• Korean Journal of Ichthyology
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• 제35권4호
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• pp.325-332
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• 2023

The feeding habits of the Fat Greenling Hexagrammos otakii were studied using 376 specimens (17.4~41.4 cm in total length) collected off the Incheon coast, Korea between March 2020 and February 2021. H. otakii ate mainly gastropoda and teleostei, incuding caridea, brachyura, polychaeta, cephalopoda and amphipoda. The diet composition of H. otakii showed changes in season. H. otakii ate mainly cephalopoda in spring and ate mainly polychaeta in summer. The teleostei feeding rate was highest in autumn, whereas the proportion of gastropoda was higher in winter than in other seasons. The mean number of preys per stomach (mN/ST, One-way ANOVA, F=2.026, P>0.05) and mean weight of preys per stomach (mW/ST, One-way ANOVA, F=1.075, P>0.05) didn't show a statistically significant difference among size classes.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• 제7권3호
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• pp.148-156
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• 2002

The coastline of Hampyung Bay, southwestern coast of Korea, was examined and measured in the field for the understanding of geomorphic changes and sea-cliff erosion processes. The Hampyung-Bay coastline is characterized by steep-face slope and soft soil and/or intensively weathered rock composition. Saw teeth-shaped coastline, and relict weathered basement-rock and "Island Stack" exposed on the beach surface are peculiar geomorphic features indicating active sea-cliff erosion. The coastline in the study area is continuously retreating with the following cyclic process: erosion of cliff base, gravitational landslide or mass wasting, formation of talus, and then erosion and removal of talus. In this study, sea-level rise during summer in the west coast of Korea is suggested as one of the key factors fur the removal of soil taluses and, thereby, accelerating sea-cliff erosion.f erosion.

• Proceedings of the KSRS Conference
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• 대한원격탐사학회 2008년도 International Symposium on Remote Sensing
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• pp.340-343
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• 2008

The Soya Warm Current (SWC) is a coastal boundary current, which flows along the coast of Hokkaido in the Sea of Okhotsk. Seasonal and subinertial variations in the SWC are investigated using data obtained by high-frequency (HF) ocean radars, coastal tide gauges, and a bottom-mounted acoustic Doppler current profiler (ADCP). The HF radars clearly capture the seasonal variations in the surface current fields of the SWC. The velocity of the SWC reaches its maximum, approximately 1 m/s, in the summer, and becomes weaker in the winter. The velocity core is located 20 to 30 km from the coast, and its width is approximately 50 km. The almost same seasonal cycle was repeated in the period from August 2003 to March 2007. In addition to the annual variation, the SWC exhibits subinertial variations with a period from 10-15 days. The surface transport by the SWC shows a significant correlation with the sea level difference between the Sea of Japan and Sea of Okhotsk for both of the seasonal and subinertial variations, indicating that the SWC is driven by the sea level difference between the two seas. Generation mechanism of the subinertial variation is discussed using wind data from the European Centre for Medium-range Weather Forecasts (ECMWF) analyses. The subinertial variations in the SWC are significantly correlated with the meridional wind component over the region. The subinertial variations in the sea level difference and surface current delay from the meridional wind variations for one or two days. Continental shelf waves triggered by the meridional wind on the east coast of Sakhalin and west coast of Hokkaido are considered to be a possible generation mechanism for the subinertial variations in the SWC.

• Journal of the Korean Society of Food Culture
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• 제18권4호
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• pp.379-395
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• 2003

