• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2008년도 International Symposium on Remote Sensing
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• pp.320-323
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• 2008

This study attempts to establish a system extracting and monitoring cultural grounds of seaweeds (lavers, brown seaweeds and seaweed fulvescens) and abalone on the basis of both KOMPSAT-2 and Terrasar-X data. The study areas are located in the northwest and southwest coast of South Korea, famous for coastal cultural grounds. The northwest site is in a high tidal range area (on the average, 6.1 min Asan Bay) and has laver cultural grounds for the most. An semi-automatic detection system of laver facilities is described and assessed for spacebome optic images. On the other hand, the southwest cost is most famous for seaweeds. Aquaculture facilities, which cover extensive portions of this area, can be subdivided into three major groups: brown seaweeds, capsosiphon fulvescens and abalone farms. The study is based on interpretation of optic and SAR satellite data and a detailed image analysis procedure is described here. On May 25 and June 2, 2008 the TerraSAR-X radar satellite took some images of the area. SAR data are unique for mapping those farms. In case of abalone farms, the backscatters from surrounding dykes allows for recognition and separation of abalone ponds from all other water-covered surfaces. But identification of seaweeds such as laver, brown seaweeds and seaweed fulvescens depends on the dampening effect due to the presence of the facilities and is a complex task because objects that resemble seaweeds frequently occur, particularly in low wind or tidal conditions. Lastly, fusion of SAR and optic spatial images is tested to enhance the detection of aquaculture facilities by using the panchromatic image with spatial resolution 1 meter and the corresponding multi-spectral, with spatial resolution 4 meters and 4 spectrum bands, from KOMPSAT-2. The mapping accuracy achieved for farms will be estimated and discussed after field verification of preliminary results.

• ALGAE
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• 제21권3호
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• pp.311-316
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• 2006

The effects of light quality and irradiance on the growth of Cochlodinium polykrikoides were investigated in the laboratory. At 25°C and 30 psu the irradiance-growth curve was described as μ = 0.34 (I-9.76)/(I+12.5), (r=0.98). This suggests half-saturation photon flux density (PFD) (Ks) of 32.0 μmol photons m–2 s–1, and a compensation PFD (Ic) of 9.76 μmol photons m–2 s–1. Because the Ic equates to a depth of ca. 15.4 m, these responses suggest that irradiance at the depth around and below the thermocline in Yeosuhae Bay would provide favorable conditions for C. polykrikoides. Photoinhibition did not occur at 300 μmol photons m–2 s–1, which was the maximum irradiance used in this study. Blue (450 nm), yellow (590 nm) and red (650 nm) light had different effects on the growth of C. polykrikoides: it grew well under blue light, but not under yellow light. This implies that C. polykrikoides is more likely to cause an outbreak of red tide in the open sea where blue-green wavelengths predominate, rather than in enclosed water bodies where suspended particles absorb most of the blue wavelengths, and yellow-orange wavelengths predominate.

• 한국수산과학회지
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• 제37권6호
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• pp.485-491
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• 2004

Spawning induction, egg development and larval growth of ark shell (Tegillarca granosa) (L.) were investigated. The most effective method of spawning induction was steady temperature increasing from$4^{\circ}C\;to\;28^{\circ}C$ with irradiation of sea water by UV after T. granosa was exposed to air at $4^{\circ}C$ Optimum condition for larval roaring was under the 32.4 psu and two temperature $regimes:\;28{\pm}1^{\circ}C\;and \;25{\pm}1^{\circ}C$. Fertilized eggs was demersal isolated eggs, and egg diameter was $60{\mu}$. D-shaped larvae appear about 20 hr after hatching with $94.1{\mu}$ in shell length and $86.7{\mu}$ in shell height. Ten days were required from hatching to umbo larva stage, of a mean shell length $125.2{\mu}$. On 25th day, the larva grew to $450{\mu}$ in shell length and began to settle on the bottom. Effect of temperature between $25^{\circ}C$ (control group) and $28^{\circ}C$ on larval growth was not different. Survival rate of larvae settled on the bottom was about $19{\%}$ in both temperatures conditions $(25^{\circ}C\;and\;28^{\circ}C)$.

