• Fisheries and Aquatic Sciences
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• v.7 no.2
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• pp.76-83
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• 2004

To supply fresh and quality quarantined seafood in live seafood specialty restaurants, facilities for short-term culture or holding of live marine fish and shellfish are a necessity. In this study, the performance of a simple recirculating aquarium system for the culture and holding of marine fish was evaluated. The aquarium system consisted of a culture tank, a foam fractionator for solids removal, and a Styrofoam bead filter for nitrification and solids trapping. In the first trial, the aquarium was stocked with a total of 12 kg Korean rockfish, which were fed approximately $0.5\%$ of the total fish body weight daily. During the 2-month culture period, total ammonia nitrogen (TAN) and nitrite nitrogen $(NO_2-N)$ concentrations remained below 1mg/L and 2mg/L, respectively. The chemical oxygen demand (COD) fluctuated between 13.6 and 31.2 mg/L on selected sampling days. The total suspended solids (TSS) removed by the foam fractionator was between 2.7 and 4.6g daily. The Styrofoam bead filter not only reduced TAN and $NO_2-N$ in the culture tank water, but also trapped solids equivalent to 8.3-26.7\% of the weight of feed supplied. In Trial 2, 30kg of live fish were held in the aquarium without feeding for a 24-hour period and the water quality parameters were monitored. TAN and $NO_2-N$ concentrations first increased and then decreased to around 0.3mg/L. These results demonstrate that the recirculating aquarium system is a functional option for the short-term culture or holding of marine fish.

• Parasites, Hosts and Diseases
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• v.42 no.3
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• pp.93-119
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• 2004

Acanthamoeba and Naegleria are widely distributed in fresh water, soil and dust throughout the world, and cause meningoencephalitis or keratoconjunctivitis in humans and other mammals. Korean isolates, namely, Naegleria sp. YM-1 and Acanthamoeba sp. YM-2, YM-3, YM-4, YM-5, YM-6 and YM-7, were collected from sewage, water puddles, a storage reservoir, the gills of a fresh water fish, and by corneal washing. These isolates were categorized into three groups based on the mortalities of infected mice namely, highly virulent (YM-4), moderately virulent (YM-2, YM-5 and YM-7) and nonpathogenic (YM-3). In addition, a new species of Acanthamoeba was isolated from a freshwater fish in Korea and tentatively named Korean isolate YM-4. The morphologic characters of its cysts were similar to those of A. culbertsoni and A. royreba, which were previously designated as Acanthamoeba group III. Based on experimentally infected mouse mortality, Acanthamoeba YM-4 was highly virulent. The isoenzymes profile of Acanthamoeba YM-4 was similar to that of A. royreba. Moreover, an anti-Acanthamoeba YM-4 monoclonal anti-body reacted only with Acanthamoeba YM-4, and not with A. culbertsoni. Random amplified polymorphic DNA marker analysis and RFLP analysis of mitochondrial DNA and of a 188 small subunit ribosomal RNA, placed Acanthamoeba YM-4 in a separate cluster based on phylogenic distances. Thus Acanthamoeba YM-4 was identified as a new species, and assigned Acanthamoeba sohi. Up to the year 2002 in Korea, two clinical cases were found to be infected with Acanthamoeba spp. These patients died of meningoencephalitis. In addition, one case of Acanthamoeba pneumonia with an immunodeficient status was reported and Acanthamoeba was detected in several cases of chronic relapsing corneal ulcer, chronic conjunctivitis, and keratitis.

• Magazine of the Korean Society of Agricultural Engineers
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• v.24 no.1
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• pp.44-52
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• 1982

