• Journal of Aquaculture
• /
• v.20 no.2
• /
• pp.81-84
• /
• 2007

We studied two research items that can be undetermined issues in the artificial seed production of the Japanese scallops, Patinopecten yessoensis, batch-specific quality of the reproductive outputs and nursery acclimation, in the embayed waters of Yangyang, Gangwon, Korea. The first batch of the spawner showed better results in terms of survival, growth, and resistance against parasitic ciliate infection over the second batch that was obtained in 5 days after first batch from the same spawner. The early attached spats directly placed in the farming ground (the unacclimated) were resistant against the water current of the open environment, by showing survival of about 80% for a month, a normal survival compared with other results. However, the spat survival during the nursery acclimation was significantly lowered in comparison with that in the unacclimated condition (P<0.01). We discussed the research results of the two items, particularly focusing on their availability for mass seed production for aquaculture in the Korean coastal waters of the East Sea (Sea of Japan).

• Journal of Aquaculture
• /
• v.21 no.1
• /
• pp.34-40
• /
• 2008

This study investigated the effect of rearing conditions on the spawning habit, juvenile growth and larvae development of Marphysa sanguinea, to develop techniques of its artificial seed production. M. sanguinea released trochophore larvae around the burrow when the water temperature was from $18^{\circ}C$ to $22^{\circ}C$. Larvae floated away after staying in the burrow for a while. Larvae secreted mucus eight days after release, covering their whole body with it, and developed ten somites 20 days after release. In preference of juveniles in different grain sizes of sediment, the highest survival rate was made in the grain substrate of $1{\sim}2$ mm in the mean diameter, but the lowest was in the $2{\sim}3$ mm grain substrate. Optimum growth was obtained at the rearing temperature of $24^{\circ}C$(SGR 1.10%), and it reached over $2{\sim}3$ times higher weight gain and specific growth rate than those reared at $21^{\circ}C(0.64),\;18^{\circ}C(0.56)$ and $15^{\circ}C$(0.42) for 50 days. Salinity also made a great difference in the growth and survival rate. The highest weight gain and growth rate were shown when the juveniles were reared at salinity 30 psu.

• Journal of Aquaculture
• /
• v.11 no.2
• /
• pp.203-212
• /
• 1998

As seed production program is growing prosperously in various fishes in southern Korea, disease problems in larval and juvenile stages have emerged as a new research object. The following results were obtained from investigation about environmental factors related to mass mortalities of young Kinki red seabream, Pagrus major in process of artificial seedling production. Total length of red seabream larvae hatched was 2.93mm, and became 18.83~20.12mm at day 40. The first noticeable mortality of red seabream larvae (7.98~9.37mm) occurred in 25~30 day-old fish with the survival rates of 59.8~60.3%. Thereafter the mortality of larvae decreased, survival rate was 20.5~25.45% in day 40. After 20~30 days, the quality of pond water was bellow II class. During the experimental period COD, $PO_4$-P, $NO_2$-N, $NO_3$-N and $NH_$-N increased up to 3, 7, 34, 6 and 8 times, respectively, compared to initial ones. The number of viable bacteria in pond water and seabream larvae were $6.3{\times}10^6$~$2.3{\times}10^7$ cfu/ml, 4.3~$7.4{\times}10^6$ cfu/g in day 25, respectively. Among the isolated bacteria from the diseased red seabream in day 25, Vibrio spp. was considered to be the causative organism. External symptoms of this disease were floated, spined near the surface and inflated abdomen. When the isolated strain of the Vibrio was bathed to seabream larvae, $LD_50$ of seabream larvae was over $10^6$ cfu/ml of Vibrio spp.

