• Journal of Aquaculture
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• v.9 no.1
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• pp.43-55
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• 1996

The experiment was performed to evaluate the possibility of utilizing underground sea water for the seed production of tiger puffer, Takifugu rubripes. For this purpose, the effects of 6 different salinities (3.5, 7.0, 14.0, 20.0, 27.0, $33.0\%_{\circ}$) were determined based on the hatching rate of fertilized eggs, survival rate and the amount of food consumed by hatched larvae, where as the effects of 3 different salinities (20.0, 27.0, $33.0\%_{\circ}$) were also examined with rearing tiger puffer juvenile ($4.29{\pm}0.50$ cm in total length) for 50 days in the closed recirculating water system. As a results, either the hatching or the survival rate of more than $70.0\%$ were obtained from the fertilized eggs reared at the salinity of 27.0 to $33.0\%_{\circ}$, the early hatched larvae at 27.0 to $33.0\%_{\circ}$, and the 10-day-old larvae at 20 to $33.0\%_{\circ}$. At three different salinities, the survival rate of 20-day- and 30-day-old larvae turned out to be $89.0\%$ and $92.5\%$, respectively. The salinity for maximum food intake thus appeared to be from 27.0 to $33.0\%_{\circ}$. In this condition, 20-day-old hatched larvae consumed $323\~342$ Artemia nauplii and 30-day-old hatched larvae ate $1,559\~1,5791$ A. nauplii. The highest growth rate of fingerlings were observed at the salinity $27\%$ and followed by 33.0 and $20.0\%_{\circ}$, respectively. The relationship between the days of rearing (X) and the total length (Y) of the fingerlings were as follows : $33.0\%_{\circ}$ group : Y=0.107X-2.532 (r=0.982) $27.0\%_{\circ}$ group : Y=0.116X-3.195 (r=0.975) $20.0\%_{\circ}$ group : Y=0.116X-2.693 (r=0.987) The slopes of regression line estimated from $27.0\%_{\circ}$ and $33.0\%_{\circ}$ groups were significantly different from that of $20.0\%_{\circ}$ group.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.8 no.4
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• pp.222-224
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• 1975

Three strains of common carp, i. e. , Israeli carp, red-and-white, and golden strains, were stocked in the same pond, and their growth rates were compared with following results: From August 12 to November 21 in 1975, fingerlings of the three strains of common carp, Cyprinus carpo, each weighing about 0.5 g with total length of 2 to 3 cm, were stocked. The pond had an area of $316m^2$ with a mean water depth of 55cm, and the bottom was covered with a 20 to 30 cm thick layer of silt containing a considerable amount of decaying organic materials. Feed given was prepared with equal amounts of fish meal and polished barley, of which, in addition, $10\%$ green grass and $1\%$ table salt were mixed together when prepared into paste feed using a chopper after boiling the barley. Total protein content of the feed was $34.9\%$ in dry state with $5\%$ moisture content. Total feed given was 30.08 kg calculated in dry state to produce 20.588 kg of the common carp fingerlings, thus the feed coefficient being 1.51. By strains, the harvested Israeli carp ranged 98 to 311g each with a mean weight of $172.69g(100\%)$, red-and-white strain 15 to 318g with mean of $104.1g(60.3\%)$, and the golden strain 30 to 268g with mean of $128.7g(74.6\%)$. During the rearing season mean water temperature was $23.9^{\circ}C$ and the assumed main growth period with the water temperature above $15^{\circ}C$ was, upto the end of October, for 80 days with a mean water temperature of $23.9^{\circ}C$. Taking this main growth period as the basis for growth rate analysis, the mean daily increments, expressed as the attained body weight in times of the starting weight, become 1.075786 times (or the Israeli strain, 1.06901 times for the red-and-white strain, and 1.07185 times for the golden strain.

• Korean Journal of Veterinary Research
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• v.32 no.3
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• pp.381-387
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• 1992

Gill epithelia of normal rainbow trout fingerlings and abnormal ones suffering bacterial gill disease by experimental infection were examined by transmitting electron microscopy (TEM) and scanning electron microscopy (SEM). TEM observations revealed that Flavobacterium branchiophila consisted of slender rods measuring 0.5 by 5 to $8{\mu}m$, and they had which were long, thin, flexible filaments measuring approximately 4 nm by $1{\mu}m$, and packed together to organize into bundles. Morphological alterations of the diseased epithelia started at hypertrophy of the lamellar epithelium. F branchiophila attached to the gill surface of infected fish through pili with a regular distance, and did not invade into gill tissue. In SEM observations, normal surface ultrastructure of epithelial cell in the outermost layer were characterized by a typical labyrinth-like structure branching and anastomosing microridges on the cell surface. Hyperplastic lesions in experimentally infected gill were most serious at near the tips. Each filament exhibited a club-like, and fusion between the filaments was sometimes observed at their tips. On the surface of gill filaments, thread-like bacterial cells attached and were entangled. The bacterial cells almost covered the surface. After immersion in 5 % NaCl, the cell of F branchiophila, however, appeared to be indeterminate shape.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.27 no.3
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• pp.232-239
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• 1994

