• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.32 no.2
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• pp.125-131
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• 1996

In order to investigate the relation between the environmental properties and the catch fluctuation of set net fishing grounds located in the coastal waters of Yosu, oceanographic observations on the fishing grounds were carried out by the training ship ofYosu Fisheries University from January, 1990 to September, 1992, and the data obtained were compared with the catch data from the joint market ofYosu fisheries cooperative society from 1984 to 1993. The resuItes obtained are summerized as follows : 1. The ranges of water temperature and salinity in the fishing ground was 7.0 to $27^{\circ}C.$and 26.6 to 33.2${\textperthousand}$, and water temperature increased from March to August and decreased from September to February of following year. 2. The salinity in the fishing grounds was relatively high without significant changes from November to June of the following year. From July, however, the salinity decreased to continue a low value till September and then increased. The salinity in the fishing ground was dominated mainly by the precipitation and its variation was large at the north entrance of set net fishing ground, influenced greatly by the land waters from the river of Somjin, but small in the offshore of the fishing grounds. 3. The fishes caught by the set nets were arranged in order of catch as follows; Spanish mackerel> Horse mackerel > Sardine > Anchovy > Hair tail. The catches of Anchovy and Sardine were high in April to May and those of Hair tail in June to July, but Spanish mackerel and Horse mackerel were caught for whole period of fishing. Spanish mackerel was caught most in September and least in April and their means were largest in August and smallest in June. 4. The ranges of optimum water temperature for fishing by the set nets was 13.5 to $25^{\circ}C.$, and in the ranges the catches increased with increasing temperature. The ranges of optimum salinity for fishing varied between 25.0 and 32.0${\textperthousand}$.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.37 no.2
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• pp.71-77
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• 2001

In order to find out the environmental factors influencing the catch of fyke nets in the coastal waters Yosu, the oceanographic factors, i.e., the waters temperature and the salinity were observed respectively from April to November in 1999, and each of them was compared with the catch of common mullet, Mugil cephalus by fyke net. The results obtained are summerized as follows : 1. The water temperature was ranged from 13.0 to $25^\circ$C and water temperature increased from April to August and decreased on September to November. 2. The range salinity in the fishing grounds was from 28.6 to 33.8$\textperthousand$, and salinity was high from April to June. From July, however, the salinity decreased to continue a low value still september. 3. The catches of common mullet caught by funnel net were the highest in may and the smallest in November. The ranges of optimum water temperature for the funnel nets fishing was 15.0 to $16.0^\circ$C, the ranges of optimum salinity for fishing varied between from 32.6 to 33.8$\textperthousand$.

• Journal of the Korean Society of Marine Environment & Safety
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• v.10 no.1 s.20
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• pp.61-67
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• 2004

This study described relationships between fluctuation of fishing conditions for common squid and oceanic conditions in the East Sea from 1990 to 1999. Annual catches of common squid have been higher since the late 1980s compared to the period of the late 1970s to the mid-1980s. These catches fluctuations might be related to the effect of regime shifts. Monthly catches of common squid appear the timing of a large catch from September to December and a poor catch from March to May. The monthly catches are also the highest in October and are the lowest in April. Annual stable fishing grounds for coefficient of variation below 1.0 are formed in waters around Guryongpo and Ullung Island Based on optimum water temperature for catch, $16^{\circ}C$, optimum water depth for catch shallow going north. It indicates that the optimum water depth of fishing work different of each area Fishing ground formation and horizontal water temperature appear the minimum $10{\sim}14^{\circ}C$ in April, the maximum $10{\sim}20^{\circ}C$ in October. If seem, that seasonal fluctuation of fishing ground is related to the extension of the Tsushima warm current in the East Sea.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.32 no.3
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• pp.249-256
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• 1996

