• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.13 no.4
• /
• pp.135-144
• /
• 1980

The reproductive cycle and the breeding season of the freshwater clam, Anodonta (Sinanodonta) woodiana (Lea) have been investigated by histological examination of the gonadal development under photomicroscopy. The materials were monthly collected from the Nakdong River for one year from September 1979 to August 1980. Sexuality of Anodonta (Sinanodonta) woodiana is dioecious, and the species are ovoviviparous. The gonads are irregularly arranged from the subregion of mid-intestinal gland in visceral cavity to reticular connective tissue of foot. The ovary is composed of a number of small ovarian sacs, The epithelium of ovarian sac has a function of the germinal epithelium. Oogonia actively proliferate along the germinal epithelium of the ovarian sac, in which young oocytes are growing. The testis is composed of a number of seminiferous tubules, and the epithelium of the tubule has function of germinal epithelium, along which spermatogonia actively proliferate. A great number of undifferentiated mesenchymal tissue and eosinophilic granular cells are abundantly distributed between the growing oocytes and spermatocytes in the early development stages. With the further development of the ovary and testis these tissues and cells gradually disappear. Then the undifferentiated mesenchymal tissue and granular cells are considered to be related to the growing of the oocytes and spermatocytes. The gonads had function year-round the individuals which have various developmental stages of gonads appearing all the time. Spawning continued year-round except for the period of high temperature of water, during August and September. The peak spawning seasons appeared twice a year between January and March, and between June and July in 1980. Individuals which have trochophore larvae in the marsupium of the adult appeared year-round except September 1579 and August 1980. The rate of individuals which have glochidia in the marsupium was 72.7 percent in May 1980 which was the highest brooding fate.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.16 no.4
• /
• pp.389-394
• /
• 1983

The right eye flounders, Limanda yokohamae Gunther widely distributed in the coastal waters of Korea and Japan. On Feburuary 3, 1983, the authors obtained a number of artificial fertilized eggs from the adult fishes(male: 285mm in total length; female: 297mm) caught by a trawl. The eggs of this species is demersal and adhesive, and the diameter of these eggs was varied in $0.71{\sim}0.80mm$. The egg capsule is colorless and transparent, and the eggs do not contain any oil globules, The hatching took place in 120 hour after fertilization at the water temperature $5.5{\sim}17.0^{\circ}C$. The newly hatched larvae were $2.64{\sim}2.72mm$ in total length with long trunk. Myotome number was $9{\sim}10+30{\sim}32=39{sim}42$ and yellowish brown melanophores were appeared. In 3 days after hatching out. The larvae attained 3.3mm in total length, and the mouth began to move. Xanthophore appeared also on the opereulum at this time. After 7 days the larvae attained 3.70mm in total length, and became the postlarvae absorbing the yolk completely.

• Fisheries and Aquatic Sciences
• /
• v.23 no.1
• /
• pp.2.1-2.6
• /
• 2020

Background: As the cost of fishmeal continues to rise, there will be a need to optimize the diet by minimizing dietary fishmeal inclusion in aquafeed. In this study, a 7-week experiment was conducted to evaluate soybean meal, fermented soybean meal (soytide), and sesame meal as fishmeal replacers in whiteleg shrimp, Litopenaeus vannamei. Methods: A 30%-based fishmeal diet was considered as control (CON), six other diets were prepared by replacing 20% or 40% of fishmeal with soybean meal (SB₂₀ and SB₄₀), fermented soybean meal (ST₂₀ and ST₄₀), or sesame meal (SM₂₀ and SM₄₀) from the CON diet. Twenty shrimp with average initial weight of 0.65 ± 0.05 g (mean ± SD) were randomly distributed into 21 tanks (45 L) and fed four times a day. Water temperature was controlled at 28 ± 1 ℃ and aeration was provided by air stones. Results: Weight gain, specific growth rate, feed efficiency, and protein efficiency ratio of shrimp fed CON showed no significant differences compared to shrimp fed all the other diets. However, growth performance of shrimp fed ST₂₀ diet was significantly higher than those of shrimp fed the SM₂₀ and SM₄₀ diets (P < 0.05). Superoxide dismutase activity (SOD) of shrimp fed CON, ST₂₀, and ST₄₀ diets was significantly higher than those of shrimp fed the SB₄₀ and SM₄₀ diets. But there were no significant differences among shrimp fed CON, SB₂₀, ST₂₀, ST₄₀, and SM₂₀ diets. Also, lysozyme activity of shrimp fed ST₂₀ diet was significantly higher than those of shrimp fed the SB₄₀ and SM₄₀ diets. Although, lysozyme activity of shrimp fed the CON diet was not significantly different compared to shrimp fed all the other experimental diets. Conclusions: Therefore, SB, ST, and SM could replace 40% of fishmeal based on growth performance and lysozyme. According to the SOD activity, SB and SM could replace 20% of fishmeal and ST could replace 40% of fishmeal in juvenile whiteleg shrimp Litopenaeus vannamei.