• Fisheries and Aquatic Sciences
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• 제21권9호
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• pp.23.1-23.8
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• 2018

Background: Russian sturgeon (Acipenser gueldenstaedtii) is an emerging candidate species in the Korean aquaculture domain owing to its highly valued caviar. Although the embryonic development of this species was previously described, the complete image data on the morphological differentiation of developing embryos have not been yet fully available. Further, with the viewpoint of larval production in hatchery, the effects of temperature on embryonic viability and the temporal window of hatching event have not been extensively studied. Hence, the objective of this study was to provide a complete set of photographic image data on the embryogenesis and also to examine the effects of incubation temperatures on embryonic viability and hatching event in farm-bred Russian sturgeon. Results: Typical characteristics of embryonic development including uneven, holoblastic cleavages with unequal blastomeres, followed by the formation of germ layer, neurulation, and organogenesis until hatching, were documented. Under different temperature conditions (12, 16, or $20^{\circ}C$), viability of embryos incubated at $12^{\circ}C$ was significantly lower as relative to those of 16 and $20^{\circ}C$ incubated embryos. Hatchability of embryos was higher, and the timing of hatching event was more synchronized at $20^{\circ}C$ than at 12 and $16^{\circ}C$. Conclusion: Data from this study suggest that the incubation of Russian sturgeon embryos at $20^{\circ}C$ would be desirable in the hatchery practice with respect to the good hatchability of embryos and the synchronization of hatching events. Additionally, the updated image data for complete embryonic development could be a useful reference guide for not only developmental researches but also artificial propagation of Russian sturgeon in farms.

• 한국어병학회지
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• 제8권2호
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• pp.99-109
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• 1995

1991년(年) 12월(月)에서 1992(년)年 4월(月) 사이에 제주도내 종묘배양장에서 사육중이던 넙치자어에서 소화관이 백탁되거나 궤양을 일으키는 질병이 발생하여 대량폐사를 일으켰다. 병든 자어의 소화관으로부터 Vibrio 속(屬) 세균을 분리하였고, 형태학적(形態學的), 생물학적(生物學的) 및 생화학적(生化學的) 성상(性狀)을 조사한 결과, 본병의 원인균을 Vibrio sp. INFL group으로 동정하였다. 본병은 rotifer 등(等)의 먹이생물을 매개로 하여 경구감염시킨 결과 자연감염 증상이 재현되었다. 분리균이 잘 발육할 수 있는 온도의 범위는 $25\sim30^{\circ}C$, 식염농도의 범위는 2.0~4.0% 그리고 pH는 6.0~8.0이었다. 분리균은 oxytetracycline, nalidixic acid, kanamycin 및 novobiocin 등에 감수성을 나타냈으나 ampicillin, erythromycin, spiramycin 및 sulfa-drug에는 내성을 나타내었다.

• 한국양식학회지
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• 제7권3호
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• pp.177-187
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• 1994

본 연구는 삼상유동층 반응기를 양어장 순환수 처리장치로 설치하여 질산화제거를 정량화하고 최적운전방법을 도출하였다. 메디아 농도가 85g/l 일시 유기물질 부하율이 2.739-0.086 kg $COD/m^3/day$인 유동층공법에서 $56.3-94.7\%$의 SCOD 제거효율을 나타냈으며 SCOD 제거효율은 유기물질 부하가 증가할수록, HRT가 작을수록 낮아지는 경향을 보였다. 본 반응조의 최대 유기물질 제거율은 1,200 mg COD/l/day였다. 암모니아성 질소부하율이 $1.575-0.128kg\;NH_4\;^+-N/m^3/day$에서 $67.3-92.6\%$의 암모니아성 질소 제거효율을 얻었으며 암모니아성 질소제거량은 $11.2-488mg\;NH_4\;^+-N/l/day$였다. 메디아농도가 50g/l에 비해 85g/l에서 유기물질 제거 및 암모니아성 질소제거효율이 더 높았으며 메디아농도의 증가는 암모니아성 질소제거에 더 큰 효과를 보인다. 공기주입율은 일단 미생물이 부착을 하고 나면 유기물질 제거에 미치는 영향을 적으나 암모니아성 질소제거에 영향을 주므로 최소 유동가능한 공기주입율과 암모니아성 질소제거측면을 고려한 공기주입율의 산정이 요구된다.

• 한국수산과학회지
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• 제54권4호
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• pp.426-433
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• 2021

This study aimed to determine the appropriate salinity condition for optimal cultivation of the juvenile hybrid grouper Epinephleus akaara♀×E. lanceolatus♂ in conditions of decreasing salinity. The survival, growth, metabolic rate, stress, and histological response were investigated in juvenile hybrid grouper exposed to different salinities for 30 days. At 0 psu, the survival rate of the juvenile hybrid grouper was 60% on the 2nd day of exposure and all individuals died on the 3rd day of exposure. At salinities above 3 psu, all animals survived throughout the exposure period. Growth rate for body weight of the juvenile hybrid grouper was the highest in the control and the lowest at 10 psu. Plasma osmolality of the juvenile hybrid grouper exposed to different salinities was 313-355 mg Osmol/kg at salinities above 10 psu, and then decreased to 225-264 mg Osmol/kg at salinities below 5 psu. The oxygen consumption rate tended to decrease as the salinity decreased. Stress responses of the juvenile hybrid grouper were analyzed with decreasing salinity. Therefore, it is considered that a salinity of more than 20 psu is suitable for the culture of the juvenile hybrid grouper.