Recently, estuary reserovoirs have been actively constructed in Korea and also in Japan there are a large number of estuary reservoirs constructed. But most of the estuary reservoirs are located at the downstream of a river where geographical condition is best for the construction of an enclosing dam. And an effective utilization of water from the estuary reservoir seems to be difficult even if estuary reservoirs are considered to be the water resources the most available for their watershed. Studies on estuary reservoirs so far have been mainly concentrated on the physical and engineering problems of the dam construction itself. The purpose of the present study is to review the estuary reservoir planning in connection with the water resources development and to study a basis of the planning. First, the levels of water use in Korea and Japan were compared with those of other countries in the world. And then, some representative reservoirs were selected to study the roles of a reservoir and water-using conditions in the watershed. Based on the study, a survey was given on the relation between a dam construction upstream and an estuary reservoir construction downstream of a river. Finally, a comprehensive examination was made of the bases of estuary reservoir planning. (1) The estuary reservoir planning is deeply related to the plan for water use develo- pment in the watershed. After the upstream water resources were fully developed up to the most, water reso- urces development by an estuary reservoir should be started. (2) If an estuary lake has a capacity big enough, it can store flood discharge of the watershed without any loss and become a basic facility that will bring about the maxi- mum use of water from the watershed. (3) Estuary reservoirs store water used in the upstream watershed, so recycling of water use is attained by the reservoir. Water in the estuary lake is difficult to be fresh water in its long run. Therefore, estuary reservoir should be located at a place where polluted water is purified and refused. All the planning should be based on the assumption that water in the estuary lake is not fresh but polluted after a long time. (4) The estuary lake can only supply water to the lower basin directly. But the upstream area is benefited from the estuary lake by exchange of irrigation water sources between the lower and the upper area. So a large-scale exchange plan between new and existing water resources is important. By constructing estuary reservoirs and the exchange of water sources between upper and lower areas, the reasonable maximum use of water from the whole watershed is at- tained. (5) The big problem coming from the water resources development by an enclosing estuary is salt water intrusion into the lake. To maintain the estuary lake salt-free, multi-purpose use of the lake should be avoided. It is necessary to take such fundamental measures as abolition of back flow operation of gate, and the closing of the fish port and the fish ladder. The results mentioned above were found in this study and these results of this study could be used for the adequate planning of estuary reservoirs in connection with the maximum water use of the watershed.

• Journal of environmental and Sanitary engineering
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• v.16 no.2
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• pp.24-31
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• 2001

This study was aimed to evaluate biodegradability for various food waste using anaerobic batch digestion. In the anaerobic biodegradability study of each food waste according to occurrence source, the cumulative methane productions of water melon and melon were 375, and 354ml and that of cucumber, fresh cabbage, radish, sprouted bean were 366, 364, 374, 384, 355ml and that of noodle, boiled rice and fish were 432, 409 and 477ml $CH_{4/g}$ VS add, respectively. And methane yield rate was about 84.1~97.2%. The reaction rate coefficiency(k) was $0.00495~0.2022day^{-1}$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.1
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• pp.34-40
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• 2009

In fresh water fish hatcheries and farms, Saprolegniales often cause serious mortality to the fish and their eggs. Malachite green is an effective antifungal agent, but is carcinogenic to fish and humans. Alternative antifungal agents are needed. Presently, we tested various concentrations of MBT-01108 (Opuntia ficus-indica extracts) alone and in combination with bronopol, formalin and sodium chloride (MBT-01108 mixture) on in vitro mycelial growth and in vivo remediation of adult eel, Anguilla japonica, infected with Saprolegnia sp. and fertilized eggs of chum salmon, Oncorhynchus keta, to evaluate the compounds' antifungal efficacy on eyed-egg and hatching rates. MBT-Oll08 mixtures incorporating bronopol and formalin at respective concentrations of 50 and 30 parts per million (ppm), and 100 and 20 ppm were most effective in controlling Saprolegnia in vitro and in vivo (P<0.05). Repeated daily exposures to 50 ppm and 100 ppm MBT-01108 were more effective than exposure every 2-3 days post-fertilization for the inhibition of Saprolegnia infection of rainbow trout, Oncorhynchus mykiss eggs as compared with control (0 ppm).

• Korean Journal of Ecology and Environment
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• v.36 no.3 s.104
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• pp.375-380
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• 2003

For some decades eutrophication poses a great problem in water quality management in fresh-waters. To solve this problem, studies based on "bottom-up" hypothesis have been mostly carried out worldwidely unlike biomanipulation. This implies that not only fish but also fish stock playa key role down to other food web components in pelagic ecosystem. It is generally accepted that biomanipulation becomes a potent tool for eutrophication control. For a practical application of this, however, further development and understanding of the food web under the specific lake condition on a whole-lake scale are needed. The question is how can we maintain the positive effects resulted from biomanipulation (fortuitous or planned) for a long period.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.9
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• pp.1272-1275
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• 2001

