• 한국수산과학회지
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• 제41권4호
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• pp.267-271
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• 2008

We experimentally determined the physico-chemical properties of seminal plasma as well as the sperm cryopreservation techniques of masou salmon, Oncorhynchus masou masou. Seminal plasma contained $18{\pm}1mmol/L$ potassium, $144{\pm}4mmol/L$ sodium, $116{\pm}3mmol/L$ chloride, $83.2{\pm}3.1mg/L$ calcium, $14.8{\pm}0.7mg/L$ magnesium, $45{\pm}9mg/L$ glucose, and $1.0{\pm}0.0g/L$ total protein. The osmolality and pH of seminal plasma were $287{\pm}7\;and\;7.7{\pm}0.1mmol/kg$, respectively, and the spermatocrit was $28{\pm}2$. The rate of embryonic survival at the eyed-stage and the hatching rate were highest in 10% methanol with 300 mM glucose. Compared to DMSO or glycerol, methanol served as a better cryoprotectant of masou salmon sperm.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2008년도 학술발표회 논문집
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• pp.1934-1938
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• 2008

본 연구에서는 시계열 항공영상을 이용하여 갑천의 토지이용 패턴을 제내지와 제외지로 구분하여 분석하였다. 먼저 제내지에서는 주거지, 도로, 공업지, 공공시설이 도시화 증가항목으로 선정된 반면, 농경지, 산림 그리고 하천은 도시화 감소항목으로 분류되었다. 또한 이러한 증가와 감소항목들이 1988년도를 기점으로 역전되는 경향을 나타내었으며 이를 통해 갑천의 토지이용이 1988년을 기점으로 도시화로 전환되었음을 추정 할 수 있다. 제외지에서는 시간이 경과함에 따라 현하천의 면적이 감소하는 것으로 나타났으며 이는 고수부지, 교량 그리고 보와 같은 도시화를 반영하는 토지이용 항목의 면적이 증가된 것을 의미한다. 또한 수문자료를 고려한 현하천에 대한 수계의 비율은 시간이 경과함에 따라 증가하였다. 전반적으로 볼 때, 항공영상은 하천관리 및 계획에 필요한 토지이용 정보를 구축하는데 유용하게 활용될 수 있으리라 판단된다.

• 한국환경과학회지
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• 제22권8호
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• pp.937-944
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• 2013

Ozone concentrations in water and air, and resulting disinfective properties, were measured following generation by either an ozone generator or a low-temperature dielectric barrier discharge plasma generator. In freshwater, ozone concentrations of 0.81 and 0.48 mg/L $O_3$ were observed after the ozone and plasma generators had been operated for five minutes, respectively. Higher levels of dissolved $O_3$ were attained more easily with the ozone generator. In seawater, both systems were capable of creating concentrations greater than 3.00 mg/L $O_3$ after 5minutes of operation. Higher ozone levels were attained more easily in seawater than in freshwater. Rates of bacterial sterilization in seawater after three minutes were 96% and 88%, using the plasma and ozone generators, respectively. In freshwater, higher concentrations of ozone were released into the atmosphere by the ozone generator than by the plasma generator. In creating equivalent levels of dissolved ozone in freshwater, the plasma generator released 4.5 times more ozone into the atmosphere than did the ozone generator. This shows that ozone generators are more effective than plasma generators for creating ozonated water. For the same concentration of dissolved ozone in seawater, more ozone was released into the atmosphere using the ozone generator than using the plasma generator. Therefore, with regard to air pollution, plasma generators seem to be less expensive than ozone generators.

• Fisheries and Aquatic Sciences
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• 제26권5호
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• pp.305-317
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• 2023

Ethiopia is branded as the Water Tower of Africa because of its abundant inland water bodies that may be used sustainably to boost the economy. This review article's goal is to examine the current status and future potential of Ethiopia's fisheries, with a special focus on reservoirs. There are 200 known fish species (194 native, 40 endemic, and 11 exotic) in in Ethiopia's inland water. Ethiopia's fish production has increased by a factor of more than five in the past three decades (3,500 tons in 1983 to 15,681 tons in 2000 and 18,058 tons in 2010). However, fish produced in reservoirs is too low (8,059 t/year). The current fish harvests from reservoirs are significantly below the predicted potential yield, accounting for only 35% of the calculated fish production capacity. In this review, 14 potential reserves were revealed. A total of 48 fish species have been reported in these, of which 26 species (or around 54%) are present in Alwero reservoir. 19 of the 48 species that have been officially recognized belong to the Cyprinidae family and made up nearly 40% of the fish population in Ethiopian reservoirs. There has been, however, a decline in the productivity of Ethiopia's reservoir fish. Hence, actively start fishing in the numerous reservoirs that have been neglected yet, link the potential of fisheries and the benefits of the fish farming supply chain, let's begin building several other reservoirs similar to the Grand Ethiopian Renaissance Dam and beginning mechanized-based fish harvesting.

