• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.4
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• pp.513-522
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• 1997

Annual variations In main fishing grounds of common squid with different angling and their fishing conditions in Korean waters were studied by analyzing catch and water temperature data. The main fishing grounds of squid angling fishery started to moved to the north in April and to the south in September in the last Sea of Korea. The catch of squid was related to the direction of thermal fronts. The catch was high when the thermal front was formed in the east-west direction, while there was low catch when the thermal front was formed in the south-north direction which runs parallel to the roast.

• Korean Journal of Plant Resources
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• v.36 no.6
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• pp.580-587
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• 2023

Androsace septentrionalis is a grass species restricted to North Korea; however, it is at the brink of extinction due to habitat loss and environmental changes caused by natural disasters and anthropogenic activities. This study was conducted to characterize the dormancy conditions of A. septentrionalis in an effort to conserve this North Korean plant resource. For this purpose, the morphological characteristics and vigor of A. septentrionalis seeds were examined, and its germination characteristics under different temperature conditions (15/6℃ and 25/15℃ ), low-temperature stratification, and gibberellin (GA₃) treatment were determined. The results revealed that A. septentrionalis exhibits non-deep type morpho-physiological dormancy, and low-temperature stratification treatment was not effective in breaking the dormancy of A. septentrionalis seeds. Meanwhile, GA₃ treatment significantly increased the mean germination time, rate, and speed of the seeds. The optimal conditions for the germination of A. septentrionalis seeds were 25/15℃ fluctuating temperature and 500 mg·L¹ GA₃ treatment. The results of this study are useful for the mass propagation of A. septentrionalis.

• Journal of Fisheries and Marine Sciences Education
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• v.3 no.1
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• pp.9-20
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• 1991

The authors investigated the existing international fishery relationship in the sea around the Korean Peninsula, and prospected on the reformation of the fishery order which might be followed by mutation of the international political condition and by effectuation of the U.N. Convention on the Law of the Sea in the future. It can be explained that the existing international fishery order in this sea has been constituted on the basis of restricting Japanese indiscriminate fishery expansion. But. when the South Korea and China proclaim the 200-mile EEZ in the future, a considerable part of existing fishery agreements will forfeit the role as general norms of the international fishery relationship. Accordingly a counterplan against the revision or abrogation of the Korea-Japan Fishery Agreement must be considered. And also a rational fishery relationship between Korea and China, as confronting countries, must be organized. The South-North Korea fishery relationship must be settled on the basis of co-operation. trust, and common interest. For this purpose, a political discussion on the establishment of the joint fishery zone around the military demarcation line and on the conservation for the fishery resources must be begun in earnest.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.4
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• pp.1109-1117
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• 2015

Recently, import supply of glass eels from Philippines has been increased in South Korea, and the species distinction was very important to import traders and Anguilla marmorata and A. bicolor pacifica are major species at Philippines. In this study, the species distinction and the rate were researched targeting imported glass eels from the estuaries of North Luzon and the South Mindanao in May and July, 2014. Dorsal fin position and pigmentation pattern at caudal fin are the trait standard for species distinction. The results about morphological identification were coincide with the result of the genetic identification, and the regional distribution of A. marmorata rate was over 90% at North Ruzon in May. However, the rates of A. bicolor pacifica and A. mamorata were 63.3% and 36.7% in May, and were 53.3% and 46.7% in July respectively at South Mindanao.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.1
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• pp.308-318
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• 2015

In order to improve the competitiveness of Korean large purse seine fishery, the purpose of this study is to find out the problems and present the improvement of the production structure of Korean large purse seine fishery by comparing to the production structure of Norwegian purse seine fishery. Norwegian purse seine fishery has been operating labor and energy-saving systems through a single wire operation and avoiding fishing competition through the introduction of IVQ system with different types of fishing vessel and obtaining benefits from Leading fishery management integrated with fish pumps and cooling water systems. In contrast, our country has a large purse seine fishery issues such as high cost and low efficiency of production structures, the volatility of mackerel resources, the lack of leading fishery management after catching fishes, the reduction of fishing ground in accordance with the North East Asia EEZ system. To solve these problems, initiatives to improve the structure of our large purse seine fishery are as follows: First, Implementing the promotion of the effective immature fishes management and establishing Korea-China-Japan resource management system. Second, the promotion of reduction of fleet size, the review of possible single fishing operation, leading out to strengthen its competitiveness by switching to energy-efficient production systems through enhanced efforts at fisheries catches steps. Third, it is necessary to realize corporate through the diversification of business areas and the large-scale commercialization of production structure.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.24 no.3
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• pp.185-192
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• 1991

