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4 Coastal Maricullure Marine resources in many coastal regions are overexploited. Mariculture, the deliberate production of marine plants and ani- mals, may offer one solution to this problem; principles of agricul- ture can be applied to improve yields of selected marine species. Marine plant and animal production is controlled by a num- ber of basic chemical and physical constraints. Assuming that the organisms under consideration for coastal mariculture are in- digenous, physical factors such as salinity and temperature should not be limiting at normal animal densities. Environmental factors such as wave action and solar energy are also important in plan- ning mariculture activities. Nutrients are essential for all plant or animal production. Some coastal areas are rich in available nutrients; In other regions, strong current flows and wave action can provide large quantities of nutrients for plant production. A critical initial consideration is the cost and availability of nutrients for the specific organisms to be cultured. In some cases, controlled enrichment may be necessary. If the animal to be cultured is a grazer of phytoplankton or benthic algae, the conditions for sufficient production of these feed sources must be present. Animals feeding higher in the food chain have similar constraints, but the requirements are more complex. Many underutilized coastal areas have potential as sea farming 1i5

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116 FISHERIES TECHNOLOGIES FOR DEVELOPING COUNTRIES sites. These activities would not compete with terrestrial farming for space, and many culture techniques are technically unsophis- ticated and could be implemented by small family units without large investments. This chapter will cover the mariculture po- tential of species in three major categories: algae, finfish, and crustacea and molluscs. ALGAE As with land plants, algae can be cultivated as animal feed, as human food, or as a source of industrial products. In addition, algae may be part of low-cost systems to recycle domestic or agricultural wastes or wastewaters. Algal Turf Mariculture Recent research by the Smithsonian Institution's Marine Sys- tems Laboratory (MSL) has shown that mariculture of fine algal turfs, commonly found on highly productive coral reefs and simi- lar hard bottom communities, is biologically feasible. The tropical open ocean is known to be nutrient poor, and its fisheries develop ment potential has long been considered rather limited. Coral reef ecosystems, however, maintain production rates of between 10 and 20 g dry material per m2 per day (10~100 times the productivity of tropical nutrient poor water). They derive nutrients from tropical currents, upwelling of deeper ocean water, and the constant wave action of trade wind seas. Under proper environmental conditions simulating reef pro- cesses, algal turfs may be grown on screens. This production can serve as feed for marine animal grazers that, ~ turn, could be consumed by humans. Several species: Mithrax spinosissimus (Caribbean king crab), cittaTium pica (whelk), and Scares (par- rotfish) have served as target herbivores for MSL algal turf re- search. The life cycles of these animals have proved satisfactory for controlled spawning and grow-out. Pilot projects for algal turf mariculture are operating in the Turks and Caicos islands, the Do- minican Republic, and Antigua. In all these projects, algal turf, a mixture of red, blue-green, and green algae, is grown on plastics screens and used as feed for the target animals (figure 4.1~.

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COASTAL MARICULTURE FIGURE 4.1 Algal turf, a mixture of red, blue-green, and green algae, is grown on screen suspended in nearshore waters. When covered with algae, the screens are used to feed caged crab (shown), whelk, and parrotfish in Caribbean pilot projects. (D. Suman) Sea Farming Many large marine algae, or seaweeds, are nutritious or pros vice special flavors and are routinely consumed by Asian peoples. Throughout the world, seaweed extracts are used in a variety

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118 FISHERIES TECHNOLOGIES FOR DEVELOPING COUNTRIES of products including foods, biomedical products, cosmetics, and textiles. Agar, a colloidal extract of the red algae Gelidium ant] Gracilaria, is used as a gelling, stabilizing, and emulsifying agent in ice cream, jelly, candy, and beer. Agar finds its greatest value as the base for microbiological culture media, critical diagnostic tools used in hospitals and research institutes. Other colloids, car- rageenans, and algins extracted from a number of red and brown algae, also have wide application in foods, cosmetics, and pharma- ceuticals as thickeners, stabilizers, and suspension agents. Calcium alginate fibers derived from [aminaTia hyperborea have been used to produce wound dressings that are highly absorbent and hemo- static. Epidemiological studies have indicated lower Evidences of some forms of cancer In areas where Laminaria or Porphyra are a regular part of the human diet. Dietary Porphyra is also reported to reduce cholesterol levels in blood. Some marine algae have been evaluated as biomass energy sources through their conversion to alcohol or methane. Gelidium and Gracilaria, the traditional sources for agar, are harvested worldwide from natural populations. This type of ex- ploitation results in a Boom or bust" industry that might be stabilized by mariculture technology. Considerable research has led to pilot seaweed mariculture in areas of California, Florida, Hawaii, the Caribbean, and China with the proper physical cli- mates for these species. Pilot projects often evaluate enclosures of varying levels of complexity. Giant kelp (such as Macrocystis and Nereocystis) are also harvested from natural populations ofl: the Pacific coast of North America. Ocean-going harvesters have been developed, and the in- dustry shows a high degree of management including pest control, replanting, and harvesting restrictions. Mariculture of red algae as a source of the colloid carrageenan is highly developed. Vegetative propagation of Eucheuma on nets in the Philippines occurs on reefy flats with good water circula- tion. Monofilament longlines are stocked with fist-sized fragments of highly productive seaweed strains. The cultivated plants are harvested at about 3-month intervals. These family farms are maintained using basic agricultural principles, including weeding, predator control, and selection for vigorous strains. Production Is 1(~15 dry metric tons per hectare per year. On the South Tarawa lagoon in Kiribati, family-scale pro- duction of Eucheuma is just beginning. Each family has about a