In order to determine the utilization of ascidian tunic, which has been blamed for problems of costal environmental pollution when discharged into the sea after being used as a natural dietary pigment sources for rainbow trout(Oncorhynchus mykiss), fingerlings were fed on experimental diets containing acetone-extracts for 6 weeks. The amounts of acetone-extracts were 11,000mg/Kg and contained 50mg/100g wet tissues of carotenoid and $6\%$ of carotenoids were astaxanthin. From the results of feeding experiments, the growth rate in the extract group was a little higher than that of the control and pink groups after 6 weeks. The redness and yellowness of the fish skin and muscle in the extract group were similar to the pink group. Therefore, acetone-extracts of ascidian tunic were judged to be a natural dietary pigment source suitable as a substitute synthetic pigment for aquaculture use.

• Journal of fish pathology
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• v.22 no.3
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• pp.275-282
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• 2009

In this study, effect of mating group, mating dam and mating sire was analyzed using olive flounder Paralichthys olivaceus challenged with Edwardsiella tarda. A challenge test was conducted using 1,708 olive flounder fingerlings obtained through $4{\times}4$ factorial cross from parents selected based on resistant degree. Regarding the means of resistant index, survival rate and days of survival by each mating group, the group(RR) produced by mating among resistant parents were 17.98, 13.77%, and 18.36 days, respectively; the group(SS) produced by mating among susceptible parents were 12.46, 2.71%, and 12.40 days, respectively. This study gives an indication that challenge test results may be successfully used as selection criteria for disease resistance to E. tarda in olive flounder, P. olivaceus.

• Journal of Bio-Environment Control
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• v.1 no.2
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• pp.123-134
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• 1992

In order to verify the usability of the greenhouse for aquaculture with nutrient culture synchronously and to obtain the fundamental data fir the establishment of efficient farming technology, the characteristics of microclimate and the growth of leafy vegetables were examined. Tilapia averaged 428.6 g grew to 784 g(1.83 times) for 147 days from May 29 to Oct. 21 and fingerlings averaged 12.9 g grew by 1.37 times for 61 days from Sep. 13 to Nov. 12. The growth of vegetables such as water dropwort, leaf lettuce, Chinese cabbage, and Welsh onion in the greenhouse was better for aquaculture with nutrient culture than for nutrient culture only. Between above two greenhouses, pH and EC of nutrient solution was same but the temperature different by about 2$^{\circ}C$. Average day temperature, relative humidity, and $CO_2$ concentration were higher by 2.9$^{\circ}C$, 6%, and 200 ppm in the greenhouse for aquaculture with nutrient culture, respectively. Net assimilation rate of vegetables in the greenhouse was a little higher for aquaculture with nutrient culture than for nutrient culture only. Therefore, provided aquaculture and nutrient culture are carried out in the same greenhouse, the saving effect of heating cost as well as the additional promotive effects of vegetable and tilapia growth can be obtained.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.14 no.4
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• pp.233-238
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• 1981

A recirculating water system without filter bed was used for a high density experimental rearing of common carp, Cyprinus carpio, during the summer of 1981. Of the water system, 3 tanks were used for stocking each tank with 10,000, 20,000 and 30,000 common carp fingerlings which averaged 0.6 g. The water in the system was maintained in dark green colour by heavy growth of phytoplankton during the most period of the experiment. In this experiment, the best daily growth rate, $3.7\%$, was obtained from the 10,000 fish group followed by $2.8\%\;and\;3.0\%$ from the 20,000 and 30,000 fish groups respectively. Thus there was no significant difference between the latter two groups. Especially, notably high concentration of total ammonia, $5\sim7$ ppm ammonia-N, in the culture water appeared during the most experimental period, but this did not seem to have affected feeding and growth of the fish when the water was kept at heavy bloom. It was also obvious that the outbreak of columnaris disease was effectively depressed in this green water recirculating system compared to that in clarified recirculating system. One tank ($7m^2$) of this system was stocked with 446 common carp of intermediate size averaging 352.2 g and after 40 day rearing they grew to 486.3 g in average with a daily growth rate of $0.8\%$. This result was a little inferior to that reared in a tank of the clarified water system as control which showed $1.0\%$ daily growth rate. Therefore, before an initiation of the commercial production of fish in this method, further studies concerning the amount of ammonium with its effect on the fish under rearing in this system and the columnaris disease problem should be carried out.

