• Journal of Environmental Science International
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• 제26권2호
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• pp.173-181
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• 2017

Catch data for the common squid (Todarodes pacificus), classified by squid-jigging fisheries per grid (size: $0.5^{\circ}latitude{\times}0.5^{\circ}longitude$), and the water temperature values KODC (Korea Ocean Data Center) were collected for the 1980-2009 period to study the changes in squid distribution and migration with climate regimes (1980s, 1990s, and 2000s). The primary fishing period in the 1990s and 2000s was approximately 2-3 months earlier than that in the 1980s. Especially in the East Sea, the fishing grounds in the 1980s stayed longer at high latitudes than those in the other decades. Moreover, in the 1980s, centers of the fishing ground were located near the Yamato bank (central East Sea), whereas in the 1990s and 2000s, they were situated near the southeastern coast of the Korean peninsula.

• Korean Journal of Fisheries and Aquatic Sciences
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• 제37권3호
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• pp.232-248
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• 2004

In order to utilize fisheries resources under a joint management scheme with adjacent nations, as well as detecting of fishing grounds, the factors which influence yellow croaker (Pseudosciaena polyactis) in Korean waters were studied using historical catch per unit effort and oceanographic data. The main fishing ground near Cheju Island was located along the thermal front formed between the Yellow Sea Bottom Cold Water (YSBCW) and northward moving warm current. When the YSBCW (index temperature: $10^{\circ}C)$ strongly extended southward, the fishing condition were worse than average. Especially, low temperatures greatly influenced stow net fisheries, which were operated in the deep water layer The concentration and dispersal of fishing ground and catch coincided with oceanographic features and the seasonality of water masses.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• 제32권1호
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• pp.24-32
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• 1996

This paper described on relation between the catches of tuna and the distribution of water temperature of eastern fishing ground of Tropical region in the Pacific Ocean. The data of catches and water temperature used in this paper were based log book which # 27 CHENG RONG(Gross tonnage : 399 ton) had been worked eastern fishing ground(Lat : 09$^{\circ}$N- 14$^{\circ}$S, Long : 115$^{\circ}$- 149$^{\circ}$W)from January to October, 1991. The obtained result are as follows : 1. On the relation between the catches and the geographical distribution, bigeye tuna was higher catches at Lat 4$^{\circ}$- 9$^{\circ}$N, Long 135$^{\circ}$- 139$^{\circ}$W area in the equatorial counter current region where surface water temperature was range of 27.5$^{\circ}C$ to 27.9$^{\circ}C$, yellowfin tuna was higher catches at Lat 4$^{\circ}$- 9$^{\circ}$S, Long 145$^{\circ}$- 149$^{\circ}$W in the south equatorial current region where surface water temperature was range of 28.$0^{\circ}C$ to 28.4$^{\circ}C$ and albacore tuna was higher catches at Lat 10$^{\circ}$- 14$^{\circ}$S, Long 120$^{\circ}$- 124$^{\circ}$W area in the south equatorial current region where surface temperature was range of 26.5$^{\circ}C$ to 26.9$^{\circ}C$ 2. On the relation between catches and distribution of vertical water temperature, bigeye tuna was higher catches at the water temperature of 1$0^{\circ}C$ to 12$^{\circ}C$ on depth layer between 300m and 360m, yellowfin tuna was higher catches at the water temperature of 15$^{\circ}C$ to 19$^{\circ}C$ on depth layer between 180m and 280m and albacore tuna was higher catches at the water temperature of 12$^{\circ}C$ to 14$^{\circ}C$ on depth layer between 280m and 310m. Above the result, it seemed that bigeye tuna distributed deeper layer than yellowfin and albacore tuna.