Regional foods is influenced by weather, local and social environment etc. The purpose of this study was to understand that regional foods in the middle of Chosun Dynasty through Domundaejac. Some of representative dishes of the Hansung and Kyonggi-do Area is duck(rice cake) of seasonally celebrated days, hangua(korea confectionary) and rice wine. Typical foods in Chungchong-do Area is included persimmon, jujube, watermelon and wax gourd. Some of the well-known food in Kangwon-do Area is pear, bangpungchuk(gruel), sukebyung(rice cake), woongjijunggua(korea confectionary) and sanat-kimchi(picked mustard leaves and stem) that is seemed characteristics of mountainous section. Some of the famous dishes in Cholla-do Area is backsanja(korea confectionary), tea, chuksun kimchi(bamboo shoot pickle), citrus fruits and ear shell. Kyongsan-do Area ia famous persimmon, bamboo fruit, dasik(korea confectionary) and yakban(glutinous rice cake). Hwanghae-do Area is famed pear and choshi as assumed the eatly form of gochujang(thick soypaste mixed with red pepper). Representative dishes are deljjuk(blue berry), herring, sangat-kimchi(picked mustard leaves and sterm) in Hamgyong-do Area and daemandu(big dumpling) in Pyongan-do Area. The coast area is famous for using lots of sea food. Fresh seafood is consumed raw, and clams, fish and seaweed are liberally added to soups and other dishes. The East coast is catched salmon, flatfish, codfish, sandfish and mackerel The West coast is catched yellow corvenia, lobster, tiny shrimp and large-eyed herring. The South coast is catched sea mussel, codfish and laver.

• Fisheries and Aquatic Sciences
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• 제15권1호
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• pp.1-8
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• 2012

The geographical distribution of the toxic blue-lined octopus (commonly known as the blue-ringed octopus), Hapalochlaena spp., around the East/Japan Sea was investigated. Observation records of the octopus were gathered using commercial search engines on the Internet. A questionnaire to complement and enhance the base data was conducted that targeted fishermen from areas where the octopus was most likely to occur, i.e., the southeast coast and islands of Korea in the East/Japan Sea. Overall, 32 observational records of the blue-lined octopus were found from Korea and Japan. In Korea, only one record, from 2003, was found on a website; none of the 240 fishermen who participated in the questionnaire reported seeing blue-lined octopus. However, a total of 31 observations of the blue-lined octopus from 2004 to July 2010 were found from 17 different regions in the East/Japan Sea and neighboring waters in Japan. Twenty-two cases were from coastal Honshu Island, and nine were from the west coast of Kyushu Island, Japan. The northern distributional boundary of the blue-lined octopus on the Japanese coast was off Fukui Prefecture around latitude $36^{\circ}$10' N. Our results indicate that the blue-lined octopus is distributed extensively along the Japanese coast, at a low frequency, in the East/Japan Sea.

• The Korean Journal of Malacology
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• 제16권1_2호
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• pp.35-41
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• 2000

We investigated the gonad index (GI), gonadal development, the reprodutive cycle and first sexual maturity of the venus clam, Cyclina sinensis by histological observation. Samples were collected from the intertidal zone of Komso Bay, Chollabuk-do, west coast of Korea, from April 1998 to March 1999. This clam is dioecious and oviparous. Monthly changes in the gonad index (GI) showed a similar pattern to the reproductive cycle. Ripe oocytes are about 90-100 ㎛ in diameter. The spawning period was between early July to September, and the main spawning occurred between July and August when the sea water temperature was over 20$\^{C}$ The reproductive cycle of this species can be divided into five successive stages: early active stage (February to April), late active stage (March to June), ripe stage (April to August), partially spawned stage (July to October), and spent / inactive stage (September to February). Percentages of first sexual maturity of female and male clams measuring 26.1-30.0 ㎜ in shell length were 53.3% and 62.5%, respectively, and 100% for the clams > 41.0 ㎜. It is assumed that both sexes begin reproduction at about two years age.

• The Korean Journal of Malacology
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• 제32권3호
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• pp.165-174
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• 2016

Feeding behaviour of the manila clam Ruditapes philippinarum was qualitatively and quantitatively characterized by comparing the contents composition in digestive tract of the clam and the phytoplankton community in surface sea water in Gomso Bay, west coast of Korea. The contents of digestive tract comprised diatoms (71.5%), dinoflagellates (13.1%), nannoplankton (6.6%), and detritus including mesozooplankton. The abundance of food organisms in digestive tract of the clam was high in winter and spring, while low in summer and autumn. But The biomass of phytoplankton in surface sea water revealed the highest value in autumn. Also, the larger the clam size increases the abundance of food organisms in digestive tract. The dominant species in digestive tract were Paralia sulcata and Navicula arenaria such as benthic diatoms and dinoflagellate cysts, whereas the dominant species in surface sea water were Chaetoceros, Skeletonema, Asterionellopsis such as pelagic diatoms in genus, cryptomonads, and P. sulcata. Analyses of digestive tract revealed that benthic diatoms especially represent an important constituent of food organisms in the malina clam and different of phytoplankton size and morphology explain preference for food selectivity.