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COASTAL MARICULTURE 119 quarter-hectare sea garden. Young growth of Eucheuma is tied to lines drawn between mangrove stakes. Trials have shown that a 200 g plant will grow to 2 kg in 8-12 weeks. Other commercial sources of carrageenan, Chondrus and ri- daea, are harvested from natural populations in coo! temperate waters. Net farming of tiara in the state of Washington has also been practical. Mariculture of the edible brown algae Laminaria (kombu) and Undaria (wakamei) is highly developed in coo} to warm temper- ate waters in China and Japan. In China, billions of Laminaria sporelings are produced in large glass houses supplied with sea- water. Longlines anchored to the bottom and floated below the surface at proper light levels are transplanted with young plants of selected Laminaria strains. Adult plants can grow to 3-6 m in length and yield about 5 wet tons per longline. Other techniques for Laminaria cultivation include the application of fertilizer in the sea, breeding of new strains, and disease control of sporeling as well as adult plants. Commercial cultivation of Laminaria is being practiced on the entire China coast from Lianoning Province in the north to Fujia Province ~ the south (figure 4.2~. About 275,000 dry tons of Laminaria were produced from 1S,000 hectares of marine farms in 1974. When ];aminaTia is cultivated where herring spawn, the her- ring lay their eggs on strands of the seaweed. This combination (kazunoku kombu) is harvested and sold as a delicacy in Japan (figure 4.3~. Porphyra, or nori, is the most popular edible seaweed In Japan, the country that dominates the worId's production of this crop. In China, Porphyra cultivation has recently become a large maricul- ture industry. The traditional farming method involved planting bundles of leafless brush or bamboo In shallow water. The floating spores of Porphyra attach to the brush and develop into edible fronds. Modern farming involves growth of spores in indoor tanks with shells of molluscs as substrate and transfer of young plants to synthetic fiber nets for cultivation in intertidal zones (figure 4.4~. Crop maintenance includes fertilizing, pest control, and weeding. New developments include floating cultivation in the subtidal zone or shallow sea areas and strain selection and breeding programs. Algal ma~iculture has a high potential for development in coastal nations. Initial considerations for such development in- clude evaluation of native and exotic species potentials for different

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120 FISHERIES TECHNOLOGIES FOR DEVELOPING COUNTRIES FIGURE 4.2 In China, mariculture of the seaweed Lanunaria begins in glass houses. The sporelings produced are transplanted to lines floating just under the surface in bays and estuaries. The plants are sprayed with fertilizer during growth and harvested when mature. (X. G. Fei) products and cost assessment for the development and implemen- tation of the related industries. FINNISH Cage or pen culture is the most promising method for culturing marine fish in coastal environments. Freshwater fish were cultured in cages only several decades ago by the Japanese; perfection of this technique has increased yields of yellowtail (Seriola quineradiata) to more than 280 metric tons per hectare of cage area. Marine fish aquaculture will inevitably become more popular in the future and might be practiced on a small scale by coastal residents. Floating fish cages make harvesting much simpler and protect fish from predators. Since the fish have a limited space in which to swim, they burn fewer calories, making food conversion more

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COASTAL MARICULTURE 121 - \~/ ,/ ^iq \ k~ ..^ \ ~ ~ ~ ~K / ~ (~)g~t i: - K]WNOKO KOMBU CULTIVATION -20m Act. ~1 , ~ 1 ~ 0.5 m 0.5 kg i450 kg \\ ~08 ~ \\\N FIGURE 4.3 When Larrunaria is grown where herring spawn, the herring lay their eggs on the fronds. This combination of seaweed and fish eggs, ka~unoko kombu, is consumed as a delicacy in Japan.

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122 FISHERIES TECHNOLOGIES FOR DEVELOPING COUNTRIES . ~ ~ ~ . ~ : FIGURE 4.4 In China, spores of the edible seaweed Porphyra are grown on mollusc shells in indoor tanks. The young plants are then transferred to nets in an intertidal zone for grow-out. (X. G. Fei) efficient. Cages can also be moved from place to place and clean, oxygenated water is not usually a limiting factor. Cage cultivation does have drawbacks. The walls of the cages become fouled or covered with algae and must be replaced and cleaned regularly. The high density can lead to disease and parasite problems. Culture is labor-intensive and requires meticulous care. Many fish are extremely sensitive to high levels of pollutants. Yellowtail The fast-swimming, pelagic yellowtail fSeriola quineradiata) is the marine fish most commonly cultured in Japan. The fry are captured from the sea and stocked in floating nylon net cages, which are between 2 and 50 m2 in area and from 1 to 3 m deep. The cages are set out in parallel rows and a platform may be built so that they can be readily attended. After 4 to 6 weeks of feeding and growth, the fry are stocked in grow-out cages. These larger cages, from 35 to 100 m2 in area and 3 to 6 m deep, may be