• Applied Biological Chemistry
• /
• v.36 no.4
• /
• pp.244-248
• /
• 1993

The fatty and organic acids, and barbaloin in various parts of aloe species dried at different temperatures were analyzed by GC and HPLC. Seven fatty acids and six organic acids were identified and quantified. In the case of fatty acids, generally, the contents of palmitic and eicosanoic acid were abundants, and compared to the total contents of seven fatty acids, Aloe arborescence variant 1 was abundant, but Aloe saponaria was poor. And six fatty acids were distributed in the aloe species with the exception of linoleic acid. The contents of malic, citric and oxalic acids in the aloe species were higher than those of other acids, and compared to the sum of contents of six organic acids, Aloe saponaria was high, but Aloe arborescence variant 1 was low. Therefore Aloe arborescence variant 1 was abundant in total fatty acids, but poor in total organic acids. The contents of fatty and organic acids in the sample dried at $65^{\circ}C$ and $80^{\circ}C$ air circulation were almost similar. The contents of fatty and organic acids in the freeze-dried samples were lower than in the other dried samples. The contents of barbaloin in Aloe arborescence and A. arborescence variant 1 were higher than those of other various samples, and barbaloin was not detected in Aloe saponaria. As the drying temperature was increased, the contents of barbaloin in the various parts of the Aloe vera decreased.

• Journal of the Korean Society of Hazard Mitigation
• /
• v.7 no.5
• /
• pp.73-78
• /
• 2007

It has been increasing that significant loss of life and property due to global wanning and extreme weather, and the climate and temperature changes in Korea Peninsula are now greater than the global averages. Climate information from regional climate models(RCM) at a finer resolution than that of global climate models(GCM) is required to predictclimate and weather variability, changes, and impacts. The new surface boundary conditions(SBCs) development is motivated by the limitations and inconsistencies of existing SBCs that have influence on model predictability. A critical prerequisite in constructing SBCs is that the raw data should be accurate with physical consistency across all relevant parameters and must be appropriately filled for missing data if any. The aim of this study is to construct appropriate SBCs for the RCM in Asia domain which will be used for the prevention of disasters due to climate changes. As all SBCs have constructed onto the 30km grid-mesh of the RCM suitable for Asia applications, they can be also used for other distributed models for climate and hydrologic studies.

• Journal of the Korean Institute of Traditional Landscape Architecture
• /
• v.32 no.2
• /
• pp.124-133
• /
• 2014

The study on Musa basjoo planting in traditional gardens in of folk villages and traditional temples was conducted to identify the phenomenon of Musa basjoo planting which frequently appears in paintings and literatures of the late Joseon dynasty and how the cultural custom is being handed down. The result of the study is as follows. As a result of studying state-designated folk villages 6 sites, the custom is being handed down in a few limited gardens including Asan Oeam Village and Seongju Hangae Village. In case of Oeam Village, there are three gardens where Musa basjoo was planted including Seolimbang, Vice Minister's Residence, and Geonjae House where Musa basjoo withered now. In case of Hangae Village, it was found in Bukbi House, Hahoe Residence and Gyoridaek Jinsa's Residence and most of them were planted in front of guesthouses and main building with the assemble-planting method. Musa basjoo planting was confirmed in 39 traditional temples and it was found that Yangsan Tongdosa Temple and attached hermitage Geukrakam are currently prevalent in Musa basjoo planting. Musa basjoo was planted on either side of the stairs of Buddhist sanctums for Buddha and Avalokitesvara Guan Yin of main temples and gwaneum temples with the assemble-planting method and it has a tendency of pair planting. Considering that Musa basjoo is a southern plant, most of Musa basjoo planting was distributed around Jeollanam-do and Gyeongsangnam-do, which is closely related to the isotherm distribution of the Korean Peninsula. Especially, it was found that planting flora was centered on $12^{\circ}C$ of Warmth Index $100^{\circ}$ and annual average temperature.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.20 no.1
• /
• pp.24-32
• /
• 1987

Bluegill, Lepomis macrochirus RAFINESQUE, has bred widely in the various districts of Korea since the Office of Fishery transplanted it into our country from Japan in December, 1969. On August 17, 24 in 1985, bluegill were caught in the reservoir of Habuk-Myon, Yangsan-Gun, $Ky\breve{o}ngsangam-Do$, Korea. They spawned in the rearing aquarium on July 13 and August 2 in 1986. The eggs of this species are adhesive and demersal. The size of the egg diameters were varied from 1.18 to 1.30 mm. Hatching took place in 40 hours after fertilization at the water temperature of $24.3-25.4^{\circ}C$. The newly botched larvae were 3.75-4.05 mm in total length possessing yolk sac, and 29-30 mytomes. Many melanophores were evenly distributed on the entire body. Ten days after hatching, the postlarvae attained 6.05-6.35 mm in total length. The yolk sac was completely absorbed and the width of the pectoral finfold had reached the maximum size. One month fifteen days after hatching, the juvenile attained 25.20 mm in total length.

