• Title, Summary, Keyword: Catch fluctuation

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A Study on the Prediction of Fishing Conditions of Common Squid , Todarodes Pacificus Steenstrup in the Eastern Korean Sea (한국동해안 오징어 어황예측에 관한 연구)

  • Park, Jong-Hwa;Choi, Kwang-Ho;Lee, Ju-Hee
    • 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.

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Studies on the Catch by Trawl Fishing in the Atlantic Coast of Africa -II Diurnal Variation of the Catch of Important Species Groups per Unit Hauling (대서양 아프리카연안 트로올어장의 어황에 관하여 -II)

  • 김진건
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.15 no.2
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    • pp.67-76
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    • 1979
  • Diurnal variation of the catch of some important species groups in the Northwestern coast of Africa were studied on the basis of fish catching data compiled by a stern trawler(G.T., 499ton 2,200ps). The experimental fishing has been conducted from September, 1975 to August, 1976. The catch of the important groups I. e. squid, cuttlefish, octopus, sole fish and sea bream revealed different fluctuation patterns. The results obtained are as follows: 1. The catch of squid caught in daytime(0900-1800) was greater than that caught in night (2100-0600). 2. The catch of cuttle fish caught in daytime was more than that caught in night. In the daytime, large size group(heavier than 300g) was caught dominately during midday (1200-1500) whereas the small size group, lighter than 300g, was caught dominately during the time of sunrise (0600-0900) and sunset (1800-2100). 3. The catch of octopus varied according to the size groups. The large sige group, heavier than 700g, was caught predominately during daytime and the small size group, lighter than 700g, was caught predominately during night. 4. The catch of sole fish caught in night was greater than that caught in daytime. 5. The catch of sea bream and miscellaneous fishes including sardin, jack-mackerel and etc. was greater in daytime.

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The Effect of Interannual Variations in Water Temperature on the Yellowtail Catch, Seriola Quinqueradiata, in the Eastern Part of the Korean Peninsula (동해 연근해 수온의 경년변화가 방어 어획량에 미치는 영향)

  • Kim, Sang-Woo;Ahn, Ji-Suk;Lee, Yoon
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.23 no.7
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    • pp.909-917
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    • 2017
  • In this study, we investigated the relationship between catches of yellowtail and water temperature at the set net fisheries of Gyeongsangbuk-do (Gyeongbuk) and Gangwon-do (Gangwon) off the east coast of Korea from May-November, 1980-2010. We also analyzed the water temperature and fluctuation of catches during the northward moving period (May-August) and southward moving period (September-November) using NOAA satellite images. Although the total catches fluctuated year by year, catches increased during the southward moving period when the water alongside the coast warmed. Yellowtail catches during the southward period in fall were higher than those during the northward period in spring or summer. The catch when the water temperature decreased was larger in Gyeongbuk than in Gangwon for all periods However, the catch when the water temperature increased was much larger in Gangwon than in Gyeongbuk. This indicates that high summer temperatures (> $25^{\circ}C$) affected the coast of Gangwon, with high water temperature ($20^{\circ}C$) maintained in the region during fall. Therefore, the increased catch in Gangwon was due to longer yellowtail presence caused by increased water temperature.

Study on the Intensive Catching Method of Anchovy for Live Bait-III Relation Between Variation of Sea Condition and Catch of Anchovy in the Southern Coast of Korea (활멸치의 집약적 생산수단에 관한 연구 -III)

  • 한영호
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.15 no.1
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    • pp.23-33
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    • 1979
  • This paper was analysed based on the oceanographic and meteorological data complied from 1971 to 1977 for that search relationships among the fluctuation of sea condition and weather condition, and the catch of anchovy. In the year when heat loss from the sea surface in winter was maximum(in 1974, 658 Iy), temperature of midwater in summer was lower 2~4\ulcornerC than normal year. While heat loss was minimum (in1973, 487 Iy), temperature of mid water was higher 2\ulcornerC. When temperature of mid water of southern coast from June to August was higher than normal year, anchovy was caught good deal, but that was lower than normal year was bad fishing. When it had much precipitation (in 1973, 256mm), plankton was checked maximum (12cc) and also the catch of anchovy too (11, OOOm/t). While precipitation was minimum (in 1976, 123mm), plankton (3cc) and anchovy (2, 800m/t) was a litle. If we calcalate heat budget in winter, we can forecast temperature of mid-water in summer of following year. Therefore we may be able to forecast catch anchovy.

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Climate Change and Expansion of Squid Catches in Korea (한국에서의 기후변화와 오징어 어획의 확장)

  • Kim, Jong-Gyu;Kim, Joong-Soon
    • Journal of Environmental Health Sciences
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    • v.43 no.6
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    • pp.516-524
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    • 2017
  • Objectives: The annual catch of the common squid Todarodes pacificus in Korean coastal waters has gradually increased since the late 1980s. We investigated the long-term effects of climate variability on the variation in catches of the squid in the offshore fisheries of Korea. Methods: Moving average method, correlation analysis, and regression analysis were used to determine the relationship between the environmental factors and fluctuation in the catch of the squid during the past 30 years (1981- 2010). A ten-year moving average was calculated and used for each variable. Results: Squid catches in Korean coastal waters increased over time, and there were significant variations within every ten years (p < 0.001). Air temperature, atmospheric pressure, and wind grade among the meteorological factors, alongside sea surface temperature (SST) and concentrations of phosphate phosphorous, and nitrite/nitrate nitrogen in the sea water increased and were positively related with the catch size of squid (p < 0.001). However, salinity decreased and was negatively related with the catch size (p < 0.001). The increase in air temperature and SST was almost parallel, although there was a time lag between the two factors. Conclusion: These results suggest that there is a causal association between climate change and squid populations. Climate change, especially ocean warming, appears to have been largely favorable for squid range expansion into Korean seas. Although the expansion may be helpful for the human food supply, the safety of the squid caught should be monitored since the concentrations of phosphorous and nitrogen in the sea water increased, which indicates that Korean seas have grown gradually more polluted.

