• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.1
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• pp.1-7
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• 2011

This study examined Tetraselmis sp. JK-46 isolated from seawater from the East Sea. Deep seawater (DSW) had a greater effect on the growth of Tetraselmis sp. JK-46 than surface seawater (SSW). The crude protein, lipid, carbohydrate and ash contents of Tetraselmis sp. JK-46 cultured with DSW were 27.2, 37.1, 13.2 and 26.3 %, respectively, and these values were similar to the results for samples cultured with SSW. The contents of Mg, Ca, Fe and K in the DSW cultured samples were 7080.3, 1009.6, 251.2, and 2749.7 mg/100 g, respectively. The fatty acid compositions of Tetraselmis sp. JK-46 cultured with DSW and SSW were 53.7 and 49.0 % polyunsaturated fatty acids (PUFA) and 25.7 and 30.7 % saturated fatty acids (SFA), respectively. The total amino acid contents of the samples cultured with DSW and SSW were 7392.6 and 6376.0 mg/100 g respectively. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity of Tetraselmis sp. JK-46 extracts increased with the concentration of the chloroform and ethyl acetate fractions. The half maximal inhibitiory concentrations ($IC_{50}$) of the chloroform and ethyl acetate fractions of DSW and SSW cultured samples were 1.2 and 2.6 mg/mL, and 3.1 and 3.3 mg/mL, respectively. The ethyl acetate fractions of DSW and SSW cultured samples has anticoagulant activity and the activated partial thromboplastin times (APTT) were 93.4 and 89.3 sec., respectively. The chloroform and ethyl acetate fractions showed antimicrobial activity against Bacillus subtilis, Escherichia coli and Candida albicans.

• ALGAE
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• v.17 no.2
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• pp.127-133
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• 2002

The red seaweed Eucheuma serra is a high yielding source of lectins. The plants were collected from a depth of 5-6 meters and cultured in the laboratory, field and deep seawater. A Daily Growht Rate (DGR) of 3.5% was observed at 18℃ with a low light of 30μmol photon $ m^{-2} · s^{_1}$ in the laboratory. When the plants were cultured in the field at different depths during winter onths of December and January, best growth was observed at 1 m depth and a DGR of 2.14±0.04% was recorded. The plants grown in the tank with a continuous supply of deep seawater showed a DGR of 8.2% The results indicate that E. serra can be cultivated in large scale both in deep seawater in the tank and in the field for the extraction of lectins at a commercial scale.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.23 no.4
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• pp.334-338
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• 1990

The approximate compositions and the taste compounds of tilapia, Oreochromis nitoticus, cultured in freshwater and seawater for six months, were analyzed. As for the approximate compositions, there were little differences in moisture and protein contents of tilapia cultured in seawater and freshwater, but somewhat higher lipids and ash than that cultured in freshwater. Also, no significant differences in the content of free amino acids, nucleoli-des, betaine, TMAO, and total creatinine were observed between both groups.

• Journal of Microbiology and Biotechnology
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• v.19 no.10
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• pp.1206-1212
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• 2009

Growth rates, photosystem II photosynthesis, and the levels of chlorophyll $\alpha$ and secondary metabolites of Chlorella ovalis were estimated to determine if they were enhanced by the addition of swine urine (BM) or cow compost water (EP) that had been fermented by soil bacteria to deep seawater (DSW) in an attempt to develop media that enabled batch mass culture at lower costs. Growth of C. ovalis in f/2, f/2-EDTA+BM60%, DSW+BM30%, and DSW+EP60% was enhanced and maintained in the log phase of growth for 16 days. The cell densities of C. ovalis in DSW+EP60% ($4.1{\times}10^6$ Cells/ml) were higher than those of f/2 ($2.9{\times}10^6$ Cells/ml), f/2-E+BM60% ($3.7{\times}10^6$ Cells/ml), and DSW+BM30% ($2.7{\times}10^6$ Cells/ml). The growth rate was also more favorable for C. ovalis cultured in DSW+EP60% ($0.15\;day^{-1}$) than that of C. ovalis cultured in the control medium (f/2) ($0.12\;day^{-1}$). Furthermore, the chlorophyll a concentration of C. ovalis cultured in DSW+EP60% (4.56 mg/l) was more than 2-fold greater than that of C. ovalis cultured in f/2 (2.35 mg/l). Moreover, the maximal quantum yields of photo system II at 470 nm (Fv/Fm) were significantly higher in organisms cultured at f/2-E+BM60% (0.53) and DSW+EP60% (0.52) than in the other treatment groups. Finally, Fourier transformation infrared (FT-IR) spectroscopy revealed that C. ovalis grown in DSW+EP60% had more typical peaks and various biochemical pool shifts than those grown in other types of media. Taken together, the results of this study indicate that the use of DSW+EP60% to culture C. ovalis can reduce maintenance expenses and promote higher yields.

