• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.1
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• pp.68-80
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• 1984

Garolim Bay is not only important fishing ground but also expected area for the tidal power plant. The construction and operation of tidal power plant will make change the ecosystem of this bay. Therefore, the actual fisheries stocks should be precisely understood for the effect estimation and overall utilization of the bay after the construction of the tidal power plant. During the study period from January through December in 1981, forty-six adult fishes species, 3 species of fish egg and 25 fishes larvae species have occurred in the bay. Considering the result on monthly distribution of eggs and larvae, the inner area of the bay seems to be important as nursing ground of larvae spawned at the outside bay in winter, e. g., Ammodytes personatus, and Enedrias sp. This inner bay is also major spawning ground for many species spawning in spring and summer, e. g., Gobiidae, Konosirus punctatus, Engraulis japonica, etc. Taking into consideration the annual mean production for three years($1978{\sim}1980$), there are two major fishing seasons. The one is in May-June for Enedrias larvae stock, and the another in October-November for big eyed herring stock. For the mariculture stocks, short necked clam, oyster and laver are important species. After construction of the tidal power plant, the migratory species, i. e., larvae of Enedrias and Ammodytes personatus, Mugil cephalus, Konosirus punctatus, etc. will be directly damaged by the interuption of migration route. On the otter hand, the change of physico-chemical factors of seawater will also affect the ecosystem of the bay. Consequently, for the overall utilization of the bay after construction, the actual ecosystem including the fisheries stocks, must bs precisely revealed, and the mechanical designs, e. g., sluice position and its demension, should be also considered with these biological characters of the bay.

• Fisheries and Aquatic Sciences
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• v.1 no.1
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• pp.82-93
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• 1998

Monthly changes of the gonad follicle index (GFI), reproductive cycle, egg-diameter composition, first sexual maturity of the Pacific oyster, Crassostrea gigas, were studied based on the samples which have been collected from the intertidal zone of Poryong west coast of Korea, from January to December, 1996. C. gigas, is dioecious, while a few individuals are alternatively hermaphroditic. Monthly variation of gonad follicle index (GFI) used for determination of spawning period, coincided with the reproductive cycle. GFI increased from April when seawater temperatures gradually increased and reached the maximum in May. And then, GFI sharply decreased from June to September due to spawning. Reproductive cycle of this species can be divided into five successive stages: in females, early active stage (March to April), late active stage (April to May), ripe stage (May to August), partially spawned stage (June to September) and spent/inactive stage (September to February); in males, early active stage (February to March), late active stage (April to May), ripe stage (May to September), partially spawned stage (June to September) and spent/ inactive stage (September to February). The diameter of fully mature eggs are approximately 50um. Spawning occurred from June to September, and two spawning peaks were observed in June and August when the seawater temperature was above $20^{\circ}C$. Percentages of the first sexual maturity of males of 20.1-25.0 mm in shell height were over $50\%$, while those of females of 25.1-30.0 mm in shell height were over $50\%$. All the males of > 30.1 mm and all the females of ^gt; 35.1 mm completed their first sexual maturity. The results suggest that C. gigas has a protandry phenomenon. Sex ratios of 919 oysters observed were 453 females $(49.29\%)$, 429 males $(46.68\%)$, 16 hermaphrodites $(1.74\%)$, and 21 indeterminate individuals $(2.29\%)$. In age class I, sex ratio of males were $64.00\%$, thus, a higher percentage than that of females. It was noted that $64.00\%$ of the young males (age class I) were more functional than females in age class I, but 2-3 year-old oysters showed higher percentage of females. Percentages of hemaphrodites in 2-3 year classes were relatively higher than those in other year classes. Histological pattern of hermaphrodites can be divided into two types: Type I (hermaphrodite having a number of newly formed developing oocytes on the oogenic tissues within a degenerating spermatogenic follicle after discharge of numerous spermatozoa) and Type II (hermaphrodite having two separate follicles in the same gonad).

• Korean Journal of Ichthyology
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• v.2 no.2
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• pp.159-168
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• 1990

Parental fish of R. uyekii(Mori) were colleted from the Nakdong River, Korea. Artificial insemination was carried out 4 times during June using the same pair (a female 52.70 mm TL and a male 56.80 mm TL). Unfertilized eggs are nearly spindly, opaque yellow in colour, measuring about 3.20-3.50 mm in length, about 1.50-1.80 mm in breadth. Hatching began about 50 hours after insemination at water temperature of $16.5{\sim}18.5^{\circ}C$. The newly hatched larvae are 4.10-4.50 mm in total length(TL), with 29-30 myomeres. Nine days after hatching, the larvae averaged 8.40 mm in total length and caudal notochord flexed at $45^{\circ}$. Eighteen days after hatching, total length reached 8.90 mm. The part of the fin-fold of the future dorsal and anal fins became high. Twenty-eight days after hatching, total length was 9.35 mm. The caudal fin-rays began to fork into two branches. The increased number of melanophores appeared newly on the head dorsal and anal fin-rays. The larvae reached the juvenile stage at 50-60 days after hatching and attained 14.50-16.20 mm in total length, and all fin-rays was formed.

