tested(Figure 15). The use of the cages pro-vided excellent protection for the coralsreducing disturbance to a minimum.Cage tops were attached loosely so thataccess to the corals was easy. However,the cage tops do need to be scrubbedevery two weeks to remove fouling, a job taking some 30-45 seconds per cage. An-other advantage to using cages was that a simpler table design (also originally usedwith giant clams) could be employed (Figure 16). This table requires only 4 pieces ofre-bar and can be made without the use of welding equipment. Details on design andconstruction of this trestle can be found in Ellis (2000) on page 43.

Figure 14. Fish foraging in coral trays.

Figure 16. Four piece trestle equippedwith cages for holding corals.

Figure 15. Square coral table equipped withpredator exclusion cages.

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Broodstock

Advances in broodstock collection and transportPrevious recommendations for broodstock collec-tion detailed the use of polyethylene bags for col-lection. This has been replaced to a great extentby the use of simple baskets such as the one inFigure 17. Using baskets allows broodstock to becollected faster because the bagging time is elimi-nated from the process. In addition, collected colo-nies receive less handling and abrasion during thecollection process. As long as colonies of thesame species are placed in the same basket theycan be packed at relatively high density without illeffects. Corals should always be collected by chip-ping away some of the substrate they are attachedto using a hammer and/or cold chisel. Leaving thebase of the animal attached to a substrate reducesthe risk of infection and makes it easier to situateat the growout site.

Depth is also an important consideration inbroodstock collection. Taking the time to find shal-low areas with dense populations of a particular species can save considerable timein the long run. Wherever possible, broodstock should be collected using snorkel gearor SCUBA gear in shallow water. This greatly reduces the cost of collection by savingtime and the cost involved in filling more SCUBA tanks for deeper diving.

During collection, broodstock were brought back to the vicinity of the boat and wereleft submerged in the baskets until all the collecting was complete. At this point coralswere quickly transferred to insulated ice chests filled with clean seawater. Previousrecommendations included keeping the corals in bags or placing them in non-insu-lated containers. As thermal shock is one of the leading stressors that kill corals dur-ing transport, this recommendation has been revised so that only insulated ice chestsare used and corals are removed from bags for the journey to the farm site.

Broodstock

Figure 17. Collection basket withanchor coral broodstock.

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Many corals have protective stinging mechanisms that can injure other coral species.For this reason corals should be placed in the coolers according to species. If pos-sible only one species should be placed in a single cooler. If this is not possible thenhard and soft corals should not be mixed as the hard corals can move around andsquash or tear the soft corals. During transport to the farm site approximately 50% ofthe water should be exchanged in the cooler at least every 30 minutes.

Recommendations for the test speciesFor the purposes of the study, broodstock for each species were collected from thesame general area and in the case of the Euphyllia from the same large colony. TheTurbinaria, Acropora, Porites and Lemnalia were all collected from shallow waterusing snorkel equipment only. Euphyllia, Long polyp Sarcophyton, Green polypSarcophyton and Pachyclavularia were all collected from a depth of 10 – 20 m usingSCUBA gear. Travel times from collection site to farm site were no more than 45minutes with the exception of the Pachyclavularia which was collected from Pakinatoll, which is an approximate two hours boat ride from the test sites.

Long polyp Sarcophyton, Green polyp Sarcophyton and Lemnalia were collected aswhole colonies by chipping away part of the attachment substrate with a hammer andchisel. Porites, Euphyllia and Turbinaria were collected by chipping large pieces ofcoral from the colony using a hammer. Acropora was collected as whole colonieswhere possible, leaving the stem to regenerate. Because of the mat-like structure ofPachyclavularia it was collected from areas of dead coral on which it had encroached.Whole pieces of the dead coral were chipped up using a hammer.

In all cases, simple rules of conservation were observed when collecting: areas werechosen where a species was abundant so that the impact of removal was minimal;only a fraction of the total amount of a species was ever removed from one area;collecting practices that limit damage to the environment were used; areas of out-standing beauty or areas where tourists regularly visit were avoided.

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Placing broodstock at the farm sitesBroodstock were placed on nursery trays on tables at each of the test sites (Figure18) with the exception of the Euphyllia and Pachyclavularia. Euphyllia were attachedto the tables using wire (Figure 19) so that the colonies remained upright. It was dis-covered shortly after collecting the Pachyclavularia that this species would need spe-cial handling. Broodstock of this species left on nursery trays in the same way as othercorals quickly became covered in filamentous algae that smothered the colony. To

Broodstock

Figure 19. Euphyllia broodstock heldupright using wire on tables.

Figure 20. Pachyclavularia broodstockheld under a coral outcrop.

Figure 21. Pachyclavularia broodstockheld under a table covered with nurserytrays.

Figure 18. Turbinaria and Green polypSarcophyton broodstock held on tables.

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overcome this the collected broodstock were hung in a darker area under a coraloverhang (Figure 20) or under tables covered with nursery trays (Figure 21). Whilethis alleviated the problem somewhat, filamentous algae continues to be a problemfor this species under farm conditions.

Broodstock regenerationThe sustainability of coral farming is an issue among prospective farmers, conserva-tionists and industry regulators alike. It would be an ideal situation for all involved ifbroodstock were collected only once from the reef and placed in a farm after cuttingwhere colonies would regenerate to their original size before being fragmented again.This one time removal would reduce impact to the reef, appease regulators and con-servationists and cut farming costs and operating logistics.

The realities of broodstock regeneration times are somewhat different. It would seem,that especially with hard corals, the long regeneration times would make it necessaryto hold large numbers of broodstock colonies on the farm. These colonies would oc-cupy tables and farm space and would need periodic maintenance. A rough estimateof the amount of space needed to house broodstock on the farm would be approxi-mately half a table of broodstock for every table of coral fragments (approximately160).For example, a farm requiring 250 cuttings per month of a particular coral that has aregeneration time of 12 months would have to house enough broodstock to supply ayears worth of cuttings. This would equate to approximately 10 extra tables just to holdbroodstock for this one species.

The alternative is to leave the broodstock in place and travel periodically to an areaand crop fragments from resident broodstock that are located in what is assumed tobe an optimal area for their growth and survival. The cost of maintaining the broodstockon the farm versus the cost of traveling periodically to collect broodstock fragmentsmust be carefully weighed in making a final decision. This will be influenced by, amongother factors, the distance to the broodstock site, cost of fuel, sea conditions, localregulations and how hard the species is to collect.

Species regeneration rates and patternsDuring the study broodstock were kept at the farm site so that a qualitative estimationof broodstock survival and regeneration times could be obtained. Estimated regen-eration times, based on field observations and fragment growth rates are as follows:

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Long polyp Sarcophyton: The relatively slow growth rate of fragments of this spe-cies (approximately 25% crown width over a 6-month growout period) and field obser-vations of broodstock indicate that regeneration would be quite slow, taking 9-12months. This species is quite abundant in Pohnpei and if large beds of broodstockcould be located close to the growout site it would be recommended to collect cuttingsfrom these sites rather than holding the broodstock on-site. Figures 22-24 show theprogression of healing and growth during the 6-month trial for Long polyp Sarcophyton.