The saury stick - held dip net fishery of Korea in the Northwest Pacific Ocean began in 1985 with 3 vessels. Since then the fishery has grown so rapidly year by year that the number of vessels increased to 34 and the catch to 40 thousands Mff in 1993. In the present study, the monthly situation and the movement of the fishing ground for the pacific saury in the Northwest Pacific were investigated and the monthly optimum fIshing tempertures were estimated, from the relationship between the catch and the sea surface temperature. In the beginning of the fishing season, June to August, the fIshing ground is formed in the very wide range, mainly in the northward area of the front meandering, as the parcific saury migrate northward. In the main season, September to November, the ground is formed in the southward area of the front, off the east coast of Japan. Andd then, the fishing season ends in December with the ground coming near to the east coast of Japan. The monthly optimum fishing tempertures showed 11~$13^{\circ}C.$ in June to July, 13-$17^{\circ}C.$ in August to November, and 15~ $17^{\circ}C.$ in December in general. The profIles of water temperature were much different in accordance by net casting position in the fishing ground, regardless of season. So, the MLD and CPUE was analyzed to find out the relation between the water temperature and the catch. Then, it is found that the CPUE shows over 0.7Mtr/haul as the MLD 40~70m.40~70m.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.34 no.2
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• pp.117-134
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• 1998

The study on the Assembling Mechanism of the Hairtail, Trichiurus lenpturus, at the Fishing Grounds of the Cheju Strait had been investigated by analyzing the relationship of the oceanographic conditions and the fishing ground of the Hairtail in the Cheju Strait. 1. The fishing grounds of the hairtail at the Cheju Strait are formed at the bottom of a high temperature of the tidal front at the coast. area of northern Cheju Island, the tip of the linguiform is high in salinity at the eastern and western entrances of Cheju Island, low salinity eddy on the surface and its surrounding front, various water masses in the Strait and coastal waters of the South Sea in Korea. 2. The fishing grounds of the Hairtail at the Cheju Strait begins with the sea surface temperature higher than $15^{\circ}C$ and the incoming of low salinity water now from the East China Sea. 3. Estimation of optimum temperature and salinity per season based upon analysis for relationship between temperature of water and salinity of the bottom layer and the catch is : 15.2~$16.4^{\circ}C$, 34.20~34.40${\textperthousand}$ in spring(June); 14.4~ $17.0^{\circ}C$, 33.70~34.30${\textperthousand}$ in summer(July~September); and 15.7~ $18.6^{\circ}C$, 33.70~34.50$\textperthousand$ in autumn(October~December). Hairtail are mostly caught at the Yellow Sea Warm Current and Tsushima Current with temperature over $14.5^{\circ}C$ and salinity over 33.70${\textperthousand}$ at the bottom layers of the Cheju Strait. 4. Considering the relationship between the amount of hairtail catch and the water temperature of bottom layer, when the bottom water being above $14.0^{\circ}C$ flowed into Cheju Strait through the western entrance of the strait in summer, the ca-h appears to have been abundant. In contrast, the catch has been poor when the temperature of such water was recorded to be below $13^{\circ}C$ Therefore, distribution patterns of water at the bottom layer can be used as a forecast index whether the catch of a certain year will be good or poor.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.11a
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• pp.107-108
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• 2017

The purpose of this study is to derive the optimum water absorbing curing time. It was found that the cement paste compressive strength was increased with the water absorbing ratio up to 40%, but the compressive strength was slightly lower when the catch level was over 50%. It is considered that the superfluous water did not react and remained in the inside of the specimen, causing microcracks in the inside due to the high temperature curing, resulting in a decrease in strength. Therefore, it is considered that the optimum catcher curing time for improving the strength through catcher curing is when the catcher reaches 40%.