The vertical distribution and chemical characteristics of water masses were measured along two south-north transects in the polar front region of the central Korean East Sea. In February, a thermocline was present at depth between 50m and loom at the southern sites of a landward A-transect, and its depth was gradually deepened northward. At an outside B-transect, a thermocline was observed at significantly deep depth of 300m to 400m at two northern stations(Stn. 10 and 11), though the depth of the southward stations was nearly identical to that at the northward stations on a A-transect. In September, there were vertically more various water masses, i.e. the Tsushima Warm surface water(TWSW) or more than $20^{\circ}C$, the Tsushima Middle water(TMW) with a range of $12{\~}17^{\circ}C$, the North Korea Cold Water(NKCW) with $1{\~}7^{\circ}C$ temperature, the Japan Sea Proper Water(JSPW) of less than $1^{\circ}C$, and the mixed water. The North Korea Cold Water could be distinguishable from the other waters, especially from the mixed water of the Tsushima Middle Water and the Japan Sea Proper Water by the pattern of $T-O_2$ diagram. For instance, the North Korea Cold Water had higher oxygen by $1{\~}2ml/l$ than those in the mixed water, although both the two water masses ranged $1{\~}7^{\circ}C$ in water temperature. AOU value was the highest in the JSPW and the lowest in the TWSW. Also, AOU indicated a nearly linear and negative correlation with water temperature. However, AOU data for two masses, the NKCW and the TMW, in September departed remarkably from a regression line. Moreover, the ratio of $$\Delta P/\Delta AOU)$ in September was about $0.45{\mu}g-at/ml$ and higher than the value observed in the open sea. This high value could be elucidated by two factors; intrusion of the NKCW with high oxygen and molecular diffusion of dissolved oxygen from the surface into the lower layer. AOU would be a useful tracer for water masses in the polar front area of the Korean East Sea.

• Korean Journal of Ichthyology
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• v.17 no.2
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• pp.123-130
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• 2005

The ichthyofauna of Lake Cheongpyeong was investigated from April 2003 to November 2004. During the surveyed period 31 species belonging to nine families were collected. Dominant species in numbers was Hemibarbus labeo (relative abundance: 29.9%), subdominant was Acanthorhodeus gracilis (22.8%). Erythroculter erythropterus (14.6%) and Cyprinus auratus (6.3%) were also numerous. There were nine Korean endemic species belonging to three families, including Acheilgnathus yamatsutae. We need close observation on population fluctuations of Micropterus salmoides, an exotic carnivorous fish from North America, and Hemibarbus labeo and Erythroculter erythropterus, the dominant species by biomass in Lake Cheongpyeong.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.3
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• pp.393-403
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• 2016

A steady, strong southward flow was observed in the lower layer beneath the Tsushima Warm Current in the deepest trough of the Korea Strait. Known as the Korea Strait Bottom Cold Water (KSBCW), this bottom current had a mean velocity of 24 cm/s and temperatures below 8–10℃. The direction of the bottom current was highly stable due to the topographic effects of the elongated trough. To determine the path of the southward bottom current, ADCP (Acoustic Doppler Current Profiler) data from 14 stations between 1999 and 2005 were examined. Persistent southward flows with average speeds of 4–10 cm/s were observed at only three places to the north of the strait where the bottom depths were 100–124 m. The collected data suggest a possible course of the southward bottom current along the southeast Korean coast before entering the deep trough of the Strait.

• Fisheries and Aquatic Sciences
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• v.21 no.9
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• pp.20.1-20.3
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• 2018

Hypoptychus dybowskii, the Korean sandlance, is widespread in cold areas of the North Pacific. Although H. dybowskii has been considered to occur on the coast of Hamgyeongnam-do in Korea, the species is also distributed along the coast of Goseong-gun, Gangwon-do, south of Hamgyeongnam-do in the eastern part of the Korean Peninsula on the basis of newly collected specimens. In addition, many Koreans confuse H. dybowskii and Ammodytes japonicus (= A. personatus for Korean specimens) because the Korean common name or dialect of both species is "Yang-mi-ri", yet the two species differ in their external morphology. Hypoptychus dybowskii differs from A. japonicus in the location of the origin of the dorsal fin and the number of dorsal and anal fin rays.

• Journal of Environmental Science International
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• v.17 no.12
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• pp.1403-1411
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• 2008

Wangdol-cho, located 23 km offshore of Hupo in southwest of East Sea, is underwater rock floor, called to Wangdol-Am or Wangdol-Jam and has three tops as Mat-Jam, Middle-Jam and Set-Jam. The composition, abundance, diversity and community structure were investigated in winter and summer in 2002 around Wangdol-cho. The temperature around the Northwest and Southeast part of Wangdol-cho was influenced by the North Korea Cold Current (NKCC) and East Korea Warm Current (EKWC), respectively. Nutrient and chlorophyll-a concentration were higher at the top of Wangdol-cho than other area. A total of 41 genera and 78 species of phytoplankton were identified. The average cell abundance of phytoplankton in winter and summer were $286{\times}10^3\;cells/m^3,\;432{\times}10^3\;cells/m^3$ respectively. The largest community was Bacillariophyta containing 52 taxa. The dominant species were Lauderia anulata and Coscinodiscus spp. which preferred cold water in winter. In contrast, warm water species such as Rhizosolenia stolterfothii and Ceratium spp. were dominant in summer. The average species diversity index of phytoplankton in winter was higher than that in summer. According to dominant species and standing crops, phytoplankton community resulted in a clear separation. One group was western area, which showed low density, and the other was eastern area, which showed the higher density. The abundance and species composition of phytoplankton. were affected by topological characteristics around Wangdol-cho.