Broodstock

Figure 22. (Top left). Long polypSarcophyton broodstock immediatelyafter cutting.

Figure 23.(Top right). Long polypSarcophyton broodstock 2 weeks aftercutting showing new polyp growth in thescar tissue.

Figure 24. (Bottom left). Long polypSarcophyton broodstock 6 months aftercutting showing new tissue growth on thecrown.

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Green polyp Sarcophyton: The relatively faster growth rate of fragments of this spe-cies compared to the Long polyp Sarcophyton (approximately 59% crown width overa 6-month growout period) combined with broodstock observations indicate that re-generation would be quite fast, taking 6-9 months. This species was relatively sparselydistributed in Pohnpei and had to be collected from a depth of 10-20 m using SCUBAgear. Given its fast regeneration time and the difficulty of obtaining broodstock it isrecommended to keep broodstock of this species at the growout site. Figures 25-27show an example of the progression of healing and growth during the 6-month trial forGreen polyp Sarcophyton.

Figure 25. (Top left). Green polypSarcophyton broodstock immediatelyafter cutting.

Figure 26.(Top right). Green polypSarcophyton broodstock 2 weeks aftercutting showing new polyp growth in thescar tissue.

Figure 27. (Bottom left). Green polypSarcophyton broodstock 6 months aftercutting, showing new tissue growth onthe crown.

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Lemnalia: Fragments of this species grew very fast (89% increase in length in 6months) and also regularly produced new stalks and buds. Estimated broodstock re-generation time is only 4-6 months. During the growth trials, inspection of broodstockfor healing was not possible after 3 months because all the branches removed hadregenerated. This species is quite fragile and difficult to transport. Given that it hassuch a fast regeneration time it is recommended to keep broodstock at the farm sitewhenever possible. Figures 28 and 29 show examples of Lemnalia directly after cut-ting and new buds appearing 2 weeks later.

Pachyclavularia: Many problems occured with the broodstock of this species be-cause it could not repel filamentous algae. Any area where tissue was removed fromthe broodstock substrate tended to be rapidly colonized by algae and other foulingorganisms thereby preventing regeneration of the corals tissue. Despite this,Pachyclavularia grew relatively fast by putting out stolons that adhered to the sub-strate. In some instances it would grow up the pieces of string that suspended it. Be-cause Pachyclavularia did not thrive at any of the test sites it is hard to estimate itsregneration time. However, under optimal conditions it is likely to be 6-9 months. Fig-ures 30-32 (next page) show regeneration patterns for Pachclavularia.

Figure 29. Lemnalia broodstock withnew buds emerging from the scartissue 2 weeks after cutting.

Figure 28. Lemnalia broodstock immediatelyafter cutting.

Broodstock

22


Acropora: Fragments of this species were the fastest growing of the hard coralstested. Broodstock quickly healed and put out new buds in the areas that had beencut. Regeneration time is estimated to be 12-18 months. Given that this species isabundant in Pohnpei lagoon and has a relatively long regeneration time it is recom-mended to collect cuttings from the wild rather than keeping broodstock on site. Fig-ures 33 and 34 show an example of broodstock regeneration over a 6-month period.

Figure 30. (Top left) Pachyclavulariabroodstock immediately after cutting.

Figure 32. (Bottom left) Pachyclavulariabroodstock 6 months after cutting.

Figure 31. (Top right) Pachyclavulariabroodstock 3 months after cutting.

23

Porites: While not a particularly fast growing species, broodstock quickly healed andput out new buds in the areas that had been cut. Regeneration time is estimated to be18-24 months. Given that this species is abundant in Pohnpei lagoon and has a rela-tively long regeneration time it is recommended to collect cuttings from the wild ratherthan keeping broodstock on-site. Figures 35 and 36 show an example of broodstockregeneration for Porites over a 6-month period.

Figure 33. Acropora broodstockimmediately after cutting.

Figure 34. Acropora broodstock 6 monthsafter cutting.

Figure 35. Porites broodstock immediatelyafter cutting.

Figure 36. Porites broodstock 6months after cutting.

Broodstock

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Turbinaria: While it survived well, fragments of this species were the slowestgrowing of all the animals tested. Regeneration time is estimated to be 24-36months. However, cut areas quickly healed and rounded out with little sign of necro-sis. Given that this species is abundant in Pohnpei lagoon and has a relatively longregeneration time it is recommended to collect cuttings from the wild rather thankeeping broodstock on site. Figures 37 and 38 show an example of broodstockregeneration for Turbinaria over a 6-month period.

Figure 37. Turbinaria broodstockimmediately after cutting.

Figure 38. Turbinaria broodstock6 months after cutting. Lightareas around the edge indicatenew growth.

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Euphyllia: As the only large polyp stony coral tested in this study, regeneration pat-terns were different from the other species. Polyps that were removed did not regen-erate from the cut stalk. Instead, polyps tended to split from existing polyps formingnew polyps. This was evident from the growth trials where approximately 80% of singlepolyp fragments split into 2 or more polyps inside the 6-month growth trial. Regenera-tion time for this species is estimated to be 18-24 months. Although this species is notabundant in Pohnpei lagoon, the relatively long regeneration time and the difficulty ofkeeping the broodstock on tables indicate that it is better to collect cuttings frombroodstock in the wild rather than keeping broodstock on-site. Figures 39 and 40show an example of broodstock regeneration for Euphyllia over a 6-month period.

Broodstock

Figure 40. Euphylliabroodstock 6 monthsafter cutting.

Figure 39. Euphylliabroodstock immediatelyafter cutting.

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Culture techniques

Substrates and their manufactureSubstrates chosen for each species depended on their ability to attach naturally andalso on feedback from wholesalers and hobbyists as to their preferences for culturedcorals.

Gravel:Locally available gravel products are generally good substrates for attaching soft cor-als. Depending on locality in the Pacific, coral or basalt gravels used in constructionare generally cheap and readily available. Basalt gravel with an average diameter of10.5-24.6 mm was chosen for these experiments because they easily identified thecoral as being cultured. The gravel was ordered in bulk and was rinsed with freshwa-ter to remove dirt and small grit prior to being used on the farms. Per each tray, 4 L ofgravel was used.

Coral gravel was also tested as a substrate prior to the start of the growth trials as thisis often the only substrate available in some areas, such as atolls. All the soft coralsreadily attached to coral rubble and no obvious differences were observed in attach-ment rates of corals on basalt versus coral gravel.

Of the species tested, Lemnalia, Green polyp Sarcophyton and Long polypSarcophyton are recommended for attachment to basalt or coral gravel.

