• 한국어류학회지
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• 제25권1호
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• pp.25-32
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• 2013

We studied the age and growth of striped beakperch (Oplegnathus fasciatus) in the Jeju marine ranching area using a total of 423 otoliths from August 2009 to August 2010. The surface reading method, which was etched with 5% HCl, was the best method to read ages of this fish. The monthly mean fork length ranged from 20.9 cm to 27.7 cm in the Jeju marine ranching area during from August 2009 to August 2010. The annual ring was formed in July to September once a year. Fish were principally composed of 3 to 5 years old and the oldest was 12 years old. The von Bertalanffy growth parameters of this species, which were estimated from a non-linear regression, were $L_{\infty}$=48.20 cm, $t_0$=-1.031yr, and K=0.123/yr.

• 수산해양기술연구
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• 제50권1호
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• pp.30-38
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• 2014

Hydro-acoustic survey was carried out to investigate the spatial characteristics of fish distribution near two artificial reefs (AO: large octagonal semi-sphere and AC: combined custom built) having different types in Jeju marine ranching area. The survey system consisted of scientific echo sounder (EK60), DGPS system, and ECDIS (Mecys). Field survey was conducted on August and October 2012 with star survey and line transect survey line method, and species composition was investigated from gill net fishing survey. The acoustic signals from individual fishes and small fish schools were mainly recorded around AO, but large and strong signals from large fish school were mainly detected in the top layer of and the water column near AC. The echogram suggest that the fish aggregation for the two types of AO and AC exist the significant difference in fish species and spatial distribution pattern.

• 수산해양기술연구
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• 제46권2호
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• pp.139-147
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• 2010

This study monitored a variety of marine fish communities in artificial reefs unit of the total 5 types (Dice type, Octagonal turtle type, Two-stage tube type, Gazebo type, Tetrapod type) which are located in the marine ranching at Jeju island by scuba diving in May, July, October and December 2009. Underwater photographing was accomplished at total 3 phases (condition of artificial reefs photographing, concentric circle movement photographing and line transect photographing). The preservation condition of artificial reefs facility was very good, and the dominant species were Chromis notatus, Sebastes thompsoni, Oplegnathus fasciatus and Halichoeres poecilopterus. Fish abundance was high in May and June, and low in October and December, 2009. Chromis notatus was dominant at the all types of artificial reefs, Halichoeres poecilopterus for Gazebo type and Tetrapod type of artificial reefs, and Sebastes thompsoni for Dice type, Octagonal turtle type and Two-stage tube type of artificial reefs.

• 한국환경생물학회:학술대회논문집
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• 한국환경생물학회 2006년도 춘계학술대회 초록집
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• pp.9-10
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• 2006

• Ocean Science Journal
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• 제42권2호
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• pp.117-127
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• 2007

The dynamics of phytoplankton abundance with seasonal variation in physicochemical conditions were investigated monthly at 10 stations around the Chagwi-do off the west coast of Jeju Island, Korea, including inshore, middle shore, and offshore in the marine ranching are a from September 2004 to November 2005. Water temperature varied from 12.1 to $28.9^{\circ}C$ (average $18.8^{\circ}C$), and salinity from 28.9 to 34.9 psu (average 33.7 psu). The chlorophyll a concentration was $0.02-2.05\;{\mu}g\;L^{-1}$ (average $0.70\;{\mu}g\;L^{-1}$), and the maximum concentration occurred in the bottom layer in April. A total of 294 phytoplankton species belonging to 10 families was identified: 182 Bacillariophyceae, 52 Dinophyceae, 9 Chlorophyceae, 12 Cryptophyceae, 6 Chrysophyceae, 4 Dictyophyceae, 13 Euglenophyceae, 6 Prymnesiophyceae, 5 Prasinophyceae, and 5 Raphidophyceae. The standing crop was $2.21-48.69\times10^4\;cells\;L^{-1}$ (average $9.23\times10^4\;cells\;L^{-1}$), and the maximum occurred in the bottom layer in April. Diatoms were most abundant throughout the year, followed by dinoflagellates and phytoflagellates. A phytoplankton bloom occurred twice: once in spring, peaking in April, and once in autumn, peaking in November. The spring bloom was represented by four Chaetoceros species and Skeletonema costatum; each contributed 10-20% of the total phytoplankton abundance. The autumn bloom comprised dinoflagellates, diatoms, and phytoflagellates, of which dinoflagellates were predominant. Gymnodinium conicum, Prorocentrum micans, and P. triestinum each contributed over 10% of the total phytoplankton abundance.

