• 수산해양기술연구
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• 제58권2호
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• pp.159-174
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• 2022

Flow prediction was carried out through observational survey and three dimensional multi-layered numerical diagnostic model experiment to clarify the time and spatial structure of tidal current and residual flow dominant in the sea exchange and material circulation of the waters around Geumo Islands in the southern waters of Korea. The horizontal variation of tidal current is so large that it causes asymmetric tidal mixing due to horizontal eddies and the topographical effect creating convergence and dispersion of flow direction and velocity. Due to strong tidal currents flowing northwest-southeast, counterclockwise and clockwise eddies are formed on the left and right sides of the south of Sori Island. These topographical eddies are created by horizontal turbulence and bottom friction causing nonlinear effects. Baroclinic density flows are less than 5 cm/s at coastal area in summer and the entire sea area in winter. The wind driven currents assuming summer and winter seasonal winds are also less than 5 cm/s and the current flow rate is high in winter. Density current in summer and wind driven current in winter have a relatively greater effect on the net residual flows (tidal residual current + density current + density driven current) around Geumo Islands Sea area.

• 수산해양기술연구
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• 제47권4호
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• pp.356-368
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• 2011

Species composition of fishes and the recruitment properties of jack mackerel, Trachurus japonicus, in the waters around the Geumo Islands in the mid-South Sea were investigated by using both sides fyke nets every month from February to December 2010. During study period, a total of 30,503 fishes (1,380.4 kg) were collected and classified into 2 classes, 16 orders, 61 families and 121 species. The dominant species was jack mackerel occupying 80.5% of total individuals and 44.4% of total biomass. The fork length range of jack mackerel was 5.5-26.8 cm and individuals about 6 cm was appeared only in the middle and southern area of the Geumo Islands in May. The new recruitment of jack mackerel appeared from May in the waters around the Geumo Islands is probably caused by the warm water intrusion associated with the development of stratification due to the extinction of seasonal coastal cold waters by the increase of solar radiation heat. Furthermore, the jack mackerels less than 6 cm recruiting in the mid-South Sea in spring were considered as mixed ones by individuals spawned in the East China Sea and in the waters around the Jeju Island considering the collected time, migration period and spawning time of them.

• 한국어류학회지
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• 제19권3호
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• pp.225-235
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• 2007

여수반도와 금오열도의 섬들 중 하천이 발달한 돌산도, 금오도, 개도의 39개 지점에서 2003년과 2005년에 걸쳐 담수어류상과 하천의 물리적 특성을 조사하였다. 조사지역 내의 하천들은 대부분 길이가 짧고 유폭이 좁았다. 주된 하상구성물질은 cobble, pebble, gravel이었으며, 하구에 인접한 곳은 주로 gravel과 sand로 되어 있었다. 39개의 조사지점 중 상류형인 Aa형이 18지점으로 가장 많았다. 담수어류상의 조사에서 모두 16과 39종 3,397개체가 채집되었는데, 생활형 구분으로는 일차담수어가 27종(69.2%), 주연성 어종 9종(23.1%)으로 대부분을 차지하였으며, 과별 어종구성은 Cyprinidae가 12종(30.8%), Gobiidae가 10종(25.6%)으로 많았다. 한반도 고유종은 Rhodeus uyekii 등 8종이 확인되었는데, 여수반도에서는 8종 모두 나타났고 금오도에서는 1종, 돌산도와 개도에서는 확인되지 않았다. 외래종은 Lepomis macrochirus 1종이 출현하였다. 각 지구별 우점종을 보면 여수반도에서는 Zacco temminckii, 돌산도에서는 Rhinogobius brunneus, 금오도에서는 Leucopsarion petersii, 개도에서는 Oryzias latipes가 우점종이었다. 군집분석의 결과 여수반도가 가장 다양하고 안정된 집단의 구조를 지니고 있었으며 섬의 크기가 작아질수록 다양도와 풍부도가 떨어졌다. Kichulchoia brevifasciata가 본 조사에서는 확인되지 않아 본 지역에서는 절멸하였을 가능성이 있다. Acanthorhodeus gracilis와 L. petersii는 본 지역에서는 처음으로 분포가 알려지게 되었다.

