• Journal of Environmental Science International
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• v.18 no.2
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• pp.141-151
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• 2009

Temperature, salinity, COD, DIN (Dissolved Inorganic Nitrogen), DIP (Dissolved Inorganic Phosphorus), and Chlorophyll ${\alpha}$ obtained from the southern coastal waters during the period of 2003 to 2005 were analyzed. Variability in temperature was not found between groups in southern coastal waters, but significantly different depending on sampling sites (p<0.05). The average temperature in 2003 estimated at $18.33^{\circ}C$ that was annually increased by 2005 and significantly different based on statistics (p<0.05). Unlikely to temperature, salinity was significantly different depending on sampling sites, as well as monthly variations (p<0.05). Likewise to temperature, the value of salinity was annually increased. COD estimated at the average of $>1.7\;mg\;l^{-1}$ for three years, indicating optimal water quality. The fluctuations of nutrients were extremely shown in different sampling sites and monthly variations. Chlorophyll a recorded above $2.0{\mu}g\;l^{-1}$ which was associated with high primary phytoplankton, whereas it showed much fluctuations in temporal and spatial, In particular, Tongyong, Jaranman, Jinjuman, and Samcheonpo located in the southeast were the highest fluctuations in water quality than any other regions. The correlation between salinity/COD and nutrients/chlorophyll a was strongly negative or positive, which was possibly associated with much the introduction of run-off water as well as rainfall in summer.

• Ocean and Polar Research
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• v.35 no.1
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• pp.63-68
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• 2013

The European Common Barnacle Balanus perforatus Brugiere (Crustacea, Cirripedia) has been introduced into the east coast of Korea, presumably via the ballast water of ships. The species has since been spreading along both the northern and southern coast to the east, most likely due to alongshore currents. We predicted the potential range expansion of Balanus perforatus in Korean waters using Genetic Algorithm for Rule-set Prediction (GARP), an environmental niche modeling technique. The results show that much of the southern coastal waters of Korea could be colonized by the spread of the nonindigenous species, but that the west coast is unlikely to be invaded. More sampling on the west coast would enhance the predictability of the model. To our knowledge, this is the first report of its kind for predicting marine nonindigenous species in Korean waters using GARP modeling.

• Fisheries and Aquatic Sciences
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• v.15 no.3
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• pp.255-257
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• 2012

The euphausiid crustacean Stylocheiron abbreviatum G. O. Sars, 1883 has been found in the southern waters of Jeju Island, Korea. This species is the third member of the genus Stylocheiron and the twelfth of the family Euphausiidae identified in Korean waters. Using descriptions of this species, a key to Korean euphausiids is presented.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.34 no.3
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• pp.259-273
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• 1998

The hydroacoustic surveys to provide the essential information for the assessment, management and utilization of fishery resources in the southern waters of Korea were carried out during five research cruises between October 1996 and October 1997 by the training ship KAYA of Pukyong National University. These hydroacoustic investigations were designed to obtain more precise estimates of the geographic distribution, absolute abundance and biological characteristics of the fishery resources, and the vertically integrated densities of fish in terms of volume backscattering strength(SV) by survey region and depth bins, such as the entire water column and the 0~ 10 m from bottom fraction, were measured separately. Hydroacoustic data were collected by using a Simrad EK 500 Scientific echo sounder operating at two frequencies of 38kHz and 120kHz and the data stored in field were later processed on a HP PC using a Simrad EP 500 echo integration and target strength analysis system. The biological compositions of echo signal were identified and sampled using a demersal trawl during daylight hours. The mean target strength to scale the echo integration data for hydroacoustic surveys was derived from the relationship between the SV and the weight of trawl catch per unit volume of the water column sampled by demersal trawls. The results obtained can be summarized as follow : 1. The mean volume backscattering strength for the entire water column in the southern waters of Korea between 1996 and 1997 were -67.2 dB and -70.9 dB at two frequencies of 38 kHz and 120 kHz , respectively, and for the bottom layer of the 0-10 m from bottom friction were -68.8 dB, -70.2 dB, respectively. That is, the volume backscattering strength for the entire water column at low frequency was higher than that at high frequency. 2. The relationship between the mean backscattering strength (〈SV〉, dB) for the depth strata of trawl hauls and the weight (C, kg/m3) per cubic meter of the catch sampled by bottom trawling in the southern waters of Korea in January and July 1997 were expressed by the following equations: 38 kHz : 〈SV〉= -28.2 + 10 log(C), 120 kHz : 〈SV〉= -32.4 + 10 log(C). The mean weight -normalized target strengths derived from these equitions were -28.2 dB/ kg, -32.4 dB/ kg at 38 kHz and 120 kHz , respectively. That is, the mean weight -normalized target strength at 38 kHz was 4.2 dB higher than that at 120 kHz. 3. The distribution density of fish in terms of biomass per unit volume in the southern waters of Korea were estimated to be 125.9 $\times$ 10-6 kg/m3 and 141.3 $\times$ 10-6 kg/m3 at 38 kHz and 120 kHz , respectively.