• 수산해양기술연구
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• 제46권2호
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• pp.157-163
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• 2010

The indirect target strength (TS) estimation method which uses the Kirchhoff ray mode model (KRM model) was discussed to apply for a biomass estimation in the water of mixed species. TS of 25 live scorpion fishes for 120kHz were measured by a tethered method and of others dominant 5 species in the marine ranching ground of Jeju coastal water including a scorpion fish were also estimated by KRM model. The measurement TS of scorpion fish well agreed with the theoretical values and the standard formula of scorpion fish was estimated as $TS_{120kHz}=20Log\;(L)-72.9$ ($r^2=0.67$). TScm values estimated on trial to each sample of dominant 5 species were from -69.3dB to -75.1dB at 120kHz and they were in the general range of swimbladdered fish. It was clarified that TS by KRM model can be used to estimate fish biomass estimation by increasing a sample number and is more effective under the condition that there is rare TS information for inhabiting species in mixed-species area.

• 수산해양기술연구
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• 제48권2호
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• pp.128-136
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• 2012

Hybrid surveys using hydroacoustic and fish sampling gears such as trammel net, trap were conducted to investigate total biomass, distribution and dominant fish species of the demersal fishes in the marine ranching area (MRA) of Jeju. Four surveys were carried out in June, August, October and November using 38kHz quantitative echo sounder. Catch data using trammel net and trap were used to calculate biomass and to examine dominant fish species. Fish schools were mainly detected in the waters of 20 meters below and around Chagwido waters. By the result of fishing experiments, fish species living in MRA of Jeju were about 40 species, dominant fish species of a detectable fish such as Family Sparidae and Family Monacanthidae etc. were identified 59.4~68.8% of total biomass. Based on the hydroacoustic data, fish length-weight function and target strength information, mean density of the demersal fish estimated were as follows; 0.88g/$m^2$ on June, 1.12g/$m^2$ on August, 1.35g/$m^2$ on October and 1.18g/$m^2$ on November. An estimated average biomass in MRA of Jeju was founded 20.5 tons in 2007, 20.6 tons in 2008, 23.0 tons in 2009, 25.9 tons in 2010. The results showed that biomass of MRA is getting increased slowly. Therefore the hybrid survey method using hydroacoustic and fish sampling gears is assured an effective biomass survey in the waters of mixed species.

• 한국산학기술학회논문지
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• 제16권11호
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• pp.7761-7772
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• 2015

제주 바다목장 해역의 식물플랑크톤 군집의 시 공간적 분포특성을 파악하기 위해 8개 정점의 표층과 10m 수심에서 2008년 4월부터 11월까지 4회 현장조사를 실시하였다. 식물플랑크톤 출현종은 63속 106종으로 다양하였다. 분류군별은 규조류가 61.3%, 와편모조류가 34.9%를 차지하였고, 시간적으로는 가을에 다양한 종이 출현하였다. 식물플랑크톤 현존량은 여름 $0.6cells{\cdot}mL^{-1}$에서 봄 $64.0cells{\cdot}mL^{-1}$의 범위로 매우 낮았다. 평균 세포밀도에 의한 연변동은 연평균 최저 11월 $0.9cells{\cdot}mL^{-1}$에서 최고 4월 $37.0cells{\cdot}mL^{-1}$로 변화하여 연평균 $11.7cells{\cdot}mL^{-1}$의 낮은 세포밀도를 나타내었다. 우점종은 4월에 Skeletonema costatum-like species(ls)에 의해 극우점되었다. 6월은 Torodinium teredo, Cylindrotheca closterium, Scrippsiella trochoidea, 9월은 S. costatum-ls, Thalassionema nitzschioides, Pseudo-nitzschia pungens, Ebria tripartita 그리고 11월은 Corethron pennatum, Dictyocha fibura, Neoceratium teres가 우점 출현하여, 기존 결과와는 다른 결과를 나타내었다. 생태지수 중에 종 다양성 지수는 4월과 9월에 낮고 6월과 11월에 높았다. 식물플랑크톤 군집으로 본 제주 바다목장 해역의 생물해양학적 특성은 연간 크기가 작은 나노플랑크톤에 의한 점유률이 높았고, 특정 종에 의해 극우점되는 외부 영양염류 유입보다는 생태내의 물질순환에 따른 재생산비율이 높은 것으로 판단되었다.

