• Title/Summary/Keyword: 유어

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Diel Feeding Activity in Summer of Juvenile Pacific Herring, Clupea pallasii in the Southeastern Coast of Korea (여름철 동해 남부에 출현하는 청어(Clupea pallasii) 유어의 일섭식 변동)

  • Park, Joo Myun;Huh, Sung-Hoi
    • Korean Journal of Ichthyology
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    • v.29 no.4
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    • pp.267-271
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    • 2017
  • Diel changes in feeding activity of juvenile Pacific herring, Clupea pallasii were investigated throughout the analysis of stomach contents of 301 fishes collected from the southeastern coast of Korea. Fish samples were collected every 3 hour over a 24 h period in summer using small bottom trawl. The ratio of empty stomach, stomach fullness, stomach contents index (SCI) and stomach fullness index (IF) of juvenile C. pallasii were varied markedly with day/night changes. The ratio of empty stomach tended be higher during nighttime, while the other values were higher at daytime, with showing peak before sunset. During daytime, the stomach contents mainly were made up of copepods and euphausiids, while the diets at midnight were composed of nearly digested and unidentifiable items.

Record of a Juvenile Eyeshade Sculfin, Nautichthys pribilovius from Goseong, Korea (강원도 고성 연안에서 출현한 검은띠눈횟대 Nautichthys pribilovius의 유어)

  • Kim, Byung-Jik
    • Korean Journal of Ichthyology
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    • v.25 no.4
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    • pp.234-238
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    • 2013
  • Based on a single juvenile specimen (32.3 mm SL) collected from the northeastern coastal waters of Goseong, Gangwon-do, Nautichthys pribilovius was described as the first juvenile record from Korea. This juvenile fish is characterized by having entire body covered with close-set villous prickles, a blunt triangular ridge above orbit with a palmate cirrus, two blunt occipital projections, preopercle with four blunt spines, and a blackish bar below eye reaching lower margin of preopercle. Some morphometric characters related with growth were also discussed.

Comparison of Volatile Flavor Compounds of Domestic Onions (Allium cepa) during Storage (국내산 양파의 저장 중 휘발성 향기성분 비교)

  • Lee, Hee-Young;Jeong, Eun-Jeong;Jeon, Seon-Young;Cha, Yong-Jun
    • Journal of Life Science
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    • v.18 no.12
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    • pp.1712-1717
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    • 2008
  • Volatile flavor compounds of onions were analyzed and compared during storage at $0.5^{\circ}C$, which harvested in 6 regions, such as Muan, Buan, Andong and 3 regions of Changnyeong (Yueo, Jangma and Seongsan). A total of 45 compounds were detected in samples by solid phase microextraction (SPME)/GC/MSD, consisting mainly of sulfur-containing compounds (21), aldehydes (13), ketones (2) and miscellaneous compounds (9). The sulfur-containing compounds were major compounds with ranges of $66.9{\sim}86.9%$ of total volatiles in 0 day of storage as regardless of harvested regions. Three regions (Yueo, Seongsan and Muan) had high amounts of over 4,043 ng/g in 0 day of storage, whereas 2 regions (Muan and Yueo) only had amounts of over 2,400 ng/g after 60 days of storage. Five sulfur-containing compounds known as having antioxidant activity (2,4-, 2,5-dimetylthiophene, 2-vinyl-1,3-dithiane, 5-methoxy thiazole and 3,5-diethyl-1,2,4-trithiolane and isomer) were the high levels in 3 regions (Yueo, Seongsan and Muan) during 60 day of storage. These 3 regions had also the highest amounts in 5 sulfur-containing compounds known as having anticarcinogenic activity ((Z)-, (E)-methyl propenyl disulfide, (Z)-, (E)-propenyl propyl disulfide, and di-2-propenyl disulfide) and kept same trend after 60 days of storage.

Effect of Salinity Change on Physiological Response and Growth of yearling Sea Bass, Lateolabrax japonicus (염분 변화에 따른 농어, Lateolabrax japonicus 유어의 생리 반응과 성장 차이)

  • 한형균;강덕영;전창영;장영진
    • Journal of Aquaculture
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    • v.16 no.1
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    • pp.31-36
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    • 2003
  • Two experiments were conducted for the physiological and growth responses of yearling sea bass, Lateolabrax japonicus (total length 24.4$\pm$1.5 cm, body weight 125.4$\pm$25.4 g) by the manipulation of salinity. To study the physiological responses of the sea bass by acute salinity change, we changed water salinity from 30 ppt into 2 ppt in rearing tank through 1 hour or 6 hour. To access the effect of salinity in the growth of sea bass, we also examined the growth of the sea bass in 2, 10, 20 and 30 ppt for 180 days. After salinity change, all yearlings appeared some stress response and ions changes in blood. The yearlings showed a slow recovery by an acute salinity exchange, but a fast recovery by slow salinity exchange. In the study about the influence of salinity in growth, although the food intake of yearlings in 20 ppt was significantly higher than the yearling in the other salinities, feed efficiency was higher in 10 ppt than the other salinities. However, the food intake and the feed efficiency in 2 ppt were significantly lower than in other groups. The growth of yearlings was significantly faster in 20 ppt than in the other salinities, but the growth showed significantly slower in 2 ppt than in the other salinities.

