• Journal of Fisheries and Marine Sciences Education
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• v.17 no.1
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• pp.58-66
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• 2005

Floating debris was observed using a training ship, KAYA, of Pukyong National University with cruising speed of about 10-12 knot during July 12~25, 2003. The area sampled was the East Sea enclosed by 3 nations, namely, Korea, Japan and Russia, and was divided into 68 unit segments on survey routes [Fig. 1]. Debris fabrication materials were categorized with 6 items, e.g., man-made or natural wood items, paper and cardboard, nylon rope, styrofoam, vinyl and plastic, floating metal and glass containers. All identified items within $100{\pm}10 m$ wide band were recorded but ignored if beyond this boundary. The results of this study are as follows: 1. The average numbers of debris per unit area, $1km^2$, were found as 16.3 pieces (items) in the sea. 2. The highest densities of numbers, $32.3pieces/km^2$, were discovered in vicinity of the Oki strait of Japan, area of 'NEK' in Fig. 1. 3. Especially, styrofoam item only was composed to 63.6% of all in the sea of 'SD', located in the southern part of Dokdo Island, Korea. The item seems to be derive from the Southern Sea of Korea. 4. Therefore, comparing the distribution of debris numbers (the results of above 2 and 3) with flow patterns of Kuroshio currents, it was shown that their relation was good agree each other. Further more surveys are being conducted and a much wider coverage can be achieved with other countries, then it can be obtained that the East Sea is polluted to some extent, where is the origin of debris, and the finding of floating routes and stationary sea.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.38 no.5
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• pp.323-330
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• 2005

Monthly distributions of fishing boats at night in the East Sea are described, using defense meteorological satellite program (DMSP)/operational linescan system (OLS) images and common squid (Todarodes pacificus) catches data. We also estimated temperature in 50m, which is main catch depth of the squid, by MCSST (multi-channel sea surface temperature). We examined DMSP/OLS, MCSST and other observation data from 1993 to 2000. We assumed that squid were caught in areas where fishing boats were located. Fishing boats at night appeared only near the Korea/Tsushima Strait from January to March. Fishing boats moved to the northward from April to Jun, distribution of fishing boats in spring appeared greater than those in winter. In summer (July-September), center of fishing grounds was formed near the Uleung Island in the south east coast of Korea. The north-south distribution range of fishing boats in October appeared to be greater than that in other months. In particular, we estimated main season of squid catches based on distribution range reflecting the number of fishing boats of north-south and east-west directions from September to December. Relationship between satellite estimate SST and in situ SST showed high correlation (0.91). The correlation between the SST and 50m depth temperature, estimated based on the satellite SST, was relatively high in February, April and October.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.1
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• pp.74-82
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• 2020

Dragonet fish (Callionymidae), living in benthic upper 900 m of all subtropical, tropical and temperate oceans, comprises 200 species in 20 genera worldwide, of which 18 species in 6 genera occur in Korea. Although dragonet fish plays an important role in linking between top predators and lower trophic levels, there are only few studies about their early life history. Herein, we present molecular and morphological data on larvae and juveniles of Bathycallionymus kaianus (Günther, 1880) collected from the Korean waters. During 2016 to 2018, one preflexion larvae [2.69 in total length (TL)], three flexion larvae (3.65 and 4.77 mm TL), six postflexion larvae (6.07 and 7.94 mm TL), and three juveniles (10.81 and 12.26 mm TL) were collected in the East Sea, Korea Strait, and Jeju Island using Bongo net. Of them, 13 individuals were identified through molecular markers (COI or 16S rRNA) and morphologically described. The larvae of B. kaianus are well distinguished from other species of Callionymidae in melanophore distribution, body shape and development of preopercular spine. It was very similar to larvae of two Repomucenus species, R. valenciennei and R. virgis, but was clearly distinguished in melanophore distribution, preopercular spine development, and head shape.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.6
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• pp.812-818
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• 2002