• 한국해양학회지
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• v.15 no.1
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• pp.49-57
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• 1980

Toxicity of Machete on the mortality of the three different life stages, namely, hatching period, prelarval stage, and juvenile stage of carp(Cyprinus carpio Linne) was observed. The effect of the various exposure times on the mortality of the prelarval stage, and the effect of different temperatures on the toxicity during juvenile stage were also analysed. Hatchability and duration time of the carp were shown to be related to the concentration of Machete. In general, hatchability and duration time were shown to be decreased when the concentration of Machete was increased. For prelarval stage, 24hr and 48hr LC 50, and 24hr and 48hr EC 50 were observed to be 0.86mg/l and 0.43mg/l, and 0.35mg/l and 0.20mg/l, respectively. For juvenile stage, 24hr, 48hr, 96hr, and Incipient LC 50 were found to be 0.625mg/l, 0.365mg/l, 0.180mg/l, and 0.135mg/l, respectively. Apparently it was appeared that eggs were most resistant, and prelarvae were most sensitive to Machete among the three life stages. Although fish were removed from the Machete solution(3.2mg/l, and 1.8mg/l) prior to their death, continuous mortality was observed. Below 1.mg/l range, however, when concentration of Machete was lowered, the toxic effect of Machete on carp was reduced considerably even to the longtime exposure(24hours) Toxicity of Machete appeared to be related to water temperature, and it was observed that higher temperature reflected more toxicity.

• Korean Journal of Ichthyology
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• v.19 no.2
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• pp.142-153
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• 2007

Fertilized eggs of Plecoglossus altivelis over than 1,000,000 were introduced into Okjeong, Jeollabuk-do, Korea by K-water, 2001. Since then, this lake and the neighbouring tributaries gave sufficient habitat to maintain their life cycle which are being the land-locked. A land-locked ayu of annual life is ascending and descending from Lake Okjeong to streams for spawning and growth. Among the streams, the Churyeong stream reaching about 32 km in length is a major site for growth and spawning. But the land-locked ayu was no longer seen in the upper regions of the Churyeong stream over than about 12 km distance from Lake Okjeong. Because there were 11 weirs along with the Churyeong stream, it was difficult for them to move freely up to upper regions, and it causes irregular growth condition although they must be actively growing with feeding for spawning. During three survey years (2004 to 2006), in lowest rainfall-recorded 2005, the ayu population was not able to move up actively across the weirs and just stayed around the weirs, and finally it let them grow slowly and unstably. Also although there are 11 weirs, only 3 fish ways existed. Such environmental factors will seriously affect growth, spawning and size of ayu population in this area.

• The Korean Journal of Community Living Science
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• v.20 no.2
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• pp.157-168
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• 2009

This study was carried out to investigate the effect of eating behavior, physical status and tendency of eating disorder on the right eating habit. The subjects of this study were 324 middle school students and 340 high school students in Osan city GyeongGi province. The average of weight and height in the middle and high school students were 48.7kg, 160.0cm and 56.8kg, 164.8cm respectively. In PIBW values, 92.9% of middle school students and 99.1% of high school students were almost close to the average. The 28.5% of high school and 21.5% of middle school students were aware of themselves as overweight. The risk of eating disorders in high school students(16.4%) were higher than that in middle school students(4.9%). Moreover, the risk of eating disorders in girls high school students(19.3%) was significantly higher than those of middle school students(5.2%) (p<0.001). The thought of food problems were realized in 57.4% of in high school students and in 39.9% of in middle school students. The intake of food group frequency, middle school students ate more fruit than high school students(p<0.01). Boys ate more frequently soy beans (p<0.05) and algae(p<0.1) than girls in high school students. The meat intake was more frequent in high school students, but the eggs and milk were more in middle school students. The boys' intakes of fish and milk were more often than the girls' in high school students. Eating disorders and food intake frequency scores were closely correlated with weights(PIBW and the gap of ideal. weight with real weight). In conclusion, the education about realizing exact healthy body shape and how to modify behavior to prevent eating disorders should be planned since junior high school. Especially in high school girls, the variety food intake education would be needed. Proper recognition of the weight is required for good food intake and for prevent eating disorders.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.9 no.4
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• pp.261-263
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• 1976

