• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.6 no.3
• /
• pp.266-274
• /
• 1994

Two-dimensional numerical analysis is performed for the simulation of tidal characteristics related to various development projects in Incheon coastal waters along the west coast of Korea. Field observation of tides and currents was made in order to provide the input boundary and validation data set to the numerical modelling. For the simulation of changes of tides and currents a depth-integrated two-dimensional shallow water model of Flather and Heaps (1975) has been used herein. Tidal model is set up with open boundary sea level from observed two major constituents, M$_2$ and S$_2$. Subsequently the established model is utilized to investigate the effect of two development projects in this region. It has been found that in spring tide the changes of tidal amplitude are small, however, those of tidal current are locally significant.

• Proceedings of the KSRS Conference
• /
• 2006.03a
• /
• pp.91-94
• /
• 2006

China Coastal Waters (CCW) usually appears in the seas surrounding Jeju Island annually(June to October) and is very pronounced in August. Generally, low-salinity water appears to the western seas of Jeiu Island from June through October and gradually propagates to the eastern seas, where CCW meets the Tsushima Current. Empirical orthogonal function (EOF) analysis of SLAs and SSTs indicated that the valiance in SLAs and SSTs was 95.05%(the first mode to third mode) and 98.09%(the first mode), respectively The PSD of the western waters for the first mode of EOF analysis of SLAs was stronger than that of the eastern waters because of the influence of CCW. The PSD for the EOF analysis of SSTs was similar in all areas (the Yangtze Estuary and the seas to the west and east of Jeju Island), with a period of approximately 260 days.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.49 no.3
• /
• pp.376-384
• /
• 2016

Seasonal catch distributions of large purse seines and daily landings of coastal set nets were analyzed to understand the migration path of the Spanish mackerel Scomberomorus niphonius around Korean waters. The Spanish mackerel start to move toward the coastal region in the South and West Sea in May for spawning and stay until July, when spawning finishes. Afterwards, they start to migrate to the East China Sea and the southern East Sea and are found irrespective of the onshore and offshore regions. Therefore, they disappear from the offshore region during the spawning season in June and July, and a new recruitment population of age 0 begins to inflow into the coastal fishing grounds in the South Sea and West Sea in August, one month earlier than in the Japanese coastal region of the East Sea.

• Korean Journal of Environmental Biology
• /
• v.30 no.4
• /
• pp.328-338
• /
• 2012

We investigated seasonal changes in the marine environments and phytoplankton communities in the western part of south coastal waters of Korea during May 2009 and February 2010. In multidimensional scaling analysis of in situ data obtained by shipboard observations, the coastal waters comprised four different water masses: Yellow Sea water mass (YW) of low temperature and salinity, and high suspended solids and nutrient concentrations; south-western coastal water mass (SW) of high salinity and nutrient concentrations; Tsushima Current water mass (TW) of low nutrient concentrations, and high temperature and salinity; and closed bay water mass (CW). The spatial extent of these water masses varied according to seasonal environmental characteristics. In particular, at most study sites, TW expanded during autumn toward coastal waters. Phytoplankton abundances peaked during autumn in CW and spring in YW, which coincided with periods of high nutrient concentrations. In particular, diatoms predominated, and attained an abundance of more than 90% in most water masses. However, dinoflagellates in TW comprised a proportion of approximately 20% abundance.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.1 no.1
• /
• pp.46-54
• /
• 1996

A study on the concentrations of total suspended matters (TSM) and their distribution pattern was conducted off the west coast of Tae-An Peninsula during the spring season. Especially non-destructive and fine-tuned analysis for the size-distribution of suspended matters was made using SPECTREX instrument. Water masses were characterized by the typical tidal front, with vertically homogenous coastal waters and the strong thermoclines on the offshore area. Concentrations of suspended matters were generally less than 10 mg/l, but the concentrations increased up to 25 mg/l at the bottom waters and mid-depth waters. Mean particle size of the suspended matters were generally 5-6$\mu\textrm{m}$ and 8-10$\mu\textrm{m}$ for the fine-grained suspended matters and the coarse-grained suspended matters, respectively. They are considered to be composed dominantly of detrital materials. On the coastal area, landward side of tidal front, bottom sediments can be easily resuspended by the strong tidal currents, and therefore, deposition of suspended materials are thought to be rather limited. On the offshore area, however, suspended sediments mostly supplied from the northern part of the present study area near Kyunggi Bay are thought to be transported southward and/or southwestward along the mid- depth layer of strong thermocline.