Effects of Climate-induced Variation in the Catch Distribution and Biological Characteristics of Skipjack Tuna Katsuwonus pelamis in the Western and Central Pacific Ocean (기후변화가 중서부태평양 가다랑어(Katsuwonus pelamis)의 어획분포와 생물학적 특성에 미친 영향)

  • Kim, Eunjung;Moon, Daeyeon;Kim, Suam
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.48 no.4
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    • pp.489-497
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    • 2015
  • To reveal the spatial and temporal variability in the distribution, growth, and maturation of skipjack tuna Katsuwonus pelamis in the western tropical Pacific, we compared two El $Ni{\tilde{n}}o$-Southern Oscillation (ENSO) signals and the sea surface temperature (SST) in the main fishing area with fishery and biological data. An index of skipjack tuna distribution was calculated using Korean purse seine fishery data from 1985 to 2003. Biological data for skipjack tuna were collected monthly from Korean catches during the 1994-2003 period. The catch was more closely related to the SST in the main fishing area than to the ENSO signals. However, cross-correlated function analysis showed delayed interactions between abiotic and biotic factors. The El $Ni{\tilde{n}}o$ events preceded the eastward movement of the fishing center by 2-3 months. El $Ni{\tilde{n}}o$ had a positive effect on the skipjack tuna catch, and the change in the Southern Oscillation Index (SOI) preceded the catch fluctuation by ca. 5-7 months. In addition, negative El $Ni{\tilde{n}}o$ effects on gonad maturation and the mean length of skipjack tuna were detected with time lags of 12 and 7 months, respectively. The length frequency indicated that the regime-specific growth pattern at each discrete period seemed to be related to the ENSO.

Variation of Fisheries Conditions of Fishing Ground of Yellow Croaker (Pseudosciaena polyactis Bleeker) in the East China Sea and the Yellow Sea (동중국해와 황해에서의 참조기(Pseudosciaena polyactis Bleeker) 어장의 어황 변동)

  • BAIK Chul-In;LEE Chung Il;CHOI Kwhang-Ho;KIM Dong-Sun
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.38 no.6
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    • pp.413-424
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    • 2005
  • The study focused on the fluctuation of the fisheries conditions in fishing ground of yellow croaker, Pseudosciaena polyactis Bleeker. A long-term decreasing trend was observed in the accumulated catches of the species since 1926, with increasing-decreasing fluctuation repeating 6 times. Periodicity was observed in 10-year interval in good fishing years, but not in poor fishing years which had irregular fluctuations. From the geographical distribution of the past catch per unit effort, it was presumed that a group of the species seasonally migrated but most of the groups stayed throughout year in the western area off Cheju Island, which was different from the assumptions of the 1970's. The fishing grounds were distributed along the migration route differently by season, throughout the Yellow Sea and the East China Sea, but shifted gradually southward and narrowed down to the area of $32^{\circ}N-125^{\circ}E$ off Cheju Island, where the center of fishing grounds was given birth to throughout the year with a relatively high density from autumn to spring. It was noted that a negative correlation was shown between the area of fishing grounds and density distribution of catch.

Analysis on the Present Business States of Coastal and Off-shore Fisheries by Type of Fishery (연근해어업의 업종별 경영현황 분석)

  • CHANG, Ho-Young
    • Journal of Fisheries and Marine Sciences Education
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    • v.15 no.2
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    • pp.166-175
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    • 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%.

Seasonal Species Composition and Fluctuation of Fishes by Beam Trawl in Yeoja Bay (빔트롤을 이용한 여자만 어류의 계절별 종조성과 변동)

  • Lee, Sun-Kil;Seo, Young-Il;Kim, Joo-Il;Kim, Hee-Yong;Choi, Mun-Sung
    • Korean Journal of Ichthyology
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    • v.23 no.3
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    • pp.206-216
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    • 2011
  • To investigate seasonal and yearly variation of fishes composition in Yeoja Bay of Korea, fisheries survey were carried out using beam trawl from 2006 to 2009. A total of 44 fish species were collected. The major dominant species were Pennahia argentatus, Thryssa adelae, Thryssa kammalensis and Cynoglossus joyneri, which were occupied over 63% total individuals, and 50% of wet weight. The diversity index (H') was about 1.62 (1.46~1.77) by seasons, and seasons of similarity by fishes were divided into two groups, which were March with December and June with September. ANOVA test showed that there were not significant difference between individuals and catch weight (kg) per unit area (km$^2$) by year and season, except for catch weight per unit area by season.

The Relationship between Coastal Cold Water and Catch Conditions of Common Squid(Todarodes Pacificus STEENSTRUP) in the East Sea of Korea in Summer (여름철 동해안 연안 냉수와 오징어 어황과의 관계)

  • Park, Jong-Hwa;Park, Kwang-Ho;Lee, Ju-Hee
    • 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.

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