• The Korean Journal of Quaternary Research
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• 제18권2호통권23호
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• pp.19-22
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• 2004

Seasonal changes of topograpy, sediment grain size and accumulation rate on the Gomso-Bay tidal flat(Fig. 1), west coast of Korea, have studied in order to understand the seasonal accumulation pattern and preservation potential of tidal-flat sediments. Seasonal levelings across the tidal flat show that the landward movement of both intertidal sand shoals and cheiers accelerates during the winter and typhoon period, but it almost stops in summer when mud deposition is instead predominant on the middle to upper tidal flat. Seasonal variations of mean grain size were largest on the upper part of middle tidal flat where summer mud layers were eroded during the winter and typhoon periods(Fig. 2). Measurements of accululation depths from sea floor to basal plate reveal that accumulation rates were seasonally controlled according to the elevation of tidal-flat surface(Table 1) : the upper flat, where the accumulation rate of summer was generally higher than that of winter, was characterized by a continuous deposition throughout the entire year, whereas on the middle flat, sediment accumulations were concentrated in winter realtive to summer, and were intermittently eroded by typhoons. The lower tidal flat were deposited mostly in winter and eroded during summer typhoons. Cancores taken across the tidal flat reveal that sand-mud interlaers resulting from such seasonal changes of energy regime are preserved only in the upper part of the deposits and generally replaced by storm layers downcore(Fig. 3). Based on above results, it is suggested that the storm deposits formed by winter stors and typhoons would consist of the major part of the Gomso-Bay deposits(Fig. 4).

• Journal of the Korean Society of Fisheries and Ocean Technology
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• 제43권2호
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• pp.126-139
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• 2007

In the autumn of 2000 and spring of 2001, field surveys were conducted to estimate the effectiveness of artificial reefs (type cube, $2{\times}2{\times}2m^3$) that were established in the four islands of Bangnyeong, Socheong, Daeyeonpyeong and Ganghwa in Kyonggi Bay, the west coast of Korea during 1995 and 1996. The condition of reefs was examined through SCUBA diving and a side-scan sonar. Much of the reefs in Daeyeonpyeong and Ganghwa area were buried in bottom sediment. Despite an intensive search in Bangnyeong area, even a cluster of reefs was not found and most of them seemed to be buried by sand waves. Thus an appropriate investigation on the sediment transport should be included in pre-assessment for the expected performance and protection of artificial reefs. Distribution of average CPUE in natural fishing ground (control) was estimated by bootstrapping simulation and possible comparison of CPUE between control and reef areas (treatment) were made in Bangnyeong and Socheong (Experiment I). Positive reef effect was detected in Socheong but CPUE of treatment in Bangnyeong was varied between or lower than the 99% CPUE confidence intervals of the control. Control/treatment abundance and biomass of fishes and invertebrates were tested by paired t-test and sign test (Experiment II). Only four cases among 22 showed significant positive effect. Based on the results, the cube artificial reef in Socheong was inferred as an affirmative one. Floor type was hypothesized to be one of the probable agents in determining the effectiveness of artificial reefs.

• Journal of the Korean Geographical Society
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• 제37권5호
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• pp.511-521
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• 2002

Coastal sand dunes in West coast of Korea are under stress. Due to the newly constructed Seohaean(West Coast) Highways, the number of visitors and the anthropogenic pressures will keep rising in near future. Sea level rise due to the global warming may cause a lot of damage to the natural resources and residents of coastal area. Therefore, many countries including United States are doing nationwide coastline survey using highly sophisticated methodology. In this study, high resolution IKONOS satellite images along with aerial photographs taken since 1960's have been sequentially analyzed using GIS software (Erdas Imagine 8.3). Onsite monitoring has been performed at the 31 measuring points in 10 beaches since the May of 2001 in order to measure the sand budget. Post-construction monitoring after installation of sand fences is also being done on sites regularly. Restoration works seem to be effective at this moment.