• Fisheries and Aquatic Sciences
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• v.3 no.2
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• pp.118-125
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• 2000

Lipid classes and fatty acid compositions of eight species of wild and cultured seawater fish in Korea were investigated. Total lipid (TL) contents of wild and cultured fish were $2.64\pm1.88\%$ and $5.42\pm1.76\%$, respectively, except for rockfish and striped beakperch. Non-polar lipids (NL) in all fish samples comprised approximately $84\%$ of the TL content. The proportion equation of NL content to TL content was y=0.9296x-0.4468 $(R^2=0.98l2, p<0.001)$. The most abundant NL class was triglyceride. The prominent fatty acids in all fish samples were 16: 0, 18: 1(n-9), 22 : 6(n-3) (docosahexaenoic acid, DHA), 16: 1(n-7), 20 : 5 (n-3) (eicosapentaenoic acid, EPA), 18 : 0 and 18 : 1(n-7). The polyunsaturated fatty acid (PUFA) group was the richest among the total fatty acids (TFA). DHA and EPA were comprised of approximately $85\%$ of n-3 PUFA. There was a positive correlation between TFA content and n-3 PUFA content; y=0.292x-0.0055 $(R^2=0.9349, p<0.001)$. The n-3 PUFA content of the cultured fish was approximately twice as much as that of the wild fish. Therefore, cultured fish were proven to provide better sources of n-3 PUFA if compared to wild fish.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.3
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• pp.254-261
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• 2018

From 2014 to 2017, mortalities of seawater-cultured rainbow trout Oncorhynchus mykiss, were observed in the Goheung and Jeju areas of Korea, with Vibrio anguillarum (seven strains: RT1, 2, 3, 4, 5, 6, and 7) identified as the etiological agent. The phenotypic (based on API 20NE, API ZYM, and E-test kits), serotypic (slide agglutination tests with O1, O2, O3, O4, and O7 antisera), and genotypic (16S rRNA and ompU sequencing) characteristics of the seven RT strains were analyzed and compared to those of seven additional V. anguillarum stains (SF, isolated from sweet fish; FM, isolated from flathead mullet; ATCC43305; ATCC43311; ATCC43307; ATCC43308; and KCTC2711). The phenotypes of the RT strains showed variance, while the slide agglutination tests of the RT1-7, SF, and FM strains all showed positive reactions with serotype O1 antiserum. The 16S rRNA and ompU sequences of the RT1-7, SF, and FM strains were affiliated with V. anguillarum ATCC43305 (Serotype O1), but the ompU sequence of the SF strain differed from those of the RT1-7, FM, and ATCC43311 strains, including one amino acid substitution. We thus confirmed that serotype O1 V. anguillarum, with multiple phenotypes, continues to infect seawater-cultured rainbow trout in Korea.

• ALGAE
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• v.18 no.2
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• pp.129-134
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• 2003

In order to examine the effects of deep seawater (mesopelagic water in the broad sense) on the growth of macroalgae, the growth and nutrient uptake (nitrate and phosphate) of Ulva sp. (Ulvophyceae, Chlorophyta) were investigated by cultivation in deep seawater (taken from 687 m depth at Yaizu, central Japan, in August 2001), surface seawater (taken from 24 m depth), and a combination of the two. Culture experiments were carried out in a continuous water supply system and an intermittent water supply system, in which aerated 500-mL flasks with 4 discs of Ulva sp. (cut sections of ca. 2 $cm_2$) were cultured at 20$^{\circ}C$ water temperature, 100 $\mu$mol photons $m^{-2}{\cdot}s^{-1}$ light intensity, and a 14:10 light:dark cycle. Nutrient uptake by Ulva sp. was high in all seawater media in both culture systems. The frond area, dry weight, chlorophyll a content, dry weight per unit area, and chlorophyll a content per unit area of Ulva sp. at the end of the experimental period were the highest in deep seawater and the lowest in surface seawater in both culture systems. These values, except for dry weight per unit area and chlorophyll a content per unit area, for each seawater media in the intermittent water supply system were higher than those in the continuous water supply system. We conclude that not only deep seawater as the culture medium but also the seawater supply system is important for effective cultivation of macroalgae.

