 | Lateolabrax japonicus |
CULTURE PRACTICES
Seabass is cultured in floating netcages. The culture method is basically the same as the one used for farming yellowtail and red seabream. The structure consists of a netcage and a floating frame to support the netcage. A typical unit frame in South Korea is constructed using 12 lauan beams (15 × 15 × 1,200 cm), 9 styrofoam floats (1,000 lb) and several anchors (50 kg each). The beams are joined by galvanized bolts and nuts. The spawning grounds of seabass are typically located near the river mouth, thus the fingerlings are easily collected. Although seabass is a highly valued species, its growth is relatively slow and it takes 2–3 years to grow the fish to market size. Netcage culture of this marine fish is mainly practiced along the southern coast of Korea and in Kanghwa Bay off the north west province of Kyonggi. Finfish mariculture is regulated by specific rules and regulations. The minimum farm size licensed per farmer is 1 hectare of which only 20 percent of it can be effectively used.
PRODUCTION
HISTORY
Seabass farming in South Korea has a relatively short history compared with yellowtail and red seabream. Its culture is still on a pilot scale. For this reason, seabass, like red seabream, has merely been an ancillary culture species to yellowtail farming. The culture of seabass in Korea however has a number of advantages. For example, it can survive throughout the coldest season as well as tolerate low salinity levels. Mainly because of the above reasons, seabass culture is gradually expanding.
TOTAL REGIONAL PRODUCTION
STATUS OF CULTURE
| TOPIC | SPECIES |  |
| Lateolabrax japonicus | ||
| Source of seed | Wild | |
| Culture method | Floating netcage | |
| Yield/ha | 25 MT/ha | |
| Market | Domestic | |
| Production area | 8 ha | |
| Status of culture | Developing | |
| Major constraints | Limited suitable areas Lack of high quality feed | KEY MAP |
 | Pagrus major |
CULTURE PRACTICES
Red seabream is cultured in floating netcage. Its culture has no major difference from that of other marine finfish. The fingerlings of red seabream are collected from the wild, however the numbers are insufficient, and therefore fry has to be artificially produced. The cultured fish are fed on inexpensive minced fresh or frozen fish such as sand lance, mackerel and sardine. Formula feeds can also be provided to the fish. Prior to harvesting, foodstuff containing carotenoids such as shrimp is provided to the fish to make the body color a vivid pink. The culture structure consists of a netcage and floating support frame. A typical unit frame in South Korea is constructed using 12 lauan beams (15 × 15 × 1,200 cm), 9 styrofoam floats (1,000 lb) and several anchors (50 kg each). The beams are joined by galvanized bolts and nuts. Netcage culture of this marine fish is mainly practiced along the southern coast of Korea. A small number of cages are also located off Cheju Island.
PRODUCTION
HISTORY
Both red seabream and yellowtail culture began in the early 1970's. Compared with yellowtail, the seabream is a slow growing fish requiring usually 3 years to reach marketable size. Therefore, red seabream has merely been an ancillary culture species to yellowtail culture. However, in recent years, seabream culture has attracted considerable attention as a result of several problems affecting the culture of yellowtail. Main constraints affecting the latter are wintering difficulty, price drop and poor quality feed.
TOTAL REGIONAL PRODUCTION
STATUS OF CULTURE
| TOPIC | SPECIES |  |
| Pagrus major | ||
| Source of seed | Wild and artificial | |
| Culture method | Floating netcage | |
| Yield/ha | 25 MT/ha | |
| Market | Domestic | |
| Production area | 87 ha | |
| Status of culture | Developing | |
| Major constraints | Limited suitable areas Lack of high quality feed | KEY MAP |
 | Seriola quinqueradiata |
CULTURE PRACTICES
Floating netcage system is mainly practiced in yellowtail culture. This system consists of a netcage and floating frame to support the netcage. A typical unit frame in South Korea is constructed using 12 lauan beams (15 × 15 × 1,200 cm), 9 styrofoam floats (1,000 lb) and several anchors (50 kg each). The beams are joined by galvanized bolts and nuts. Finfish mariculture is regulated by specific rules and regulations. The minimum farm size licensed per farmer is 1 hectare of which only 20 percentage can be effectively used. Therefore, one finfish farm generally comprises 20 raft units, 1 working raft and 2 boats. Netcage culture of this marine fish is mainly practiced along the southern coast of Korea and Yongil Bay in North Kyongsang province. The highest number of floating netcages in the south are off Koje Island and around Rang and Kae Islands. Several cages have been established off Haenam Peninsula and along the northern coast of Cheju Island. One constraint to the expansion of this activity is the limited suitable areas.
