• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.1
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• pp.25-29
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• 2012

Marine actinomycetes isolated from seaweed were screened for growth activation effects on the biodiesel-producing microalgae Dunaliella salina. Of the 98 actinomycetes studied, strain 288-11 isolated from the rhizosphere of Undaria pinnatifida showed potent growth activation. The strain was identified as Streptomyces anulatus based on 16S rDNA sequence analysis. The cell density increased up to 2.1-fold with the addition of 1 mg/mL of extract to the medium. To understand the effect of adding S. anulatus extract, the gross biochemical composition and fatty acids of D. salina were determined.

• Fisheries and Aquatic Sciences
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• v.8 no.4
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• pp.207-212
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• 2005

Directional (sinistral) asymmetry (DA) occurs when the traits of one side of a supposedly bilaterally symmetrical organism differ in a random way from those of the other side. We examined asymmetries in gonadal growth traits within both sexes of hatchery reared ayu, Plecoglossus altivelis. The pattern of the gonadal growth from hatching to 320 days after hatching was a type of DA except for the growth in gonad weight from 140 to 180 days after hatching, although the ovary of the right side tended to exhibit more pronounced DA phenomenon.

• Korean Journal of Ichthyology
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• v.25 no.1
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• pp.25-32
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• 2013

We studied the age and growth of striped beakperch (Oplegnathus fasciatus) in the Jeju marine ranching area using a total of 423 otoliths from August 2009 to August 2010. The surface reading method, which was etched with 5% HCl, was the best method to read ages of this fish. The monthly mean fork length ranged from 20.9 cm to 27.7 cm in the Jeju marine ranching area during from August 2009 to August 2010. The annual ring was formed in July to September once a year. Fish were principally composed of 3 to 5 years old and the oldest was 12 years old. The von Bertalanffy growth parameters of this species, which were estimated from a non-linear regression, were $L_{\infty}$=48.20 cm, $t_0$=-1.031yr, and K=0.123/yr.

• Journal of Korea Port Economic Association
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• v.31 no.1
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• pp.51-68
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• 2015

Recently, it has been emphasized that 'marine special economic zone' need to be designated and developed. Therefore, the purpose of this paper is to analyse on successful growth factors of 'marine special economic zone'. This study deals with the terms of three connection success factors which are a firm's subjective factors, a industrial environment factors, and a governmental policy factors. According to analysis results of the three successful growth factors, a firm's subjective factors(4.11 score) are scored at the most ones of the three successful growth factors, to be compared with a industrial environment factors(3.89 score). with a government policy factors(3.72 score). Therefore, first of all, it is important to enhance competitiveness of 'marine special economic zone' through as follows, a firm's subjective factors : (1) to procure concentrated market strategy and real market capacity, (2) to promote customer service, (3) to procure speedy satisfaction of customer needs and confidence, (4) to enhance competitiveness through standing in a trio of connection growth model. And, the next, we have to enhance competitiveness of 'marine special economic zone' through considering a industrial environment factors, that is, sustainable growth of marine industry, clustering of marine industry, expansion of infrastructure, etc., and a government policy factors, that is, leading law improvement and policy of leading 'marine special economic zone' designation and development, etc.,

• Journal of Microbiology and Biotechnology
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• v.27 no.6
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• pp.1078-1089
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• 2017

Biofilm formation of Staphylococcus aureus is one of its mechanisms of drug resistance. Anti-biofilm screening of 106 compounds from marine-derived fungi displayed that 12 compounds inhibited S. aureus biofilm formation by >50% at the concentration of $100{\mu}g/ml$, and only secalonic acid D (SAD) and B inhibited by >90% at $6.25{\mu}g/ml$ without inhibiting cell growth after 24-h incubation. Meanwhile, it was found that the double bond between C-1 and C-10 of citrinin derivatives and the C-C connection position of two chromone monomers may be important for their anti-biofilm activities. Moreover, SAD slightly facilitated biofilm eradication and influenced its architecture. Furthermore, SAD slowed the cell growth rate in the preceding 18-h incubation and differentially regulated transcriptional expression of several genes, such as agr, isaA, icaA, and icaD, associated with biofilm formation in planktonic and biofilm cells, which may be the reason for the anti-biofilm activity of SAD. Finally, SAD acted synergistically against S. aureus growth and biofilm formation with other antibiotics. These findings indicated that various natural products from marine-derived fungi, such as SAD, could be used as a potential biofilm inhibitor against S. aureus.