Live rock disks:When searching for a suitable disk-type substrate for attaching corals, both hobbyistsand wholesalers preferred a non-concrete disk that still showed the coral to be cul-tured but did not look too artificial. One suggestion from Mrs. Joy Meadows, an aquariumwholesaler at Harbor Aquatics in Chicago, USA, was to use pieces of live rock thathad been cut, using a saw, into flat disks (Figure 41). This type of live rock substratewas tested on all coral species used in the study and was adopted as the substrate ofchoice for Pachyclavularia, Acropora, Porites, Euphyllia and Turbinaria.

While the Long polyp Sarcophyton attached readily to basalt gravel (40.0%), percentattachment was higher on the live rock disks (63.3%). However, problems arose dur-ing the growout trials with the result that these disks are not recommended for growingsoft corals. Once the toothpicks that were holding the soft coral cuttings onto the diskswere removed, the corals had a tendency to migrate to the edge of the disk and often

27

attached themselves partially to the disk and partially to loose pieces of basalt in thetrays (Figure 42) . The resulting corals appeared asymmetrical in appearance andmany were deemed not saleable for this reason. In addition, the live rock disks withlightweight soft coral fragments on them had a tendency to flip over in strong currentsor wave action, causing extra maintenance work, and again, rendering the fragmentnon-saleable.

Live rock disk manufacture:

Live rock, usually from thick branching species suchas Porites and Goniopora, was collected fromPohnpei lagoon and left for approximately one weekon land to kill any sponges and algae. Minimum widthof the branches for cutting was 40 mm (Figure 41).The dry branches were cut using a commercial bandsaw (Figure 43). The size and width of the disks var-ied depending on the species for which they would beused. For stemmed soft corals such as Lemnalia,Green polyp Sarcophyton and Long polypSarcophyton a base 40-60 mm in diameter and 10-mm thickness was used. A 2.4-mm hole was alsodrilled in the center of the base for attachment using atoothpick. For Pachyclavularia, larger disks with the

Figure 42. A Long polypSarcophyton fragment that hasmigrated to the edge of the diskand attached to a piece ofbasalt.

Figure 41. Substrate disks made from live rock.

Figure 43. Cutting live rockdisks using a bandsaw.

Culture Techniques

28


same thickness as the other soft corals but with diameters of 55-105 mm were usedso that the animal could spread over the substrate’s surface (Figure 41, third fromleft). Turbinaria disks averaged 14 mm in thickness and 49-70 mm in diameter andhad a 9-mm channel across the middle which was made using a hand-held anglegrinder (Figure 41, far right and Figure 44). Disks for the Acropora, Porites andEuphyllia averaged 19 mm in thickness and varied from 41-54 mm in diameter (Fig-ure 41, second from left and Figure 45). A hole ranging from 13-18 mm was drilledapproximately 10 mm deep in the center of each disk into which the stem of the frag-ment was glued. The size of the hole was chosen depending on the width of the stem.The Euphyllia were put into the disks with the largest holes (16-20 mm) and the Poritesand Acropora into the disks with smaller holes (13-16 mm).

While liverock disks were attractive they were relatively time consuming and expen-sive to make. A farmer interested in using these disks would have to buy a bandsaw,hand operated drill and angle grinder and constantly replace the blades and bits forthis machinery. Average time to make 1 disk using a “production line” method of cut-ting all pieces at one time, drilling all pieces at one time etc. was estimated at 53seconds. Average cost of manufacture of each disk, taking into account labor costs ofUS$1.35 per hour, depreciation on machinery, the cost of electricity and the cost andexpected life of saw blades, drill bits etc. in Pohnpei was US$0.06.

Figure 44. Live rock substrates used forplanting Turbinaria.

Figure 45. Live rock substrates used forplanting Acropora, Euphyllia and Porites.

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To overcome the cost and investment relatedto having to cut the live rock disks some ex-perimentation was done with simply chippingappropriate pieces of live rock with a ham-mer and attaching the corals into natural crev-ices and dips that result from the breaking ofthe live rock (Figure 46). This has a more natu-ral appearance and is also cheaper and fasterper substrate. The major disadvantage to thismethod is that it is often hard to recognizethe substrate as being man-made.

Concrete disks:During discussions with aquarium wholesaler and hobbyists it was determined thatconcrete disks were generally disliked and that many hobbyists simply break the coralfrom the concrete disk prior to putting them in the tank. Primary complaints aboutconcrete disks were the fear of them leaching chemicals into the water and a distinctman-made appearance. Despite these concerns it was decided to still test concreteas a substrate. To overcome customer concerns a growout time of 6 months wasadopted so that the disks could leach properly and disks were made in less uniformshapes to make them look less man-made. The primary advantages to concrete disksis that they are cheap and quick to produce requiring very little materials and equip-ment. In addition, their manufacture does not require electricity.

Concrete disk manufacture:

All concrete disks were made using a table filled with beach sand as shown in Figure47. The sand was first smoothed out on the table. Concrete was then made by mixing70% beach sand with 30% cement and water and was scooped out into small, irregu-larly shaped mounds on the sand and appropriately sized holes (12-20 mm) or chan-nels (8-10 mm) were formed in the wet concrete using a finger or small spatula (Figure48-50). An experienced technician can easily make 75 disks per hour at an estimatedcost of US$0.028 per disk (concrete and labor). After the disks had set they weresubmerged in freshwater for a minimum of 3 days, prior to being used, to allow pre-liminary leaching.

Figure 46. Substrate made by chippinglive rock with a hammer.

Culture Techniques

30


Figure 48. (Top right). Freshlypoured concrete substrates.

Figure 50. (Lower). Concretesubstrates used for plantingEuphyllia, Porites and Acropora.

Figure 47. (Top left). Sand filledtable used for making concretesubstrates.

Figure 49. (Middle). Concretesubstrates used for plantingPachyclavularia and Turbinaria.

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CuttingCutting always took place adjacent to, but not on, the planting area. All the soft coralswere cut using a pair of stainless steel scissors available at most hardware or craftstores. Lemnalia were fragmented by removing whole 40-60 mm branches from thecolony (Figure 51). The Long polyp Sarcophyton and Green polyp Sarcophyton werefragmented by cutting the loose flesh off the crown, close to the stem leaving only thecentral tissue over the stem (Figures 52-54). The removed tissue was then cut into 20-30 mm squares for planting. Cutting took place in an open basket so that fragmentswere consolidated in one area. Cuttings were then placed in a covered basket orplastic bag filled with clean seawater for transport to the planting area.

Culture Techniques

Figure 51. Taking Lemnalia cuttingsusing scissors.

Figure 53. Strips of Long polypSarcophyton tissue removed from thecrown.

Figure 52. Taking Long polyp Sarcophytoncuttings using scissors.

Figure 54. Green polyp Sarcophyton aftercutting removal.

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The tissue of the broodstock Pachyclavularia adhered very strongly to the substratemaking fragments hard to collect. Where loose edges were present on the broodstock,cuttings were made using scissors (Figure 55). When scissors could not be usedfragments were removed using a sharp knife or scalpel (Figure 56). Average size of acutting was 10-20 mm2.