Spatio-temporal distributions of nighttime fishing fleet are descirbed with the aid of geographic information system(GIS) technology in the East/Japan Sea, using daily mean composite images of the Defense Meteorological Satellite Program(DMSP) /Operational Linescan System(OLS) in 1993. We selected a study area from $30^{\circ} N to 44^{\circ} N in latitude and from 124^{\circ} E to 142^{\circ}$ E in longitude in order to describe the monthly and seasonal changes of nighttime fishing fleet. The GIS software package Image Analyst (ArcView 3) are used to analyze spatio-temporal distributions of fishing nut. And the OLS images of nighttime visible band provide useful information about the spatio-temporal distribution of the fishing nut. Density areas of nighttime fishing fleet are around Tsushima/korea Strait. the east coast of the Korea Peninsula, the coast of Honshu, and around Yamato Bank.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.5
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• pp.695-706
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• 1998

SST (Sea Surface. Temperature) fronts which were found in the South-West Sea of Korea and the northern area of the East China Sea were examined in order to clarify their positions, shapes, seasonal changes and the formation mechanism, For this study used SST data rearranged from the SST IR image during 1991 to 1996 and oceanographical data obtained by National Fisheries Research and Development Institute. Temperature front in the Cheju Strait was analyzed by the data obtained from a fisheries guidance ship of Cheju Provincial Government, The coastal frontal zone in the South-West Sea of Korea and the offshore frontal zone in the northern area of the East China Sea can be divided into several types (Type of Winter, Summer, Spring, Autumn and late Autumn), Short term variations of SST fronts have a tendency not to move to any Bleat extent for several days. The location of the frontal zone in the southwestern sea of Cheju Island changes on a much large scale than that of the one in the southern coast of Korea, The frontal Tone, formed every year in the southern sea of Korea approaches closer to the coastal area in winter, and moves closer to the south in spring and autumn. The frontal zone of the southwestern sea of Cheju Island moves in a westerly direction from the east, and reaches its most westerly point in the winter and its most easterly point in the summer related to the seasonal change of the Tsushima Current. Additionally, the frontal zone of the southwestern sea of Korea becomes extremely weak in March, April and November. SST fronts are formed every year around the line connecting Cheju Island to Yeoseo Island or to Chungsan Island in the Cheju Strait. A Ring-shaped tidal mixing front appears along the coastal area of Cheju Island throughout the year except during the months from November to January. Especially, in May and October fronts are formed between the coastal waters of Cheju Island and the Tsushima currents connecting the frontal zone of the coastal region in the southern sea of Korea with that of the southwestern sea of Cheju Island.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.24 no.2
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• pp.318-331
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• 2019

In this study, comparative analysis is performed on the long-term persisted warm eddies that were generated in 2003 (WE03) and in 2014 (WE14) over the East Sea using the HYCOM reanalysis data. The overshooting of the East Korea Warm Current (EKWC) was appeared during the formation period of those warm eddies. The warm eddies were produced in the shallow Korea Plateau region through the interaction of the EKWC and the sub-polar front. In the interior of the both warm eddies, a homogeneous water mass of about $13^{\circ}C$ and 34.1 psu were generated over the upper 150 m depth by the winter mixing. In 2004, the next year of the generation of the WE03, the amount of the inflow through the western channel of the Korea Strait was larger, while the inflow was lesser than its climatology during 2015 corresponding to the development period of the WE14. The above results suggest that the heat and salt are supplied in the warm eddies through the Tsushima Warm Current (TWC), however the amount of the inflow through the Korea Strait has negligible impact on the long-term persistency of the warm eddies. Both of the warm eddies were maintained more than 18 months near Ulleung island, while they have no common feature on the pathways. In the vicinity of the Ulleung basin, large and small eddies are continuously created due to the meandering of the EKWC. The long-term persisted warm eddies in the Ulleung Island seem to be the results of the interaction between the pre-existed eddies located south of the sub-polar front and fresh eddies induced by the meanderings of the EKWC. The conclusion is also in line with the fact that the long-term persisted warm eddies were not always created when the overshooting of the EKWC was appeared.

