• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2000.05a
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• pp.233-234
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• 2000

Formalin, 37% formaldehyde, has been employed as a chemical for controlling ectoparasites and aquatic fungi responsible for infectious fish of diseases in hatcheries and culture facilities (Roberts, 1978; Schnick, 1991; Rach et al., 1997). Regarding the commercial usage of formaldehyde in the aquaculture industry, the U.S. Food and Drug Administration (FDA) approved three commercial products as parasiticides in a species-specific manner: Paracide-F and Formalin-F for bluegill, catfish, largemouth bass, salmon, and trout and Parasite-S for all finfish (FDA, 1998). Withdrawal time for these products was legally zero when used as permitted under the regulations. With the increased production of cultured fish in Korea, such as olive Hounder Paralichthys olivaceus and black rockfish Sebastes schlegeli, application of formalin to diseased fish has become more frequent. Moreover, there is still some concern about environmental exposures caused by effluents from fish culture facilities. The purpose of the present study was to evaluate residues in fish resulting from therapeutic usage of formalin in the aquaculture industry and to document the rate of disappearance of formaldehyde in seawater treated with formalin. (omitted)

• Clean Technology
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• v.17 no.4
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• pp.395-405
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• 2011

To develop the technology for cultivation of high-density seaweed, sea tangle was cultured from varying depths(0.5 m, 3 m) of seawater at Gijang and Wando area. Proximate composition, component sugar, total amino acid, fatty acid composition, and element composition of different parts of sea tangle (Saccharina japonica) have been examined. Significant differences were found in the amount of crude protein and ash content in lower, middle, and upper parts of algal blades. The upper parts of the sea tangle was rich in crude protein, while lower parts was rich in crude ash. Crude lipid content was higher in the middle parts than those of the other parts. The component sugars were not significantly different from all parts of algal blades. The highest content of most of the amino acids were found in the upper parts of the blades. The amount of saturated fatty acids concentrated mostly in lower parts of blades, while the content of polyunsaturated fatty acids concentrated in the upper parts. The highest N element contents were found in upper part of algal blades. However, the contents of those chemical component were not affected by the depths of seawater.

• The Korean Journal of Malacology
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• v.25 no.3
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• pp.213-222
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• 2009

In order to investigate contamination of heavy metal in seawater and cultured oyster, samples were collected November 2003 to July 2004 from 12 sites (13 sites for seawater) along the coast of Tongyeong, Korea. The mean concentrations of metal in oyster tissues were as follows: 0.09 (0.01-0.3) ${\mu}g/l$ for Cd, 0.47 (0.01-1.4) ${\mu}g/l$ for Cr, 0.59 (0.2-2.3) ${\mu}g/l$ for Ni, 1.02 (0.1-4.2) ${\mu}g/l$ for Pb and 0.48 (0.01-3.9) ${\mu}g/l$ for Hg in the seawater, whereas 2.45 (0-5.47) mg/kgDW for Cd, 3.63 (0.10-12.91) mg/kgDW for Cr, 3.2 (0.01-15.73) mg/kgDW for Ni, 3.51 (0.01-6.47) mg/kgDW for Pb and 0.39 (0.004-0.74) mg/kgDW for Hg, respectively. Most metal concentration values were below the permissible range for the related regulations. Mean bioconcentration factors (BCF) for each metal were as follows: 38,964 (1,771-207, 171) for Cd, 9,583 (1,231-80, 162) for Cr, 191 (3-20, 980) for Ni, 1,416 (245-5, 207) for Pb and 180 (5-716) for Hg, respectively. The BCF values from this study corresponded to the transitional phase from the pristine to the contaminated waters. Notably, Cd showed the highest BCF, which suggest that the Pacific oyster could be utilized as a useful biomarker for Cd contamination in sea water. The multidimensional scaling analysis suggested that the metal contaminants are mainly originated from combustion of fossil fuel and accumulated to oyster through food web.

• Ocean and Polar Research
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• v.37 no.3
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• pp.201-209
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• 2015