Hard coral cuttings were taken primarily using a pair of aviation snips (Figures 57-60).For Turbinaria, the back of the coral was also lightly tapped with the head of a coldchisel to aid fragmentation. Ideal starting sizes for fragments are 70-80 mm2 forTurbinaria (Figure 59), and 30-60 mm for Acropora and Porites (Figures 57 and 58).One single polyp was used to start the Euphyllia colonies (Figure 60). Hard coralcuttings were also made in open baskets.

Figure 57. Acropora cuttings beingtaken using aviation snips .

Figure 58. Porites cuttings beingtaken using aviation snips.

Figure 56. Taking Pachclavulariacuttings using a scalpel .

Figure 55. Taking cuttings from looseedges of Pachyclavularia using scissors.

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Attachment and planting methods

Toothpicks:A number of attachment methods were experimented with depending on the speciesin question. All soft corals tested showed the ability to reattach to the substrate oncefragmented. For the Lemnalia, Long polyp Sarcophyton and Green polyp Sarcophytonthe best method for attaching was to use a wooden toothpick to hold the fragmentclose to the substrate until it had time to attach (Figures 61-63). This method proved

Figure 60. Euphyllia cuttings beingtaken using aviation snips.

Figure 59. Turbinaria cuttings takenusing aviation snips and a cold chisel.

Culture Techniques

Figure 61. Lemnalia cuttings attachedusing toothpicks.

Figure 62. Green polyp Sarcophyton cuttingsattached using toothpicks.

34


more effective (Long polypSarcophyton 40%, Green polypSarcophyton 83% and Lemnalia93%) than simply nestling the cut-ting into the substrate (Long polypSarcophyton 27%, Green polypSarcophyton 77% and Lemnalia96%) for all three species.

To plant in basalt gravel a cut endof the fragment was nestled intothe gravel and a toothpick forcedthrough the cutting into the gravelat an angle of approximately 20-30 degrees from the perpendicu-lar. To plant on liverock disks thecutting was again placed so that

one of the cut edges was in contact with the substrate and a toothpick was used to pinit to the disk After the fragment had attached adequately (2-4 weeks) the toothpickwas removed. It was better to remove the toothpick as soon as the fragment wasloosely attached to the sub-strate because the cutting oftenadhered so strongly to thetoothpick that it could not be re-moved without tearing the frag-ment from the substrate.

Rubber bands:The Pachyclavularia showedthe best rate of attachment whenheld to the substrate using arubber band (57%) (Figure 64)rather than a toothpick (37%).Rubber bands were placed onthe substrates prior to hangingthem so that planting wasquickly and easily accom-plished by tucking the fragmentunder the rubber band with the

Figure 64. Pachyclavularia planted using a rubberband on live rock disk.

Figure 63. Long polyp Sarcophyton cuttingsattached to live rock disks using toothpicks.

35

flat side (the side originally in contact with the broodstock substrate) touching the disk.The band was removed between 2 and 4 weeks after planting.

Epoxy glue:All the hard corals were attached to the appropriate substrates using an epoxy glue.While Porites and Acropora will attach passively given time, the use of epoxy allowedmass production of corals at very little added expense. Prior to the start of experi-ments in situ trials were conducted using a variety of commercially available two-partepoxy glues. Glues were rated on working time, ease of use, cost per unit and howwell they held the fragment in place. The overall winner by far was a two part epoxymanufactured by Z-Spar called 788 Splash Zone Epoxy. The two parts are black and

Figures 65. (Top left). Putty underwater injars prior to mixing.

Figures 66. (Top right). Putty being mixed intwo equal parts.

Figures 67. (Bottom left). Putty when fullymixed into an unobtrusive olive color.

Culture Techniques

36


mustard colored which when mixed form an unobtrusive olive color (Figures 65-67).Pot life is approximately 40 minutes and it can be mixed and applied entirely underwater. Price per coral planted was also the lowest at approximately US$0.035 perpiece. Care needed to be taken directly after planting not to disturb the corals until theepoxy had set properly. Corals planted using this epoxy showed almost 100% attach-ment at the end of the growth trials approximately 6 months after planting.

To expedite planting of hard corals the prepared disks were loaded into open basketsand carried to the work site (Figure 50, page 30). Fragments were taken frombroodstock by one worker while other workers laid out the disks in baskets or traysand/or mixed the glue. Fragments were then planted by matching the stem of the frag-ment to the appropriate hole or slot and adhering it with a small amount of epoxy(Figures 68). Newly planted fragments were then left for about 1 hour to allow the glueto set before being carried to the growout tables (Figure 69).

Planting was most time effective for all species when done on a mass scale using aproduction line method. Up to 300 cuttings could be made and stored in open, wellflushed baskets prior to planting.

Figure 68. Turbinaria fragments beingplanted using epoxy putty.

Figure 69. Turbinaria fragmentsattached with putty being left to hardenprior to transfer to the grow-out site.

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Growout and husbandryCorals require very little attention once planted but each table should be checked atleast every two weeks. Corals were easily knocked over by grazing fish, sea cucum-bers, fast currents and wave action. This was alleviated somewhat by using cages(see Section “Use of cages” on page 14) to prevent animal activity and to preventcorals being washed off the tables. However, the tops of the cages needed to bescrubbed with a brush every two weeks to remove algal fouling.

Growth rates and patternsUnder optimal conditions growout times varied dramatically depending on species.Growth rates reported below are presented as percent increase of original size, alsocalled relative growth rate.

Lemnalia: Of all the corals tested, Lemnalias grew fastest and performed best in theenvironment with fast flowing oceanic water. At this site their height increased by anaverage of 89% over the 6-month growth trial from a starting size of 45 mm (Figure 70,page 38). They also grew well at the turbid, eutrophic site (58% increase in height) butdid not grow well at the mid-lagoon site with poorer water exchange (-9.5%). Theyreached a recommended harvest size of approximately 60-80 mm in 4 months underoptimal conditions. This species also spawned many new stems and branches (Fig-ures 71, page 38), becoming much thicker and bushier in appearance. At the optimalsite, survival and number of saleable* corals at harvest were both 62%.

* Saleable corals for all species tested were specimens that fell within a reasonablesize range for sale that did not have any blemishes or scars.

Long polyp Sarcophyton: This coral grew the best at the fast flowing, oceanic site,registering a 16.7% increase in crown diameter over the 6-month growing trial. Whilethis seems quite low the morphology of the animals changed significantly during thetrial indicating a high growth rate. The original cuttings, with a crown diameter of 42mm (Figure 72, page 38) started by differentiating into a stem and crown at approxi-mately 2 months (Figure 73, page 38) after planting. The crown then rounded out toform the final product (Figure 74, page 38). Growth at the eutrophic site and mid-lagoon sites was negligble and the corals showed a decrease in crown diameter of –20% and –29% respectively. Primary problems with this species planted on the liverock substrates at the fast flowing and eutrophic sites were currents and wave actionoverturning the corals. Optimum initial fragment size for this species is 60-70 mm. Atthe fast flowing, oceanic site, survival was 76% from planted cuttings and 60% weredeemed saleable.