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COASTAL MARICULTURE 123 constructed from nylon or metal. They must be carefully located in protected, accessible areas with good water quality and circulation and appropriate temperature and salinity. Yellowtail are fed fish scraps anct less desirable species, so these must be available. The yellowtail are harvested after a 6-month grow-out period. Dolphm Fish (Mahi main] Recent work on dolphin fish (Coryphaena) in the University of Hawaii's Sea Grant Program has shown them to be extremely fast growers and suitable for cage culture. This species is circum- tropical and would be ideal for culture in coral atoll lagoons. More work is needed on hatchery and grow-out techniques, however. Groupers, Snappers, and Sea Base Pilot cage culture projects for groupers and snappers have been implemented in Malaysia and the trench West Indies. Float- ing net cages are being tested to fatten undersized fish of fast- growing marine species, such as mangrove snappers (Lutianus spp.) and estuarine groupers (Epinephelus spp.~. These species are found naturally, are readily accessible, and have a high market value. Juvenile fish weighing 150 g or more are stocked in the cages. In Malaysia, bamboo rafts (12 x 12 m) are built and floated on discarded oil drums. Four 5-m3 knotless nylon-net cages are suspended from each bamboo raft. The net is removed from the water and cleaned when its openings are about half blocked by fouling organisms. The rafts are anchored with of} drums filled with concrete, sand, and stone. In the French West Indies, 10 x 3 m cylindrical floating nets are used. In Micronesia, rabbitfish (Sigamus spp.), herbivores, are used in floating net cages to con- sume the fouling organisms and reduce the maintenance of nets. Mi~kfish (Chanos chanos) Milkfish have been reared in brackish waters for centuries. Growth in ponds and pens is very rapid, if adequate algal foods are provided. A recent breakthrough in spawning adults in captivity was achieved at the Oceanic Institute in Hawaii. This should lead to increased availability of juveniles for greater production of this

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124 FISHERIES TECHNOLOGIES FOR DEVELOPING COUNTRIES species in Pacific basin countries. The herbivorous nature of this fish would allow the use of low-protein pellet feeds or algae grown either in the culture area or on an appropriate substrate elsewhere. It is a good candidate for polyculture because of its nonpredatory and herbivorous nature. Mullet The culture of mullet from the hatchery to pens is still in the pilot stage. Mullet hatchery production is relatively routine, but economic production of this species has yet to be demonstrated in cages, pens, or ponds. However, the desirability and availability of this species makes it a good candidate for culture in certain areas of the world. In Israel, Taiwan, Indonesia, and the Philippines, mullet are incidental crops in milkfish and shrimp-pond culture. Tilapia Tilapia have a long history of culture in freshwater systems and have also been commercially reared in coastal waters. The develop- ment of salt-tolerant strains, couplet! with the limited availability of fresh water in many areas, may encourage coastal production of tilapia in cages. At low stocking densities, tilapia have growth rates of about one g per day. However, in commercial operations with high density and pelleted feed, growth rates of 22-33 g per day have been reported. There are major technical problems with hatchery production or grow-out with this species. Several new strains have been developed, including a red-colored strain, which make the fish more marketable. Tilapia are also being grown in combination with shrimp and various fish species throughout the world. Rabbitfish Rabbitfish are a popular herbivorous fish of the tropical Pa- cific. Hatchery operations have produced marketable sizes on a pilot scale, but commercial culture has not yet been successful. Recent development of the algal turf production technology by the Smithsonian Institution's Marine Systems Laboratory could pro- vide a means for producing low-cost food, which would allow the culture of this species in nutrient-poor tropical waters. Rabbitfish

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COASTAL MARICULTURE 125 can be used in certain cage culture operations to control fouling of nets and screens; in innovative applications, oyster culture strings were cleared by being placed in cages containing rabbitfish. Salmon Pen culture of salmonids is well established In Norway, Scot- land, and other northern climates, and several projects are under- way for areas of North and South America. Commercial feeds are available, and cage and pen designs have been successful. There are no problems with hatchery rearing before transfer to cages in the marine environment. Specially formulated pelleted foods are provided until market size is reached. New work on manipulating the gene complement of salmon may yield faster growing or sterile fish for certain aquaculture applications. Ocean ranching, where salmon are produced in the hatchery and then released to the environment, has been successful in Japan and North America and is being tested in Chile. In Chile, only 1 percent of the first generation returned for capture. Their goal is for 5-10 percent of the annual batch to come back to the release point. Salmon return in 2-4 years after release and are then cam tured. Technologies have been developed in which salmon literally swim directly into the processing plant. CRUSTACEANS AND MOLLUSCS Invertebrates now being cultured include crustaceans and mol- Juscs. The culture method of molluscs depends primarily on the organisms' mode of feeding. Bivalves (oysters, mussels, clams, and scallops) are filter feeders. These animals require a substrate that allows them access to large quantities of water for filter feeding. In the culture of oysters, mussels, and scallops, the substrates are typ- ically ropes, stakes, and mud. Off-bottom rope and stake culture is generally more efficient than bottom culture. In recent years, clam production has been improved by tilling and cultivation of natural mud substrates to improve pH and texture. Gastropods are snails that feed mostly on bottom-dwelling or benthic algae. In this case, an effective growing surface for the algae as well as a protective cage for the snails are the primary requirements for culture.

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COASTAL MARICULTURE 131 sedentary, predator resistant, ecologically innocuous, and com- mercially valuable. At the Micronesia Mariculture Demonstration Center in the Republic of Palau, methods for the mass culture of giant clans have been developed. Through careful observation of spawning behavior, larvae were captured and reared in tanks and raceways. Once young clams reached shell lengths of ~10 mm, mortality rates dropped dramatically, and clams larger than 3~40 mm had a high survival rate in the laboratory. In nature, 1~20 mm clams suffered total mortality from predation within a few days of unprotected release on a reef near the mariculture center. In protective cages, clams of this size survived well, ~d clams released at a shell size of 130 mm required no protection for high survival rates. Preliminary estimates of potential biomass production capac- ity in giant clam culture indicate that 16 tons of edible clam meat per hectare per year could be produced. This compares well with mussel culture and exceeds most fish-based aquaculture yields (fig- ure 4.7~. The Palau mariculture center has also developed packing tech- niques that allow juveniles to be shipped throughout the world with minimum losses. ScaBops In recent years, methods of culturing scallops that are similar to those for oysters, mussels, and clams have been attempted. Because they are mobile, these bivalves must be caged at relatively low densities. Research is now underway in the United States at the University of South Carolina and the University of Georgia sea grant programs to test the use of suspended lantern nets and polyculture of scallops with fish in ponds. This is a promising area that is likely to be of increasing significance. Marine Snails The culture of snails is likely to become a major area of de- velopment in mariculture. In most cases, these animals feed on small algae (see discussion above under algal turf mariculture), and the basic requirements are those of providing an algal growth surface and sometimes a protective cage. Wild young have not been a major source of juveniles for these organisms, and the