• Journal of the Korean Society of Marine Environment & Safety
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• v.16 no.3
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• pp.259-268
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• 2010

Data on squid catches by the Korean jig fishery in sea blocks ($30'{\times}30'$), water temperatures at depth(30m, 50m and 100m) and zooplankton biomass in the East Sea from 1980 to 1999 were analyzed to examine the mechanism of formation of the high density stock area. Japanese common squid (Todarodes pacificus) catch in the East Sea was low in 1980s, while the catch was high in 1990s. The five sea blocks (No. 76, 82, 83, 87, 88) of the southern part in the eastern coastal waters of Korea showed high levels of percentage of total catch (35.1%), whereas the four sea blocks (No. 65, 71, 72, 78) of the coastal waters of Uleung Island showed high levels of percentage of CPUE (61.2%) for 20 years. Squid catches showed monthly fluctuations according to the vertical distribution of optimum water temperature for fishing ($14^{\circ}C{\sim}19^{\circ}C$). High total catch and high CPUE area matched well with $10^{\circ}C$ isothermal lines at 100m depth indicating northern limiting of Tsushima Warm Current, and temporal and spatial change in $10^{\circ}C$ isothermal line caused the change in total catch and CPUE. Horizontal distribution of zooplankton biomass by sea block was not matched well with those of total catch and CPUE, however pattern of time-series change in total zooplankton biomass was similar to that in total squid catch.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.22 no.3
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• pp.8-16
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• 1986

The fishing conditions of flying squid, ommastrePhes barsram(Lesueur), in the North Pacific Ocean was studied based on the horizontal water temperature data, satellite data from NOAA and statistical data of flying squid fisheries which were collected from 1980 to 1984. The obtained results were as follows; 1. Since 1979, the Korean drift giIlnet fishery for flying squid was launched in North Pacific. Number of operating vessel and catch of flying squid increased gradually every year. The number of vessels were 111 and their annual catches were 42, 977 M/T in 1984. Therefore, Korean drift giIlnet fishery for this species has played an important role in the products of Korean high-sea fisheries. 2. In the beginning of the fisheries, fishing grounds was formed in the west of long. 1800E. In 1982, in consequence of the center which extended eastward, the fishing ground was formed long. 166$^{\circ}$W in the central North Pacific Ocean. Since 1983, the fishing grounds were formed as far as long. 161$^{\circ}$W. The range of general fishing season in the central North Pacific was from June to August. After september, fishing ground was shifted to the west, in the Northwestern Pacific. 3. The Predominant fishing season for the flying squid was August through January of the coming year. Optimum water temperature for flying sguid at surface layer in the Pacific Ocean ranged from 11 $^{\circ}$e to 17$^{\circ}$e in winter, 13$^{\circ}$e to 17$^{\circ}$e in spring, 12. 8$^{\circ}$C to 19.7$^{\circ}$e in summer and 1O.6$^{\circ}$e -18.7$^{\circ}$e in fall. 4. In summer, the Oceanographic condition in the North Pacific Ocean showed that the water temperature at surface layer was lower in 1980, 1983 and higher in 1981, 1982 and 1984 as compared with mean annual water temperature. 5. The characteristics df oceanographic conditions in the fluation, disformation, mixing and other factors of the Kuroshio and Oyashio currents, which have considerably influenced upon the water masses of the areas. 6. The data and information on surface thermal Structure interpreted from Infrared Satellite Imaginary from NOAA-7 and NOAA-8 are very available in estimating water temperature on the areas and investigating the major fishing grounds. 7. According to the fisheries statics of Japanese drift gilInet, the annual catches of flying squid considerably decreased from 225, 942 M/T in 1983 to 133, 217 M/T in 1984. 8. The fishing grounds in the central North Pacific in several fishing seasons were formed as follows: In June, the initial fishing season, the fishing grounds were formed in the vicinity of lat. 35 - 40oN, the central North Pacific east of 179$^{\circ}$E. In July, the fishing ground were formed in the wide arEa of the central North Pacific north of 400N and long. 174$^{\circ}$E-145$^{\circ}$W In Auguest, concentrative fishing operation carried out in :he central North Pacific north of 43$^{\circ}$N and East of 165$^{\circ}$W. On the other hand, in September, main fishing grounds were disappeared and moved to the west.