• Journal of Aquaculture
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• v.11 no.4
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• pp.495-503
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• 1998

The present study investigated the effects of Bisroot, that contains live bacteria (Bacillus polyfermenticus, Bacillus mesentericus, Streptococcus faecalis, & Bifidobacterium breve) and digestive enzymes (protease, lipase), on the growth, body composition and immune response of Nile tilapia fingerlings. One percent of the Bisroot was added to the experimenta feed. All exprimental fish were fed for 60 days. The weigh gains among the experimental fish were not significntly different (P>0.05). Hematocrit value, hemoglobin, total protein, glucose, GOT, and GPT were unaffected by Bisroot treatment. However, it was observed that glucose, GOT, and GPT value in the fish that were fed Bisroot, were lower than the control. The complement activity ($CH_50$) tended to be significantly increased by Bisroot treatment, but not lysozyme activity. Phagocytosis and respiratory burst activities of macrophages in the head kidney were enhanced by Bisroot. Therefore, the Bisroot diet enhances the cellular immune activities were enhanced by Bisroot. Therefore, the Bisroot diet enhances the cellular immune activities of non-specific immune responses. When fish were challenged with a virulent strain of Edwardsiella tarda, the Bisroot treated fish were more resistant than the control. The present results suggest that the introduction of Bisroot into the diet of Nile tilapia could increase their resistance against bacterial infection, reduce fish mortality, and offers economic benefits.

• Journal of fish pathology
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• v.13 no.2
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• pp.121-127
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• 2000

From August to October 1998, over 60% mortality of cultured striped beakperch Oplegnathus fasciatus was occurred in net cages along the southern coast of Korea. Moribund fish showed some clinical signs of lethargic behavior, dark coloration or decoloration, severe gill anemia and enlargement of spleen. Also enlarged basophilic cells showing Feulgen -positive reaction were observed in the tissue section of spleen, kidney, liver and heart of the diseased fish. GF cells inoculated with spleen homogenate of diseased fish produced cytopathic effect of enlarged and rounded cells, therefore the causative virus was isolated from diseased fish. Striped beakperch fingerlings intraperitoneally inoculated with the causative virus ($10^4TCID_{50}$/0.1 ml) revealed symptoms similar to those of naturally infected fish and died from 7 to 14 days post injection. Transmission electron microscopy revealed that the causative virus was enveloped icosahedral particle with 120~130 nm in diameter. PCR products of the expected size (500 bp) were amplified with a primer set based on the ATPase gene of RSIV(red sea bream iridovirus) using template DNAs which were extracted from the spleen of diseased fish and GF cells inoculated with the causative virus. According to the analysis of nucleotide sequence of these PCR products, the sequence from ATPase cDNA gene of the causative virus showed 95% homology with that of RSIV. These results indicate that the mass mortality in the cultured striped beakperch was caused by the infection of iridovirus similar to RSIV.

• Journal of Aquaculture
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• v.19 no.1
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• pp.25-32
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• 2006

An experiment was carried out to investigate changing of water quality during the seed production of dark-banded rockfish Sebastes inermis in large scale tanks. Ten broodstock of dark-banded rockfish were held in three circular tanks (diameter 6.5 m; depth 2 m; water volume 50 ton) each (stocking density $0.061kg/m^3$). During the experiment the temperature ranged from 14.2 to $16.1^{\circ}C$. The fingerlings were 134 with rotifers only during 1 to 9 days after parturition, rotifers with Artemia nauplii during 10 to 20 days after parturition, Artemia nauplii only during 21 to 35 days after parturition, Artemia nauplii with commercial diet during 36 to 80 days after parturition and commercial diet only during 81 to 85 days after parturition. Water quality (dissolved oxygen, pH, $NH_4^+-N,\;NO_2^--N,\;NO_3^--N\;and\;PO_4^{3-}-P$) in rearing tanks measured every 5 days in long term monitoring investigation or every 2 hours in diurnal monitoring investigation. In 85 days after parturition, the body weight of fish grew up to 0.88 f and specific growth rate was 8.0%/day in body weight. In long term monitoring investigation, with the increase of the amount of supplied commercial diet, the concentration of dissolved oxygen (DO) and pH decreased, but the concentration of $NH_4^+-N\;(4.5\;to\;76.3{\mu}M),\;NO_2^--N\;(0.02\;to\;0.06{\mu}M),\;NO_3^--N\;(3.0\;to\;5.9{\mu}M)$, and $PO_4^{3-}-P\;(0.41\;to\;0.59{\mu}M)$ increased. In the diurnal monitoring investigation, the concentration of $NH_4^+-N$ showed great fluctuation and ranged from 3.0 to $9.1{\mu}M$ when fed rotifers, 16.3 to $45.8{\mu}M$ when fed Artemia nauplii and 36.5 to $120.1{\mu}M$ when fed commercial diet. After daily feeding with each of feed, the amount of dissolved inorganic nitrogen (DIN) and phosphorus (P) wastage were 7.0 g and 0.7 g when fed rotifers, 24.7 g and 0.7 g when fed Artemia nauplii and 140.9 g and 2.2 g when 134 commercial diet. The amount of DIN and phosphorous wastage during 134 commercial diet was significantly higher than that of fed rotifer and Artemia nauplii (P<0.05). Results will provide valuable information far water quality management and culture of dark-banded rockfish in commercial seed production systems.