PRODUCTION
HISTORY
Marine finfish culture was first attempted in 1964 in the southern coast with the pilot scale floating netcage system. Since then marine finfish culture has gradually developed in areas suitable for locating floating netcages. Starting from 1980, yellowtail culture rapidly developed as a result of the increased local demand for this highly valued fish and poor natural catch. In 1986, the total marine finfish production from seafarming activities reached 2,915 MT of which 2,910 MT come from the culture of the yellowtail.
TOTAL REGIONAL PRODUCTION
STATUS OF CULTURE
| TOPIC | SPECIES |  |
| Seriola quinqueradiata | ||
| Source of seed | Wild | |
| Culture method | Floating netcage | |
| Yield/ha | 50 MT/ha | |
| Market | Domestic and export | |
| Production area | 142 ha | |
| Status of culture | Developed | |
| Major constraints | Wintering Limited suitable areas Lack of high quality feed | KEY MAP |
 | Crassostrea gigas |
CULTURE PRACTICES
In South Korea oysters are cultured mostly through the suspended method but several traditional ones are still practiced in some regions of the country. Traditional methods, mostly practiced in the intertidal zone, are the bottom sowing, stone, and stick methods. Suspended culture includes raft and long-line culture which are mainly practiced in offshore areas, particularly the latter method. The basic feature of a long-line culture unit is a series of styrofoam floats arranged in a row and secured at each end with two heavy anchors. One long-line is usually 100 m long consisting of about 51 floats connected by a polyurethane rope 15 mm in diameter. A series of strings, also known as “rens”, on which the oysters are attached and grow are suspended from the long-line. One ren usually measures 5 m in length however, the exact length varies with the water depth. The raft method, which is practiced in more sheltered areas, consists of a wooden frame normally 18 m long and 9 m wide kept afloat by 30–40 floats. About 400–500 rens are suspended from a raft.
PRODUCTION
HISTORY
Starting from the early 1960's the suspended method for growing the Pacific oyster received considerable attention and was the subject of a lot of research. Culture practices gradually evolved and established to suit the specific conditions and needs of the region. At present, most of the oyster production derives from the long-line method, which is mainly practiced in provinces of South Kyongsang and South Cholla. In 1987, there were 9,190 hectares of licensed growing water producing 288,018 MT, or a per hectare yield of about 31.34 MT.
TOTAL REGIONAL PRODUCTION
STATUS OF CULTURE
| TOPIC | SPECIES |  |
| Crassostrea gigas | ||
| Source of seed | Wild | |
| Culture method | Botton and hanging (Long-line) | |
| Yield/ha | 31.35 MT/ha | |
| Market | Domestic and export | |
| Production area | 9,190 ha | |
| Status of culture | Developed | |
| Major constraints | Environmental pollution | KEY MAP |
 | O Mytilus crassitesta □ Mytilus edulis |
CULTURE PRACTICES
Two basic culture methods are practiced for mussel: bottom and hanging. In the former method mussel spat are scattered on the culture ground and reared to commercial size. Suitable culture grounds are reef areas in the open or shallow sea. In the hanging method mussel spat, fixed to the collectors, are suspended from a raft or long-line, and cultured to the commercial size. Mussel spat are exclusively collected from the wild. The yield from culture practices amounted to 34,577 MT in 1986 and 26,064 MT in 1987. Both mussel species are only cultured in the southern provinces of Korea and extensive culture grounds are located in Chinhae and Posong Bay. However, potential culture grounds are found along the entire coastline of the country, and particularly in Kanghwa and Asan Bay on the northwestern coast (Kyonggi Province). One major constraint affecting existing culture grounds is environmental deterioration due to industrial, agricultural and urban waste discharges.
