• Journal of the korean society of oceanography
• /
• v.38 no.4
• /
• pp.211-215
• /
• 2003

A huge freshwater reservoir (ca. 12,000 ha) will be created when the construction of a 33­km dike on a huge mud flat of the Saemankeum areas is established. A large quantity of freshwater will emerge to the adjacent sea from the reservoir through two big gates. Marine organisms outside the dike are expected to frequently experience low salinity waters. To investigate the salinity effects on the dominant metazooplankton in the coastal waters off Saemankeum areas, we measured the survival (Survival 1H and Survival 24H) of 11 different taxa (the copepods Acartia omorii, A. pacifica, Calanus sinicus, Centropages abdominalis, Paracalanus indicus, Pseudodiaptomus inopinus, Tortanus forcipatus, and a hydromedusa, and barnacle nauplius, polychaeta larva, and a chaetognath Sagitta sp.) at salinities of 0, 5, 10, 15, 20, 25, 30, 35, and 40 psu when the organisms were exposed for 1 and 24 h, respectively. Survival 1Hs of P. inopinus and barnacle nauplius were 100% between 5 and 35 psu, while they were 0% at salinities of 0 and 40 psu. Survival 1Hs of A. omorii and A. pacifica, P. indicus, T. forcipatus, and polychaeta larva were 100% at $salinities\;\geq\;10$ psu, while they were 0% at lower salinities. Survival 1Hs of a hydromedusa and Sagitta sp. were 100% at $salinities\;\geq\;15$ psu, while they were 0% at lower salinities. Survival 1H of C. abdominalis and C. sinicus was 100% at $salinities\;\geq\;20$ psu, while they were 0% at lower salinities. Survival 24Hs of A. omorii, A. pacifica, C. abdominalis, barnacle nauplius, and polychaeta larva were the same as Survival 1 Hs at the same salinity, while those of the other metazooplankton were lower than Survival 1Hs. The results of the present study suggest that low salinity water emerging from big gates may cause the death of the metazooplankton, but the salinities at which death of the metazooplankton occurs may differ by species.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.17 no.4
• /
• pp.269-279
• /
• 2005

Numerical simulations were done using depth integrated ADCIRC model in order to evaluate dynamic response on the inner Saemankeum reservoir due to flood flow and gate operation for the both situations of dike construction and inner development. According to 2-dimensional dynamic flood routing, temporal variation of hydrographs shows sensitive at upstream riverine region while it becomes stable from the center part of the reservoir due to sudden expansion of physical changes. Dynamic response of hydraulic changes such as water surface elevation and velocity on the inner region arises suddenly by gate operation and more rapidly after the inner development than dike construction. Temporal surface fluctuation arises during inflowging of outer sea water and propagates upstream up to 10km to 16km in accordance with inner development status.

• Ocean and Polar Research
• /
• v.32 no.3
• /
• pp.213-228
• /
• 2010

In late 2010, the Korea Hydrographic and Oceanographic Administration proposed a national monitoring project involving the deployment of 8 realtime ocean data buoys. The area occupied by the buoy-array, located south of the Ieodo Ocean Research Station, can be regarded as a kind of gateway to Korean waters with respect to warm currents and the shipping industry. The acronym for the project, KOGA (Korea Ocean Gate Array) was derived from this aspect. To ensure the success of the project, international cooperation with the neighboring countries of China and Japan is highly desirable. Once KOGA is successfully launched and the moored buoys start to produce data, the data will be applied to various areas such as data assimilation for operational oceanography, circulation dynamics, biogeochemical studies, satellite observations, and air-sea interactions. The aim of this paper is to provide suggestions for KOGA planning and applications.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.57 no.1
• /
• pp.57-68
• /
• 2021