• 수산경영론집
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• 제37권3호
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• pp.1-24
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• 2006

In terms of the size of aquaculture farms and production volume, inland freshwater aquaculture is much smaller than marine aquaculture in Korea. However, freshwater aquaculture provides fish which is not produced in the sea. Freshwater aquaculture plays an important role in the efficient use of resources, development of local areas and economy vitalization in under - developed areas. freshwater aquaculture also helps ecosystem recovery by stocking farmed fry. As addressed above, inland freshwater aquaculture plays various roles and can not be ignored. However, freshwater aquaculture has been off the interest of fisheries authority. Considering a series of changes in the circumstances such as the government's disapproval of pen - raised aquaculture, higher standard for discharged water from aquaculture farms and a rapid increase in import of low price fish from other countries, it is difficult to expect the quantitative expansion of the freshwater aquaculture any more. Furthermore, freshwater aquaculture lost the trust of people because of the use of Malachite green, and the consumption of farmed product plummeted last year. Even though it would be difficult to expect the quantitative expansion, we could expect qualitative growth and let the inland freshwater aquaculture keep playing the own roles. In order to achieve competitive advantage and regain the trust by providing safer farmed product, the government's support and freshwater aquaculture industry's active and voluntary efforts are very important. This paper suggests several points for the future oriented inland freshwater aquaculture in Korea such as strategic intensive development of selected species, the technical improvement and its diffusion, increased cooperation among the government authority, industry and scientists.

• 대한원격탐사학회지
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• 제33권2호
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• pp.111-123
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• 2017

피코시아닌(phycocyanin, PC) 색소는 부영양화 된 담수역에서의 남조류를 정량하는 지표로 활용된다. 남조류의 대발생에 의한 잠재적 위험성으로인해 조기 경보 발령이 중요하지만, 혼탁한 수체 내 소량으로 추정되는 PC 농도를 정확하게 산정하는 것은 분광학적으로 매우 복잡하고 어렵다. 이를 위해 현장에서 측정 된 원격반사도로부터 PC 및 물 이외의 입자성 물질에 의한 흡수계수를 분리하여 기존 PC 농도를 추정하는 방법을 개선하여 낮은 농도에서도 향상 된 결과를 보였다. 본 연구에서 제안 된 IOPs 변환 모델 적용 결과 PC 흡수계수 $R^2$는 0.8 이상으로 $a_{pc}(620)$를 적절히 재현하였다. 또한 알고리즘은 기존 널리 사용되는 반경험적 알고리즘에 비해 $0.71{\leq}R^2{\leq}0.85$, $rRMSE{\leq}39.4%$, 그리고 $RE{\leq}78.0%$로 정확도 높은 결과를 보였다. 특히, PC 농도가 $50mg/m^3$ 이하 및 PC: Chl-a ratio가 낮은 조건에서도 잘 예측됨을 확인할 수 있었다.

• Journal of Ecology and Environment
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• 제41권3호
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• pp.45-53
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• 2017

Background: There have been many studies on the growth conditions of Zostera marina and Zostera japonica, but few studies have examined how spatial and temporal factors affect growth in established seagrass beds or the distribution range and shoot density. This study aims to clarify the factors that determine the temporal and spatial distribution of Zostera marina and Zostera japonica in the Seto Inland Sea east of Yamaguchi Prefecture. Methods: The study site is in Hiroshima Bay of the Seto Inland Sea, along the east coast of Yamaguchi Prefecture, Japan. We monitored by diving observation to confirm shoot density, presence or absence of both species and observed water temperature, salinity by sensor in study sites. Results: The frequency of occurrence of Zostera marina was high in all seasons, even in water depths of D.L. + 1 to -5 m ($80{\pm}34%$ to $89{\pm}19%$; mean ${\pm}$ standard deviation), but lower (as low as $43{\pm}34%$) near the breakwall, where datum level was 1 to 2 m, and it was further reduced in datum level -5 m and deeper. The frequency of occurrence of Zostera japonica was highest in water with a datum level of +1 to 0 m. However, in datum level of 0 m or deeper, it became lower as the water depth became deeper. Datum level +1 m to 0 m was an optimal water depth for both species. The frequency of occurrence and the shoot density of both species showed no negative correlation. In 2011, the daily mean water temperature was $10^{\circ}C$ or less on more days than in other years and the feeding damage by S. fuscescens in the study sites caused damage at the tips. Conclusions: We considered that the relationship between these species at the optimal water depth was not competitive, but due to differences in spatial distribution, Zostera marina and Zostera japonica do not influence each other due to temperature conditions and feeding damage and other environmental conditions. Zostera japonica required light intensity than Zostera marina, and the water depth played an important role in the distribution of both species.

