Aquaculture of marine finfish in Korea has been developed very rapidly after establishment of the large-scale artificial seed production technology for flatfish (
Paralichthys olivaceus) in 1985 and for black rockfish (
Sebastes schlegeli) in 1990s. Recently, twelve hatcheries belonging to National Fisheries Research and Development Agency and 395 private fish farms are engaged in producing artificial seed production for mariculture industries and reinforcement of marine finfish resources. The number of artificial seeds of marine finfish produced by government-established hatcheries appeared to be 2, 810, 000 and those by private farms were 190, 450 in 1995. The produced seeds include several species such as flounder, black rockfish, tiger puffer, yellow puffer, gray mullet, red seabream, black porgy, and rock bream. On the other hand, some hatcheries and farmers also produce crustacean artificial seeds and the number of seeds from both blue crab and prawn reached to be 232, 750, 000 in 1995.
Considering only marine finfish seed production, seed production leans largely upon black rockfish and flatfish, which shows 51.82% and 44.99%, respectively, and thus summed to be 96.8% of total number of the artificially produced seeds. As the production of mariculture industry relies too much on a few species, farmers are confronted with some problems such as disorder of circulation and decline in the price and thus it is necessary to develop seed production technology for other kinds of economically important marine finfish.
The following strategies can be suggested to overcome such problems and to guide future directions for the artificial seed production.
First, as the coastal water temperature in Korea is usually fallen down to 7 to 8°C in winter which is lethal to the warm-water fish, wintering of such fish is a difficult matter in mariculture. Thus, the priority in the development of seed production technology would rather be on the low temperature tolerant species such as sea bass, black porgy, gray mullet, spotty belly greenling, etc.
Second, difficulties of wintering caused by low temperature in mariculture of the warm water fish such as orange spotted grouper, seven banded grouper, kelp grouper, rock bream, tiger puffer, and yellow puffer, can be solved by using warm discharged water from the atomic or steam power plant. The young fish reared up to 200 to 300 g in their body weight at such locations can reach marketable size within a year.
Third, Cheju island, locating at the southernmost region of Korea, has abundant ground water whose water temperature maintains 17°C and thus it can be used as a seed production base. The young fish can be cultivated using ground water until their body weight reaches to about 300 g and then they can be moved to the net-cages which are common in the southern coast of Korea. In this case, they can grow to be marketable size within a year.
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