• Fisheries and Aquatic Sciences
• /
• v.3 no.2
• /
• pp.143-150
• /
• 2000

Assuming that summer surface waters in the South Sea (northern East China Sea) are formed mostly by a mixing of three source water (Changjiang Discharge Water; Kuroshio Water and Yellow Sea Surface Water) we apply optimum multiparameter (OMP) analysis to calculate the mixing ratio of each source water to a given surface water. Since OMP requires more parameters than the number of water types (three in this study), we utilize two radium isotopes of dissolved $^{226}Ra\;and\;^{228}Ra$ along with temperature and salinity. Parameter values of each source water are deduced from in situ and historical data. Results with three source of waters on the surface waters are quite promising with less than $1\%$ of unanswered portions. Results not only reproduce the measured temperature and salinity faithfully but also discern the water masses of similar T and S according to their source water mixing. Extending OMP analysis to a whole water column obviously requires more parameters because more source waters are involved in the water mass formation. Original OMP routine utilized dissolved oxygen and nutrients. However, they seem to be perturbed too much by biological activities in the case of shallow waters. We discussed the use of other potential parameters. Also the benefit of parameter substitution is briefly introduced for the future OMP application on shallow waters.

• Journal of Navigation and Port Research
• /
• v.30 no.4
• /
• pp.295-302
• /
• 2006

This study is to integratedly examine coastal management policy and marine tourism development project for Korean coasts, especially for the South Sea of high development pressure, presenting sustainable tourism development policies for the future. To do so, it is examined central government-level coastal development projects set up by the Ministry of Culture and Tourism, the Ministry of Maritime Affairs and Fisheries and the Ministry cf Construction and Transportation, setting the direction of south coastal management and tourism development at a level of national territory planning. The problems of coastal management first and then the problems of the South Coast Tourism Belt Project are analyzed in order to present political and administrative alternatives. To overcome such problems and make Korea a marine tourism base in East Asia, there is a need for re-recognition of the value of the project and its continuous push through cooperation between central and local governments. Also, under the presupposition of consensus building among local people and the sustainable development of environments, there should be are-recognition that the future cf Korean marine tourism in the 21st-century and the success of an inverted $\pi-axis$ national development depend on the South coastal Tourism Belt Development Project.

• Korean Journal of Ichthyology
• /
• v.32 no.2
• /
• pp.97-102
• /
• 2020

The feeding habits of larval Ammodytes japonicus were examined. A total of 208 individuals were collected by RN80 Net from January to February, 2019 in the coastal waters of Gujora and Mangchi, Geoje, Korea. Range of notochord length of larval A. japonicus was 1.46~8.00 mm and fed mainly on copepods that constituted 99.9% in %IRI. The results of analysis in ontogenetic changes, divided with 3 classes (≤2 mm, 3~4 mm, ≥5 mm, Notochord length), was all classes mainly fed copepods. An opposite relationship was found between the calanoida and cyclopoida. When percentage of calanoida of copepods increased, cyclopoida of copepods decreased.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• v.1
• /
• pp.525-528
• /
• 2006

South Korea has about 80 permanent GPS stations, being used for a variety of applications such as DGPS, RTK, survey and geodesy. Some of them are installed in or near the coastal area for the purpose of maritime navigation. But, until recently, none of them are used for tide gauge benchmark monitoring. In order to monitor the absolute sea level changes, it is necessary to monitor the land uplift or subsidence occurring at tide gauge sites. It is a common practice to use GPS stations installed at tide gauges to determine absolute sea level. This collaborative efforts coordinated by IGS are called TIGA Pilot Project. Many countries including U.S., Canada, European Union nations, Australia and Japan are participating in TIGA, but South Korea is not a member yet. Recently, we established continuously operating GPS stations at tide gauges located in Incheon and Jeju to monitor the movement of tide gauges sites. This paper will introduce goals and progress of the efforts.

• Animal Systematics, Evolution and Diversity
• /
• v.39 no.3
• /
• pp.127-132
• /
• 2023

Aquilonastra doranae, a newly recorded sea star, was collected from the southern coast of Jejudo Island by a trimix SCUBA diving survey in May 2021. The newly collected specimen is distinguished from a previously known Aquilonastra species in South Korea by having a fissiparous body form with six arms. Results of pairwise genetic distance analysis showed that the new specimen was identical or close to A. anomala from Hawaii (0.0%), Australia (3.1%), and Samoa (3.3%). However, morphological characteristics of the Korean Aquilonastra specimen corresponded with the original description of A. doranae, not that of A. anomala, including the number of inferomarginal spines, the absence of pedicellariae, and the inhabit locality. Thus, this study agrees with the original morphological study of A. doranae and presents this specimen as the first record of A. doranae in South Korea.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.56 no.2
• /
• pp.94-104
• /
• 2020

An ecological study for species composition and abundance of the fish assemblages in the coastal waters of Gujora and Mangchi of Geoje, Korea was conducted using monthly larval collection by an RN80 net from June, 2018 to May, 2019. A total of the 5 Orders, 15 Families, 21 species were collected. The dominant species were Ammodytes japonicus and Engraulis japonicas. Gobiidae was the most dominant species in June, Spratelloides gracilis in July, Chelidonichthys sp. in August, Gobiidae in September, Repomucenus beniteguri in October, Sebastiscus marmoratus in November, Sebastiscus marmoratus and Hexagrammos otakii in December of 2018, Pleuronectes yokohamae in January, Ammodytes japonicus in Febraury, Engraulis japonicus in March, Sebastes sp. and Gobiidae in April and Engraulis japonicus in May of 2019. The highest number of species and individuals were found in July and the smallest in August. Thus, the diversity index was the highest in July and the lowest in August. As a result of the similarity by month was divided into Group I in January and February and Group II in April, June and September. The most dominant species in the Group I were the Ammodytes japonicus and Sebastes inermis, and the most dominant species in the Group II was Gobiidae.