• 한국토양비료학회지
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• 제44권6호
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• pp.1314-1319
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• 2011

This study was carried out to investigate the surface soil organic carbon fractions affecting by different land use types, including needle-leaf forest (FN), broad-leaf forest (FB), pasture, annual upland cropping land (upland), and paddy rice land (paddy). We chose seven regions across Korean inland, considering sea level altitude, and measured soil organic carbon content and physico-chemical properties such as bulk density at a depth of 0~15 cm using core samples in April for the each land use type. In addition, labile organic carbon fractions in soil including light fraction and hot water extractable carbon were investigated. From this study, organic carbon storage (Mg C per ha) in the upper 15-cm soils was highest in FB (37.8), and decreased in the order of pasture (29.1), FN (28.8), paddy (21.9), and upland crop (19.9). In forest, more than 20% of soil organic carbon existed as light fraction, the free organic matter. Hot-water extractable carbon contents of soils in five land use types were lower than 7% of their soil organic carbon content.

• 한국수산과학회지
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• 제46권2호
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• pp.160-167
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• 2013

The influences of inland pollution sources nearJeokyang and Jangpoports following rainfall events on the bacteriological water quality and safety of commercial shellfish were investigated in the Changseon area, Korea. Stream flow rates exhibited 1.9- to 5.7-fold increases after rainfall events and then fell to 68~81% of that level after 24 h. The calculated impact area of inland pollution sources was 0.47 $km^2$ in the Jeokyangport area and 0.27 $km^2$ in the Jangpoport area at 24 h following 11 mm of rainfall. When the flow rate of inland pollution increased, the level of male-specific bacteriophage (MSB) decreased, and no MSB could be detected in seawater samples, whereas 30 PFU/100 g was detected in shellfish samples. Fecal coliform levels in seawater and shellfish samples did not exceed their respective tolerance levels (4.5 MPN/100 mL) and 130 MPN/100 g, respectively and thus complied with the standard for approved shellfish growing area. The sanitary conditions of areas adjacent to Jeokyang and Jangpoports under conditions of rainfall below 29 mm met the criteria for approved growing area under the United States National Shellfish Sanitation Program and the EC Regulations.

• 한국패류학회지
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• 제31권4호
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• pp.307-314
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• 2015

본 조사는 2013년 6월부터 8월까지 금강 상류에서 멸종위기야생생물 I급인 두드럭조개 (Lamprotula coreana)의 서식지를 조사하였다. 서식지 평가를 위하여 하천의 물리적 구조인 여울, 소 및 유수역이 모두 포함된 다양한 서식환경에서 서식상태를 조사하였으며, 하천단면, 수심, 유속, 하상재료 및 서식지 유형 등을 현장에서 측정 하였다. 서식 확인된 두드럭조개는 크기, 무게 및 연령을 기록하고 서식지에 재살포하였고, 서식지적합도지수 (Habitat suitability index, HSI)와 PHABSIM (physical habitat simulation system)에 의한 최적 생태유량 산정을 위하여, 각각의 채집 장소에서 수심, 유속 및 하상재료 등을 기록하였다. 서식지 평가는 수위, 유량 및 하천단면의 현장조사 결과와 두드럭조개의 HSI를 PHABSIM에 적용하여 가용서식지면적 (weighted usable area, WUA)과 유량의 관계 곡선을 작성하였다. 금강 상류에서 채집된 두드럭조개는 각장 $73.1{\pm}18.4mm$ 및 전중 $131.6{\pm}72.3g$ 이었으며, 연령은 2-7년생까지 서식하는 것으로 확인되었다. 두드럭조개의 HSI는 수심 0.4-0.5 m, 유속 0.3-0.5 m/s, 하상재료는 모래-호박돌로 나타났다. PHABSIM에 의해 모의된 최적유량은 2.1 cms였으며, WUA는 $3,730m^2$/1000 m로 나타났다. 두드럭조개의 서식지 평가 결과는 최근 각종 하천 공사 및 생태적 교란 등으로 서식 범위가 감소하고 있는 시점에서 서식지 복원 및 관리를 위한 기초자료로 활용될 수 있을 것이다.