16 MARCH 2015 • WORLD AQUACULTURE • WWW.WAS.ORG hard bottom in cages and poor during winter. Korean rockfish, seabream and parrotfish are some of the most common species cultured in floating net pens and cages. Mollusks. Mollusk aquaculture ranked second (291,000 t) after seaweed, based on the volume of marine aquaculture production in 2013. Although it ranked second, mollusk aquaculture has declined in 2013 by 18 percent when compared with production in 2010. Pacific cupped oysters are the most important mollusk species cultured (Fig. 3), with an annual production of 239,000 t in 2013. In the same year, 34,000 t of Korean mussel and 4,000 t of carpet shell were produced. Abalone aquaculture (Fig. 4) accounted for 7,000 t in the same year. Other species of mollusks farmed include ark shell, blood cockles but those are produced in much smaller volumes than the other species indicated. Longline-based oyster farming is practiced on the southeast and southern coasts, including the Tonnegyoung blue belts where water depths are 5-20 m. Longlines of about 100 m long are stretched horizontally along the water surface, spaced 5-10 m apart, and floats are used to keep longlines near the water surface. Vertical ropes are hung from longlines at intervals of 50-70 cm, to which spat collectors are attached every 30-50 cm. Normally longlines are polyethylene and floats are styrofoam. The farming TABLE 4. Seaweed aquaculture by species (1,000 t). Species 1975 1985 1995 2005 2010 2013 Sea mustard 111 256 386 281 393 327 Japanese Kelp 3 12 27 108 241 373 Laver 44 109 192 197 235 405 Brown seaweeds 0 8 37 30 21 20 Green laver 1 10 4 1 5 5 Others 1 1 1 2 6 1 TOTAL 162 397 650 621 901 1,131 SOURCE: FAO (2012), KOSTAT (2014) TABLE 5. Freshwater finfish aquaculture (1,000 t). Species 1975 1985 1995 2005 2010 2013 Japanese eel 0.15 0.73 2.47 5.81 8.02 5.21 Rainbow trout 0.03 0.41 2.80 3.32 2.65 3.39 Pond loach - 0.003 0.49 1.95 0.73 0.46 Amur catfish - - 2.15 2.57 4.28 3.90 Tilapia - 0.11 0.69 0.26 0.25 0.14 Carp 0.11 0.67 15.39 3.94 5.90 2.35 Others 0.11 0.98 5.23 5.99 4.49 4.96 TOTAL 0.30 2.90 29.22 23.84 26.32 20.41 SOURCE: FAO (2012), KOSTAT (2014) FIGURE 3. Oyster farm at Gyeongsangnam-do, Tongyeong-si. FIGURE 4. Abalone farm at Tongyeong-si, Sanyang town, gonli-island, jiseon, Gyeongsangnam-do.
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