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132 FISHERIES TECHNOLOGIES FOR DEVELOPING COUNTRIES ..i..~.. -~.~.~ ~~.~: : ~ - - ~~-~,~ ~~ ~~ ....... ......... ~ . -. ~ I. ... ,, .':: ' A.: ::: ' ~ ~ ~: :: A': 1 .~ ~~.~.~.~.~. . , ~,.,.~, .~ I :.2..''.~.'.2.'.'..'..:.~'t'~'.", .:~.~.~,~2. .,',~,'",' ".'::":""' ~ '-'''''' '' .:~ ~ '" .: '.:. :: :A it' ~'~'~ ~ ~~ :~ ~ ~ A::: :~:: ::: ~ :~: I'':: :~ :: :: ~ I: : :~ : :: :: F ~~ ~ : ~ ~ ~ ~ ~ 'I ~ ~:~ ~~: ~ ~ ~ ~~ Gil- ~ : ~ ~ ~ ~ ~ ~ ~ ~ ~ :~ ~~ Ail: ~ : ~ I:: :~: ~ : ~ : ~ ~ I, ~ ~~ ~~ ,~ ~~ ~~ ~ ~ :: ~ ~ :~: ~~ ~ ~~ : I:: It'd :, ~~ :~ ~~ ~ ~ ~~ ~ ~ ~ ~ ~ ~ ~ ~ ~ S~ ~ ~ ~ ~ ~ ' :: ~ ~ ~ ~ ~ ~ ~ I' ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ : .~ :::. ~ ~ ~~ ~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ :: :~ ~~ If: ~ ~ :: : .,,,::,, ~~:~:~ ',,: ~::~ ~~:~ ~:~:~:~'~.~ ~~: ~~ If: :~ :~: ..... '.:, ~~.~ a' i:': I: ~~:~:~? ~2:.~:~:~: :~: :~:: i~ ~~: ~ ~ ."',.~ ~ ~ ~ ~ :~ ~~ :' ~~: :: ,: ~ I: p2~i2~,:~,~'~-~:~ ~~ ~~ ~~ ~~ ,:,:,:~::S:~ ~:~:::~::::~:::::,::,S::::: ::-:~::~ ::::: :::::::::: ::::: :: ~.~.~,~ ~~ ~~ ~ ~ .'..' ~ ~ ~~,~,~'~'~'~ ~~: :':,,":' ~~ ~ It'd 2.~:~:"'~:~ '.' "'~'.:~:' .' ~~.~:~.~'~'~ ~ ~ ':.." ... ~: ~ I'd.: 'I ~~ ~ :~ ::'S ~.~ ~ ..:,. .~ .'~"2'~':.' ,' '. .~2~'~.~ : ~ ~,~.~'~.~:~ .: ~~ ~ ~ ~-~,~'~:'~ ~~ I': ~:~'~.~ . .: , -. ~ ,2. 2 ~ ".~"'~,~.~.~ ~ .~ 2 ~',~'~'~ ~:~ ~~'~'~ ~~.~'~ ~~:~,~ ~~'~ ...... ' I., ,~,.2,:~'~.~'~ ~ ~'~.~ ~'.':~',: I'm ~'~,~,~,~'~.'~:~ ~~ ~ ~: ~'~'~ ':'' .jS:,, ,.' ,~. ""'.' ~.~..'~''.'.~'~'~..,'~".~'.~..~ I'm ~~ ~ ..: ,~ ~ ~ '.:'',':..,2,: :','~:'. ~.~."',.,"~'~",'~'' ~~ ~2~'~.~'~.~,~'~ j ~ ~ 2~ ""I ~~ ~2 ~~: ~~ ~ ~ ~ ~~ ~~ ~ ~ ~ ~ ~~ ~ ~2~: ~ ~~: s' ' 2:sis a sip SO ~~ ~~-~ ~.~:~-~ ...:.s.s.s..i.s,:,.:,.,:,:,:,:... i: .':: i:. .. Isis- s .~z,Z,5... ~~,,,'~,~,~,~,~j~'~,~,~.~,~,~2,,~,~,~',~,~,~,~,~,~.,~'~'~,~'~.~ ss..'.2 ....- ~ - ~~.~.~ .~si.-, .'.~..~-..,~ .. -a. I. ss;.S Z. sss...~.~s 'I I... : - s ~ ~ ~ .s S .. :... ..s....s: : . ss:~:: .: sass:: :: :::s:: :::::::: ::::: ::, :: :.:.:: :: .: ~ . ~ ~~ ~~ ~~-~ ma- ~ - ~~ ~~ -~ ~ ~ ~~ -my 'I've'-' "~",2,s;~'~2~'~.~-~.~.~.- ~~--~':" ~~'~ "-'''""~2~2~ '."