• The Journal of Fisheries Business Administration
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• v.26 no.2
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• pp.53-74
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• 1995

The purpose of this paper is to compare China's and Korea's marine fisheries industries in order to present the main features of China's marine fisheries and show the comparative advantages they have in production. The results indicate that China's marine fisheries have the following features. (1) The marine proportion of the fisheries industry economic activity is less than 60%. Fishing is 71.3% of that marine activity. (2) The production trends of marine fisheries history in China can be classified as follows: 1) an early growth period, 2) a deliberation/consolidation period, 3) a second growth period, 4) a third growth period, and 5) a fourth growth period. The growth rate has rapidly increased recently. (3) Fish production is over 70% of marine fishing fisheries, the next major product is crustacea. The production of shellfish occupies over 70% of marine aquaculture, seaweed production however, is only 22% of total marine aquaculture. (4) The licensed area for marine aquaculture in China is 586.3 ha and that area is 5.4 times larger than that of Korea. The allotted area for shellfish aquaculture is 60% of marine aquaculture, production areas of crustaceans occupy 27.3%, fish has 7 1%, and seaweed production only 5.7% of allocated marine aquaculture areas. (5) The proportion of power vessels for marine fisheries of China's total power vessel fleet is around 65%, and the marine fisheries portion of non - powered vessels constitutes only 12%. The highest proportion of power vessels engaged in marine fisheries activities is between 10 tonnes to 100 tonnes. (6) The portion of marine fishery workers of all fishery industry employees is 22%, and 70% of them are full - time workers. Of marine fishery workers, 64% are in the fishing sector, 22%, aquaculture workers, and the number of employees in marine fisheries is increasing every year. The analysis of China's fishery industry in the production competitiveness indicates as follows : (1) The licensed areas in marine aquaculture, number of fishing vessels, number of marine fishing workers in China's fishery industry are much more than those of Korea's. Therefore China is much more competitive than Korea in the quantity of production side. However, licensed areas for seaweed aquaculture are more extensive in Korea than China. In China, the number of power vessels of between 10 tonnes and 100 tonnes, the licensed shellfish aquaculture areas, and the number of fishing workers within the fisheries industry are much more than those of Korea. (2) It is estimated that the licensed areas in marine aquaculture, number of medium sized power vessels, number of marine fishery workers will be increased as the quantity of production factors grow in China. (3) At present, yield per Ha. in marine cultures is very low in China. Therefore it is estimated that aquaculture techniques have only been diffused recently in China. Yield of fish per Ha especially is much lower than that of Korea. So the level of aquaculture techniques seems much lower than that of Korea. (4) China is behind Korea in production technique, however the number of HP per boat in China is lower than that of Korea. Therefore, China is much more competitive than Korea in Costs. (5) Average fish catches per marine fishery worker in China is only 1/3 that of Korea's, and average marine aquaculture production in China is only 1/2 that of Korea. Therefore we can say Korea is more competitive than China in efficiency. The average income of marine fishery workers in China is higher that that of other Chinese industries. However, the competitiveness of the fisheries industry in China will be increased as more capital is invested and advanced techniques are developed.

• Fisheries and Aquatic Sciences
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• v.7 no.1
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• pp.1-9
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• 2004

Sweet smelt (Plecoglossus altivelis) were fed four different diets supplemented with either perilla oil $(2.0\%)$ rich in 18:3n-3 (CP), and perilla oil and Enteromorpha compressa meal $(2.0\%)$ (CPA), soybean oil rich in 18:2n-6 (CO), or soybean oil and algal meal (CA) for 4 weeks. The growth performance, fatty acid composition of muscle, plasma lipid peroxidation and blood components of the sweet smelt were then determined. The specific growth rate and feed efficiency in the fish fed the CPA diet were the highest, while the other groups showed similar results. The fatty acid composition of muscle in sweet smelt reflected the dietary lipids; 18:3n-3 was higher in the fish fed the CP and CPA diets, and 18:2n-6 was higher in the fish fed the CO and CA diets. The other fatty acid profiles presented almost no differences with respect to the diet composition. The fish fed the CA, CP and CPA diets contained significantly lower levels of triglyceride, thiobarbituric acid-reactive substances and hydroxyl radical in their plasma than that fed the CO diet. Phagocytic activity was the highest in the fish fed the CPA diet and higher in those of the fish fed the CP and CA diets compared to the CO diet group. The results from this study suggest that a dietary supplement of $2.0\%$ perilla oil together with $2.0\%$ E. compressa meal may improve the growth and health of cultured sweet smelt.

