• 수산해양기술연구
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• 제32권2호
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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${\textperthousand}$.

• 수산해양기술연구
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• 제34권1호
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• pp.67-73
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• 1998

In order to find out the environmental factors influencing the catch of anchovy lift nets in kamakbay, the three oceanographic factors, i. e., the water temperature, the salinity, the amount of chlorophyll-a were observed respectively from August 1 to 12, 1995 and from September 20 to 26, 1995, and each of them was compared with the catch of anchovy by the lift net. The results obtained are summerized as follow : 1) The water temperature was ranged from 17.3 to 29.6$^{\circ}C$ and its difference between the surface and bottom was 1 to 3$^{\circ}C$. In the three areas, A, B and C, the area A was the hightest in temperature, the area B being a second, and the area C being the lowest. 2) The salinity was ranged from 32.20 to 33.47$\textperthousand$ and its difference between the surface and bottom was not significant. In the three areas, the area A was the highest in salinity, the area B being a second, and the area C being the lowest. 3) The amount of chlorophyll-a was ranged from 0.19 to 5.30mg/m supper(3) and its difference among the three areas was not significant. Daily variation of the amount was very irregulated because the position operated was changed daily. 4) A comparison of the water temperature, the salinity and the amount of chlorophyll-a with the catch gave that the water temperature and the amount of chlorophyll-a had large influence on the catch and the salinity did not so. However, the influence of the amount of chlorophyll-a was larger than that of the water temperature. 5) The catch of anchovy was large respectively during two hours after sun set and during two hours before sun rise.

• 수산해양기술연구
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• 제59권4호
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• pp.315-327
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• 2023

In the last five decades, there has been a consistent decline in the total catch of fisheries in the Korean jurisdiction since the peak in 1986. The decline in catch slowed and slightly rebounded in the 2000s, but changed back to a decline in the 2010s. As indicators that can identify changes in the marine ecosystem, trophic level (TL), biodiversity index (H'), and the ratio between pelagic fish and demersal fish (P/D) were analyzed by each local marine ecosystem. There were some different changes in each local marine ecosystem, but the mean TL and H' decreased and P/D increased in general in Korean waters. Demersal fish, which were dominant in the 1970s and 1980s, declined, and small pelagic fish and cephalopods have dominantly changed since the 1990s. However, these changes are not simple, and they are fluctuating in complex ways relating to each marine ecosystem and the timing. It is believed that changes in marine ecosystems in Korean waters are likely caused by a combination of fisheries and climate change. The ecosystem indicators reflected a change in the total catch, a sharp drop in catch of demersal fish, and increasing catch of pelagic fish since the mid-1980s.

• 수산해양기술연구
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• 제23권4호
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• pp.177-183
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• 1987

정치망어업에 의한 최근 15년 간(1971~1985년)의 어획통계자료를 이용하여 어획량의 경년변동과 계절변동, 해역별 및 어종별 어획량 변동 등을 조사한 결과는 다음과 같다. 1. 정치망어업의 어획량은 1971년에 16,787M/T, 1985년에 84,103M/T으로서 대체로 증가추세에 있으며, 1978년부터 급격히 어획량이 증가하기 시작하여 1979년에 99,475M/T으로서 최대치를 나타내었는데, 이것은 쥐치가 대량 어획되어 어획량의 64%를 차지하였고, 1976년 수산어법의 개정에 따른 통계수치의 증가에 원인이 있으며, 연안 수온의 변화와도 밀접한 관계가 있었다. 2. 월평균어획량이 10~11월에 8,000~12,000M/T으로서 년평균 어획량의 32%를 차지하므로 정치망어업의 주어기는 10~11월로 볼 수 있다. 3. 1976년 이전에는 남해구에서, 1977~1980년에 동해구에서 정치망어업을 주도해 왔으나, 1981년 이후에는 그 경향이 불규칙하였다. 4. 어획량변동의 유사성 측면에서 볼 때, 어종별 어획량변동은 뱅어, 도루묵, 갈치, 멸치, 등과 같이 어획량이 감소하는 군, 노가리, 밴댕이, 망둥어, 전어, 양미리, 쥐치 등과 같이 증가하는 군 및 그 외 증감경향이 불분명한 군의 3개 군으로 대별할 수 있다