Growout and Husbandry

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Figure 71. (Top right). Representative picture ofa Lemnalia cutting at the end of the growthtrials.

Figure 70. (Top left). Representative picture ofLemnalia cuttings at the start of the growthtrials.

Figure 72. (Middle left). Representative pictureof a Long polyp Sarcophyton cutting at the startof the growth trials.

Figure 73. (Bottom left). Representative pictureof a Long polyp Sarcophyton cutting 2 monthsafter the start of the growth trials.

Figure 74. (Bottom right). Representativepicture of a Long polyp Sarcophyton cutting atthe end of the growth trials.

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Figure 79. (Bottom right). A Pachyclavulariacutting after 6 months covered by filamentousalgal growth.

Figure 75. (Top left). Representative picture of aGreen polyp Sarcophyton cutting at the start of thegrowth trials.Figure 76. (Top right). Representative picture of aGreen polyp Sarcophyton cutting 1 month into thegrowth trials.Figure 77. (Middle left). Representative picture ofa Green polyp Sarcophyton cutting at the end ofthe growth trials.Figure 78. (Bottom left). A Pachyclavulariacutting showing new stolon growth.

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Green polyp Sarcophyton: This coral grew best at the fast flowing site showing a58.7% increase in crown diameter over the course of the trial. This compared to acrown size increase of only 7.5% and –5% at the eutrophic and mid-lagoon sitesrespectively. Initial fragments with a crown diameter of 32 mm (Figure 75, page 39)began differentiating into a stem and crown within one month of planting (Figure 76,page 39) and reached a minimum marketable size (50-mm crown diameter) by theend of the 6-month growing period (Figure 77, page 39). Survival was highest at thefast flowing and eutrophic sites (88% and 90% respectively). However, poor health ofcorals, manifested as small lesions and areas of necrosis resulted in only 10% beingdeemed saleable from the eutrophic site as opposed to 82% from the fast flowingsite. Estimated optimum initial fragment size of this species, based on wholesalerfeedback, is 50-70 mm crown diameter.

Pachyclavularia: The Pachyclavularia performed worst of all the corals tested. Op-timum growth of 37% increase in width and 52% increase in length were recorded atthe fast flowing, oceanic site but these figures are misleading because the animalgrew outward by extending thin stolons across the live rock disk that only covered asmall fraction of the disk surface area (Figure 78, page 39). In addition, the disks andthe corals rapidly became overwhelmed by filamentous algae making them unsightly(Figure 79, page 39). At the mid-lagoon site the corals shrank by an average of 29%and at the eutrophic site no animals survived. Survival at the other sites was 32-34%and no specimens from either site were deemed saleable.

Acropora: The Acropora grew fastest at the fast flowing, oceanic site showing a101% increase in width and 31% increase in height during the growout period. Fromthe initial planting at a size of about 16 mm (Figure 80, page 42), growth followed adistinct pattern at each site starting with a spreading of tissue over the substrate within1 month of planting (Figure 81, page 42). At the fast flowing and eutrophic sites thesubstrate became covered in 3-4 months and corals began budding. By the end of the6-month growout period the corals had totally covered the base and were showingsignificant budding both from the original stem and also from the newly formed basetissue (Figure 82, page 42). Minimum time to market size for this species is 4 months.Survival was highest at the mid-lagoon and fast flowing sites (96% and 90% respec-tively). At the eutrophic site survival was only 72% primarily because wave action keptoverturning the corals. The number of saleable corals at the fast flowing site was 88%compared to only 66-68% at the other sites. Corals at the latter sites were either toosmall or had poor color by the end of the trial. Corals from the eutrophic site were verybrown in color with none of the characteristic blue tissue on growing tips. When speci-mens from the this site were moved to the fast flowing site, blue growth areas becameapparent within 4 weeks of transfer. Optimum initial fragment size for this species is30-40 mm.

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Porites: Results from the Porites growth trial indicated that this species might begrown with relative ease at any of the three sites tested. While growth was highest atthe mid-lagoon and fast flowing, oceanic sites (88-89% increase in width and 44-51%increase in height from a starting height and width of 32 mm and 19 mm respectively),corals at the eutrophic site had a greater spreading of tissue onto the substrate (Fig-ure 84, page 42) and had a higher percentage of saleable animals (66%) than theother sites (46-48%). Corals that had not covered the portion of the base where theglue showed (Figure 83, page 42) were classified as non-saleable. Therefore coralsat the fast flowing and mid-lagoon sites may have had a greater percentage of sale-able animals had the growout period been longer. This species was also prone tosmall blemishes and necrotic areas at all sites that reduced the number of saleablespecimens.

Turbinaria: Percent increase in height ranged from 4 to 10% with the highest in-crease coming at the mid-lagoon site. Percent increase in width was highest at theeutrophic site and ranged from 7 to 11.5% between the sites. Starting heights andwidths averaged 31 mm and 45 mm respectively (Figure 85, page 43). While growthrates appeared relatively slow for this species the results were somewhat distorted bythe fact that the edges of the fragments began to curl as they grew making the relativegrowth rates seem less than they actually were (Figure 86, page 43). The fast flowingsite was once again deemed the best site for growing this species with a survival rateof 98% with 92% of fragments deemed saleable (Figure 87, page 43). Corals at theeutrophic site also fared well but corals grown there had a much browner color whichreduced their potential marketability. Specimens moved from this site to the fast flow-ing site at the end of the growth trials did NOT turn a more attractive yellow color within4 weeks of transplant. Growout time for this species should be a minimum of 6 monthsand optimal initial fragment size should be 70-80 mm based on wholesaler feedback.

Euphyllia: The eutrophic site was the best overall site for growing this species. Per-cent increase in width was 64% and 79% of corals planted as a single polyp (Figure88, page 43) split to become 2 or 3 polyps by the end of the trial (Figure 89, page 43).In addition, corals at the eutrophic site looked healthier than at other sites as evi-denced by the extension of soft tissue down the stem of the coral (Figure 89). Survivalwas high at all sites, ranging from 92-100% and the percentage of saleable animalswas highest at the eutrophic and fast-flowing sites (94% and 96% respectively). Growouttime for this species should be a minimum of 6 months and the optimal initial fragmentsize is a single polyp on a stalk approximately 40-70 mm long.


42


Figure 80. (Top left). Representative picture ofan Acropora cutting at the start of the growthtrial.

Figure 81. (Top right). Representative pictureof an Acropora cutting 1 month into the growthtrial.

Figure 83. (Bottom left). Porites cutting with notissue growth over the base after 6 months.

Figure 82. (Middle left). Representative pictureof an Acropora cutting at the end of the growthtrial.

Figure 84. (Bottom right). Porites cuttings withbasal tissue growth after 4 months.

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Figure 85. (Top left). Representative picture of aTurbinaria cutting at the start of the growth trial.