-'-'"" ~~'~'~,~',~,-~'~'~.'~j~ ~~,~ ~ ~ ~.~ ~.~,~,~ ~~.~..~.~ '~:~,~'~.~'~'~'~ ~~-~-~:~:~:~:~: :-~:Z:~:~:~.':~:~:::~.~.:'~ ::::: A:.::: ::::: ~ ::ZZZ:~::~:~:~:~:~:~ . ~.~, ~~ ~~ ~~ ~~ ~~.~ ~ ~~ ~:~ ~~ ~ ~~:.~ '': -- ~~ ~'~:~ ~.~ -me .~.s ~~.~.~ ~~.~ ~~ :~-~.~- ~ ~~ ~~,~ ... ~ ~ .- ~ ~.~ ~~ -, ~~ I,., ~~ ,~ ~ ~ ~ ~~ em: ~ -: ~ ~ ~~.~.~ .~.~,~.~,~.~ .,.. -, ~ ~. ,...,-.-,. .-. ~,~.~,~:.~,~ ~~,:.-~. ~~ ~...i.. Its S S , . '~'~,,~,~,~.,,"~,~ 'my'. , :.s~,: : :ss~s~.~:~:~:~:~:~:s~.~.: 55.:.'.izfi - .;s . =....--- is ~ ~f5 ''it ~: ~ ~ I. ~~ ~ ~ ~ ~ ~ ~~ ~ ~ ,:, Z,2Z~.Z~,~'~'~'~'~'~'~'~"'~'~'~"'~'~-'~.'~'~' ..:. -... I: ~ ~ ~ ~ ~~ ~~.~.~ ~~,~ ~~..~ ~.~ ~ ~.~:~.~ 'I'd . i., i. - ~ ::,,,,: :~ ~ ~ ~ I'd: ~ ~ ~:~ ~ I:: :: '::':::::: :: : :~ : ZZ'"~2: "~"~'~'~ ~~ :.:, :~:~ :. ::~:~::~:~:~::~:~:~:~::::~: ~ ::::::: I: Suez: ::::::: am: ~~: ~ ~~ ~ ~~:~:~:::~: ~ ~~ ~~ ~~ ~ ~ ~~ :: ..': ~ .: ~ : ~~:~,~ ~ -it ~ ~ ~~ aft, ~~ ~~ ~~ ~ ~~ ~ ~~'~ ~.~ ~~ ~ ~~ ~~ ~ ~ ~ i. ~~ : ~~ ~.~ ~ ~ ~~ ~ ~~ ~~ ~ ~ ~ ~ ~~ ~~ ~ ~ ~~ ~ ~ ~ ~ ~ ~ I. ~~ ~ ~ ~~ ~.~ ~ ~~..A ii~z ~~ ~ ~ ~ ~ 'A ~~ ~ T~ ~ ~~ ~ ~ I: ~ ~-~ ~~ ~~ ~ ~ ~ :- ~ ~ I- ~~ :. :~ ~ 'i ~ ~ ~~ I: All: : ~ ~ ~~ : ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ :- 'zip .~.:''Z"~-~.~'''~'~'~'~'~:~'~''~.~'~'~'~'~. ~~'~.~'~ ~2~,~ ~~ ~~ ~',~ ~ ~~ ~~'~ ~~ ~~'~'~ 'id ~~ ~~.~:~ :~ ~ ~~'~ ~~ i,'~.'~'~.~...~2~':'~'.~'~' ~~ ~ ~ ~ Aid' ~~ T~ ~~ ::: ~ ~ ~ ~~ ~ ~ '' ~~ .~ ~,~:~_ Z,Z','~2.,,,'~,~,~ ~'~ ~~''~ ~~ ~ ~~ ~:~ ~ ~~ ~~ ~~ ~~ ~ :~ . I', I: ~ ~ ~ ~ ~ I'd ~ ~ ~ ~ ~ ~ ~ ~ ~~ ~ .__,. .~'~:~ ~ I'm ~ ~ ~ I: ~ ~ ~ 'a ~ ~ 'I ~~ ~ I::': :~: :~zZ.~ 5_01 so.'.... ~ :~.:z~: ~::~: ::: i~ :: ., .~ ~:~ ~~ all:: ~ my: :: I'm ~ :: ~ :~ Gil ~~ .:_ : ,, .,. ': ,,.,,, ..~ ~~ my: . I: ~ ~ ~ :: ~~ ~~ ~~ .~'szf.z>~Z. ~ ~~ ~ ~ . ~:~.~ ~~ aft. : Id: :~ I: :~::~ :~:: ~~:~ ~ .Z.>z.z.i.$.; . ~~.~ I. z go z: ~ liii '.:::-::::::: :: ::::: ?:::::::::::::::::::::_ of :- 5 z.: ':::::::-:: :~ I: I: ~ :~ I: _ - .~z>~s :.`,.,.,,.~ ,~ , ,., , .i :;: FIGURE 4.6 Inspection of the growing mussel crop simply involves lifting the rope out of the water. At harvest time, the rope is untied from the raft and brought to shore. (L. Bell)

