• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.34 no.2
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• pp.105-116
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• 1998

This paper, examines the relationship between water temperatures and fishing conditions of common squid by the squid angling fishery from June to September in 1993-1995. The condition of the common squid fishing largely depended on the fluctuation of water temperature in the coastal area of Gampo. Monthly mean water temperatures during June m September in 1993 and 1994 were relatively higher than those in 1995 in Gampo area. But the values between July and August in 1995 were about 5$^{\circ}C$ lower than those in 1993 and 1995. Coefficients of variation (CV) of water temperature showed the lowest value during July ~ September in 1993, however, the highest value was observed in July and August in 1994. Catch per unit effort (CPUE ; kg/angling) showed a peak with 73.7kg in 1993 when the CV was low. On the other hand, the lowest CPUE of 39.6kg was observed in 1994 when the CV was high. It was concluded that the high stability of water temperatures and the weak strength of cold water have caused the good fishing conditions of common squid.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.40 no.4
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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.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.28 no.4
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• pp.327-336
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• 1992

In order to establish one of the forecasting model for the fishing conditions of squid angling fisheries in the Eastern Korea Sea, the catch data for the years of 1955~1991 and the water temperature data for the years of 1979~1990 were analysed, and then some parameters, that is, the water temperature normal year anomaly in the spawning and the rapidly growing season, the adult resource amount and etc were examined statistically correlation with the catch fluctuation of the main fishing seasons. From the result, authors suggested a formula as a forecasting model, Y=25785+1099X sub(1)+1074X sub(2)+6.033X sub(3)+3.95X sub(4)+1.330X sub(5)(M/T)(R super(2)=0.867, P<0.01) in the case that Y is the yearly catch, X sub(1) and X sub(2) are the water temperature normal year anomalies in October and December of the previous year and that in February and April, and X sub(3), X sub(4) and X sub(5) are the catches in October, in September, in November of previous year respectively. Because these parameters could be checked in earlier time of a half year before the main fishing season, this model was assumed to be very useful for the prediction of fishing conditions of squid angling fisheries.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.46 no.4
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• pp.430-440
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• 2010

To investigate the catches of jack mackerel fishery, a series of fishing experiments was conducted in the high seas of the southeastern Pacific Ocean ($30^{\circ}S-38^{\circ}S,\;82^{\circ}W-95^{\circ}W$) during the period of 9 August to 18 December, 2003 by commercial fishing vessel and research vessel. The number of 205 tows fishing was carried out in the southeastern Pacific Ocean. The total catch was 1,988 ton and CPUE was 2.4 ton/hour. CPUE showed high values in the frontal zone during the survey. Main target species caught from the experimental fishing were the jack mackerel, Trachurus murphyi (98.1%) and chub mackerel, Scomber japonicus (1.9%) as bycatch. Body length of the jack mackerel was different between female and male. The high mean catch per unit effort of jack mackerel was showed when the fishing ground of jack mackerel fishery was over the $110^{\circ}W$ in the southeastern Pacific Ocean. But the fluctuation of the catch per unit effort in the western part of fishing ground was not matched with those year. Reliable physical and oceanographical information will be useful for the efficiency of fishing activity. According to the result of monthly movement of center of fishing ground, the fishing activity of jack mackerel fishery was performed northward in the southeastern Pacific Ocean as time passes.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.57 no.3
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• pp.194-204
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• 2021

The research was analyzed the catch data of the five years (2016-2020) for six joint venture company tuna purse seiners in the Atlantic Ocean, with the aim of suggesting improvement measures for responsible and sustainable fishing according to changes of recommendation by International Commission for the Conservation of Atlantic Tuna (ICCAT) on the tropical tunas. In the last five years, the average catch of six tuna purse seiner gradually increased to 7,745 tons, 8,364 tons and 9,053 tons from 2016 to 2018, but decreased to 7,761 tons in 2019 and 6,214 tons in 2020. The reason for the decrease in fishing volume in 2019 and 2020 was the fluctuation of the formation of the cold water zone (22-23℃), and the total ICCAT convention area of FAD closure in January and February due to the expansion of the FAD closure area and poor free school catching during two months period, respectively. The analysis on fishing area showed that the percentage of fishing in the high sea was about 85% although the FAD closure area included the EEZ zone in coastal countries; the rise of the fishing license in coastal countries is also believed to be a factor. In order to overcome such situations and improve catching volume, it will be possible if excellent manpower is secured, school fishing is expanded, and the production of high value-added catch (purse seine special: PS).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.5
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• pp.619-625
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• 2013

We investigated yearly fluctuation of the fish species composition of beam trawls off Maemuldo in the east southern sea of Korea, from March 2007 to November 2009. A total of 75 fish species were collected during the period. The number of fish species accumulated amounted to 54, 64 and 75 species in 2007, 2008 and 2009, respectively. The number of newly occurring species increased with time. The number of expected resident species in Maemuldo was estimated as 9 species including Conger myrister, Okamejei kenojei and Pholis nebulosa, each of which appeared more than 14 out of a total 27 times. Cluster analysis showed that the years 2007 and 2008 were closely clustered, while the year 2009 was distantly clustered with 2007 and 2008. This may be due to the high catch ratio of Clidoderma asperrimum in 2009 alone, when a low water temperature phenomenon was observed unlike the situation in 2007 and 2008.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.25 no.2
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• pp.44-53
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• 1989