Figure 89. (Bottom right). Representative pictureof a Euphyllia cutting that has split into 3 individualpolyps by the end of the growth trial.

Figure 88. (Bottom left). Representative picture ofsingle Euphyllia polyps at the start of the growthtrial.

Figure 87. (Middle left). Representative picture ofa Turbinaria cutting at the end of the growth trial.

Figure 86. (Top right). Natural curling of theTurbinaria cuttings during the growth trial.


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Positioning and stocking density

For all the species tested with the exception of the Pachyclavularia, corals were grownin the nursery trays on the table top. Stocking density was 20 corals per tray or 160corals per table (Figure 90). During initial trials with Pachyclavularia it was observedthat cuttings quickly became overrun with filamentous algae when they were placedfacing the water surface in a nursery tray. To overcome this problem the disks werehung vertically underneath the tables (approximately 50 can be hung under each table)so they were shaded by the nursery trays (Figure 91). While this cut down on algalgrowth, the Pachyclavularia cuttings did not grow well and most specimens were notfit for the market after a 6-month growout.

Figure 90. Culture table stockedwith 8 trays at 20 corals per tray.Corals were randomly distributedin groups of 10 among the tablesfor the growth trial.

Figure 91. Pachyclavulariacuttings were hung under thetables to minimize growth offilamentous algae.

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Pests and diseases

Pests

Primary pests to corals on the trays were fish, seacucumbers and hermit crabs. While these animalsrarely attacked or harassed the corals, their feed-ing activity and foraging in the trays knocked cor-als over and made soft corals contract their pol-yps. This was addressed by introducing the use ofcages at sites where this was a problem (see sec-tion titles “Use of cages on page 14). At the fastflowing oceanic site, substrates and trays becamecolonized by a variety of ascidians. These animalsdid not kill the corals but would start to grow up thestem of the hard corals causing blemishes and lo-calized bleaching. Time had to be taken to peri-odically remove these fouling organisms from thecoral substrates.

The only evidence of predation on any of the cor-als tested was with the Lemnalia. In this case, itappeared that the corals were being eaten by fish (Figure 92). As most soft corals areregarded as toxic to marine fish, incidences of attack were sporadic and corals quicklyregenerated.

Diseases

For corals kept in optimum conditions there was rarely any sign of disease. Greenpolyp Sarcophyton and Long polyp Sarcophyton that were kept in less than optimumconditions showed signs of bleaching and small areas of necrosis on the crown. Longpolyp Sarcophyton held at the eutrophic site, which often had heavy wave action andsiltation, showed signs of bleaching and atrophy, possibly due to the heavy silt load inthe water.

Figure 92. Lemnalia fragmentsshowing signs of fish predation.

Pests and Diseases

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Harvest and transportHarvesting of the corals wassimply a case of picking themout of the trays and transport-ing them to the site of shipping.Prior to transport, substrateswere cleaned to remove anyfouling organisms with a knifeor brush. As with thebroodstock it is important tominimize the amount of timethe corals are out of the waterand also to reduce the possi-bility of thermal shock. Har-vested corals were placed inopen-sided baskets (Figure93) for carrying to the boat.

Corals were transported in icechests filled with fresh seawa-

ter. To optimize space, plastic baskets with lids containing the corals can be stackedon top of each other in the ice chests (Figure 93). Baskets used to collect corals in thewater were the same as the ones used inice chests, thereby eliminating the need totransfer corals at the surface. Because theLemnalia were so sensitive to air expo-sure they were collected in closed-sidedtubs that were also placed directly into thecoolers so that the corals were never ex-posed to air (Figure 94). Approximately100-120 corals could be transported in astandard 120-liter capacity ice chest. Forjourneys longer than 30 minutes, water ex-changes were done in the ice chests.

Figure 93. Open-sided plastic baskets stacked insidean ice chest used to transport corals.

Figure 94. Closed sided tub used fortransporting Lemnalias.

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Holding in the land-based facility

Corals were held in land-based, concrete raceways with a 50% light occluding shadedcloth overhead (Figure 95). Water depth was kept at 40-50 cm and water in the race-ways was exchanged at least three times per day with 25-mm filtered seawater (Fig-ure 96). Corals kept in this manner remained healthy with little loss of color. It is rec-ommended to hold the corals for approximately one week in the land-based facilityprior to shipping to allow them to recover from the stress of transport from the field.

Figure 95. Concrete racewaysused to hold corals prior toshipping.

Figure 96. Corals being held inshallow water prior to shipping.

Harvest and Transport

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Shipping

Specific packing instructions

All corals were packed for shipping in doublebags with an intermediate layer of newspaperfilled with seawater and oxygen as described inEllis (2000) and Ellis and Sharron (1999). Bagshad a thickness of 3 mm. Pachyclavularia wereshipped in bags 23 cm in width. All other coralswere shipped in bags 15 cm in width. Bags wereplaced into Styrofoam lined cardboard boxes(Figure 97). Prior to shipping to the wholesalerall corals underwent 24 and 48 hour simulatedshipping trials to test these standard techniques.Different methods of packing recommended forthe different species of corals are detailed be-low.

All hard corals were suspended up-side down on a piece of Styrofoamapproximately 5-6 cm2 and 1.5 cmthick by rubber bands for shipping(Figure 98). This prevented the cor-als from touching the side of the bagand also protected the bag from sharpareas of the substrate or coral itself.The bag was filled with water so thatthe suspended coral would remain atleast 3 cm clear of the bag bottom.At least half the bag volume was oxy-gen.

Figure 97. Newspaper lined doublebags inside a Styrofoam insulatedshipping box.

Figure 98. Coral suspended on Styrofoam inpreparation for packing.

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Soft corals were not attached to Styrofoam for shipping but were placed directly intothe bag and were allowed to contact the bag sides. Enough water was used to coverthe specimen by at least 3-4 cm and at least half the bag volume was oxygen. The onlyspecies to fare badly using this method of shipping was the Lemnalia. For this spe-cies between 65-75% of the bag volume was filled with water and the remainder withoxygen.

Permits, CITES and shipping documents

Of the species tested, only the hard corals (Acropora, Porites, Turbinaria andEuphyllia) and one species of soft coral (Pachyclavularia) are currently listed underAppendix II of the Convention on the International Trade in Endangered Species(CITES). Procedures for using and examples of necessary export permits, shippingdocuments and CITES permits are detailed in Ellis and Sharron (1999) and Ellis (2000).

Shipping

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Industry FeedbackTo get a better idea of the saleability and quality of the cultured corals in this experi-ment, feedback was sought from individuals in the marine aquarium industry. Ship-ments of approximately 100 corals were air freighted to two independant wholesalers/retailers of marine invertebrates in the United States (Reef Rascals in Indialantic, Floridaand Harbor Aquatics in Valpraiso, Indiana). Feedback was given on the health of thecorals after they had been shipped, their size and color, customer satisfaction and thetype of substrate that was used. Wholesalers were also asked to give an approximateprice they would pay for the product as presented. In addition, Mr. Roderick Bourke,manager of Robert Reimers Enterprises Wau Mili Giant Clam Farm in Majuro, Re-public of the Marshall Islands, was asked to provide input on general product qualityand pricing.