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COASTAL MARICULTURE FIGURE 4.7 At 4 months, about 100 giant clams are a handful, but at 3 years it only takes one. Culture In shallow sandy coastal areas and in raceways both give excellent yields. (G. A. Heslinga) basic limitation to developing marine snail mariculture has been that of the hatchery process. Major advances have been made in spawning, hatching, and grow-out processes, but culture has not progressed past the pilot stage. Cage culture for abalone also seems promising, and several organizations in Caribbean countries have been testing larger scale operations. The transition period from the hatchery to grow-out conditions seems to be especially critical, and more work is needed on nursery systems to reduce high juvenile mortality. Crustaceans Extensive efforts over many decades have been made to hatch crabs, shrimp, and lobsters of various genera and species. The larval development process has often proved complex, difficult, and expensive, en cl is probably not of near-term interest to arti- sanal fisheries. Marine shrimp hatchery technology is now routine,

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134 FISHERIES TECHNOLOGIES FOR DEVELOPING COUNTRIES but crabs and lobsters have yet to be produced under commer- cial hatchery conditions. However, recent work with the grazing Caribbean king crab (Mithrax spinosissimus) has shown promise. Mithrax Crabs Mithrax crab eggs are obtained from gravid females caught in the wild or grown in captivity. When the female is about to release her eggs, she is placed in a juvenile cage, where she spawns. The larval crabs grow undisturbed without the mother for 60 days. During this period, the small crabs feed on algae growing on the screen of the box. Between 60 and 100 days after hatching, screens covered with algal turf are introduced into the cages to provide food to the juvenile crabs. The juvenile crab cage is a wooden frame box, covered with fine mesh (375 micrometers) screen. During the crabs' first 100 days, the cage is anchored about 3 m below the surface in a shallow area with moderate wave action. After 100 days, the crabs are about 15 mm in diameter and are transferred to grow-out cages fitted with the plastic algal screens for grazing. The growth rate of the crabs depends on adequate feeding and replenishing of tale algal screens. Stocking densities must be decreased as the crabs grow and increase their consumption of algae. Four hundred days after hatching, the crabs will have grown to about 1 kg in weight, 100 mrn in length, and will need about one-third of a screen of turf algae per day. Marine Shrimp Marine shrimp culture is expanding rapidly in ponds adjacent to estuaries. Pond culture will not be covered in this report, but the enhancement of natural areas with juvenile shrimp has had some success in Italy and Japan. This ocean ranching, where juveniles are raised in the hatchery and allowed to grow out in a natural environment, may be appropriate for certain tropical areas where stocks have been depleted because of overfishing. In this method, it is best to grow the shrimp in transition ponds to bring them to a larger size before release.

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COASTAL AGRICULTURE 135 INTEGRATED SEA FARMING Integrated sea farming has been suggested as a possibility for inhabitants of the South Pacific who live by reef foraging. Several precedents exist for this type of activity. The Seruti people in Trian Jaya, Indonesia, live in wooden houses on stilts over the water and raise fish in floating cages. Farmhouses are often built in the Eucheuma farm areas, raised on bamboo stilts over the reef flats on which the farms are located. A reef flat is the ideal location for such an integrated farm. The water is shallow, protected, and productive. POLYCU[TURE Polyculture is a technique developed by the Chinese for the culture of several aquatic species in the same body of water. The Chinese obtain very high production with several species of carp that feed at different trophic levels in freshwater ponds. Polyculture in the marine environment has been practiced in Southeast Asia with shrimp and milkfish, and Israel has experi- mented with mullet and shrimp. Work is currently being done in Hawaii with a combination of oysters, tilapia, and shrimp. The South Carolina Sea Grant Program is working on a combination of clams or scallops with striped bass. Many other combinations are possible and should be considered in any new development project. RESEARCH NEEDS The life cycles of many marine species are not well understood. Without this basic knowledge, modern culture techniques are im- possible. An increased number of marine animals and plants will inevitably be farmed once husbandry techniques have been devel- oped. Special attention needs to be given to the cage culture of marine fish, a technique that is still in its infancy. Increased productivity of cultured marine species must be a basic research goal. The environmental conditions for optimal production, as well as the constraints, must be identified and then considered in choosing the most appropriate species and cultivation sites. Much has been {earned in recent research on the control of reproduction and growth of molluscs. In many species of molluscs,

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136 FISHERIES TECHNOLOGIES FOR DEVELOPING COUNTRIES spawning is induced by the enzymatic synthesis of prostaglandins. This production of prostaglandin hormones can be initiated by a low concentration of hydrogen peroxide in the seawater surround- ing these organisms. After development to the larval stage, the organism must attach to some suitable surface and undergo metamorphosis. This transformation is also biochemically controlled. Specific chemicals extracted from red algae, for example, will induce abalone larvae to settle and continue their growth to adulthood. For the oyster Crassostrea virginica, bacterial by-products have been demonstrated to induce metamorphosis. Oyster larvae have a preference for surfaces coated with specific bacteria. In these and other instances, metamorphosis-inducing bio- chemicals have been shown to originate from some feature of the preferred adult environment. These features can include individ- uals of the same species, algal or bacteria] films, or other plant species that may serve as nutrients for the adult organism. In addition to biochemical control of spawning, larval settle- ment, and metamorphosis, research is also in progress on growth enhancement. The use of growth-regulating hormones isolated from mammals has accelerated early growth in abalone, giving increases of about 25 percent over the mean growth rate in the first few days after metamorphosis. Thus, various biochemicals already present or readily intro- duced to the environment can serve to benefit marine aquaculture. Research is needed on the identification of more of these materials and methods for their use. [IMITATIONS The major drawback to the expansion of mariculture is the need to collect larvae in the wild for stocking many sea-farming systems. Better hatchery techniques for more species are needed. Mariculture systems that are generally located in protected near- shore areas will be threatened by pollutants and siltation unless proper conservation methods are followed. Another consideration is the possible damage or destruction of culture systems by storms or waves. Control of a coastal area will be necessary for many maricul- ture systems. Therefore, cooperation with governmental regulat- ing agencies and local fishing communities must be considered.