To examine the effects of increased $CO_2$ concentration and seawater temperature on the photosynthesis and growth of forest forming Ecklonia cava (Laminariales, Phaeophyta), sporophytic discs and gametophytes were cultured under three $pCO_2$ concentrations (380, 750, 1000 ppm), four temperatures (5, 10, 15, $20^{\circ}C$ for sporophytes; 10, 15, 20, $25^{\circ}C$ for gametophytes), and two irradiance levels (40, $80{\mu}mol$ photons $m^{-2}s^{-1}$) for 5 days. Photosynthetic parameter values ($ETR_{max}$, $E_k$, and ${\alpha}$) were generally higher as sporophytic discs were grown under low temperature and increased $CO_2$ concentration at 750 ppm. However, photosynthesis of Ecklonia sporophytes was severely inhibited under a combination of high temperature ($20^{\circ}C$) and 1000 ppm $CO_2$ concentration at the two photon irradiance levels. The growth of gametophytes was maximal at the combination of 380 ppm (present seawater $CO_2$ concentration) and $25^{\circ}C$. Minimal growth of gametophytes occurred at enriched $pCO_2$ concentration levels (750, 1000 ppm) and high temperature of $25^{\circ}C$. The present results imply that climate change which is increasing seawater temperature and $pCO_2$ concentration might diminish Ecklonia cava kelp beds because of a reduction in recruitments caused by the growth inhibition of gametophytes at high $pCO_2$ concentration. In addition, the effects of increased temperature and $pCO_2$ concentration were different between generations - revealing an enhancement in the photosynthesis of sporophytes and a reduction in the growth of gametophytes.

• Animal cells and systems
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• v.11 no.2
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• pp.117-124
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• 2007

The present study demonstrates the changes in body weight (BW) and plasma sex steroid hormone profiles during artificial maturation induced by human chorionic gonadotropin (HCG) or salmon pituitary extract (SPE) injections in cultured eel, Anguilla japonica, kept in seawater for 3 months. In the weekly SPE-injected female group, BW was relatively stable during vitellogenesis. Following induction of vitellogenesis, females exhibited a rapid increase of BW, and the oocytes were observed to be in the migratory nucleus stage at the end of the experiment. Plasma testosterone (T) and $estradiol-17{\beta}$ ($E_2$) levels increased slightly during vitellogenesis and peaked at an average of 5.82 ng/mL and 4.76 ng/mL, respectively, at the end of the experiment. In the weekly control and HCG-injected female groups, BW slowly decreased during the experimental period, and the oocytes of the two groups were observed to be at the primary yolk globule stage. In the weekly HCG-injected female group, plasma T and $E_2$ levels increased slightly during vitellogenesis and decreased afterward. In the control female group, however, plasma T and $E_2$ levels were not altered during the experimental period. Furthermore, plasma $17{\alpha},20{\beta}-dihydroxy-4-pregnen-3-one$ (DHP) was not detected in all experimental groups. Fertility and hatching rates of SPE-injected females were significantly higher in those that ovulated 15 h after DHP injection than 18 h. These results indicate that long rearing in seawater increases responsiveness to SPE in ovarian maturation of the Japanese eel, resulting in shortened period from completion of vitellogenesis by sex steroid hormone production.

• Journal of Fisheries and Marine Sciences Education
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• v.25 no.4
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• pp.828-835
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• 2013

Products from aquaculture have sometimes been focused on the problems caused by the contamination of chemical agents as the use of chemical agents in aquaculture has been annually increased. The risk of contamination of products by chemical agents is greater in freshwater than in seawater. In order to evaluate the food safety of a fish grown in freshwater, we investigated the residues of antibiotics (tetracycline, oxolinic acid and ciplofloxacin) and malachite green in cultured rainbow trout, Oncorhynchus mykiss. Malachite green, which was prohibited in the application of aquaculture, was not detected in samples tested in this study. The residual content of tetracycline was determined to be less than the permissible amount, <0.2 mg/kg. The contents of ciplofloxacin was also less than the permissible amount, <0.1 mg/kg. However, in case of oxolinic acid, one of samples was only exhibited higher content than the permissible amount (<0.1 mg/kg). The results obtained in this study suggested that the control and regulation of chemical agents such as antibiotics was important to maintain a safe and worry-free seafood supply.

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.37-37
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• 2003

Intraspecific hybrids have been proven to be a useful tool for increase growth rate in some freshwater fish species. However the effects of intraspecific hybrids in seawater fish species is little known. To assess whether intraspecific hybrids in red sea bream was associated with growth enhancement, growth performances of offspring from two inbred lines, selected Korean line (KORDI-F4) and cultured Japanese line (IPN) and two intraspecific hybrids lines (KORDI-F4♀×JPN♂ and JPN♀×KORDI-F4♂) of red sea bream were compared. There's no significant difference in body weight between offspring groups during seed production period (until 4 months old). At seven months old (after three months rearing trials on sea cages communally), the offspring from KORDI-F4 (41.0±11.1g) and JPN♀×KORDI-F4♂ (39.3±8.1g) showed significantly better performance in body weight than that of the offspring from KORDI-F4♀×JPN♂ (37.0±8.1g) and IPN (35.7±9.7g). At 15 months old, the offspring from JPN♀×KORDI-F4♂ showed best growth performances in body weight, weight gain, specific growth rate among four offspring groups. As the results, the intraspecific hybrids between cultured Japanese line and selected Korean line showed superior growth performances than their paternal and maternal inbred lines.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.37 no.1
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• pp.7-12
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• 2004