General commentsSubstrates: Both wholesalers preferred live rock over the concrete discs althoughone commented that customers had not indicated a preference. Mr. Bourke of RREcommented that many customers remove the coral fragment from the substrate priorto putting it into their tank anyway. Basalt gravel was not the choice of one wholesalerwho preferred to use live rock or coral rubble instead.

Price: Estimated farm gate prices the 2 wholesalers would pay for individual speci-mens varied drastically with one estimating only between US$1.50-4.00 per coral andthe other US$5.00-10.00 per coral. Mr. Bourke of RRE recommended a minimumfarm gate price for cultured corals in general of US$5.00 per piece based on his ownsales experience.

Size: Both wholesalers made general comments that the corals sent were smallerthan the wild collected specimens they sell and they would pefer larger cultured speci-mens in order to be able to compete better.

Specific commentsLemnalia: This species shipped very poorly with 80-90% mortality within 1 week ofarrival. Other comments included that they were popular with customers (average 6.5on a scale of 10) but that a brighter color variant would be preferred. Price range$1.50-$5.00.

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Green polyp Sarcophyton: This species had 100% survival during shipping andwas extremely popular with customers (average 9 on a scale of 10) due to the greenpolyps. Both wholesalers commented that the size was a little small. Price range $2.50-8.00.

Long polyp Sarcophyton: This species had 100% survival during shipping andwas popular with customers (average 8.5 on a scale of 10) due to the long polypextension. Both wholesalers commented that the size was a little small. Price range$2.00-8.00.

Pachyclavularia: This species shipped poorly and although normally popular the poorcoverage of the substrate and infestation with filamentous algae in the shipped speci-mens made them unsaleable.

Acropora: This species had 80-90% survival during shipping and was very popular(average 9 on a scale of 10) because of its color. One wholesaler really liked the sizebut the other generally sells larger colonies but commented that the smaller fragmentsoften acclimate better. Price range $4.00-10.00.

Porites: This species had 70-90% survival during shipping but was not particularlypopular (average 3 on a scale of 10). Price range $2.00-8.00.

Turbinaria: This species had 100% shipping survival. Popularity was mixed (3 and10 on a scale of 10) with the price range varying accordingly at $2.00-10.00.

Euphyllia: This species had 80% survival in shipping and were very popular (aver-age 9 on a scale of 10). One wholesaler commented that these were the most popularof the corals sent. Both wholesalers commented that the cultured specimens weresmaller than the wild collected specimens they usually sell but this did not hinder sales.Price range $2.00-12.00.

Industry Feedback

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A revised economic model for coralfarming in Pohnpei usingrecommendations from this studyDescription:This model is based on a fully integrated farm that produces only corals for the marineaquarium industry. The farmer has three full-time employees and takes a salary fromthe profits. The model assumes that a loan was taken to start operations and includesservicing of debt at approximately 30% of operating costs.

Assumptions:

1. All farming is ocean-based using metal trestles, nursery trays and cages.

2. The growout site is similar to the fast flowing site described in this study.

3. All production figures are based on growth and survival rates obtained in thisstudy.

4. A small land-based facility is used for office space and holding and packingcorals for air transport.

5. The land-based facility is approximately 4 km from the growout site and thebroodstock is collected from within a 4 km radius of the growout site.

6. The farm grows 6 of the species tested (Long polyp Sarcophyton, Lemnalia,Green polyp Sarcophyton, Acropora, Euphyllia and Turbinaria). Pachyclavulariais discarded as a culture species due to poor test results and Porites is discardeddue to poor marketability. While Lemnalia had poor shipping results it is assumedthat with perseverance a reliable shipping method could be determined for thisspecies.

7. A single owner/operator takes a salary from the profits.

8. All costs of packing and air transport are passed onto the buyer.

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Capital costs

FixedLand and buildings $ 15,000Boat and motors $ 14,000Truck $ 4,000Diving gear $ 1,500Construction labor $ 6,000Subtotal $ 40,500

Semi-variableOffice equipment (desks, chairs, air conditioner etc.) $ 5,075Land-based tanks (8) $ 2,400Ocean tables (130) $ 3,250Cages $ 1,300Equipment (saws, drills, hammers etc.) $ 3,825Pumps and plumbing $ 1,500Construction labor $ 2,000Subtotal $ 19,350

Grand total capital costs $ 59,850

Operating costs

Fixed3 full-time employees @ $2 per hour $ 12,000Office (supplies, telephone, website, utilities) $ 4,000Maintenance and insurance (10% of capital) $ 4,050Capital charge (9% on 5 year loan) $ 10,125Land lease $ 3,600Subtotal $ 33,775

Economics

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Semi-variableMaintenance and insurance (10% of capital) $ 1,950Capital charge (9% on 5 year loan) $ 4,838Subtotal $ 6,788

VariableFuel $ 3,500Supplies (gravel, epoxy etc.) $ 1,300Tank fills $ 3,600Subtotal $ 8,400

Grand total operating expenses per annum $ 48,963

Table 1. Predicted revenues for varying coral prices and production volumes. (Note:lower production volume will lower operating expenses and therefore breakeven price.However, for the purposes of this model operating costs will remain constant).

Price per coral

Pieces ofcoral soldper month

Breakevenprice per

coral$5.00 $7.50 $10.00

2000 $2.04 $120,000 $180,000 $240,00

1500 $2.72 $90,000 $135,000 $180,000

1000 $4.08 $60,000 $90,000 $120,000

500 $8.16 $30,000 $45,000 $60,000

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Species summaries

LemnaliaBroodstock location: keep broodstock on farm.Estimated broodstock regeneration time: 4-6 monthsOptimal initial fragment size: 40-60 mm tallBest growing conditions: fast flowing with oceanic water exchangePreferred substrate: basalt or coral gravelTime to harvest: 3-4 monthsPercentage of saleable animals from planting: 66%Expected increase in height during growout: 89%Optimal harvest size: 80-100 mmExpected farm gate price: $5.00Ease of handling and shipping: poorMarket acceptance: 6.5 on a scale of 10Aquarium hardiness: mediumGeneral comments: Once established this species is extremely hardy and grows rap-idly. It cannot withstand rough handling and quickly succumbs to excessive contact.Further work is needed to improve shipping survival.

Green polyp SarcophytonBroodstock location: keep broodstock on farm.Estimated broodstock regeneration time: 6-9 monthsOptimal initial fragment size: 40-50 mm squareBest growing conditions: fast flowing with oceanic water exchangePreferred substrate: basalt or coral gravelTime to harvest: 5-6 monthsPercentage of saleable animals from planting: 82%Expected increase in crown diameter: 59%Optimal harvest size: 60-80 mmExpected farm gate price: $5.00-8.00Ease of handling and shipping: excellentMarket acceptance: 9 on a scale of 10Aquarium hardiness: highGeneral comments: This species is a fast grower with bright green polyps. It can with-stand handling and transport well. It is not abundant in the wild so it is recommended tomaintain broodstock on the farm.

