• 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.

• Fisheries and Aquatic Sciences
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• 제23권9호
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• pp.25.1-25.9
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• 2020

Fish is an extremely perishable food product which requires proper handling soon after harvest. The present study was aimed at assessing post-harvest fish losses and preservation practices in Siavonga district, Southern Zambia. Structured and semi-structured questionnaires were used to collect data on post-harvest fish losses and preservation practices from aquaculture producers, artisanal, and commercial fishers. All the fishers who landed on the lakeshore were interviewed, while aquaculture producers were randomly selected based on the information provided by the local department of fisheries. The results of the study revealed that all the fishers experienced post-harvest fish losses at varying degrees with those losing up to 10% of the total catch being in the majority. In contrast, aquaculture producers did not report any post-harvest fish losses. Most aquaculture producers commonly used chilling as preservation practice contrary to artisanal and commercial fishers who commonly used smoking and sun sun-drying respectively. Furthermore, fish product safety and quality control were poorly practiced in the district. Lack of cold storage facilities and fluctuating weather conditions were the major challenges impacting fish post-harvest activities. Therefore, to curb the loss of revenue due to post-harvest fish losses, we propose the introduction of new technology, self-development skills for fishing communities, and enhanced access to refrigeration facilities.

• Fisheries and Aquatic Sciences
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• 제22권1호
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• pp.1.1-1.8
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• 2019

Five experimental diets were formulated to evaluate the effects of dietary enzymatically hydrolyzed tuna by-product on growth, non-specific immune responses, and hematology of juvenile rainbow trout (Oncorhynchus mykiss). A basal diet with 50% of fishmeal was used as control (CON) and four other diets replaced 12.5% ($TBB_{12.5}$), 25% ($TBB_{25}$), 37.5% ($TBB_{37.5}$), and 50% ($TBB_{50}$) of fish meal in the CON diet. Juvenile rainbow trout ($4.87{\pm}0.05g$) were randomly distributed into 15 tanks (50 L) and fed 3-4% of wet body weight two times a day. At the end of 7 weeks of feeding trial, weight gain, specific growth rate, feed efficiency, and protein efficiency ratio of fish fed CON diet were significantly higher than those of fish fed $TB_{50}$ diet (P < 0.05). But there were no significant differences among fish fed CON, $TBB_{12.5}$, $TBB_{25}$, and $TBB_{37.5}$ diets (P > 0.05). There were no significant differences in GPT levels among fish fed CON, $TBB_{12.5}$, $TBB_{25}$, and $TBB_{37.5}$ diets. Also, there were no significant differences in lysozyme, superoxide dismutase, glucose, and total protein levels in all experimental diet (P > 0.05). The broken-line analysis indicated that the minimum dietary level of enzymatically hydrolyzed tuna by-product to replace fishmeal could be 29.7% in rainbow trout. These results indicated that the optimum level of dietary enzymatically hydrolyzed tuna by-product could replace greater than 29.7% but less than 37.5% of fishmeal in juvenile rainbow trout diet.

• 수산경영론집
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• 제44권1호
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• pp.15-24
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• 2013

Recently the Korean court accepts two typies of fisheries damages caused by oil pollution.. One is the direct loss of fisheries production originated from pollution of oil spillover. The other is the indirect loss of fisheries production originated from governmental measure of restricting fishing activities because of safety of marine product of oil spillover areas. The paper tries to suggest the appropriated measure of oil pollution damages of hanging and floating netcage aquaculture fisheries using the court judgement for responsibility restriction on Herbei Spirit Case. The paper tries to compare the damge estimation method of floating netcage aquaculture fisheries with that of natural aquaculture fisheries using conventional theory of the population biology of living resources characterized with age distribution.

• 수산경영론집
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• 제34권2호
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• pp.75-90
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• 2003