In order to grasp the characteristics of a fishing ground at yeosu bay, the fluctuation in condition of the coast and that in catch by pound nets in the coast were investigated respectively. The results obtained are summarized as follows: 1. The water temperature in spring and summer was higher at the coast side than off shore, but in autumn and winter took the reverse. 2. The salinity was higher in spring and winter than in summer and autumn. A lower salinity zone was found at the Dolsan Do coast and higher ones were made off shore. 3. A eddy current was found at the Dolsan Do coast and a thermocline were made at the depth of 30 to 40 m in summer. But in autumn and winter the water became homogeneous. 4. The annual catch by the pound net was highest in 1984 and then decreased gradually. The monthly catch was highest in June and then decreased gradually. 5. The catches seemed to increase with the sea water temperature and salinity, and great catch was shown in 21$^{\circ}C$ to 27$^{\circ}C$ and 33.80% to 34.00%. 6. The component rate of fishes was 28.4% in spanish mackerel, 17.9% in anchovy, 19.5% in horse mackerel, 21.0% in sardine, 7.2% in hairtail, and 1% in common mackerel. 7. The fishes appeared continuously on way of fishing operation were spanish mackerel, hairtail, Yellow talil, crab, etc. An anchovy and sardine were caught mainly from March to July or August, horese mackerel and common mackerel from May to November. but puffer, swell fish, saury and filefish were caught mainly from April to October. 8. The sum of catch was largest in June, at which the wind direction was NE to SSW, the speed below 3.2m/sec, the atmospheric pressure below 1008mb, and precipitation beyond 154mm.

• Journal of Fisheries and Marine Sciences Education
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• v.10 no.1
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• pp.15-30
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• 1998

The variation of the catches of Skipjack(Euthynnus pelamis) and the relationships between the SST and the fishing ground is examined using the catches data of skipjack obtained by Iwawada Fisheries Cooperative of Chiba Prefecture in Japan from 1982 to 1988. The annual mean catch for Skipjack was 151,375.1kg. the annual fluctuation of catch was that the catch in 1984 was increasing, but it was decreased less than 50% in 1985, and was repeated after being a little recovered in 1986, and it was recovered with the level of 1984 in 1988. The fluctuation of catch for Skipjack in every fishing term is that daily mean catch of the primary fishing term (January, February and March) is 894.6kg, but the middle fishing term(April and May) more than four times of the primary fishing term is 3,666.0kg, the last fishing term(June and July) was decreasing at 767.9kg and the fishing ground gradually becomes extinct. The annual mean SST in fishing ground was an extent of from $19.0^{\circ}C$ to $20.2^{\circ}C$, the mean SST of every year except 1983 was from $19.0^{\circ}C$ to $19.9^{\circ}C$. It is said that the optimum SST of Skipjack in Sotobo sea area is the degree of $19.0^{\circ}C$. Therfore, the thing which will guess the time and the location appeared the optimum SST is the very important factor to operate efficiently. About the extent of SST in fishing ground, it was from $17.0^{\circ}C$ to $19.0^{\circ}C$ on March, from $17.5^{\circ}C$ to $20.5^{\circ}C$ on April and from $17.5^{\circ}C$ to $23.5^{\circ}C$ on May, which the extent of SST was gradually larger and larger, on June from $21.0^{\circ}C$ to $23.5^{\circ}C$, fishing ground was formed only the degree of SST more than $21.0^{\circ}C$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.16 no.4
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• pp.341-348
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• 1983

The Relationship between the distribution of the fishing grounds of anchovy and the oceanographic conditions in the Korean Waters are investigated by using the data of the catch of anchovy by the gill net fishery (Fisheries Research and Development Agency, 1969-1982) and the oceanographic observation data (Fisheries Research and Development Agency, 1979). The main fishing ground of anchovy by the gill net fishery was five fishing areas located in the adjacent seas of Sockcho, Kuryong-po, Kijang, Keoje island and Chungmu, the area of which occupies no more than $20\%$ of all fishing grounds, and it appeared that about $80\%$ of mean catches of fourteen years was concentrated in this area. The main fishing periods were from April to June and October to November. The coefficient of variation of the catch for the main fishing ground were from 0.3 to 0.6 and the condition of all fishing ground was generally stable. The mean CPUE was 81.2 kg/set at the main fishing ground. The annual mean catch of anchovy by the gill net was the smallest in February and the largest in May through a year. It was found that the fluctuation is related to the expansion and reduction of the isothermal line of $10^{\circ}C$.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.52 no.2
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• pp.130-140
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• 2016

This study analyzed annual catch trend during 45 years and monthly catch of the least 10 years (2005~2014) for chub mackerel caught in the Korean coastal waters. To determine fishing status of chub mackerel, fork length measurements were conducted at least twice every week for 100 individuals randomly selected at the Busan Cooperative Fish Market from January of 2012 to December of 2014; and biological characteristics and proximate composition (moisture, protein, fat, ash) were analyzed by length class (I~IV) on a monthly basis from January to December of 2014. Monthly catch trend showed low level below 5,000 mt from February to July, whereas high level above 15,000 mt from October to December. For the period between 2012 and 2014, annual average catch proportion of juvenile were relatively high at 68.1%, 53.1% and 53.2% from January to April, before spawning season, while those were low at 21.5%, 20.7% and 29.12% from June to November. As for the change in the proximate composition per 100 g of muscle, protein and ash did not change much by seasons and length class, whereas fat and moisture contents showed large fluctuations and complementary relationship between the two factors. Regardless of length class, monthly average fat content, containing Omega-3, showed the lowest at 7.18 g in April and highest at 19.27 g in December, which exhibited 2.6 times difference from one another. Regardless of fishing seasons, fat content by length class were 19.06 g for the class I and 6.43 g for the class IV, which showed three times difference. Fat contents of the class I were high at 26.97 g and 27.19 g in November and December, while low at 8.37 g and 9.99 g in April and May. Especially, fat contents from January to May were 5.0 g, which was the lowest. Therefore, it is expected that consumer could indirectly contribute fisheries management through their understanding and wise consumption based on fishing status and fluctuation of proximate composition.