• Korean Journal of Ichthyology
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• 제13권3호
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• pp.210-219
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• 2001

The fisheries resources of the set net fishery on four fishing grounds (Pyuong Dae, Gu Eum, Du Moah, Gang Jeong) in coastal waters of Jeju Island were studied to the determine catch-variation characteristics from January, 1998 to December, 1999. A total catch of 153,862 kg was made through the survey period. The large total was related mainly to the high catch of Trachurus japonicus, which comprised 58.2% of the total. Other dominant species which account for 23.0% of the total catch were Siganus fuscescens, Todarodes pacificus, Loligo chinesis, Seriola lalandi, Sepioteuthis lessoniana, and Seriola quinqueradiata. Catch density was high in Gu Eum (more than 100,000 kg), whereas those in Pyuong Dae, Du Moah, and Gang Jeong were less than 30,000 kg in total. The fishing period of the set net fishery was from April to December, which was also closely related to the variation of the sea water temperature in the fishing grounds. The ranges of water temperature in the four fishing grounds were $18{\sim}26^{\circ}C$ in Pyuong Dae, $16{\sim}26^{\circ}C$ in Du Moah, $15{\sim}26^{\circ}C$ in Gu Eum, and $15{\sim}26^{\circ}C$ in Gang Jeong.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• 제20권2호
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• pp.83-90
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• 1984

The secular fluctuations of catches and fishing grounds of mackerals and the oceanographic conditions for the fishing grounds are examined by using the data of catches of mackerals by middle and large class purse-seiner during 1951 to 1981 and those of oceanographic observation carried out by Japan Meteorological Agency. The results are as follows; The fishing grounds of mackerals are respectively distributed at northeastern and southwestern areas from the central part of the East China Sea through every season of the studied years: 1968, 1974 and 1980. The narrow belt type of fishing grounds were formed inside of the Kuroshio in spring and winter of the three years. In summer mackeral species move northward and the fishing grounds are formed in the southern sea of Korea. In winter, however, mackeral species move southward and the fishing grounds are appeared in the Tsushima Current region. The dispersion of fishing grounds is generally larger in summer and smaller in spring, and especially it is the largest in summer in 1980. It seems that the concentration and dispersion of fishing grounds are related to the depth of thermocline and the position of horizontal temperature gradient in this area.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• 제21권1호
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• pp.41-61
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• 1985

The purse-seine fishery is very important in the coastal fishery of Korea and the main fish species of this fishery are mackerals and also the main fishing grounds are Tushima Current region, To investigate the relationship between the fishing grounds of mackerels and oceanographic condition, the distribution of mean catches of mackerals of each size (1974~1982) was firstly examined and the oceanographic observation carried out in eastern and western area of Cheju island, being main fishing grounds, in July and October, 1983. The results are as follows: The main fishing grounds of mackerals were also in the Tsushima Current region in southern sea of Korea and the season of the good catches are in May and September to October. The small and medium size of mackerals of which the body lengths are 27 cm to 31 cm, about 2-3 ages, occupied about 90% but the smaller size mackerals of which body lenth is 22 cm (1 age)were about 40 to 70% in February to March. The locations of seasonal fishing grounds could founded by 15$^{\circ}C$ isotherm which indicates the Tsushima Current Water. With trace of this isotherm it was founded that the fishing grounds near the Korean Strait than that of south of Cheju island moves faster northward and/or later southward. The main fishing grounds eastward and westward of Cheju island were the front areas formed between the Tsushima Current Water and the southern coastal water of Korea or Yellow Sea Bottom Cold Water. And also the distributions of transparences, water colors and the penetration of sun light of this fishing grounds were similar to that of the temperature, the salinity or volume of planktonic organism.

• Journal of the Korean Society of Marine Environment & Safety
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• 제26권2호
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• pp.195-205
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• 2020