• Proceedings of the Korean Society of Fisheries Technology Conference
• /
• 2001.05a
• /
• pp.99-100
• /
• 2001

Although cultured sweet smelt production recently have been rapidly increased from 89 metric tons (M/T) in 1997 to 500M/T In 1999 in Korea, wild fish have been still used as broodstock for cultured fish seed. This is considered due to having higher sperm and e99 qualify in wild fish broodstock than cultured fish. However, capturing a number of wild sweet smelt broodstock might lead to decreasing of the production of wild fish, In truth, of which production has been greatly decreased so that a number of artificial juvenile have been stocked some rivers in Korea. (omitted)

• Journal of Practical Agriculture & Fisheries Research
• /
• v.25 no.3
• /
• pp.35-46
• /
• 2023

It was in the 1982 that artificial seed production research for olive flounder (Paralichthys olivaceus) farming was first conducted in Korea (Currently, National Institute of Fisheries Science, Fish Breeding Research Center). In 1985, fertilized eggs were obtained from natural olive flounder adapted to land tanks, and artificial seed production technology was established and fertilized eggs were distributed. In the late 1980s, halibut aquaculture began to prosper in land-based tank farming in Jeju Island and Busan's Gijang region, where water temperatures are relatively high in winter. Currently, aquaculture is being carried out all over the country, centering on Jeju Island and Wando, Jeollanam-do. However, olive flounder farming, which started with a small group in the 1980s, reduced genetic diversity through inbreeding over generations, resulting in side effects such as slow growth, reduced resistance to disease and environmental conditions. In order to solve these genetic problems of farmed olive flounder in Korea, the Fish Breeding Research Center of the National Institute of Fisheries Science introduced a wild-caught parent fish group to the existing aquaculture group from 2003 to 2004. Genetic diversity was secured and KingNupchi with fast growth and improved body shape was developed. In this study, the current status of breeding technology development of olive flounder, a major aquaculture breed in Korea, is reviewed and future research directions are suggested.

• Journal of Korean Society of Forest Science
• /
• v.69 no.1
• /
• pp.19-27
• /
• 1985

Introgressive hybridization of Pinus densiflora in Korea was investigated by examining the position of resin ducts in 4,992 trees from 67 populations. Judging that P. densiflora has only external resin ducts, P. thunbergii only medial resin ducts, and any tree which has even one needle with external and medial resin ducts is hybrid, hybrids are found at all populations investigated. As variation in position of resin ducts was found among needles on a tree, the number of needles investigated from a tree affects judgment of the tree's hybridity. Therefore, hybridity seems to be judged by many traits rather than by the single trait, position of resin ducts. Seed production by artificial pollination between P. densiflora and P. thunbergii was very poor, i.e. one full seed from five female flowers or from two mature cones. This poor seed production, in addition to the low hybrid vigor, if any, seems to make the artificial pollination between the two species for mass-production of seeds for planting impractical.

• Korean Journal of Plant Resources
• /
• v.31 no.4
• /
• pp.372-377
• /
• 2018

This study was investigated the effect of immature rhizome production according to harvest times-based treatment method for seed production of Gastrodia elata. The results revealed that when the tuber weight of G. elata harvested in spring (GEHS) was ${\geq}100g$, the rate of artificial fertilization, protocorm formation, and immature rhizome formation was 90.9%-94.8%, 3.1%-5.4%, and 10.1%-15.3%, respectively. When G. elata harvested in fall (GEHF) was treated at a low temperature for 4 weeks or more, the rate of artificial fertilization, protocorm formation, and immature rhizome formation was 70.4%-87.6%, 2.2%-2.6%, 8.7%-9.5%, respectively. Therefore, to produce seeds and immature rhizomes, GEHS must have tubers of more than 100 g, whereas GEHF requires breaking dormancy by low-temperature treatment for 4 weeks or more. Compared with those of GEHS, the rate of artificial fertilization, protocorm formation, and immature rhizome formation was lower in GEHF; however, it was higher than those in the natural germination state. Thus, it can be expected that G. elata can be produced throughout the year by ensuring that the seeds and immature rhizomes of G. elata are produced using a constant tuber weight and by breaking dormancy with low temperature treatment.