• Ocean and Polar Research
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• v.25 no.4
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• pp.625-631
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• 2003

While phytoplankton diversity and productivity in the Southern Ocean has been widely studied in recent years, most attention has been given to elucidating environmental factors that affect the dynamics of micro-plankton (mainly diatoms) and nano-plankton (mainly Phaeocystis antarctica). Only limited effects have been given to studying the occurrence and the potential risks associated with the blooming of dinoflagellates in the relevant waters. This study focused on the appearance and toxicological characteristics of a toxic dinoflagellate, Alexandrium tamarense, identified and isolated from the Drake Passage in a research cruise from November to December 2001 The appearance of A. tamarense in the Southern Ocean indicates the risk of a paralytic shellfish poisoning (PSP) outbreak there and is therefore of scientific concern. Results showed that while the overall quantity of A. tamarense in water samples from 30meters below the sea surface often comprised less than 0.1% of the total population of phytoplankton, the highest concentration of A. tamarense (20 cells $L^{-1}$) was recorded in the portion of the Southern Ocean between the southern end of South America and the Falkland Islands. Waters near the Polar Front contained the second highest concentrations of 10-15 cells $L^{-1}$. A. tamarense was however rarely found in waters near the southern side of the Polar Front, indicating that cold sea temperatures near the Antarctic ice does not favor the growth of this dinoflagellate. One strain of A. tamarense from this cruise was isolated and cultured for further study in the laboratory. Experiments showed that this strain of A. tamarense has a high tolerance to temperature variations and could survive at temperatures ranging from $5-26^{\circ}C$. This shows the cosmopolitan nature off. tamarense. With regard to the algal toxins produced, this strain of A. tamarense produced mainly C-2 toxins but very little saxitoxin and gonyailtoxin. The toxicological property of this A. tamarense strain coincided with a massive death of penguins in the Falkland Islands in December 2002 to January 2003.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.27 no.3
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• pp.299-305
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• 1994

Egg distribution and mortality rate for anchovy, Engraulis japonica, and sardine, Sardinops melanosticta, during spring in the southern waters of Korea were estimated using the data from ichthyoplankton surveys conducted from March to April 1991, 1992. Anchovy and sardine eggs were found simultaneously in high density in the southwestern waters of Tsushima Island during March 1991 and late in March${\sim}$early in April 1992. Distribution areas of anchovy and sardine eggs in 1992 was extended to the middle area of the southern waters compared to 1991. Sea surface temperatures in the survey area ranged from 8.6 to $17.8^{\circ}C$. Anchovy and sardine eggs occurred with high densities between $14^{\circ}$ and $15^{\circ}C$. Instantaneous mortality coefficients were estimated to be 0.268/day for anchovy, and 0.132/day for sardine during $4{\sim}15$ March in 1991.

• Journal of the Korean Society for Marine Environment & Energy
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• v.5 no.4
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• pp.27-40
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• 2002

The circulation of sea water was simulated by two dimensional tide model using the main four tidal components and permanent current driven by inflow/outflow across open boundaries. According to the residt of tide model, the maximum speed of eastward flow on the Cheju Strait is twice higher than that of westward flow. According to the result of permanent current, the flow of permanent current showing semi-circle pattern in the southern part of Kojedo was due to variation of topography. According to the result of circulation model in the Cheju Strait, eastward flow entering in the southern waters from the Yellow Sea of Korea were dominant, but outflows westward were weak. These results suggest that it was difficult to move for suspended particulate matter into the Yellow sea from the southern waters through Cheju Strait.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.57 no.3
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• pp.214-227
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• 2021

The distribution of tidal current and tidal induced residual current, topographical eddies and tidal residual circulation in the waters surrounding the Geumo Island-An Island channel were identified through numerical model experiments and vorticity balance analysis. Tidal current flows southwest at flood and northeast at ebb along the channel. The maximum flow velocity was about 100-150 cm/s in neap and spring tide. During the flood current in the neap tide, clockwise small eddies were formed in the waters west of Sobu Island and southwest of Daebu Island, and a more grown eddy was formed in the southern waters of Geumo Island in the spring tide. A small eddy that existed in the western waters of Chosam Island during the ebb in neap tide appeared to be a more grown topographical eddy in the northeastern waters of Chosam Island in spring tide. Tidal ellipses were generally reciprocating and were almost straight in the channel. These topographical eddies are made of vorticity caused by coastal friction when tidal flow passes through the channel. They gradually grow in size as they are transported and accumulated at the end of the channel. When the current becomes stronger, the topographic eddies move, settle, spread to the outer sea and grow as a counterclockwise or clockwise tidal residual circulation depending on the surrounding terrain. In the waters surrounding the channel, there were counterclockwise small tidal residual circulations in the central part of the channel, clockwise from the northeast end of the channel to northwest inner bay of An Island, and clockwise and counterclockwise between Daebu Island and An Island. The circulation flow rate was up to 20-30 cm/s. In the future, it is necessary to conduct an experimental study to understand the growth process of the tidal residual circulation in more detail due to the convergence and divergence of seawater around the channel.

• Journal of Environmental Science International
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• v.21 no.2
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• pp.125-133
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• 2012

Climatological trend for the period of 1970 to 2009 in sea water temperature around the Antarctic Peninsular waters in the Southern Ocean was investigated. During the period from 1970 to 2009, sea water temperature in the top 500 m water column except 100 m increased at a rate of $0.003-0.011^{\circ}C{\cdot}yr^{-1}$, but at 100 m it decreased at a rate of $-0.003^{\circ}C{\cdot}yr^{-1}$. Although long-term trend is generally warming, there were several periods of sharp changes between 1970 and 2009. Annual mean sea water temperature between surface and 500 m except 100 m decreased from the early of 1970s to the end of 1980s, and then it increased to the end of 2000s. In the entire water column between the surface and 500 m, sea water temperature closely correlated with the El Nino events expressed as the Southern Oscillation Index(SOI), and SOI and sea water temperature have a dominant period of about 3-5 years and decade.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.5
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• pp.667-670
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• 2014

Six adult fish of Laemonema nana, belonging to the family Moridae, were collected in a bottom trawl in the southern coastal waters of Korea. These specimens were characterized by having 46-52 second dorsal fin rays (vs. 57-67 for Lotella phycis and 68 for Physiculus japonicus), two pelvic fin rays (vs. 9 for L. phycis and 6-7 for P. japonicus), and lateral line descending abruptly below the anterior part of the second dorsal fin.