Oceanic conditions in walleye pollock habitat in the East Sea have shown decadal fluctuations between warm and cold periods in turn. Specifically, sea surface temperature (SST) has shown a dramatic increase between the late 1980s and the middle 2000s, and abrupt decreasing patterns after the late 2000s. Oceanic conditions in the Dong-han Bay (spawning ground) and middle eastern coastal waters (fishing ground), however, indicated different fluctuation trends in SST, increasing in the Dong-han Bay after the late 1980s, and decreasing after the late 2000s. These fluctuation patterns were especially clear in February and March. Sea surface temperature in the middle eastern coastal waters of Korea soared continuously after the late 1980s, but did not show a distinct decreasing pattern after the late 2000s compared with Dong han Bay, except for February SST values. These long term water temperature changes in both walleye pollock spawning and fishing ground are related to variation in walleye pollock landings. Especially, abrupt changes in spawning ground SST can be one of the factors influencing survival in the early ontogenesis of walleye pollock, including egg and yolk larval stages. During the 1980s, the area of suitable spawning temperature (2-5℃) was wider, and the length of Walleye pollock egg and larval stages greater compared with past and present oceanographic environments. However, such patterns did not correspond with the optimal spawning temperature range and greater length of development of walleye pollock during the late 1980s likely triggering a decline in pollock stock. In conclusion, it has been supposed that the dramatic decrease in walleye pollock landings in the East Sea since the late 1980s was caused by increasing water temperature leading to both early mortality and unsuitable spawning conditions.

• Journal of Advanced Marine Engineering and Technology
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• 제25권6호
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• pp.1317-1323
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• 2001

The circumstance is giving the blow against fishermen with the incoming-decreasing and the difficulty of crew's supply & demand and management. In addition, the depression of the external situation like the departure of WTO system and the plan of EEZ proclaim is forcing fishery into improving their fishing condition. By this international and domestic circumstance, development of the sea water cooling apparatus for fish hold storage is demanded sincerely. First of all, we Investigated load characteristics which based on development of sea water cooling system and optimum fish hold storage. The experimental results is as follows. In creasing the speed of compressor and mass blew rate of refrigerant, the temperature of NaCl solution is low. And the load characteristics experiment on fish hold storage outlet is as fellows. As time goes by, increasing the mass flow rate of NaCl solution, temperature difference between inlet and outlet is small in a model of fish hold storage. These results provide many useful informations applicable to an actual design of sea water cooling system and optimum fish hold storage.

• Journal of Power System Engineering
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• 제21권2호
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• pp.64-69
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• 2017

The purpose of this study is to investigate the performance characteristics of seawater cooling system for a fishing vessel. The circulation amount of refrigerant, condensation capacity, evaporation capacity, compression work and coefficient of performance(COP) were analyzed as the heat source temperature changed. The experimental setup consisted of an open-type compressor, a shell&tube type condenser, an evaporator and an expansion valve. The heat source was controlled by a constant temperature chamber. The main results of this study are summarized as follows. The condensation capacity increased with increasing heat source temperature, and it was confirmed that the effect of circulating amount of refrigerant was dominant. The amount of heat for vaporization was almost constant even though the temperature of the heat source increased. On the other hand, the compression power was increased. This is because the compression ratio increases as the condensation pressure, the enthalpy difference between inlet and outlet, the amount of circulating refrigerant increases. The performance coefficient of this system showed a tendency decreasing with increasing heat source temperature. Therefore, the basic data of the seawater cooling system for the maintenance of the catch line of the shore fishing boats was acquired through this study, and it is considered that it will be sufficient for the actual design.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• 제40권4호
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• pp.282-294
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• 2004

Catches of Argentine shortfin squid Illex argentinus showed a sharp decrease, reaching 99,000ton in 1993 and 56,700ton in 1994, and then increased again reaching 130,300ton in 1997 from 78,600 ton in 1996. The Korean squid jigging fishery around Falkland for Illex argentinus commences usually its operation in January and lasts August and peak in catch was showed from March to May. To elucidate possible environmental effects on their abundance during the main fishing season in 1993-1994 and 1996-1997, sea surface temperatures were used as an indicator of the position and strength of the oceanographic structures in the Southwestern Atlantic Ocean. The high catch and catch per unit effort of Illex argentinus was showed when the Faliland Current was not affected in the fishing area in 1993 and 1997. But they were sharply decreased from the middle of April 1994 and the late of April 1996 when the Faliland Current directly affects the fishing ground.