• Journal of Plant Biotechnology
• /
• v.33 no.4
• /
• pp.243-248
• /
• 2006

A optimal procedure for plant production via repetitive secondary somatic embryogenesis in Tilia amurensis is described. Somatic embryos were induced directly from the culture of zygotic embryos on medium with 1.0 mg/l 2,4.-D. Repetitive secondary somatic embryos formed on the surface of the cotyledons and hypocotyls except for the radicles when explants of somatic embryos were cultured on medium with 4.0 mg/l 2,4-D. The highest frequency of secondary embryo-genesis was obtained in the cotyledons (90%) and hypocotyls(83.33%) on MS medium with 1.0 mg/L 2,4-D. The average number of secondary embryos per explant was 25.74 in cotyledon and 24.92 in hypocotyl. When the cotyledon and hypocotyl segments from somatic embryos at different developmental stages were cultured on MS medium with 1.0 mg/L 2,4-D, the highest frequency of secondary embryogenesis was obtained from late cotyledonary secondary embryos. Somatic embryos were transferred to MS basal medium and then they germinated within 2 to 4 weeks of culture. Germinated somatic embryos grew normally into plantlets on WPM medium, producing new shoots. The converted plantlets were acclimatized on artificial soil mixture. These results indicate that the repetitive secondary somatic embryogenesis in T amurensis can offer the possibility to use in vitro culture system for the micropropagation.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.32 no.1
• /
• pp.112-116
• /
• 1999

In theprevious Hizikia cultivation, holdfasts were threw into the sea after harvesting in May; the young thalli(5$\~$10cm in length) of Hizikia are annually collected from natural bed by seed collectors for the cultivation, resulting in a ruined natural populations. Therfore, the reuse method of holdfasts by regeneration capability of Hizikia fusiformis, was investigated. The effects of emergence on the growth of regenerated thalli from holdfasts over 6 months of outdoor culture from May to November, 1995. The vegetative growth from the holdfasts was good under the emergence of 3hrs/day on the air than 0, 1 and 2hr/day. The regeneration of holdfasts was determined by measuring total length, number of stipe and weight. The growth was facilitated under the exposure condition of 1$\~$3 hrs/day on the air. Outdoor cultivation for the comparsion of to artifical natural seeds were conducted from December 1995 to May 1996. There was no significant differences(0.05< P) between the two kinds of seeds. Therefore, artificial seed maybe used as a replacement for the natural seed in Hizikia cultivation. From the results, an useful method was established to obtain young fronds for the cultivation using the reuse method of holdfast, to conserve the natural population of Hizikia.

• The Korean Journal of Malacology
• /
• v.24 no.2
• /
• pp.153-159
• /
• 2008

We investigated artificial mass seed production of a Chinese scallop, Patinopecten yessoensis, in 2004. The GSI(gonad somatic index) of the Chinese scallop, P yessoensis was 17.2 on mid-February, 20.2 on mid-March, while that of Korean scallop, P yessoensis was 6.9 on mid-February, 10.8 on mid-March. Matured 120 females and 350 males were selected for artificial mass production. They were exposed in air for 1 hr at over $20^{\circ}C$, and placed into a spawning tank(20 ton) containing sea water treated with UV radiation at $12^{\circ}C$. We gained a total of 228,000 thousand scallop embryos between March 10th and 15th, and reared larvae at the indoor tank during 25 days. When the mean shell length of larvae reached 250 ${\mu}m$ and they have eye-spots, the number of pre-settling larvae was 47,500 thousand. We gained 1,850 thousand attached scallop spats from two kinds of collectors. Attached spats were reared in indoor tank for different periods from 5 days to 60 days. They were divided into 5 groups according to the length of reared days. Each group of attached spats was moved to intermediate rearing sites at Yangyang fishing port in Gangreung-city for acclimation to ocean environments. The highest survival rate of attached spats was 13.0% shown at the group reared for 12 days, but the significant difference in their growth was not found between the groups. The shell length of artificial attached spats increased from 0.9 ${\mu}m$ on July 10th to 24.7 ${\mu}m$ on December 16th with the survival rate of 85.0% while that of natural attached spats increased from 0.6 ${\mu}m$ on July 10th to 23.9 ${\mu}m$ on December 16th with the survival rate of 85.7%.