• Development and Reproduction
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• v.13 no.1
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• pp.35-41
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• 2009

In the present study, we investigated the effects of rearing condition during the winter period on artificial maturation and reproduction of cultured female eel, Anguilla japonica. The female eel was adapted by combination of environmental conditions (seawater/low temperature, $10^{\circ}C$; seawater/high temperature, $20^{\circ}C$; freshwater/low temperature, $10^{\circ}C$; freshwater/high temperature, $20^{\circ}C$) during 8 weeks of the winter period. Then, the female eel cultivated by different conditions during the winter were transferred to seawater at $20^{\circ}C$ for induction of artificial maturation by salmon pituitary extraction (SPE) injection. The results shown that gonadosomatic index (GSI) and plasma levels of estradiol-$17{\beta}$ (E2) were significantly higher in female eel were reared in seawater than in freshwater, and were the highest at eel adapted by seawater/low temperature. Also, reproduction coefficient were higher in seawater/low temperature than in the other groups. These results will provide valuable information for elevation of the artificial maturation and reproduction coefficient in the cultured female eel.

• Journal of Aquaculture
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• v.13 no.1
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• pp.39-46
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• 2000

Successive management of prawn farm is strongly dependent upon monitoring of pond seawater quality which is generally influenced by an excessive food supplied sediment type and phytoplankton composition in the pond. For good condition of seawater quality it must need exchangning of fresh seawater by tidal current. Two distinct shrimp ponds Galha and Yunho which were different in seawater exchanging system and sediment type were selected to understand how some factors affected to seawater and sediment qualities in the pond. Prawn growth was also determined. Galha pond characterized by sand bottom with water exchanging by turn of the tidal current accumulated 1.8 mgS/g-dry as sulfide in sediment while Yunho pond mud- bottomed with seawater exchanging of pumping system showed 4.7mgS/g-dry when it was highest, Ammonia-N and hydrogen sulfide measured in the seawater were 0.31mg/${\ell}$ and 21.2 ${\mu}$${\ell}$/${\ell}$in Yunho and 0.10mg/${\ell}$and 10.8${\mu}$${\ell}$/${\ell}$in Galha pond respectively. Dissolved oxygen remained below 6.0mg/${\ell}$ in Galha and 5.0mg/${\ell}$in Yunho pond from June through August. Less growth of prawn was found in Yunho pond than in Galha pond. Prawn growth expressed as body length and weight were 138.3mm 22.9g in Yunho pond while they were length 158.2mm and 28.9g in Galha pond respectively when they were harvested in October. These results indicate that higher levels of ammonia-N and hydrogen sulfide and lower dissolved oxygen in bottom seawater of Yunho pond might affect the growth of cultured prawn.

• Biomedical Science Letters
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• v.22 no.4
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• pp.150-159
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• 2016

Knowledge of the distribution and biodiversity of environmental bacteria and the ecosystem that influences them is crucial for predicting an ecosystem. However, bacterial culture methods can only analyze approximately 0.1% of the existing microorganisms, those that are readily cultured under laboratory conditions. By contrast, next-generation sequencing (NGS) has generally been known to obtain more diverse profiling of bacterial composition. We compared the bacterial communities using both a culture-dependent (MALDI-TOF) and culture-independent (NGS) methods. Environmental specimens were obtained from both freshwater and seawater. Water samples were also analyzed by both pyrosequencing and MiSeq sequencing, in order to select one NGS platform which could analyze comparatively more diverse microbiota. Bacterial distribution analyzed with MALDI-TOF showed no difference between the microbiota of freshwater and seawater, whereas the results analyzed with NGS distinguished between the two. The diversity indexes of MiSeq sequencing were higher than for Pyrosequencing. This indicated that MiSeq sequencing is capable of analyzing a comparatively wider diversity of bacteria. The genus of Flavobacterium and Planktophila were identified as being unique to freshwater, whereas EU801223 and OM43 were found in the seawater. Difference between the bacterial composition of the freshwater and seawater environments was identified by MiSeq sequencing analysis.