PRODUCTION
HISTORY
There are two major species of mussel in Korea, Mytilus crassitesta and Mytilus edulis. With the development and expansion of oyster culture by the hanging method, starting in 1958, mussels were considered as a fouling organism and therefore undesirable. However, as the yield of mussels gradually increased in subsequent years, they begun to be marketed as food for local consumption and exported. Since then mussels have became a major candidate of the seafarming activity in the country.
TOTAL REGIONAL PRODUCTION
STATUS OF CULTURE
| TOPIC | SPECIES |  |
| M. crassitesta & M. edulis | ||
| Source of seed | Wild | |
| Culture method | Bottom and hanging | |
| Yield/ha | 27.6 MT/ha | |
| Market | Domestic and Export | |
| Production area | 943 ha | |
| Status of culture | Developed | |
| Major constraints | Environmental pollution | KEY MAP |
 | □ Anadara subcrenata O Anadara granosa |
CULTURE PRACTICES
Cockles in South Korea are only cultured on the bottom. The culture methods of Anadara subcrenata and the ark shell Anadara broughtonii are similar. Spat size of A. subcrenata suitable for stocking in the culture grounds range between 3–10 mm in shell length. Sowing density ranges from 20–50 individuals per square meter. Cockle spat spread over the culture grounds in spring attain the commercial size of 30 mm by autumn. A. granosa is cultured in the tidal zone along the southern coast of South Cholla province. The geographical distribution of this species is limited to the south of the country being a tropical species. Juvenile cockles are sown in a muddy bottom area which has been fenced out by a net supported by wooden poles firmly fixed to the bottom around the perimeter of the cultured ground. The above structure serves to delimit the culture ground as well as reduce losses due to predation from other marine organisms such as some species of finfish and crabs.
PRODUCTION
HISTORY
Cockle production in South Korea in the early 1960's was minimal. However, it rapidly increased during the following decade. In 1987, there were about 11,006 hectares of licensed growing water producing 15,207 MT. At present, all of the cockle produced comes from bottom culture. Cockle spat are collected from the wild and transplanted in the selected growing areas. Of the two species cultured in ROK, Anadara subcrenata, the largest of the two, has the higher production output as it is also cultured in the northern part of the country.
TOTAL REGIONAL PRODUCTION
STATUS OF CULTURE
| TOPIC | SPECIES |  | |
| A. subcrenata & A. granosa | |||
| Source of seed | Wild | ||
| Culture method | Bottom and Intertidal | ||
| Yield/ha | 0.11 MT/ha | 2.74 MT/ha | |
| Market | Domestic | ||
| Production area | 5,688 ha | 5,318 ha | |
| Status of culture | Developed | ||
| Major constraints | Environmental pollution | Environmental pollution Limited seed supply | KEY MAP |
 | Anadara broughtonii |
CULTURE PRACTICES
This fairly large bivalve is cultured mainly in the southern provinces of South Kyongsang and South Cholla although culture grounds also exist along the coast of South Chungchong province. Two culture methods are practiced: bottom sowing and suspended method. In the bottom method, seed of 3 cm in shell length are sown on sandy muddy culture grounds, and attain the commercial size after 1.5 to 2 years. The stocking density of 3 cm spat (about 7 gram in weight) is about one MT per hectare, or 10–15 seeds per square meter. Suspended culture has not been successful due to the high mortality rate and poor development of the adductor muscles which also lowers the market value. The seafarming output of this species has steadily increased since 1980. However, production in the last few years has levelled mainly due to environmental pollution; extensive culture areas are located near Pusan, the second largest city in South Korea and a major commercial port.
PRODUCTION
HISTORY
The collection of wild ark shell spat was first attempted in Jinhae Bay during the early 1930's while culture started only during the late 1970's. At present, most of the ark shell production comes from bottom sowing culture. Seed supply of this mollusc still derives from the wild as they can be successfully collected in large quantities during natural spatfall. In 1987, there were 8,128 hectares of licensed growing water and a production of 58,092 MT or a per hectare yield of about 7.15 MT.