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COASTAL MARICULTU~3 137 Fishermen working as sea farmers may require a change in life style that may involve social and cultural difficulties. Socioeconomic considerations will determine the ultimate suc- cess or failure of any sea-faming venture. Fluctuating prices for marine products complicate planning and economic assessment. The materials required for the construction and maintenance of culture systems may not be available at remote sites. SELECTED 1lEADINGS General Bardach, J. E., J. H. Ryther, and W. O. McLarney. 1972. Aquaculture: the Farming and Husbandry of Freshwater awl Marine Organistru. John Wiley and Sons, New York, USA. Brewer, W. A., and J. S. Corbin. 1984. Aquaculture development for the Pacific islands. In The Emerging Marine Economy of the Pacific. C. Gopalakrishman (ed.~. Butterworth Publishers, Boston, USA. Colwell, R. R. 1986. Manne Biotechnology and Developing Cour~trics. UNIDO/ IS.593. Vienna, Austria. Iversen, E. 1976. Fartrung the Edge of the Sea. Fishing News Books Ltd. Surrey, U.K. Kuronuma, K., and K. Fukusho. 1984. Rearing of Manna Fish Larvae in Japan IDRC, Ottawa, Canada. Smith, I. R. 1985. Social feasibility of coastal aquaculture. ICLARM Ncw~let- tcr 8~3~:6-8. Uwate, K. R., P. Kunatuba, B. Raobati, and C. Tenakanai. 1984. A Review of Aquac?alturc Activities in the Pacific Islands Rcgior~ East-West Center, Honolulu, Hawaii, USA. Algal Turf Adey, W., and R. Steneck. 1984. Highly productive eastern Caribbean reefs: synergistic effects of light, wave action and geology on coral reef primary production. National Oceanic and Atmo~pEcric Administration Symposium Series for Undereca Research 1~2~. NOAA, Washington, D.C., USA. Kerr, R. 1983. Are ocean's deserts blooming? Scicnec 220:397-398. Spectorova, L., O. Goronkova, L. Nosova, and O. Albitskaya. 1981. High density culture of marine microalgae promising items for mariculture. Aquaculturc 26:289-302. Shellfish Culture Amare, A. 1983. La granja ostricola de Jururu. Mar y Pica (Cuba) 208:28- 31.

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138 FISHERIES TECHNOLOGIES FOR DEVELOPING COUNTRIES Bell, L. A. J., and E. J. Albert. 1984. First harvest results from the green mussel culture project in Western Samoa. SPC F"heric~ Ncu~lettcr No. 29:24-26. Glude, J. B., M. Steinberg, and R. Stevens. 1982. Tic Feasibility of Oyster and Mussel Farnung by Municipal Fi~hermcn in the Philippines. Report SCS/82/WP/103 of the South China Sea Fisheries Development and Coordinating Programme, Manila, Philippines. Heslinga, G. A. 1986. Biology and culture of the giant clam. In Clam Culture in North America, J. Manzi and M. Castagna (eds.~. Elsevier, London, U.K. Heslinga, G. A., F. E. Perron, and O. Orak. 1984. Mass culture of giant clams (F. tridacnidae) in Palau. Aquacu~turc 39:197-215. Hickman, R. W. 1983. An Annoted Bibliography of New Zealand Marinc Mw- ecle ~~ilidac) 188~1982. Publication 40, Ministry of Agriculture and Fisheries, Wellington, New Zealand. Mann, R. 1978. Erotic Species ire Mariculturc. MIT Press, Cambridge, Mas- sachusetts, USA McVey, J. P. 1984. CRC Handbook of Mariculturc, Vol. I. Crmiacean Aquaculturc. CRC Press, Boca Raton, Florida, USA. Morse, D. E. 1984. Biochemical and genetic engineering for improved pro- auction of abalones and other valuable molluscs. Aquacuiturc 39:263-282. Morse, D. E., and K. K. Chew. 1984. Resent Innovations in Cultivation of Pacific Mollusks. Elsevier, London, U.K. Rabanal, H. R., U. Pangsuwara, and W. Poochareon. 1977. Shellfish cries of Thailand Background and Proposal for Dcvelopmerd. Report SCS/77/WP/61 of the South China Sea Fisheries Development and Coordinating Programme, Manila, Philippines. Ubeda, L. 1984. Cuando de ostidn se trata. Mar y Pica (Cuba) 226:20-23. Cage Culture Agriculture and Fisheries Department, Hong Kong, and Division of Fisheries, Malaysia. 1978. Cagc C?dfurc of Marinc Fish in East Coast Peninsular Malaysia. Report SCS/78/WP/69 of the South China Sea Fisheries Development and Coordinating Programme, Manila, Philippines Cho, C. Y., C. B. Cowey, and T. Watanabe. 1985. Finfiah Nutrition in Ada: Methodological Approaches to Research and Dcvelopmcnt. IDRC, Ottawa, Canada. Neff, G. N., and P. C. Barrett. 1979. Profitabic Cagc Chiturc. Report by the Inqua Corp., Dobbs Ferry, New York, USA. Seaweed Dixon, B. 1986. Seaweed for wound dressing: BID/TECHNOLOGY 4:604. Doty, M. S. 1986. Biotechnological and economic approaches to industrial development based on marine algae in Indonesia. Pp. 31-43 in Workshop on Marinc Algae Biotechnology: Summary Report. National Academy Press., Washington, D.C., USA.