When we think of fundamental problems of the aquaculture industry, there are several strict conditions, and consequently the aquaculture industry is forced to change. Fish aquaculture has a structural supply surplus in production, aggravation of fishing grounds, stagnant low price due to recent recession, and drastic change of distribution circumstances. It is requested for us to initiate discussion on such issue as “how fish aquaculture establishes its status in the coastal fishery\ulcorner, will fish aquaculture grow in the future\ulcorner, and if so “how it will be restructured\ulcorner” The above issues can be observed in the mariculture of yellow tail, sea scallop and eel. But there have not been studied concerning seabream even though the production is over 30% of the total production of fish aquaculture in resent and it occupied an important status in the fish aquaculture. The objectives of this study is to forecast the future movement of sea bream aquaculture. The first goal of the study is to contribute to managerial and economic studies on the aquaculture industry. The second goal is to identify the factors influencing the competition between production areas and to identify the mechanisms involved. This study will examine the competitive power in individual producing area, its behavior, and its compulsory factors based on case study. Producing areas will be categorized according to following parameters : distance to market and availability of transportation, natural environment, the time of formation of producing areas (leaderㆍfollower), major production items, scale of business and producing areas, degree of organization in production and sales. As a factor in shaping the production area of sea bream aquaculture, natural conditions especially the water temperature is very important. Sea bream shows more active feeding and faster growth in areas located where the water temperature does not go below 13∼14$^{\circ}C$ during the winter. Also fish aquaculture is constrained by the transporting distance. Aquacultured yellowtail is a mass-produced and a mass-distributed item. It is sold a unit of cage and transported by ship. On the other hand, sea bream is sold in small amount in markets and transported by truck; so, the transportation cost is higher than yellow tail. Aquacultured sea bream has different product characteristics due to transport distance. We need to study live fish and fresh fish markets separately. Live fish was the original product form of aquacultured sea bream. Transportation of live fish has more constraints than the transportation of fresh fish. Death rate and distance are highly correlated. In addition, loading capacity of live fish is less than fresh fish. In the case of a 10 ton truck, live fish can only be loaded up to 1.5 tons. But, fresh fish which can be placed in a box can be loaded up to 5 to 6 tons. Because of this characteristics, live fish requires closer location to consumption area than fresh fish. In the consumption markets, the size of fresh fish is mainly 0.8 to 2kg.Live fish usually goes through auction, and quality is graded. Main purchaser comes from many small-sized restaurants, so a relatively small farmer and distributer can sell it. Aquacultured sea bream has been transacted as a fresh fish in GMS ,since 1993 when the price plummeted. Economies of scale works in case of fresh fish. The characteristics of fresh fish is as follows : As a large scale demander, General Merchandise Stores are the main purchasers of sea bream and the size of the fish is around 1.3kg. It mainly goes through negotiation. Aquacultured sea bream has been established as a representative food in General Merchandise Stores. GMS require stable and mass supply, consistent size, and low price. And Distribution of fresh fish is undertook by the large scale distributers, which can satisfy requirements of GMS. The market share in Tokyo Central Wholesale Market shows Mie Pref. is dominating in live fish. And Ehime Pref. is dominating in fresh fish. Ehime Pref. showed remarkable growth in 1990s. At present, the dealings of live fish is decreasing. However, the dealings of fresh fish is increasing in Tokyo Central Wholesale Market. The price of live fish is decreasing more than one of fresh fish. Even though Ehime Pref. has an ideal natural environment for sea bream aquaculture, its entry into sea bream aquaculture was late, because it was located at a further distance to consumers than the competing producing areas. However, Ehime Pref. became the number one producing areas through the sales of fresh fish in the 1990s. The production volume is almost 3 times the production volume of Mie Pref. which is the number two production area. More conversion from yellow tail aquaculture to sea bream aquaculture is taking place in Ehime Pref., because Kagosima Pref. has a better natural environment for yellow tail aquaculture. Transportation is worse than Mie Pref., but this region as a far-flung producing area makes up by increasing the business scale. Ehime Pref. increases the market share for fresh fish by creating demand from GMS. Ehime Pref. has developed market strategies such as a quick return at a small profit, a stable and mass supply and standardization in size. Ehime Pref. increases the market power by the capital of a large scale commission agent. Secondly Mie Pref. is close to markets and composed of small scale farmers. Mie Pref. switched to sea bream aquaculture early, because of the price decrease in aquacultured yellou tail and natural environmental problems. Mie Pref. had not changed until 1993 when the price of the sea bream plummeted. Because it had better natural environment and transportation. Mie Pref. has a suitable water temperature range required for sea bream aquaculture. However, the price of live sea bream continued to decline due to excessive production and economic recession. As a consequence, small scale farmers are faced with a market price below the average production cost in 1993. In such kind of situation, the small-sized and inefficient manager in Mie Pref. was obliged to withdraw from sea bream aquaculture. Kumamoto Pref. is located further from market sites and has an unsuitable nature environmental condition required for sea bream aquaculture. Although Kumamoto Pref. is trying to convert to the puffer fish aquaculture which requires different rearing techniques, aquaculture technique for puffer fish is not established yet.

• 한국수산과학회지
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• 제55권3호
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• pp.319-327
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• 2022

An eight-week feeding trial was conducted to evaluate the effects of a diet consisting of different onion juice processing by-product (OJPB) levels on juvenile black rockfish Sebastes schlegelii growth, feed utilization, and, lysozyme and antioxidant enzymes activities. Juvenile rockfish (2.2 g) were randomly distributed into 15 flow-through tanks (30 fish/tank). Five experimental diets were prepared in triplicate. The experimental diets were supplemented with OJPB at different levels of 0 (control), 0.25, 0.5, 0.75 and 1% (designated as OJPB0, OJPB0.25, OJPB0.5, OJPB0.75 and OJPB1, respectively). At the end of the feeding trial, the results revealed that the fish that were fed the OJPB0.75 and OJPB1 diets showed enhancement in growth (weight gain and specific growth rate) and feed utilization (feed efficiency and protein efficiency ratio) compared with the fish that were fed other diets. Plasma lysozyme, glutathione concentration, and superoxide dismutase and catalase activities significantly increased in the fish that were fed the OJPB0.75 and OJPB1 diets. In conclusion, dietary supplementation of 0.75-1% OJPB in juvenile rockfish diet improved the growth performance and antioxidant status.