• 한국수산과학회지
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• 제50권5호
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• pp.553-560
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• 2017

Fluctuations in the abundance and species composition of fishes in the coastal waters of Geumo-do, Yeosu, Jeollanam-do, Korea were investigated from 2002 to 2005. A gill net with entrances on both sides was used to collect a total of 469 individuals (55,180 g) of 3 orders, 18 families, and 28 species. The dominant species was Sebastes inermis (60 individuals, 5,670 g), followed by Neoditrema ransonneti (46 individuals, 2,290 g), and Pseudaesopia japonica (38 individuals, 3,080 g). The highest number of individuals was found in 2004, while the biomass was highest in 2005. The diversity index was highest in 2004 (H'=2.703) and lowest in 2002 (H'=2.580). The dominance index was highest in 2004 (D=3.983) and lowest in 2002 (D=3.404). The richness index was highest in 2003 (RI=0.337) and lowest in 2002 (RI=0.261). Changes in temperature and salinity affected the community structure and the location of spawning grounds. The number of individuals and total biomass increased with changes in temperature and salinity each year.

• 수산해양기술연구
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• 제55권3호
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• pp.252-263
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• 2019

In order to understand the tidal current and mean flow at the west channel of Yeoja Bay in the South Sea of Korea, numerical model experiments and vorticity analysis were carried out. The currents flow north at flood and south at ebb respectively and have the reversing form in the west channel. Topographical eddies are found in the surroundings of Dunbyong Island in the east of the channel. The flood currents flow from the waters near Naro Islands through the west channel and the coastal waters near Geumo Islands through the east channel. The ebb currents from the Yeoja Bay flow out along the west and the east channels separately. The south of Nang Island have weak flows because the island is located in the rear of main tidal stream. Currents are converged at ebb and diverged at flood in the northwest of Jeokgum Island. Tidal current ellipses show reversing form in the west channel but a kind of rotational form in the east channel. As the results of tide induced mean flows, cyclonic and anticyclonic topographical eddies at the northern tip but eddies with opposite spin at the southern tip are found in the west channel of Yeoja Bay. The topographical eddies around the islands and narrow channels are created from the vorticity formed at the land shore by the friction between tidal currents and the west channel.

• 해양환경안전학회지
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• 제25권5호
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• pp.589-600
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• 2019

한국 남해안 금호열도 주변 다도해역의 조류특성과 해수순환 구조를 파악하기 위해 대조와 소조시 ADCP bottom tracking을 이용한 25시간 선박 항주관측을 실시하였다. 대조시 낙조와 창조 방향은 남동-북서이며, 최강유속은 표층 약 40 cm/s이다. 개도주변은 지형적 특성으로 주변해역의 탁월유향과 다르고, 유향 유속의 분산이 크다. 전 구간 표~저층 흐름에 두드러진 경압모드 성분은 없었다. 이는 좁은 수로와 얕은 수심, 빠른 유속으로 지형성와류나 eddy로 인한 연직혼합이 활발했음을 나타낸다. 소조시 조류는 남남동-북북서, 평균유속은 대조의 85 %이다. 탁월유향은 대조보다 우세하지 못하고 지속시간도 짧다. 흐름은 연직방향 유속시어, 수평와류, 비대칭 조류혼합으로 물질의 수평 연직이동이 왕성할 것으로 추정된다. 일평균조류는 개도 서~북서 수로해역이 북서~북동, 금오도 서쪽은 서남서~남남서 방향 최대 21 cm/s의 흐름이 존재한다. 소리도 서쪽에는 좌선환류나 와류가 형성되었다.

• 수산해양기술연구
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• 제46권4호
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• pp.346-357
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• 2010

Characteristics of age and growth of the black rockfish, Sebastes inermis sampled in the Jeonnam Marine Ranching Area (JMRA) around Geumo Islands south of Yeosu were investigated using 642 otoliths from March 2009 to February 2010. The opaque zone was formed in September once a year and hence it was used as an annulus. The parturient period was December to January, and therefore the duration from fertilization to the complete formation of the opaque zone was nineteen months. From the parameters calculated using the average length when the year ring was formed, growth of S. inermis were expressed by von Bertalanffy growth equation as $L_t$=23.267 ($1-e^{-0.4406(t+1.1971)}$) for females and $L_t$=22.030 ($1-e^{-0.5312(t+0.6834)}$) for males when is total length in age t. Through the growth equations, the maximum length was determined as 23.27cm for females and 22.03cm for males and the growth factor as 0.4406/yr and 0.5312/yr, respectively. Finally, the growth of female S. inermis is larger than the one of male S. inermis.