• Fisheries and Aquatic Sciences
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• 제5권1호
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• pp.64-74
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• 2002

The proper conditions for cold storage of milt in four species of flatfish were investigated. Various diluents were tested for the preservation of marbled sole, brown sole, starry flounder and olive flounder milt at $1\pm0.5^{\circ}C$ for 7 days. The most effective diluent was $1\%$ NaCl for marbled sole and Stein's extender for brown sole, starry flounder and olive flounder. After 7 days of storage in different dilution ratios (milt: diluent), marbled sole milt diluted with 1:3-10 and brown sole, starry flounder and olive flounder milt diluted 1:1-10 maintained good sperm activity index (SAI). SAI was affected by storage volume and presence of antibiotic. SAI was lower after 7 days storage in the volume of 1.5 mL than in 0.5 or 1.0 mL. SAI after 29 days storage was markedly enhanced by addition of antibiotic in marbled sole (400 ppm gentamicin, 400 ppm neomycin, 200-400 ppm streptomycin), brown sole (600 ppm gentamicin), starry flounder (1,000 ppm gentamicin) and olive flounder (200-1,000 ppm gentamicin, 200-400 ppm neomycin, 200-1,000 ppm streptomycin).

• 한국양식학회:학술대회논문집
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• 한국양식학회 2003년도 추계학술발표대회 논문요약집
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• pp.76-77
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• 2003

Olive flounder Paralichthys olivaceus larvae and early juveniles were reared for 43 days after hatching in order to observe the effects of starvation during development and metamorphosis. Morphological, histological and biochemical measurements were made to assess the nutritional condition during growth and starvation from pre-matamorphic through post-metamorphic phases. Two groups of fish were compared ; one with sufficient food supply and one under continuous starvation until death. Among morphometric analyses, both ratios of body height at anus/head height and pre-/post-anal lengths appeared to be sensitive to starvation during which substantial reduction was observed within a day of food deprivation. Histological variables as intestinal and rectal epithelial heights and gall bladder volume changed significantly with onset of starvation. The gut epithelial heights of starving fish decreased with advances in starvation, although they fluctuated during mid-metamorphic phase. In contrast, gall bladder volume increased remarkably soon after starvation. Ontogenetic changes in both gut epithelial height and gall bladder volume were evident, those associated with settlement and/or completion of metamorphosis. Abrupt decrease in the RNA/DNA ratios of starving fish were found right after onset of starvation. Even in the fed fish marked fluctuations in its ratios during metamorphosis were observed, evident by decreasing from late-metamorphic to post-metamorphic stages. These findings suggest that a combination of morphologically and histologically sensitive characteristics, and biochemical measurement could be utilized as a measure to evaluate nutritional condition related to starvation in wild olive flounder larvae and juveniles.

• Fisheries and Aquatic Sciences
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• 제14권1호
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• pp.31-42
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• 2011

Three novel hepcidin isoforms were isolated and characterized from the perciform fish species Oplegnathus fasciatus. These hepcidin isoforms (designated rbhepc5, rbhepc6 and rbhepc7) were found to share a conserved, tripartite gene structure and a considerable sequence homology one another. A comparison of their mature peptide sequences with those of other perciform hepcidin orthologs indicated that these three hepcidin isoforms as well as four other isoforms previously identified in this species, appear to belong to the HAMP2 group of hepcidin genes. Analysis of the 5'-upstream sequences showed that the proximal non-coding regions of rbhepc5~7 do not possess canonical TATA signals; instead, they harbor several binding motifs for transcription factors involved in immune modulation. Reverse transcriptase-PCR analysis demonstrated that the rbhepc5~7 are expressed predominantly in the liver, and that the transcription of rbhepc5~7 is rapidly induced in the liver, but not in other tissues, by experimental challenge with any of three different bacterial species. However, transcription of rbhepc6 appeared to be negligible under both basal and stimulated conditions, as judged by the redundancy count of randomly chosen reverse transcriptase-PCR clones.