TOTAL REGIONAL PRODUCTION
STATUS OF CULTURE
| TOPIC | SPECIES |  |
| Anadara broughtonii | ||
| Source of seed | Wild | |
| Culture method | Bottom and suspended | |
| Yield/ha | 7.15 MT/ha | |
| Market | Domestic and Export | |
| Production area | 8,128 ha | |
| Status of culture | Developed | |
| Major constraints | Environmental pollution | KEY MAP |
 | Ruditapes philippinarum |
CULTURE PRACTICES
Bottom culture is the only method practiced in rearing the Manila clam. The harvested spat are scattered on selected culture grounds and reared to commercial size. Juvenile clams are collected from the natural spatfall areas when they have reached the optimum size of 15–22 mm in shell length. Suitable culture grounds are tidal flats with sandy bottoms. The proper culture density is 1–31 per square meter. Prior to seeding the clams, the culture areas are levelled and potential predators killed or manually removed where possible. In addition the area is usually fenced in by a net supported by wooden poles firmly fixed to the bottom. The above structure serves to delimit the culture ground as well as to potentially reduce losses due to predation from other marine organisms such as some species of finfish and crabs. Although the production of this species has steadily increased since the mid-80's future yields may well be affected by the increasing pollution of the environment.
PRODUCTION
HISTORY
Short-necked clam culture in Korea was initially practiced in the tidal mudflats of Kyonggi-do in 1912 and subsequently expanded to the west and south of the country. There is one species of short-necked clam in Korea: Ruditapes philippinarum or Manila clam as it is often referred to. The spat of this clam are collected exclusively from the wild. The production in 1986 was 35,992 MT, 54,132 MT in 1987.
TOTAL REGIONAL PRODUCTION
STATUS OF CULTURE
| TOPIC | SPECIES |  |
| Ruditapes philippinarum | ||
| Source of seed | Wild | |
| Culture method | Bottom | |
| Yield/ha | 8 MT/ha | |
| Market | Domestic and Export | |
| Production area | 6,769 ha | |
| Status of culture | Developed | |
| Major constraints | Environmental pollution | KEY MAP |
 | □ Pactinopecten yessoensis O Pecten albicans  Chlamys farreri |
CULTURE PRACTICES
Two basic methods of scallop culture are practiced in South Korea: the bottom and the hanging netcage method. Bottom culture is practiced in gravelly or sandy bottoms at water depths ranging between 20–40 m. The spats with shell length of 3 cm are scattered on the selected grounds and cultured to the commercial size. The hanging method, which uses netcages for holding the scallops, is practiced in muddy bottoms. In shallow waters, the raft method is commonly used, while the long-line method is used in the open sea. Typical netcages used for culturing these bivalves are lantern and pocket nets. The former structure is usually constructed in 5 mm plastic-coated or galvanized wire hoops of 50 cm diameter and monofilament netting to give ten or more compartments 15 cm high. Each chamber has a lateral opening through which scallops are introduced. Pocket nets consist of a plastic-coated or galvanized wire framework on which a mesh is fixed. On the mesh itself several pockets are stitched, into which the young scallops are inserted.
PRODUCTION
HISTORY
In the Republic of Korea scallops were initially harvested from natural grounds. However, since the use of scallop shell as collectors for oyster spat, the culture of this bivalve has received considerable attention. The collection of natural seed was first attempted in 1973 in Yongil Bay. At present, this seafarming activity relies exclusively on spat from the wild. The amount produced in 1986 was 294 MT, 239 MT in 1987. Scallop culture is being carried out in the sea area nearby Kadok Island.
TOTAL REGIONAL PRODUCTION
STATUS OF CULTURE
| TOPIC | SPECIES |  |
| P. albicans & C. farreri | ||
| Source of seed | Wild | |
| Culture method | Bottom and hanging | |
| Yield/ha | NA | |
| Market | Domestic | |
| Production area | NA | |
| Status of culture | Developed | |
| Major constraints | Limited seed supply | KEY MAP |
 | O Haliotis discus hannai □ Haliotis discus |
CULTURE PRACTICES
Two species of abalone are cultured in South Korea, Haliotis discus hannai and Haliotis discus. The former is cultured all around the coast of the peninsula, while the latter is cultured on Cheju island. Two basic culture methods are practiced: natural culture by releasing juveniles in specific grounds (a form of sea-ranching), and hanging netcage method. The former method makes use of artificial reefs and/or natural rocks to provide shelter to the young abalone from potential predators. This culture method is commonly practiced in areas with gravelly or rocky bottoms and densely populated by edible seaweed. The hanging method, which makes use of various types of netcages used to contain the abalones, is usually practiced in muddy or sandy bottoms. The netcages are hanged from a long-line or polycultured with kelp. Culturing the two organisms together gives better utilization of space. Fresh food (the seaweed) is also available to the abalone.