• Animal Systematics, Evolution and Diversity
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• v.16 no.1
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• pp.39-53
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• 2000

The ascidians specimens were collected from Tangsa and its adjacent waters in Korea by scuba divers during the period from 1994 to 1999. They were identified into 30 species which are reported for the first time in Tangsa. Out of them one species, Molgula hozawai, was turned out to be new to the Korean fauna, and six species, such as Eudistoma illotum, Symplegma connectans, Boltenia trasversaria, Microcosmus nultitentaculatus, Pyura squamata and Molgula hozawai, were newly recorded in Chundo Island and Geojedo Island, which are influenced by warm waters of the Kuroshio Current.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.2
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• pp.186-194
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• 2013

We compiled and analyzed long-term time-series data collected in Korea to evaluate changes in oceanographic conditions and marine ecosystems near Jeju Island ($33^{\circ}00^{\prime}-34^{\circ}00^{\prime}\;N$, $125^{\circ}30^{\prime}-127^{\circ}30^{\prime}\;E$) from 1981 to 2010. Environmental data included depth-specific time series of temperature and salinity that have been measured bimonthly since 1961 in water columns at 175 fixed stations along 22 oceanographic lines in Korean waters by the National Fisheries Research & Development Institute, and time series of estimated volume transport of the Tsushima Warm Current (TWC) and Korea Strait Bottom Cold Water (KSBCW) for the period from 1961 to 2008. We analyzed the species composition in terms of biomass of fish species caught by Korean fishing vessels in the waters near Jeju Island (1981-2010). Data were summarized and related to environmental changes using canonical correspondence analysis (CCA). The CCA detected major shifts in fish community structure between 1982 and 1983 and between 1990 and 1992; the dominant species were a filefish during 1981-1992 and chub mackerel from 1992 to 2007. CCA suggested that water temperature and salinity in the mixed layer and the volume transport of the TWC and the KSBCW were significantly related to the long-term changes in the fish community in the waters off Jeju Island. Fish community shifts seemed to be related to the well-established 1989 regime shift in the North Pacific. Further studies are required to elucidate the mechanisms driving climate change effects on the thermal windows and habitat ranges of commercial species to develop fisheries management plans based on reliable projections of long-term changes in the oceanographic conditions in waters off Jeju Island.

• Animal cells and systems
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• v.16 no.5
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• pp.415-424
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• 2012

Four species of ophichthid leptocephali were identified using 12S rDNA sequences, and their morphological descriptions were first provided based on six individuals (S1-S3,M1, and E1-E2) collected from the East Sea and the Korea Strait between September 2008 and October 2010. Mitochondrial 12S rDNA 859-861 base pairs of ophichthid leptocephali were compared with those of 16 ophichthids adult and 2 outgroups (Anguilla japonica and Conger myriaster). Leptocephali of S1 and E1 were very closely clustered with adult of Scolecenchelys borealis (D=0.002) and Echelus uropterus (D=0.000), respectively. However, leptocephali of S2-S3 andM1 were slightly far clustered with leptocephalus of S1 (D=0.006) and adult of Muraenichthys gymnopterus (0.034), respectively. We believe that S1 and E1 are S. borealis and E. uropterus, respectively, in which the former is unrecorded species in Korea. However, S2-S3 and M1 may be undescribed species belonging to genus Scolecenchelys and Muraenichthys, respectively, because total numbers of myomeres for S2-S3 (148-158) and M1 (151) were not consistent with total numbers of vertebrae or distribution for any adult of Scolecenchelys spp. and Muraenichthys spp. in the world. We propose the new Korean name 'Dong-hae-mul-baem' for S. borealis.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.55 no.4
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• pp.335-348
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• 2019

We found ten species of larvae belonging to the family Pleuronectidae as a result of analysis on ichthyoplankton collected monthly from the East Sea, Yellow Sea, Korea Strait and East China Sea between February 2016 and May 2018 using bongo net. The ten species of pleuronectid larvae were divided into three groups in morphology. Group A had three or four bars on the lateral side of the tail: Glyptocephalus stelleri, G. kitaharae, Pseudopleuronectes yokohamae, and Hippoglossoides dubius. Group B had a row of melanophores along the dorsal and ventral side of tail: Cleisthenes pinetorum, Eopsetta grigorjewi, Dexistes rikuzenius, and Platichthys bicoloratus. Group C had dense melanophores which are covering trunk and tail entirely except caudal peduncle: Platichthys cornutus and Platichthys japonicus. The three groups did not associate with previous molecular phylogenetic studies except for the G. stelleri and G. kitaharae of the group A.