• The Korean Journal of Malacology
• /
• v.19 no.1
• /
• pp.33-40
• /
• 2003

To obtain the basic information on culture conditions for the larvae of Saxidomus purpuratus, experiments were conducted on the population from southern coast for (1) the success in fertilization and development from artificial fertilization among different months of a year, (2) the viability of sperms after exposure to seawater, (3) and the effects of temperature, salinity, and food organism on the survival and growth of larvae. Gametes obtained from dissection showed high rate of fertilization at all months. But the rate of development was higher only May-July. Developmental success seemed to be related with the quality of eggs at the time of fertilization. Developmental times for 2-cell, 4-cell, 8-cell, blastula, trochophore larva, and veliger larva at 20$^{\circ}C$ were 1.5, 2, 4, 18, 24, and 32 hr, respectively. Sperms could survive for more than 8 hr, however, actively swimming sperms could be found within 1 hr after exposure to seawater. It is recommended that sperms should be used for fertilization as soon as possible when they are exposed to seawater. At temperature of 35$^{\circ}C$, all the larvae died during 48 hr. Larval survival decreased when salinity was either lower than 20 psu or higher than 40 psu, and was 0% when salinity was 10 psu. Optimal range of temperature and salinity for rearing larvae of S. purpuratus were 20-25$^{\circ}C$ and 20-40 psu, respectively. Larvae grew from 111.5 to 235.3 ${\mu}$m during 21 days. Larvae fed mixed diets grew faster than unialgal diets. The fastest growth was observed when larvae were fed on the mixture of Isochrysis galbana and Nannochloris oculata.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.50 no.1
• /
• pp.39-49
• /
• 2014

Morphological and positional characteristics of anchovy aggregations, confirmed by trawling, were examined in two locations of the southern part of theWest Sea (T1) and the western side of South Sea (T11) of South Korea. Morphological characteristics (mean length, height and area) of the anchovy aggregations at T1 were smaller than those at T11, however the positional characteristics (distributional depth and bottom depth) of the aggregations at T1 were larger than those at T11. Diverse dataset such as the ship's cruise track, the cruse map, and interpolated three-dimensional-like water temperature were visualized in multiple dimensions. For a comprehensive understanding of the anchovy aggregations within their surrounding circumstances, the interpolated water temperature transferred to the location of anchovy aggregations at both stations were visualized based on geospatial information. Using quantitative investigation, the overall range of change in water temperature and salinity of anchovy aggregations at stations was considerably small. However, the water temperature and salinity of anchovy aggregations at T11 were somewhat higher than those at T1.

• Ocean and Polar Research
• /
• v.27 no.3
• /
• pp.341-349
• /
• 2005

Temporal variation of the natural planktonic community in the Southern Sea of Korea was investigated by using low floating enclosed bags (3.2m deep and 2,500 liter) in order to understand the effect of enriched nitrate on the planktonic community in the spring (March-April) of 2002. Prior to beginning the incubation, the bags were placed in two different concentrations of nitrate, which consisted of control (ambient water) and experimental mesocosms (final concentration of $12{\mu}M$). The nitrate concentration in the experimental mesocosms remained significantly higher than those in control mesocosms throughout the study period (ANOYA, p<0.001). Following the addition of nitrate, abundance and chi-a concentration of phytoplankton peaked on Day 1, when diatoms established the peak in the experimental mesocosms. Diatoms consisted mainly of Thalasxiosira decipiens, Pseudo-nitzschia pungem, Leptocylindrus danicu, Thalassionema nitzschioides, Chaetoceros pseudocrinitus and Actinoptychus senariu. However, the peak did not lead to the difference in abundance and composition of phytoplankton between control and experimental mesocosms during the study period. The dinoflagellates began to increase soon after the diatoms decreased in all mesocosms. Copepods, as a dominant group in the rnosozooplankton community, showed no immediate peak in relation to the nitrate addition, but only their own developmental process from the eggs to adult stage during the study period. The bottom-up control from enriched nitrate via phytoplankton to adult copepods was not distinguished in terms of the abundance of the planktonic community. This might stem from the relatively low nitrate availability of phytoplankton at no N-limited seawater and the weak coupling between rapidly sunken diatoms and copepods through the water column.

• Journal of Life Science
• /
• v.18 no.2
• /
• pp.284-286
• /
• 2008

Octopus minor (O. minor) is widely distributed along the coastal regions of Korea, but most of them are caught in southern waters which are associated with one of the important fisheries stock. At present, O. minor from China has been introduced to the fishery markets in Korea. Here, we attempt to discriminate their origin for Korea or China using molecular techniques. Based on the O. minor mitochondrial DNA sequence, we developed a PCR-based origin discrimination system. The assay specificity was assessed by testing four individuals of O. minor from Sangdong, China, as well as 20 additional O. minor from Namhae, Muan, Yeosu and Jindo, Korea. Only four isolates of O. minor originated from China tested as positive in our distinction system. All PCR-positive products yielded identical sequences from Chinese O. minor, whereas Korean O. minor appeared to be PCR amplification. This result suggested that the primers used in this study are O. minor species specific, especially originated from China. The detection system appeared to be positive results in the use of 0.1 ng of Chinese O. minor DNA as template, however, the Korean O. minor even using $1{\mu}g$ of DNA showed no amplification. Consequently, the assay provides a simple, rapid and accurate method for the detection of Chinese O. minor.