PRODUCTION
HISTORY
Commercial culture of abalone in South Korea started in the early 1970's when attempts at artificial mass seed production finally succeeded. At present several million juvenile are produced by government and private hatcheries. Young abalone seed (2–3 cm in shell length) are sold or provided free of charge to farmers for ongrowing. The amount yielded in 1986 was 447 MT and 315 MT in 1987. The drop in production in recent years was caused by a combination of limited seed supply and higher natural mortality rate during the long on-growing period.
TOTAL REGIONAL PRODUCTION
STATUS OF CULTURE
| TOPIC | SPECIES |  |
| H. discu hannai & H. discus | ||
| Source of seed | Artificial | |
| Culture method | Searanching and hanging (Netcage) | |
| Yield/ha | 0.25 MT/ha | |
| Market | Domestic | |
| Production area | 1,257 ha | |
| Status of culture | Developed | |
| Major constraints | Limited seed supply | KEY MAP |
 | O Laminaria japonica □ Laminaria angustata |
CULTURE PRACTICES
Although kelp culture has been expanding in the last few years, suitable culture sites are limited, as this plant is closely associated to water temperature. Kelp culture is carried out using the long-line method in areas with a water depth ranging between 15–25 m. One culture unit is constituted of one long-line, usually 100 m in length, a series of floats and two anchors. Several mono-lines can be interconnected to form a floating raft. The kelp seedlings are attached to ropes 1.5–3 m in length which are then suspended from the main floating lines. The seedling ropes are usually placed 50–100 cm apart and can be suspended either vertically or horizontally (between two lines) from the main floating lines. The ropes hung vertically are stabilized by tying stones weighing about 0.5 kg each to their ends so that they sway with a pendulum-like motion in the water. The culture depth of these ropes can be conveniently regulated according to environmental conditions, particularly water transparency and wave action.
PRODUCTION
HISTORY
Laminaria culture was first started in Kangwon-do in 1968, however its culture, including artificial seedling production, has since been introduced to the southern provinces of the country. There are two species of kelp in Korea: Laminaria japonica and Laminaria anqustata Originally kelp was mainly utilized as a medical plant and harvested from natural grounds. In 1987 the culture area expanded to 50 ha while culture output was about 10 MT. At present, kelp culture is mainly concentrated off the south east coast of South Kyongsang province.
TOTAL REGIONAL PRODUCTION
STATUS OF CULTURE
| TOPIC | SPECIES |  |
| L. japonica & L. angustata | ||
| Source of seed | Artificial | |
| Culture method | Hanging (Long-line) | |
| Yield/ha | 200 MT/ha | |
| Market | Domestic | |
| Production area | 50 ha | |
| Status of culture | Developed | |
| Major constraints | Limited suitable areas | KEY MAP |
 | O Porphyra tenera □ Porphyra yezoensis |
CULTURE PRACTICES
There are numerous types of manmade structures for growing laver ranging from the traditional bamboo bundles (or any other tree) fixed just above the mean water level to the floating net culture system fixed with anchor. The traditional methods (now rarely used except in the estuary of Sumjim river) have been largely replaced by the recently developed floating net technique of which there are two types: the floating net system and the movable net type with pole. The first is widely used in relatively deep waters while the other method is typically used in shallow waters. The system consists of a net kept in position by a number of wooden poles fixed to the sea bottom. The advantage of this system is that the net can freely move up and down the length of the poles, therefore following the tidal cycle of the sea water. Laver culture is mainly practiced along the western coast of Korea although some areas in the southern coast are also being utilized.
PRODUCTION
HISTORY
Laver culture started in the 1950's in Kwangyang Bay in the southern coast of Korea. By the early 60's the techniques of artificial seedling production and culture method had been widely adopted. During the 70's the floating net culture system and cold storage of nursery nets became popular. In the 1980's research aimed at producing high yielding and disease resistant varieties was initiated. There are two species of laver in South Korea: Porphyra tenera and Porphyra yezoensis. The total laver production in 1988 was 115,749 MT.