This study investigated the possibility of salinity acclimation of freshwater rotifers (Brachionus calyciflorus) as live food for sweetfish (Plecoglossus altivelis) larvae, and also examined the optimal salinity for the growth of sweetfish. Freshwater rotifers cultured in 0 and 4 PSU and seawater rotifers (B. rotundiformis) cultured in 33 PSU were supplied to the larvae with four kinds of enrichment material (condensed freshwater Chlorella, $\omega-yeast,$ baker's yeast, Super Selco) and larval growth at 4 PSU was examined. Growth of the freshwater rotifers positively increased from 0 PSU to 6 PSU, but decreased when over 8 PSU was reached. Growth and survival of the sweet fish larvae reared in 0 PSU were significantly lower than those reared in either 4 PSU or 33 PSU. This indicated that the freshwater rotifers (B. calyciflorus) could be used as live food for sweetfish larvae reared in 4 PSU. The body weight of sweetfish larvae fed on freshwater rotifers enriched with Super Selco was the highest at 0.163 mg, but there was no significant difference in survival and body length of the fish fed with the other enrichment materials. The content of n-3 HUFA of the sweetfish larvae fed on the freshwater rotifers enriched with Super Selco and the condensed freshwater Chlorella was higher than that enriched with $\omega-yeast$ and baker's yeast. These results indicated that B. calyciflorus cultured with the condensed freshwater Chlorella could be used for the sweetfish larvae without enrichment, and the most efficient enrichment material for B. calyciflorus is Super Selco.

• Ocean and Polar Research
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• v.27 no.2
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• pp.215-219
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• 2005

We isolated and identified three protease-producing bacteria that had inhabited the region around the Korean Arctic Research Station Dasan located at Ny-Alesund, Svalbard, Norway $(79^{\circ}N,\;12^{\circ}E)$. Biofilms were collected from the surface of a floating pier and from dead brown algae in a tide pool near the seashore. The biofilm samples were transported to the Korea Polar Research Institute (KOPRI) under frozen conditions, diluted in sterilized seawater, and cultured on Zobell agar plates with 1% skim milk at $10^{\circ}C$. Three clear zone forming colonies were selected as protease-producing bacteria. Phylogenetic analysis based on 16S rDNA sequences showed that these three stains shared high sequence similarities with Pseudoalteromonas elyakovii, Exiguobacterium oxidotofewm Pseudomonas jessenii, respectively. We expect these Arctic bacteria may be used to develop new varieties of protease that are active at low temperatures.

• Fisheries and Aquatic Sciences
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• v.8 no.2
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• pp.76-82
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• 2005

We analyzed the paralytic shellfish poisoning (PSP) toxins of the toxic marine dinoflagellate Alexandrium tamarense collected from Dadaepo and Gaduck-do in Busan and from Sujeong-ri in Jinhae Bay, Korea, in April 2003. We also analyzed the PSP toxin of mussels (Mytilus galloprovincialis) and oysters (Crassostrea gigas) collected around Busan and Jinhae Bay. PSP toxin analyses were conducted by high performance liquid chromatography (HPLC). Fifteen cultured A. tamarense isolates contained 2.78 to 57.47 fmol/cell, with nearly identical toxin profiles: major components C2, GTX4; minor components C1, GTX1, NEO; and trace components GTX2, GTX3, STX. PSP toxin contents were 0 to $492\;\mu{g}$ STXeq/100 g in mussels and 0 to $48\;\mu{g}$ STXeq/100 g in oysters. Mussels at Gijang and Sujeong-ri contained the most PSP toxin contents ($492\;\mu{g}\;STXeq/100\;g\;and\;252\;\mu{g}\;STXeq/100\;g,\;respectively$), exceeding the quarantine level ($80\;\mu{g}$ STXeq/100 g). Their dominant toxin components were C2, C1, GTX2, and GTX3; the minor components GTX1, GTX4, GTX5, and NEO were sporadically detected. Phytoplankton contained 0.774 fmol/L seawater and 1.228 fmol/L seawater at Gijang and Sujeong-ri in April. At that time, Alexandrium cells were present in the water column at Gijang at 2,577 cells/mL and at Sujeong-ri at 6,750 cells/mL. Overall, we found the high and similar PSP toxin contents in AZexandrium isolates and mussels, and a correlation between occurrence of toxic Alexandrium cells in the water column and mussel intoxification. High densities of toxic Alexandrium cells in the water column immediately preceded shellfish intoxification at Gijang and Sujeong-ri in April.