• 한국수산과학회지
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• 제44권5호
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• pp.499-505
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• 2011

The fishing grounds of Korean large-pair trawlers have shifted since exclusive economic zones (EEZs) were established in a fisheries agreement involving countries neighboring Korean waters. The distributions of marine ecosystems and fisheries resources have been changing with environmental changes such as global warming and with the shift in species targeted as a result of changes in fishing technology and fishing gear. This study analyzed variation in the species assemblages caught in Korean waters by large-pair trawlers as a result of these geopolitical and environmental changes. The data used in this study were obtained from the Fishery Production Statistics of Korea and the Port Sample Survey of the National Fisheries Research and Development Institute (NFRDI) from 1990 to 2007. Hierarchical clustering analysis (HCA) and correspondence analysis (CA) were used to explore the characteristics of the catch-species composition. The overall variation in the species composition of the catch of Korean large-pair trawlers showed that the proportions of croaker Johnius grypotus, small yellow croaker Larimichthys polyactis, eel Anguilla japonica, and blue crab Portunus trituberculatus decreased, whereas those of hairtail Trichiurus lepturus, Spanish mackerel Scomberomorus niphonius, anchovy Engraulis japonicus, and common squid Todarodes pacificus increased in Korean waters over the 18-year period. The results of the HCA of the annual catch data by species showed four different distributions of fish species according to year. Results of the CA showed that the species assemblages differed between the 1990s and 2000s.

• 한국수산과학회지
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• 제47권4호
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• pp.419-423
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• 2014

We consider changes in the fishing ground of the small yellow croaker Larimichthys polyactis and discuss their utility in predicting fishing conditions for this species. The fishing ground, which having been formed around Jeju Island since the 1970s, is dominated by the Yellow Sea Bottom Cold Water (YSBCW), and variation in its southward expansion from the Yellow Sea is the single most key environmental factor affecting the L. polyactis catch. When the YSBCW showed strong expansion and the fishing ground shifted to the west and southwest of Jeju Island, as occurred in the late 1980s, late 1990s, and early 2000s, the L. polyactis catch was low; conversely, when expansion was weak, as in the early 1990s and late 2000s, the L. polyactis catch was high. This relationship was statistically significant and should be useful in predicting fishing conditions for L. polyactis.

• 한국수산과학회지
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• 제46권6호
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• pp.917-922
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• 2013

Changes in fishing ground of the large pair trawler were investigated by year, month and species off Korean waters. We used catch data by sea-block lat.${\times}$long.:$30^{\prime}{\times}30$) of the National Fisheries Research and Development Institute (NFRDI) and monthly fishing production statistics of Korean statistic information service from 1990 to 2007. In the 1990s, the demersal fish like Larimichthys polyactis, Collichthys sp, Portunus trituberculatus and Muraenesox cinereus were the dominant species, and in the 2000s, they were changed from demersal fish into pelagic fish like Scomberomorus niphonius, Scomber japonicus, Engraulis japonicus and Todarodes pacificus. Species composition of catch showed temporal variation by cluster analysis deviding into 4 period, 1990-1994, 1995-2000, 2001-2003 and 2004-2007. Fishing ground in the 2000s was decreased up to 2/3 in the 1990s, while the density of catch in the fishing ground in 2000s was higher than the 1990s.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2008년도 춘계학술발표회
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• pp.143-145
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• 2008

동해의 오징어 어획량은 연변동 및 3-5년 그리고 10년 이상의 장주기적인 변동 특성을 보인다. 동해의 오징어 어획량은 어장이 분포하는 해역의 해양환경 뿐만 아니라 자원량 변동의 1차적인 요인으로 작용하는 산란장의 환경도 중요하게 고려된다. 오징어의 분포에 영향을 미치는 인자들 중 수온의 영향을 우선적으로 분석하였다. 동해에서 수온의 분포는 오징어 어장의 공간적인 분포 위치에 영향을 끼친다. 동해에서 어획되는 오징어는 대부분 난류어종으로 쓰시마난류수의 분포 형태에 따라 중심 어장의 위치도 변할 가능성이 높게 나타난다. 한편, 주 산란시기인 겨울철, 가을철 그리고 여름철의 산란장의 환경 변화 및 산란장의 면적 변화는 성어의 어획량과 밀접한 관련을 가진다.