TOTAL REGIONAL PRODUCTION
STATUS OF CULTURE
| TOPIC | SPECIES |  | |
| P. tenera & P. yezoensis | |||
| Source of seed | Artificial | ||
| Culture method | Floating (Fixed net structure) | ||
| Yield/ha | 3.4 MT/ha | ||
| Market | Domestic | ||
| Production area | 50,952 ha | ||
| Status of culture | Developed | ||
| Major constraints | Diseases Short culture period | Unsuitable strains | KEY MAP |
 | O Undaria pinnatifida □ Undaria undarioides |
CULTURE PRACTICES
At present Undaria is been culture using the floating rope method. Prior to the culture of the young thalli, spore collectors are hung from the main rope of the culture structure for a period of about two weeks, until the thalli measure 0.5–1 cm in length. The strings covered with young thalli of Undaria are then wound around the main or branch line of the floating rope structure which is then placed in the sea for on-growing. At present seafarming of sea mustard is concentrated along the south and south west coasts of the country. Over 50% of the national production comes from the province of South Cholla followed in terms of quantity produced by the province of South Kyongsang. About 30 000 MT are produced around the coast off Pusan while about 2,000 MT are produced in North Kyongsang province. This seaweed is highly appreciated in South Korea and it is entirely consumed by the local market. Environmental pollution is one major constraint to the expansion of sea mustard culture in South Korea.
PRODUCTION
HISTORY
Artificial seeding of sea mustard initiated in 1963. In 1967 the floating rope culture method was widely adopted. During the early 70's and particularly in 1974, the amount of culture output was in the range of 180 thousand MT per annum. However, the decrease in market price due to over-production lead to a decrease in production. However, as a result of the strong demand of the Japanese market the seafarming output has increased ever since. At present the annual yield is in the range of 200–300 thousand MT.
TOTAL REGIONAL PRODUCTION
STATUS OF CULTURE
| TOPIC | SPECIES |  |
| U. pinnatifida & U. undarioides | ||
| Source of seed | Artificial | |
| Culture method | Floating (Rope structure) | |
| Yield/ha | 26.9 MT/ha | |
| Market | Domestic | |
| Production area | 11,369 ha | |
| Status of culture | Developed | |
| Major constraints | Environmental pollution Diseases of the fronds | KEY MAP |
 | Halocynthia roretzi |
CULTURE PRACTICES
Sea squirt juveniles are produced from November to February of the following year. The method used to artificially stimulate spawning is the heat-shock method (2–3 degree centigrade above normal sea water temperature). Settling larvae are collected on seed-ropes (collectors) made from palm fibre. Sea squirt culture is practiced by the long-line method and it's carried out in two time steps: seed-rope culture (in order to harden the young sea squirt) and culture of hardened seed up to the market size. The culture period ranges between 2 to 2.5 years. About 9,000 MT of fresh sea squirt are produced annually off the coast of North Kyongsang, accounting for about 90% of the total production in South Korea. A further 9% comes from culture grounds in South Kyongsang province while about 1% of the annual output comes from Pusan City and Kangwon province. This highly appreciated marine organism is entirely consumed in the country. One major constraint to sea squirt culture is the high seed mortality which often occurs during the summer months when sea water temperature rises.
PRODUCTION
HISTORY
Artificial seedling production and culture techniques were first developed during the mid-70's. Since then, production has been increasing steadily and culture output per hectare yielded 9.9 MT in 1986. Sea squirt culture is popularly practiced in the southern and eastern provinces of the country. The seeds of sea squirt are mainly produced by small hatcheries, all privately owned. At present, there are 1,670 hectares under cultivation with a 1987 output of 10,048 MT.
TOTAL REGIONAL PRODUCTION
STATUS OF CULTURE
| TOPIC | SPECIES |  |
| Halocynthia roretzi | ||
| Source of seed | Artificial | |
| Culture method | Hanging (Long-line) | |
| Yield/ha | 6 MT/ha | |
| Market | Domestic | |
| Production area | 1,670 ha | |
| Status of culture | Developed | |
| Major constraints | Mass mortality in summer | KEY MAP |