Two hundred and forty post-larvae (PL) of fresh water prawn, Macrobrachium rosenbergii were distributed in eight treatment groups with three replicates each. Eight experimental diets were prepared by using squilla (Orato squilla nepa), squid (Sepia pharonis) and clam (katelysia opima) alone or in different combination as source of animal protein and compared to a control diet containing fish meal. Total crude protein content for all dietary treatments was around 32%. Total protein content of fish meal was replaced by an equal amount of protein from different animal protein sources on isonitrogenous basis. Diets were fed at 5% of the body weight of post-larvae twice daily. The experiment was conducted for a period of 60 days. It was found that all the above three protein sources could be used by completely replacing fishmeal except clam meal at higher level of inclusion (26%). A combination of squid and squilla meal at 14% each in the diet increased the growth performance of PL significantly (p<0.05) in terms of Specific growth rate (SGR) % (5.17), FCR (2.12) and PER (1.51). Squilla meal can be used to the maximum level of 38% without any growth depression.

• Journal of fish pathology
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• v.21 no.3
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• pp.157-166
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• 2008

Streptococcal diseases are known as serious problems in fresh water and marine fish culture industry worldwide. Recently, the importance of the infection of Streptococcus parauberis has been increased among the streptococcicosis since severe outbreaks in cultured olive flounder (Paralichthys olivaceus) were recorded in Korea. The aims of the present study were to investigate immunomodulatory differences between S. parauberis and S. iniae. In this study, S. parauberis isolated from diseased olive flounder was investigated on the characteristics of morphological and immune responses. Immune response of the fish to the pathogen was characterized by bactericidal activity in the serum, phagocytic activity and reactive oxygen intermediaters (ROIs) production of olive flounder. The capsules of both bacteria, S. parauberis and S. iniae seem to be associated with the ability to resist killing activity of normal sera. Also, capsulated strains could survive in the phagocytes and induce to lower ROIs production.

• Journal of fish pathology
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• v.30 no.1
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• pp.25-39
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• 2017

A total number of 668 apparently healthy fish were obtained from farm to study the effect of two heavy metals in a form of (Copper sulfate and Mercuric chloride) on some hematological and biochemical parameters of blood. The $LC_{50}$ /96 hr. of Cu and Hg were estimated and fish exposed to $\text\tiny{^1/_2}$ $LC_{50}$ for 7 days and for $1/_{10}$ $LC_{50}$ for 8 weeks from each product separately. Results showed decrease in RBCs count, PCV% and Hb in acute and chronic mercury while a significant increase was shown in acute and chronic copper toxicity, total leucocytic count showed decrease in acute mercury toxicity and increase in the chronic case, while in copper toxicity non-significant decrease in acute and significant decrease in chronic toxicity was noticed. Elevated serum urea and creatinine in both acute and chronic mercury and copper toxicity was detected. No changes in total bilirubin in the acute mercury and chronic copper toxicity while significant increase in chronic mercury and acute copper. Elevation of serum AST and ALT in some days of acute toxicity of mercury and copper while in chronic mercury toxicity a significant elevation of both serums AST and ALT were detected .while in chronic copper toxicity serum AST was fluctuated and ALT showed no significant changes. CK study revealed significant decrease in acute mercury with fluctuation in the chronic toxicity while in copper toxicity it showed fluctuation in acute and significant decrease in chronic toxicity. Glucose value decreased in acute and chronic mercury toxicity while in copper toxicity it showed significant increase in the acute and increase followed by significant decrease in the chronic copper toxicity.

• Ecology and Resilient Infrastructure
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• v.10 no.4
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• pp.201-207
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• 2023

Suspended solid in river is resource serious contamination. Suspended solid have a pernicious influence to fish and aquatic ecosystem. Flood and sediment and land use in river are largely[mainly] responsible of suspended solid. Especially, resuspension phenomenon of sediment will be dangerous effect to aquatic ecosystem. Study of fish and aquatic ecosystem on suspended solidus slight in fresh water. This study was basic research to manage fish and aquatic ecosystem on turbidity. It was conducted to analyze and monitor fish response on turbidity. Result in this study was confirmed the insensitive and die of fish on reduction of oxygen supply.