First Occurrence of a Juvenile Halfband Cardinalfish, Apogon semiornatus (Apogonidae: Perciformes) from Jeju Island, Korea (제주도 연안에서 처음 출현한 동갈돔과 유어 Apogon semiornatus)

  • Kim, Byung-Jik;Park, Tae Seo
    • Korean Journal of Ichthyology
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    • v.24 no.3
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    • pp.227-229
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    • 2012
  • Based on a single juvenile specimen (20.7 mm SL) collected from Jeju Island, Apogon semiornatus was described as a new Korean record. The species is characterized by having VI-I, 9 dorsal fin rays, 12 pectoral fin rays; II, 8 anal fin rays and two blackish oblique bands on yellowish red body. A new Korean name, "Geom-eun-du-jul-bulg-eun-dong-gal-dom", is proposed.

Estimating the Economic Value of Recreation Sea Fishing in the Yellow Sea: An Application of Count Data Model (가산자료모형을 이용한 서해 태안군 유어객의 편익추정)

  • Choi, Jong Du
    • Environmental and Resource Economics Review
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    • v.23 no.2
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    • pp.331-347
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    • 2014
  • The purpose of this study is to estimate the economic value of the recreational sea fishing in the Yellow Sea using count data model. For estimating consumer surplus, we used several count data model of travel cost recreation demand such as a poisson model(PM), a negative binomial model(NBM), a truncated poisson model(TPM), and a truncated negative binomial model(TNBM). Model results show that there is no exist the over-dispersion problem and a NBM was statistically more suitable than the other models. All parameters estimated are statistically significant and theoretically valid. The NBM was applied to estimate the travel demand and consumer surplus. The consumer surplus pre trip was estimated to be 254,453won, total consumer surplus per person and per year 1,536,896won.

Growth and Habitat Conditions of Young Stage Right Eye Flounder (Kareius bicoloratus) in the Saemangeum Reservoir (새만금호 유어기 돌가자미 (Kareius bicololaratus)의 성장과 서식환경)

  • Choi, Youn
    • Korean Journal of Environmental Biology
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    • v.27 no.1
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    • pp.1-5
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    • 2009
  • This study was to investigate the habitat conditions and growth of right eye flounder (Kareius bicoloratus) in the Saemangeum Reseorvoir during 1995$\sim$2007. The planktonic larvae of K. bicoloratus appeared in early March, and then the juveniles started the benthic life in the tide-pools inside the reservoir, being 1.5$\sim$2.5cm in total length in early April and 6.0$\sim$7.2cm in mid-July. This species was not collected in the tide-pools after July, indicating that the juveniles began to move to outer seas for growing. When the tide barrier of Saemangeum was constructed, the juveniles of K. bicoloratus decreased as the tidal pools were covered continuously, then they could not be collected after 2005. Thus, it is concluded that the environmental change has taken important influence on distribution and spawning of K. bicoloratus since the reservoir was constructed.

Assessing an Economic Feasibility of Coastal Marine Ranching Project in Uluengdo (울릉도 연안바다목장사업의 경제적 타당성분석)

  • Pyo, Heedong
    • Journal of Korea Port Economic Association
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    • v.37 no.1
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    • pp.1-18
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    • 2021
  • A coastal marine ranching project in Uleungdo had been conducted for 5 years from 2013 to 2017 with investment costs of 5 billion won, for the special purpose of the deployment of artificial reefs, the release of young fishes. The paper focuses on an ex-post analysis of the economic feasibility for the project after completing the project, which is apart from a preliminary viability. For economic analysis, the economic benefits are derived from direct benefits including increasing effects of fisheries income and saving effects of harvesting costs, and indirect benefits including increasing effects of recreational fishing and preservation effects of coastal marine ecosystems while economic costs include releasing and purchasing costs of artificial reef and juvenile fish, R&D costs, maintenance costs and harvesting costs. The result shows that the project should not be accepted according to NPV=-0.125 billion won, IRR=4.5% and B/C ratio=0.98 under Scenario 1 which considers direct benefits and indirect benefits excluding the preservation values, while the project should be accepted under Scenario 2 indicating NPV=30.9 billion won, IRR=11.3% and B/C ratio=1.49 which considers the direct benefits as well as the indirect ones including the preservation values, based on 4.5% of the social rate of discount.