In 1975, a trial for channel catfish spawning was made for the first time in Korea, by stocking 11 pairs of brood fish in a $470m^2$ earthen pond provided with 5 cans of 35 cm in diameter with depths of about 60 cm as spawning nests. The same trial and another pen cage method combined with pituitary injection were practiced in 1976. All these trials failed without any spawning. On the other hand 4 females and 1 male were put in a recycling water system indoor aquarium for exhibition purpose it late spring of 1976. After removing 3 females which were injured from being bitten by the male, remaining one pair of the catfish spawned successfully in July and the most eggs developed normally. The water in the recycling system showed the pH range of 7.2 to 7.4,and mean water temperature of every 10 day period of a month gradually increased from 19.3 to 23.6C until spawning. The outdoor .ponds where the spawning was failed received water from the same origin as the indoor recycling system, and the mean temperature of every ten day period ranged Iron 17.2 to $29.8^{\circ}C$ in 1975 and 19.7 to $28.4^{\circ}C$ in 1976 these being considered well falling in the optimum range for catfish spawning, but pH ranged from 7.3 to 9.5 under the influence of photosynthesis of algae and weeds in the ponds. The high pH value may suppress the spawning of catfish as pointed out by Nelson in 1957.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.6
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• pp.779-784
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• 2003

Nitrate a common component of man's chemical environment, is present in foods either naturally or in an additive introduced during processing of foods. Nitrate level of foods have been found depending on nitrosation of soils and other various environmental factors. Therefore data on nitrate contents of foods reported in other countries can not be adapted to Korean foods. Also data on nitrate levels of Korean foods available were reported 10 years ago, which would be assumed to differ from those of foods currently consuming by Koreans. The present study was attempted to determine nitrate contEnts of common foods. Based on National Nutrition Survey Report 143 food items out of 14 food groups were selected for this study Nitrate levels of common foods used in the study were from N.D (not detected) to 6733.33 mg/kg foods. Mean nitrate levels of food groups 27.2 mg/kg of cereal and grain products, 78.1 mg/kg in potatoes and potato products, 8.3 mg/kg in legumes and their products N.D of seeds and nuts, 1012.1 mg/kg of vegetables and their products,76.3 mg/kg fungi and mushrooms 42.2 mg/kg fruits,34.5 mg/kg of meat, poultry and their products,0 mg/kg in eggs, 23.9 mg/kg in fish, shellfishes and their products,23.0 mg/kg in seaweeds, 7.7 mg/kg milk and dairy products, 26.3 mg/kg in seasonings, 68.0 mg/kg in others.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.5
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• pp.509-512
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• 1992

With the annual report of National Nutrition survey, the trend of food intake of Korean is analyzed from 1969 to 1989. Total food intake is about 1,000g. The amount of plant foods intake is decreased but the amount of animal food intake is increased. Among plant foods, the consumption of cereals and grain product and starch and starch roots is decreased gradually. The degree of decreasing are evident in the amount of cereal and grain product intake, The amount of vegetable intake is kept fluctuating, but the amount of processed vegetable products intake shows an upward trend. The amount of legumes and their products, vegetables, fruits and seaweeds intake is increased each year. In addition, among animal foods, the amount of meat and products, eggs, fish and shellfish and milk and milk products intake is increased greatly.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.10
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• pp.1567-1582
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• 2015

The purpose of this study was to examine the status of environmentally-friendly ingredients and dietitians' perceptions toward them in order to find for improvement. Data was collected from questionnaires completed by 202 school dietitians and nutrition teachers in Chungbuk, and this data was analyzed utilizing the SPSS 20.0 program. The results obtained from this study were as follows: 'mixed grains (58.9%)' and 'eggs (36.6%)' were found to be the most used environmentally-friendly ingredients. 81.7% of the respondents said they 'never used' marine products, whereas 'fruits (43.6%)', 'pork (40.8%)', and 'fish (54.5%)' were the most preferred ingredients. Dietitians and nutrition teachers used environmentally-friendly marine products less than other ingredients, had a poor understanding about environmentally-friendly marine products, and demonstrated low reliability and belief in the necessity of the system. In order to verify the environmentally-friendly status of the ingredients, marks on the product and documents of certification were mostly used. In order to improve the supply system, a more strict tracking system in the distribution process by securing more reliable suppliers is required.