• Korean Journal of Ichthyology
• /
• v.32 no.3
• /
• pp.143-147
• /
• 2020

The feeding habits of ocellate spot skate (Okamejei kenojei) were studied by analysis of stomach contents. Specimens of O. kenojei (n=379) were collected in the cosatal waters five west Islands of the Korea, monthly from January to December 2019. The size of O. kenojei ranged from 5.9 to 34.5 cm in disc width (DW). O. kenojei was consumed mainly macrura (77.9%) and pisces (21.9%) in % IRI. But, brachyura, stomatopoda, cephalopods, and others showed a low ratio. The macruara feeding rate was highest in summer, whereas the proportion of pisces was the higher in winter than other seasons.

• Animal Systematics, Evolution and Diversity
• /
• v.32 no.4
• /
• pp.272-280
• /
• 2016

Most scyphomedusae jellyfishes recorded in Korean waters are temperate and subtropical species. In the present study, two cold-water jellyfishes from Korean waters are first described. Scyphomedusae were collected from the coasts of Gangneung and Ulsan of the East Sea, and Boryeong, and the eastern area of the Yellow Sea from June 2006 to May 2015. Scyphomedusae collected in Ulsan and Gangneung were identified morphologically as Aurelia limbata Brandt, 1835. Their umbrella was 250-500 mm in width and 30-50 mm in height; the exumbrella was white and the subumbrella was dark brown in color. The vascular system was complex with anastomosed branches. Individuals of this species lived at about 6.6-9.9℃ and 30-50 m depth in Korean waters. Scyphomedusae collected from the center of the Yellow Sea and from Boryeong were identified as Parumbrosa polylobata Kishinouye, 1910. Their umbrella was disc-shaped, 80-200 mm in width and 20-40 mm in height. Its milky white gonads could be seen through the transparent exumbrella. The stomach cavity was round and flat with four interradial cavities connected by subgenital cavities, and the four oral arms were bifurcated and spear-head shaped. Individuals were found at about 6.4-10.0℃ and 40-90 m depth in Korean waters. The identities of both species were confirmed by molecular analysis using nuclear ribosomal DNA sequences.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.8 no.2
• /
• pp.132-137
• /
• 2003

Observations of internal waves in the southwest coastal waters of Korea have been made using a mooring measurement and satellite SAR together. From May 28 to May 30 in 2002, thermistor chains with RCM and ADCP mooring measurements were carried out at 10 kin west of Ocheong-Do, together with a CTD field sur-vey on the surrounding waters. Also, a SAR image was acquired on May 29 at 06:53. The data from the in-situ measurement show several internal wave packets passing through the mooring point and the SAR image reveals numbers of internal wave packets distributed around the point. Temporal and spatial characteristics of internal waves in the southwest coastal waters were analyzed using the data from mooring measurement, SAR image, and the K-dv equation. The internal waves are important phenomena in terms of physical oceanography and military as well as marine biology. They should be considered as one of important features in the southwest coastal waters in summer.

• Korean Journal of Remote Sensing
• /
• v.21 no.6
• /
• pp.469-482
• /
• 2005

China Coastal Waters (CCW) usually appears in the seas surrounding Jeju Island annually(June to October) and is very pronounced in August. Generally, low-salinity water appears to the western seas of Jeju Island from June through October and gradually propagates to the eastern seas, where CCW meets the Tsushima Current. Empirical orthogonal function (EOF) analysis of SLAs and SSTs indicated that the variance in SLAs and SSTs was $95.01\%$(the first mode to third mode) and $98.09\%$(the first mode), respectively. The PSD of the western waters for the first mode of EOF analysis of SLAs was stronger than that of the eastern waters because of the influence of CCW. The PSD for the EOF analysis of SSTs was similar in all areas (the Yangtze Estuary and the seas to the west and east of Jeju Island), with a period of approximately 260 days.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.55 no.5
• /
• pp.575-582
• /
• 2022

This study revealed the reproductive biology of pointhead flounder Cleisthenes pinetorum, in the middle of the West Sea of Korea. We collected samples using gill net and drag net fisheries in coastal waters from January to December 2019. Mmonthly gonodosomatic index and maturity stage results showed that the spawning period was October to December, and the females grew faster than the males. The fecundity ranged from 16,728 to 1,039,616 number of eggs, and the relationship between TL and fecundity (F) was 0.0000003TL^4.7434 (R²=0.4898). The size-frequency distribution of eggs suggested that C. pinetorum spawm once during a spawning period. The length at 50% maturity for females was estimated to be 18.9 cm.