• 한국산학기술학회논문지
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• 제15권10호
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• pp.6388-6398
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• 2014

제주 바다목장 해역의 크기별 식물플랑크톤 조성비 및 물질순환 특성을 파악하기 위해 2008년 4월에서 11월까지 4회 현장조사를 하였다. 제주 바다목장 해역의 표층에서 초미세플랑크톤은 $0.03{\sim}0.84{\mu}g/L$에서 평균 $0.30{\mu}g/L$로 17.3%, 미소플랑크톤은 $0.22{\sim}3.93{\mu}g/L$에서 평균 $1.35{\mu}g/L$로 78.0%, 소형플랑크톤은 $nd{\sim}0.24{\mu}g/L$에서 평균 $1.73{\mu}g/L$로 4.7%를 차지하였다. 10m 수층도 측정값에서 다소 차이는 있지만 경향은 표층과 매우 유사하여, 계절에 따라 엽록소 a의 측정값은 변화하지만, 미소플랑크톤 조성비는 연중 높게 나타났다. 또한 제주 바다목장 해역의 크기별 엽록소 a의 분포는 지리적으로 인접한 우리나라 연안해역이나, 쿠로시오나 쓰시마난류의 영향을 받는 동중국해 및 일본연안보다도 계절풍 이후의 열대 해역 연안환경과 유사한 것으로 나타났다. 즉 제주 바다목장 해역의 물질순환은 전통적인 먹이사슬보다는 저차영양단계는 미세먹이망으로 구성되어, 기초생산은 영양염류 공급보다 미소동물플랑크톤의 포식압 등의 top-down 동태에 의해 조절될 가능성이 큰 것으로 판단되었다.

• 한국수산과학회지
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• 제48권6호
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• pp.947-959
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• 2015

Variations in the species composition, biomass and size distribution of fisheries resources in the Uljin marine ranching area were investigated using trammel nets at two stations (artificial reef and natural rocky area) from 2009 to 2010. During the survey, a total of 74 species were sampled with a mean density of 132 ind./net and mean biomass of 21.56 kg/net. In the natural rocky area, a total of 45 species were sampled at a mean density of 202 ind./net and mean biomass of 28.81 kg/net, while in the artificial reef area, samples included a total of 56 species, with means of 62 ind./net and 14.30 kg/net. The dominant species, comprising over 3% of the total number of individuals, were Suberites ficus (30.8%), Ovalipes punctatus (19.2%), Paralichthys olivaceus (11.7%), Pleuronectes herzensteini (4.7%), Kareius bicoloratus (3.5%), Pseudopleuronectes yokohamae (3.5%) and Eopsetta grigorjewi (3.0%). The dominant species, in terms of biomass, comprising over 5% of the total biomass, were P. olivaceus (22.1%), S. ficus (18.7%), O. punctatus (7.2%), Hexagrammos otakii (6.6%), P. yokohamae (5.7%), K. bicoloratus and P. herzensteini (5.3%). A cluster analysis and non-metric multidimensional scaling (nMDS) analysis based on the Bray-Curtis similarity of fourth root transformed data for number of species and individuals, was divided into two groups: the artificial reef area (group A) and the natural rocky area (group B).