• 환경생물
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• 제32권4호
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• pp.382-388
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• 2014

최근 뱀장어 양식장에서 사육 중이던 동남아산 뱀장어에 몸통 근육의 요철현상을 나타내면서 폐사를 일으키는 질병이 발생하였다. 병어의 몸통 근육 내 환부는 흰색 또는 황색으로 변해있었다. 병리조직학적인 변화는 근조직내에 수많은 포자와 크고 작은 시스트들이 변형된 근육근섬유 내에 관찰되었다. 병어의 근육 환부를 취하여 PCR을 실시하여 H. anguillarum이 가지는 특정 유전자인 Small subunit ribosomal RNA (SSU-rRNA)를 증폭하였다. 좀 더 정확한 동정을 위해 PCR product를 Cloning 후 Sequencing하여 서열들을 분석한 결과 H. anguillarum의 Small subunit ribosomal RNA (Gene bank accession number: AB623036) 서열과 일치하게 나타남을 확인할 수 있었다. primer 18F과 1537R의 PCR product는 약 1366 bp 길이가 일치하였으며, V1과 1392R를 이용한 PCR product는 1200 bp가 일치하게 나타났다. 또한 H1과 H2의 PCR product의 경우는 800 bp 정도 일치하였으며 이의 서열은 나머지 2개의 product가 공통적으로 가지고 있는 서열이었다. 이를 토대로 본 연구에서는 동남아산 뱀장어에 감염된 포자충은 H. anguillarum임을 동정할 수 있었다.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2003년도 춘계학술대회 논문집
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• pp.79-82
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• 2003

An aquaculture system for feeding the caged fishes in the open water is suggested for ocean application. Survival and operation conditions are defined at the conceptual design. Wave and current drag forces are discussed to determine the proper dimension of the aquaculture system and the related mooring system. Second order wave drift force at the survival condition is the dominant force, which be reduced by minimizing the superstructure open to the surface. Automation in feeding, sorting, cleaning is introduced to use the ongoing technology for quality product. The suggested system has advantage compared to onshore culturing, but not to shallow water culturing system. There is room for real application in future by the countries, such as Korea and Japan, which are in short of fish supply and have willingness to venture towards the ocean aquaculture.

• 수산경영론집
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• 제45권3호
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• pp.99-110
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• 2014

Flounder was selected as one of the 10 strategic export aquaculture products for seafood export expansion in 2013. The flounder aquaculture industry has promoted export market diversification and product diversification from live to processed goods as a it's main strategy. The purpose of this study is to find an improvement plan for export expansion to the United States, as it emerged as a new target export market for the flounder. A summary of the key findings is as follows. First, the western region of the United States prefers to consume live and fresh flounder, whereas the eastern region prefers to consume fresh flounder. Second, because of it's high quality, Korean flounder is favored in the western region of the United States despite it's high price, whereas in the eastern region of the United States, where production volume is high, Korean flounder has to compete with US flounders because of it's high price. Third, according to the survey results, US consumers tend to enjoy seafood, as well as flounder cuisines. Fourth, the main consumption place of flounders by US consumers are restaurants, and they prefer to consume them in the form of sashimi and sushi. Fifth, 70% of US consumers expressed willingness to consume flounder when eating out. which shows great market potential. However, the high price of Korean flounder and limited size of the live fish market act as major obstacles to expanding export volume. To expand exporting Korean flounder, continuos efforts such as price reduction, exporting highly fresh fish, the co-development of processed food with the US are needed.

• Journal of the korean society of oceanography
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• 제39권3호
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• pp.163-171
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• 2004

Sequences of the large subunit ribosomal (LSD) rDNA D1-D2 region of Alexandrium catenella(=A. sp. cf. catenella) and A. tamarense isolates, which were collected along the Korea coasts, were analyzed to understand their phylogenetic relationships and geographical distributions. All A. catenella and A. tamarense isolates belonged to the A. tamarense/catenella/fundyense complex and were grouped with the North American and temperate Asian ribotypes, respectively, regardless of the presence or absence of a ventral pore in the first apical plate. A consistent and peculiar characteristic that differentiated the Alexandrium isolates was amplification of a second PCR product with a lower molecular weight in addition to the predicted one; ten A. catenella isolates belonging to the temperate Asian ribotype yielded this additional PCR product. Sequence alignment revealed that the shorter PCR product resulted from an unusual large deletion of 87 bp in the LSD rDNA D1 domain. The North American and temperate Asian ribotypes were prevalent along the Korean coasts without geographical separation. Given the high genetic homogeneity among widely distributed Alexandrium populations, each ribotype appeared to be pandemic rather than to constitute a distinct regional population.