In order to collect basic data for the improvement of fishing systems in coastal improved stow net fishery, a questionnaire survey and on-site hearing were conducted from May 10 to June 11, 2019 on the basic items of coastal improved stow net fishery and safety accidents that occurred during fishing operation. The questionnaire for the survey on the actual conditions of coastal improved stow net fishery consisted of a survey on basic matters (six questions) and a questionnaire (six questions) on safety accidents occurring during fishing operation. The results of the survey on basic items were analyzed by region (Incheon, Seocheon, Gunsan and Mokpo), by the captain's age (less than 50 years of age, 50 to 60 years and more than 60 years of age), by the captain's career (less than 20 years, 20 to 30 years, 30 to 40 years and more than 40 years) and by the age of fishing vessel (less than 10 years, 10 to 20 years and more than 20 years). According to the survey on basic items of coastal improved stow net fishery such as the captain's age, the captain's career, the age of fishing vessel, the fishing nets in use, the crews on board and the operation days per voyage by region, the average captain's age was 55.7 years, the average captain's career was 20.5 years, the average age of fishing vessels was 9.0 years, the average numbers of nets used by fishing boats was 14.0 sets, the average numbers of crew on board a fishing boat was 4.4 persons and the average numbers of operation days per voyage was 4.9 days (p < 0.05). As a result of the survey on safety factors during fishing operations, such as experience of ship accidents, major causes of ship accidents experienced, causes of ship accidents (first priority), experience of human accidents, major causes of human accidents, and causes of human accidents (first priority), more than 96% of the respondents experienced ship accidents including collisions with other vessels or fishing gear during fishing operations. The most significant cause of the accident was the other's fishing gear installed in the fishing grounds. The first possible causes of ship accidents during fishing operations were found to be other fishing gear installed in fishing grounds, steering or engine failure, and inability to avoid accidents during casting and hauling nets. The survey of the experience of human accidents, such as injuries or sea falls, showed that more than 90% of the respondents experienced human accidents during fishing operations. The most important cause of accidents experienced during fishing operations was stucked in a fishing gear during casting and hauling nets. The first important causes of accidents during fishing operations were movement of the fishing gear during casting and hauling nets, damage of the fishing gear such as rope cutting. The results are expected to be provided as a basic data to prevent safety accidents occurring during fishing operation and improve the fishing system in the coastal improved stow net fishery.

• Journal of Fisheries and Marine Sciences Education
• /
• v.15 no.2
• /
• pp.166-175
• /
• 2003

In order to offer fundamental data for the standard of comfilation of the budget on the compensation money for the reduction of fishing baot and index of investigation for computation on the average earnings of reduction of fishing boat, the fluctuation of actual outputs, expenses, earnings and the difference by type of coastal and off-shore fishery was investigated and analyzed. The results are as follows : 1. The average ouput money by large powered purse seine fishery was much with about 3,510 million won, but the average output money by off-shore gill nets fishery was little with about 8.4 million won. 2. The average catch by large powered purse seine fishery was many with about 296,000 M/T, but the average catch by eastern sea danish seine fishery was few with 4,600 M/T. 3. The average expense by large powered purse seine fishery was much with about 3,360 million won, but the average expense by diving fishery was little with 6.3 million won. 4. The average earning by large powered purse seine fishery was much with about 240million won, the average earning by offshore long line fishery was little with 18 million won. 5. The average earning rate by diving fishery was much with 31.62%, but the average earning rate by large powered purse seine fishery was little with 7.30%.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.10 no.1
• /
• pp.10-17
• /
• 1998

Based on field observed tide, tidal currents and depth data, hydrodynamic changes on the Keum River Estuary has been analyzed in which huge complex constructions has been made simultaneously. According to the analyses from acquired data over 2 years, rapid increasing of tidal currents and resulting scouring of 50 cm/yr has been reported in flow-guided dikes region of Kunsan Outer Port. However inner part of the Saemankeum sea dike and Kunjang Industrial Complex dike, 30 cm of sedimentation were found during 2 months of fall season in tidal flats and hence very rapid transition of hydrodynamic system on this area are resulted from those constructions which are still on going nearby.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.21 no.4
• /
• pp.158-170
• /
• 2016