• 한국어류학회지
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• 제18권3호
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• pp.223-233
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• 2006

2001년 4월부터 10월 사이에 돌산도 율림 앞바다, 2002년 4월부터 10월 사이에 연도 앞바다, 그리고 2003년 4월부터 12월 사이에 돌산도 임포 먼바다에서 정치망에 어획된 수산생물의 일일 어획자료를 이용하여 종조성과 양적 변동을 파악하고, 연도별, 장소간 종조성을 분석하였다. 2001~2003년에 여수 해역에서 정치망에 의해 삼치(Scomberomorus niphonius), 방어류 (Seriola spp.), 갈치(Trichiurus lepturus), 멸치 (Engraulis japonicus), 줄삼치(Sarda orientalis), 살오징어(Todarodes pacificus), 덕대(Pampus echinogaster), 밴댕이(Sardinella zunasi), 고등어(Scomber japonicus), 황아귀(Lophius litulon), 꼴뚜기(Loligo beka) 등이 양적으로 우세하게 어획되어 여수해역에서 정치망으로 어획된 어류의 종조성은 주로 표영성 어류가 대부분을 차지하였다. 연안역에서는 밴댕이, 덕대, 양태 (Platycephalus indicus), 꼴뚜기, 외해역에서는 삼치, 방어류, 갈치, 덕대, 살오징어, 검복(Takifugu porphyreus), 참돔(Pagrus major)의 표영성 주거종 (pelagic resident species)이 우세하였으며, 멸치는 남해 전체에서 계절적으로 연안과 외해를 이동하는 대표적인 우점종이었다. 봄에 연안에 밴댕이와 멸치가, 수심이 보다 깊은 외해에는 내유하는 멸치와 황아귀, 방어류 등 대상으로 어기가 시작되어 여름에 갈치, 삼치, 고등어, 방어류, 줄삼치, 덕대, 살오징어 등의 외양종이 연안과 외해에 회유하여 어획량이 높았다. 가을에는 연안에서 삼치, 멸치, 꼬치고기 (Sphyraena pinguis), 독가시치 (Siganus fuscescens), 주둥치 (Leiognathus nuchalis) 등이 우점하였고, 외해에서는 삼치, 덕대, 학공치(Hyporhamphus sajori), 고등어, 갈치 등이 여름에 이어 계속 출현하였으나 어획량은 감소하는 온대 해역의 전형적인 계절성을 보였다. 남해안에서 정치망에 어획된 출현종은 대부분 부어류이었으며 그 변화 정도가 심하였으나, 대형정치망 일일 어획자료은 부어류 종조성의 계절변동을 분석하는데 유의한 의미를 가질 것으로 판단된다.

• 수산해양기술연구
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• 제15권1호
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• pp.23-33
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• 1979

한국 연안에서는 연간 5~8만m/t정도의 멸치가 어획되고 있으나 주 어장은 경남 일원을 중심으로 남해안이다. 따라서 남해안의 어황변동을 예보할 수 있으면서 어업경영의 합리화에 크게 이바지 할 수 있을 것이고, 그에 따라 황멸치의 수급 계획 수립에도 크게 도움이 될 것이다. 여기서 먼저 1971~77년 7년간의 수온, 부유생물, 강수량과 열수지를 조사, 계산하고 그 해 봄철의 강수량을 조사하면 그 해의해황이 예측될 수 있고 그에 따라 멸치의 어황도 예보할 수 있을 것으로 기대된다