• Development and Reproduction
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• v.20 no.4
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• pp.305-314
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• 2016

The marine medaka, Oryzias dancena is a suitable sample as a laboratory animal because it has a small size and clearly distinguishes between female and male. Data on the growth and maturity of the diploid and triploid sea cucurbit species suitable for laboratory animals are very useful for studying other species. Triploidy was induced in the marine medaka by cold shock treatment ($0^{\circ}C$) of fertilized eggs for 45 min, applied two minutes after fertilization. The diploid and triploid male fish were larger than their female counterparts (P<0.05), and the concentrations of thyroid stimulating hormone (TSH) and thyroxine (T4) were higher in the induced triploids over 1 year (P<0.05). In both the diploid and tri-ploid groups the concentrations of TSH and T4 were higher in the male fish than in the females (P<0.05), while the testo-sterone and estradiol-$17{\beta}$ concentrations in the induced triploids were lower than in the diploids (P<0.05). The gonadosomatic index (GSI) of the triploid fish was lower than that for the diploids, and the GSI for females in each ploidy group were higher than that for the males. For both groups the GSI was highest at 4 months of age, and decreased thereafter to 12 months. Analysis of the gonads of one-year-old triploid fish suggested that the induction of triploidy probably causes sterility in this species; this effect was more apparent in females than in males.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.8
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• pp.1138-1144
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• 2012

This study was conducted to evaluate the efficacy of the dipeptide form of phenylalanine as a new source of amino acid in terms of growth performance and whole-body amino acid composition in comparison to the free form for red seabream (Pagrus major). Fish ($1.46{\pm}0.001g$) were fed four isonitrogenous and isocaloric experimental diets containing 0.7 or 1.4% phenylalanine either in free or dipeptide form. A feeding trial was carried out in three replicates and the fish were fed to apparent satiation for six weeks. At the end of the feeding trial, feed intake of fish was influenced by both phenylalanine form and level and significantly higher values were obtained at an inclusion level of 0.7% and by the use of dipeptide form. However, the other growth parameters did not significantly differ among treatments. Whole-body amino acid compositions revealed no significant changes in concentrations of both essential and non-essential amino acids regardless of the increase in phenylalanine levels or the use of its different forms. The finding in this study indicates that juvenile red seabream can utilize dipeptide phenylalanine as efficiently as free form without any undesirable effects on growth performance or whole-body amino acid composition.

• Korean Journal of Ecology and Environment
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• v.50 no.1
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• pp.16-28
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• 2017

In an aquatic environment, toxicity of metals to organisms depends on external factors (type of metal, exposure concentration and duration, environmental parameters, and water quality) and intracellular processes(metal-binding sites and detoxification). Toxicity of copper(Cu) on the marine microalga Tetraselmis suecica was investigated in this study. Dose-dependent (Cu concentration dependent) inhibition of growth and cell division, as well as, variation of intra- and extra-cellular Cu, Fe and Zn content was observed. T. suecica was sensitive to Cu; the 96 h $EC_{50}$ (concentration to inhibit growth-rate by 50%) of growth rate (${\mu}$) ($21.73{\mu}M\;L^{-1}$), cell division $day^{-1}$ ($18.39{\mu}M\;L^{-1}$), and cells $mL^{-1}$ ($13.25{\mu}M\;L^{-1}$) demonstrate the toxicity of Cu on this microalga. High intra-($19.86Pg\;cell^{-1}$) and extra-cellular($54.73Pg\;cell^{-1}$) Cu concentrations were recorded, on exposure to 24.3 and $72.9{\mu}M\;L^{-1}$ of Cu.