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COASTAL MARICULTURE 139 Edwards, P. 1979. Seaweeds: an underexploited resource in developing countries. Appropriate Technology 6~1~:252-27. Evans, L. V. 1986. Seaweed bioproducts. Scicnec Progress. 70~279~:287-303. Fei, X.G. 1983. Macroalgal culture in California and China. Pp. 301-308 in Raft arid Farm Dcs*n ire the United Statce and China. L. McKay (ed.~. New York Sea Grant Institute, New York, USA. Hansen, J. E. 1985. Strain selection and physiology in the development of Gracilaria mariculture. Hydrobiologia 116/117:89-94. Hansen, J. E., J. E. Packard, and W. T. Doyle. 1981. Mancu~ture of Red Seamcede. Report T-CSGCP-002. California, Sea Grant College Program Publication. University of California, La Jolla, California, USA. Harger, B.W.W., and M. Neushul. 1983. Test-farming of the giant kelp. Macrocyst" as a marine biomass producer. Journal of the World Mariculfwc Society 14:392-403. Jacobs, R. S., P. Culver, R. Langdon, T. O'Brien, and S. White. 1985. Some pharmacological observations on marine natural products. Tctrahedror~ 41 :981-984. Khan, A. 1986. Seaweed farming shows bright promise. Agricultural Informatior~ Dcvelopmcnt Bulletin 8~3~:4-5. Lim, J. R. 1982. Faring the Oculars (The Gcnu Story). R. P. Garcia Publishing Co., Manila, Philippines. Mattel, M. G. 1982. Er~haneemcnt of the Marine Environment for Fubene~ and Aquaculture in Japan. Technical Report No. 69, Department of Fisheries, Olympia, Washington, USA. Neushul, M. and B. W. W. Harper. 1985. Studies of biomass yield from a near-shore macroalgal test farm. Journal of Solar Er~crgy Engineering 107:93-96. Trono, G. R., H. R. Rabanal, and I. Santilka. 1980. Report SCS/880/WP/991 of the South China Sea Fisheries Developments and Coordinating Pro- gramme, Manila, Philippines. Tseng, C. K. J. 1981. Commercial cultivation. Pp. 680-725 in The Biology of Scamcede C. S. Lobban and M. J. Wynne (eds.~. Blackwell Scientific Publications, London, U.K. Tseng, C. K. J. 1983. Oceanographic factors and seaweed distribution Occanus 26~4~:48-56. Wong, J. L. 1986. Cancer and chemicals...and vegetables. CHEMTECH 16~7~:436-443. RESEARCH CONTACTS General Aquaculture Development Program of the State of Hawaii, 335 Merchant St., Room 359, Honolulu, Hawaii 96813, USA (John S. Corbin). Asian Institute of Technology, P.O. Box 2754, Bangkok, Thailand (S. Boromthanarat). FGAPP/UNDP Network of Aquaculture Centers, c/o SEAFDEC Aquacul- ture Department, P.O. Box 22256, Iloilo, Philippines (T. E. Chua). International Center for Living Aquatic Resources Management, P. O. Box 1501, M.C.C., Makati, Metro Manila, Philippines.

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140 FISHERIES TECHNOLOGIES FOR DEVELOPING COUNTRIES National Sea Grant College Program, 6010 Executive Blvd., Room 804, Rockville, Maryland 20852, USA (J. McVey). National Institute of Oceanography, Dona Paula, Goa 401 004, India (S. Z. Qasim). South China Sea Fisheries Development and Coordinating Programme, P.O. Box 1184, M.C.C., Makati, Metro Manila, Philippines. Algal Turf Marine Systems Laboratory, Smithsonian Institution, Washington, D.C. 20560, USA (W. Adey). Shellfish Aquaculture Department, Southeast Asian Fisheries Development Center, Tigbauan, Iloilo, Philippines (W. G. Yap). Binangonan Research Station, Aquaculture Department, Southeast Asian Fisheries Development Center, Binangonan, Rizal, Philippines (M. Tabbu). Council of Agriculture, Taipei, Taiwan 107 (J. C. Lee). Fisheries Division, P. O. Box 206, Apia, Western Samoa (L. Bell). Foundation for Pride, 7600 S.W. 87 Ave., Miami, Florida 33173, USA (C. Hesse). Granja Ostr~cola de Jururu-Bariay, Holgu~n, Cuba (F. Orestes). Institute of Zoology, Academia Sinica, 7 Nan Hal Road, Taipei, Taiwan 115 (K. H. Chang). International Center for Living Aquatic Resources Management, South Pa- cific Office, P.O. Box 1531, Townsville, Queensland 4810, Australia (J. L. Munro). Marine Advisory Service, University of Connecticut, Avery Point, Groton. Connecticut 06340, USA (T. Visel). Marine Biological Laboratory, Woods Hole, Massachusetts 02543, USA (C. Berg). Micronesian Mariculture Demonstration Center, Marine Resources Division, P.O. Box 359, Koror, Palau, Western Carolina Islands 96940, USA (G. A. Heslinga). Motupore Island Research Centre, University of Papua New Guinea, Univer- sity P.O., Port Moresby, Papua New Guinea. Cage Culture of Marine Fish Binangonan Research Station, Aquaculture Department, Southeast Asian Fisheries Development Center, Binangonan, Rizal, Philippines. Council for Agricultural Planning and Development, 37 Nanttai Road, Taipei, Taiwan 107 (J. C. Lee). Inqua Corp., P.O. Box 86, Dobbs Ferry, New York 10522, USA. Institute of Zoology, Academia Sinica, Taipei, Taiwan 115 (K. H. Chang).

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COASTAL MARICULTURE 141 International Center for Aquaculture, Auburn University, Auburn, Alabama 36849-4201, USA (E. W. Shell). Seaweed Department of Botany, University of Hawaii, 3190 Maile Way, Honolulu, Hawaii 96822, USA (M. S. Doty). Harbor Branch Foundation Inc., Fort Pierce, Florida 33450, USA (J. H. Ryther). Institute of Oceanology, Academia Sinica, Qingdao, People's Republic of China (X. G. Fei). Neushul Mariculture Inc., 5755 Thornwood Dr., Goleta, California 93117 USA (B. W. W. Harger, M. Neushul). Plant Sciences, Inc., 514 Calabassas Road., Watsonville, California 95076 USA (J. E. Hansen).