We investigated the occurrence of the dinoflagellate genus Alexandrium in the nineteen Korean coastal sites from July to October 2013. Alexandrium-like planktonic cells were microscopically observed only in four out of the 19 sampling sites. From the samples containing Alexandrium-like cells 22 clonal cultures of Alexandrium species were established by single cell or single chain isolation method. Taxonomic identity of the 4 different strains ascertained by the robust analyses of morphological and molecular genetic characteristics were confirmed to be A. catenella, A. affine, A. fraterculus and an unidentified Alexandrium sp. for which strain WEB-Alex-01 was assigned. It was ascertained that in spite of hot summer diverse Alexandrium species attaining up to four were distributed in the study area, in contrast with the long empirical recognition that the emergence of Alexandrium species is restricted to cooler seasons like spring or autumn in Korean coastal waters. Morphology and genetic characteristics of Alexandrium sp. strain WEB-Alex-01 are different from any other previously reported Alexandrium species from Korean seas, which implies that further studies on taxonomic, physiological, ecological and toxicological properties of the newly recorded Alexandrium species are needed.

• Journal of Fisheries and Marine Sciences Education
• /
• v.14 no.2
• /
• pp.149-160
• /
• 2002

I have been analyzed the marine accidents during 10years(1992~2001) based on the maritime inquire court decision, the results were as follows: 1. The rate of accident occuring were showed fishing boat(69.9%), freighter(12.3%), tanker(4.3%), tug boat(3.8%), passenger boat(2.1%) by the usage. 2. The marine accident had been showed operational fault(67.3%), mishandling of engine equipment(21.7%), meteorological condition, etc(11%) by the reason, most accidents had been occured by the operator fault and rack of experience. 3. The marine accidents had been showed damage of hull and engine(27.5%), collision(24%), foundering(11.3%), fire(3.9%), agrounding(10%), by the kind of accidents. 4. The accidents had been occured (74.6%) at the coastal sea, harbour and (25.4%) at the open sea by the sectors. The accidents of the vessel less than 500ton were much increased (54.3%) also, The accidents were much occured at the time between 0400~0800 hours by the time.

• The Korean Journal of Malacology
• /
• v.29 no.4
• /
• pp.313-323
• /
• 2013

Gonad development, the reproductive cycle, first sexual maturty and size at 50% of group sexual maturity (the biological minimum size) of Gomphina (Macridiscus) veneriformis were investigated for clams collected from the coastal waters of Donghae City, the East Sea of Korea by histological, and morphometric analysis. Monthly variations of the gonad index showed a pattern similar to that of the reproductive cycle. The reproductive cycle with the gonad developmental stages in female and male G. (M.) veneriformis can be classified into five successive stages: early active stage (December to March), late active stage (March to June), ripe stage (June to July), partially spawned stage (June to August), and spent / inactive stage (September to December). The spawning period continued from June to August, with a peak between July and August when the seawater temperature exceeds $20^{\circ}C$. The percentages of first sexual maturities of female and male clams ranging from 25.1 to 30.0 mm were 56.3% in females and 61.1% in males, and for clams over 30.1 mm shell length, it was 100%. Shell lengths at 50% of group sexual maturity (biological minimum size, $RM_{50}$) were 27.71 mm in females and 26.31 mm in males. Because harvesting clams < 26.31 mm in shell length could potentially cause a drastic reduction in recruitment, a measure indicating a prohibitory fishing size should be taken for adequate fisheries management.

• Korean Journal of Ichthyology
• /
• v.30 no.4
• /
• pp.232-237
• /
• 2018

The feeding habits of Beringraja pulchra were studied using 203 specimens collected from February 2017 to March 2018 in the coastal waters of Incheon, Korea. The size of B. pulchra ranged from 31.1 to 77.7 cm in disc width (DW) and the stomachs of 16 specimens were empty. B. pulchra was a carnivore that mainly consumed fishes and shrimps, but also ate various benthic crustaceans and other invertebrates with small amounts. The main prey items in the diets of shrimps and fishes were Crangon hakodatei and Ammodytes personatus, respectively. The proportion of fishes in prey items increased with size-related while that of shrimps decreased. With increasing disc width of B. pulchra, the mean number of preys per stomach (mN/ST) and the mean weight of preys per stomach (mW/ST) were increased.