Species Summaries

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Long polyp SarcophytonBroodstock location: keep broodstock on farm unless available locallyEstimated broodstock regeneration time: 9-12 monthsOptimal initial fragment size: 60-70 mm squareBest growing conditions: fast flowing with oceanic water exchangePreferred substrate: basalt or coral gravelTime to harvest: 5-6 monthsPercentage of saleable animals from planting: 60%Expected increase in crown diameter: 17%Optimal harvest size: 70-80 mmExpected farm gate price: $5.00Ease of handling and shipping: excellentMarket acceptance: 8.5 on a scale of 10Aquarium hardiness: highGeneral comments: This species grows more slowly than the Green polyp Sarcophytonbut cuttings differentiate into a definite stalk and crown that rounds out over time. Useof live rock disks for the growout trial was a mistake and it is likely that an increasedpercentage of saleable animals can be obtained using gravel as a substrate. Thisspecies is resilient to handling and general aquarium condition and is abundant inPohnpei lagoon and broodstock should be available locally.

PachyclavulariaBroodstock location: collect cuttings from the wild.Estimated broodstock regeneration time: 6-9 monthsOptimal initial fragment size: 10-20 mm squareBest growing conditions: fast flowing with oceanic water exchangePreferred substrate: live rock diskTime to harvest: 5-6 monthsPercentage of saleable animals: 0%Expected increase in length: 44.5%Optimal harvest size: when covering at least half the diskExpected farm gate price: not available.Ease of handling and shipping: poorMarket acceptance: poor (wild collected specimens have high market acceptance)Aquarium hardiness: mediumGeneral comments: This species proved unsuccessful as a culture candidate due toits inability to repel filamentous algae and live in relatively calm lagoon conditions. Thefinished product was not attractive although it was hardy in the aquarium. Broodstockfor this species were also hard to obtain.

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AcroporaBroodstock location: collect cuttings from the wildEstimated broodstock regeneration time: 12-18 monthsOptimal initial fragment size: 30-40 mm tallBest growing conditions: fast flowing with oceanic water exchangePreferred substrate: live rock diskTime to harvest: 4-6 monthsPercentage of saleable animals from planting: 88%Expected increase: width - 101%, height - 31%Optimal harvest size: greater than 60 mm in heightExpected farm gate price: $5.00-10.00Ease of handling and shipping: very good.Market acceptance: 9 on a scale of 10Aquarium hardiness: highGeneral comments: This species grows fast by first spreading over the substrate thenputting out new buds. The characteristic blue color of the tips can be lost if it is not keptin the proper light. It sheds a lot of mucus when handled but is resilient to shipping andaquarium conditions. Different color morphs and species could diversify a farm’s prod-uct line dramatically.

PoritesBroodstock location: collect cuttings from the wildEstimated broodstock regeneration time: 18-24 monthsOptimal initial fragment size: 30-60 mm tallBest growing conditions: mid-lagoon site or fast flowing with oceanic water exchangePreferred substrate: live rock diskTime to harvest: 6 monthsPercentage of saleable animals from planting: 66%Expected increase in width 90% and height 51%Optimal harvest size 60-70 mm tallExpected farm gate price: $5.00Ease of handling and shipping: very goodMarket acceptance: 3 on a scale of 10Aquarium hardiness: highGeneral comments: This is a very abundant species in Pohnpei and can nearly alwaysbe collected locally. It is resilient to handling, shipping and aquarium conditions buthas poor market acceptance, which will limit sales.

Species Summaries

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TurbinariaBroodstock location: collect cuttings from the wild.Estimated broodstock regeneration time: 24-36 monthsOptimal initial fragment size: 70-80 mm squareBest growing conditions: eutrophic or fast flowing with oceanic water exchange.Preferred substrate: live rock diskTime to harvest: 6-8 monthsPercentage of saleable animals from planting: 92%Expected increase in width 8-11% and height 7-10%Optimal harvest size: 90-100 mmExpected farm gate price: $5.00-10.00Ease of handling and shipping: excellentMarket acceptance: range of 3-10 on a scale of 10Aquarium hardiness: highGeneral comments: This is a relatively abundant species in Pohnpei and can nearlyalways be collected locally. While it is a slow grower, it rounds out well after fragmen-tation and starts to curl attractively at the edges after 5-6 months of growth. It is resil-ient to shipping and aquarium conditions but has a tendency to turn brown in low lightconditions.

EuphylliaBroodstock location: collect cuttings from the wildEstimated broodstock regeneration time:18-24 monthsOptimal initial fragment size: single polyp 40-50 mm tallBest growing conditions: eutrophic or fast flowing with oceanic water exchangePreferred substrate: live rock diskTime to harvest: 6-8 monthsPercentage of saleable animals from planting: 94%Percentage split >1 polyps: 79%Expected increase in width: 63%Optimal harvest size: when split to 2 or 3 polypsExpected farm gate price: $5.00-12.00Ease of handling and shipping: very goodMarket acceptance: 9 on a scale of 10Aquarium hardiness: highGeneral comments: This species is quite rare in Pohnpei but because of the difficultyof keeping broodstock should be collected locally. It was the only species to thrive,grow and survive significantly better at the eutrophic site. It is resilient to handling,shipping and aquarium conditions.

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ReferencesDelbeek, J.C. and J. Sprung. 1994. The reef aquarium. A comprehensive guide tothe identification and care of tropical marine invertebrates. Volume one. RicordeaPublishing, Florida 33133, USA. 544 pp.

Ellis, S. C. and L. Sharron. 1999. The culture of soft corals (order: Alcyonacea) forthe marine aquarium trade. Center for Tropical and Subtropical Aquaculture,Publication Number 137. Waimanalo, Hawaii, USA. 73 pp.

Ellis, S. C. 2000. Nursery and grow-out techniques for giant clams (Bivalvia:Tridacnidae). Center for Tropical and Subtropical Aquaculture, Publication Number140. Waimanalo, Hawaii, USA. 103 pp.

Green, E. and F. Shirley. 1999. The global trade in coral. WCMC Biodiversity SeriesNo. 9. 70 pp.

Highsmith, R.C. 1982. Reproduction by fragmentation in corals. Marine Ecology -Progress Series 7:207-226.

Puterbaugh, P. and E. Borneman. 1996. A practical guide to corals for the reef aquarium.Crystal Graphics, Lexington, Kentucky, USA. 112 pp.

Sprung, J. and J.C. Delbeek. 1997. The reef aquarium. A comprehensive guide to theidentification and care of tropical marine invertebrates. Volume two. Ricordea Pub-lishing, Florida 33133, USA. 546 pp.

Wilkens, P. and J. Birkholz. 1992. Marine invertebrates: organ-pipe and leather cor-als, gorgonians. Karl-Heinz Dahne Publishing, Germany. 134 pp.

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