• Nuclear Engineering and Technology
• /
• v.24 no.1
• /
• pp.75-85
• /
• 1992

The texture changes and their effect on the 0.2% yield strength of Zircaloy-4 sheet were examined after quenched from the ($\alpha$+$\beta$) phase temperature. When the prior ($\alpha$+$\beta$) gram size was slightly larger than that of the $\alpha$-annealed, the observed texture was similar to the $\alpha$-annealed texture having an ideal orientation of the (0001) basal pole at 30$^{\circ}$away from the normal direction toward the transverse direction. When the prior ($\alpha$+$\beta$) grain size was twice as large as that of the $\alpha$-annealed, the location of maximum basal pole intensity was distributed between the transverse and the rolling direction making an angle 15$^{\circ}$from the normal direction, and the observed texture became isotropic. It was found that the Kearns texture parameter, fr, in the rolling direction increased steadily, and fr in the transverse direction increased slightly, while fr in the the normal direction decreased with increasing heat treatment time. With a small increase in fr, the 0.2% yield strength increased drastically. The influence of texture was analyzed by deriving the Schmid orientation factors and the resolved shear stresses for the deformation systems. It was found that the large increase in the 0.2% yield strength was attributed mainly to the microstructural changes and partly to the texture changes by the ($\alpha$+$\beta$) heat treatment.

• Korean Journal of Soil Science and Fertilizer
• /
• v.44 no.2
• /
• pp.187-193
• /
• 2011

RDA has been conducting soil survey for farmland all over the korean countries (1964-1999), including small islands and areas of the civilian passage restriction line (2000-present). We conducted a soil survey in Dokdo and Ulreungdo islands and found a new soil series "Dokdo" in Dokdo island. Soil properties of Dokdo were similar to those of Ulreungdo. Representative profiles of Dokdo soil was located at the south 20m of Daehan peak on Seodo (longitude $131^{\circ}$51'53", latitude $37^{\circ}$14'35"), Dokdo. The soil series "Dokdo" was interpreted as the soils were derived from trachyandesite, trachyte, rhyolite, and tuff. The soil properties of Dokdo series were classified as different ones from Korean soil series previously. The soil depth of Dokdo series was very shallow (0-20cm) and soil layer was consisted of very dark brown (10YR 2/2) rocky sandy loam and dark brown (7.5YR 3/2) gravelly silt loam in AC layer. The soils of Dokdo displayed characteristics of a mesic temperature regime, similar as Ulreungdo soils, which were classified as coarse loamy, mesic family of Lithic Udorthents. The total area of Dokdo soil was 18.7 ha, containing Dongdo (7.3 ha), Seodo (8.9 ha), and the others (2.6 ha). The area of Dokdo series in Dokdo was 10.47 ha (Dongdo 4.13 ha, Seodo 6.34 ha) and 808.56 ha in Ulreungdo, where the total soil area was 7,256 ha.

• Korean Journal of Ichthyology
• /
• v.7 no.1
• /
• pp.64-70
• /
• 1995

Vertical distribution of eggs and larvae of Maurolicus muelleri were studied in the south-eastern waters of Korea during 1985 and 1986. Samples were collected vertically at three different layers, 0~30 m, 30~50m and 50~100m. The densities of egg and larva were high in August. Eggs and zooplankton were abundant around the thermocline in the temperature range of $10{\sim}15^{\circ}C$ at the layers of 50 m depth in 1985, and 30~100m depth in 1986. Eggs in the cleavage stage were abundant at the layer of 50~100m depth, while those of processing embryonic body formation were tended to concentrate at the layer of 30~50m depth. The vertical distribution of each developmental stage differed according to sampling time. They were distributed uniformly at water column from 30 m to 100m depth in the midnight, but concentrated at the layer from 30 m to 50 m from dawn to sunset. Before and after midnight, eggs in the cleavage stage were most abundant. It was assumed that M. muelleri spawned at the layer of 50~100m depth around the midnight, and the eggs ascended to the layer of 30~50m depth with development.