• Journal of Microbiology and Biotechnology
• /
• 제31권3호
• /
• pp.456-463
• /
• 2021

In this study, the culture conditions for Porphyridium cruentum were optimized to obtain the maximum biomass and lipid productions. The eicosapentaenoic acid content was increased by pH optimization. P. cruentum was cultured with modified F/2 medium in 14-L photobioreactors using a two-phase culture system, in which the green (520 nm) and red (625 nm) light-emitting diodes (LEDs) were used during the first and second phases for biomass production and lipid production, respectively. Various parameters, including aeration rate, light intensity, photoperiod, and pH were optimized. The maximum biomass concentration of 0.91 g dcw/l was obtained with an aeration rate of 0.75 vvm, a light intensity of 300 μmol m-2s-1, and a photoperiod of 24:0 h. The maximum lipid production of 51.8% (w/w) was obtained with a light intensity of 400 μmol m-2s-1 and a photoperiod of 18:6 h. Additionally, the eicosapentaenoic acid and unsaturated fatty acid contents reached 30.6% to 56.2% at pH 6.0.

• Fisheries and Aquatic Sciences
• /
• 제24권4호
• /
• pp.171-179
• /
• 2021

To better understand the ecological functioning of the coastal ecosystem in Gamak Bay on the southern coast of Korea, seasonal changes in the density, biomass, and secondary production of the copepod community were investigated. Environmental measurements (temperature, salinity, and chlorophyll a) and copepod sampling were performed seasonally from January to December 2006. The mean density of copepods (excluding nauplii) varied from 949 to 5,999 ind · m^-3; copepod density was at its highest from March to July. The copepod community comprised 32 taxa, including Calanoida, Cyclopoida, and Harpacticoida. The predominant species were Paracalanus parvus s. l., Acartia omorii, Eurytemora pacifica, Oithona similis, A. erythraea, Centropages abdominalis, Pseudodiaptomus marinus, and Calanus sinicus. There were significant spatial and seasonal variations in copepod total biomass, which ranged from 0.33 to 43.10 mg C m^-3. Mean secondary production of the copepods in Gamak Bay, estimated as 2.05 ± 1.63 mg C m^-3 d^-1 using the Huntley and Lopez growth model, was over 2 times higher than the value given by application of the Hirst and Bunker model (1.09 ± 0.85 mg C m^-3 d^-1). The daily production rate to biomass (P/B) ratio varied between 0.08 and 0.86 d^-1 (Huntley and Lopez model), and 0.18 and 0.33 d^-1 (Hirst and Bunker model). Our results emphasize the ecological significance of using models to estimate the secondary production of copepods and provides the first report of copepod production in Gamak Bay.

• 한국수산과학회지
• /
• 제51권2호
• /
• pp.135-141
• /
• 2018

This study investigated the immuno-potentiating activities of Japanese mud shrimp Upogebia major. We examined the effects of enzymatic hydrolysate from U. major on the production of nitric oxide (NO) and prostaglandin $E_2$ ($PGE_2$) and on the expression of pro-inflammation cytokines including $TNF-{\alpha}$, IL-6 and $IL-1{\beta}$ in RAW 264.7 cells. The treatment of six enzymatic hydrolysates of U. major (alcalase, ${\alpha}$-chymotrypsin [${\alpha}-Chy$], trypsin, pepsin, neutrase, protamex) significantly increased the production of NO in RAW 264.7 cells, with ${\alpha}-Chy$ having the greatest effect. This hydrolysate was fractionated by two ultrafiltration membranes at 3 and 10 kDa to created three fractions (below 3 kDa, between 3 and 10 kDa, and above 10 kDa). Of these, the <3 kDa and >10 kDa fractions showed significant increases in NO production. These two fractions also induced $PGE_2$ production in RAW 264.7 cells and showed significant increases in the expression of all cytokines studied. These results suggest that enzymatic hydrolysate from U. major is a potentially useful food material with immune-potentiating effects.

• 수산해양교육연구
• /
• 제28권5호
• /
• pp.1444-1458
• /
• 2016

The expansion of high-density aquaculture in the limited waters has caused a wide variety of problems. The problems include environmental problems nearby aquaculture sites, growth rate of aquatic organisms, quality decline of farmed fish and price fall in the market. The phenomenon of aquaculture industry happens in not only inshore but also offshore. Therefore, the fisheries authorities have been changing their policy paradigms from mass production to sustainable production based on ecosystem. Other countries, however, focusing on relieving poverty and providing protein from fish production have not recognized the degree of seriousness. When it comes to enhancing the problems, National Institute of Fisheries Science has been developing the technology of Integrated Multi-Trophic Aquaculture (IMTA) to reduce and to prevent contaminants from fish and aquaculture sites, remained feed from fish farming process. In long-terms of view, the system is one of the most sustainable fishery production methods based on ecosystem. As integration of nutrient feed system from aquatic organisms is firmly established, the earlier mentioned problems will be diminished gradually. In term of the substantiality, this study was conducted. The research on management system for IMTA also has been incorporated. This study also investigated the features and current status of IMTA and demonstrated the developed management system and direction for the future advancement.

• 수산해양교육연구
• /
• 제21권3호
• /
• pp.373-389
• /
• 2009

The aims of this study are to examine urgent problems for reorganization into future-proof large purse seine fisheries in order to positively cope with rapidly changing domestic and foreign fisheries circumstances. First, this paper provides current situations of the large purse seine fisheries. The current situations of it are composed of fisheries influence such as vessel number, vessel power, and fisher number, use of resource and fishing places, and changes in products and sales of species caught by the large purse seine. Secondly, this paper reviews current problems of the large purse seine fisheries including cost reduction and increase of value added. Thirdly, this paper suggests basic development direction and countermeasures for strengthening competitiveness of the large purse seine fisheries. In conclusion, urgent problems of the larger purse seine fisheries can be summarized as inefficiency of distribution structures and retarded landing system and facilities as well as the worse of profitability according to shrink of fishing places, reduction of products, lack of workers, and increase in oil price. To solve the urgent problems, the large purse seine fisheries should be changed into an industry with low cost and high efficiency, and also need to introduce of new production system, strengthen autonomous management of natural resource, and increase in value added to products.

• 수산경영론집
• /
• 제31권2호
• /
• pp.11-26
• /
• 2000

The study tries to extend the Kang and Kim's model(1997) for evaluating fisheries damages caused by a large scale coastal reclamation. The paper tries to suggest a more generalized model by adopting new applicable variables such as the decreasing rate of production quantity amount and decreasing numbers of variables for simplification and derivation of quantative results. The paper also tries to suggest the decision model for fisheries administrative measures on the basis of the degree of damages.

• 수산경영론집
• /
• 제52권4호
• /
• pp.45-63
• /
• 2021

The purpose of this study is to analyze the structure, status and economic ripple effects of the fisheries processing industry in Korea using interindustry analysis. Five input-output tables published over the past twenty years have been reclassified with a focus on the fisheries processing sector. Through these multi-period tables, we analyzed changes in the inducing effects in production, value added and employment as well as the backward-forward linkage effects. As a result of the analysis, it was found that the industrial scale of the fisheries processing industry is very small compared to other food manufacturing industries. The backward linkage effect of the fisheries processing industry was greater than that of other industries, but the forward linkage effect was rather low. This means that the fisheries processing industry can be greatly affected by industrial depression of the downstream industries such as fishery and aquaculture. Production and employment-inducing effects of the fisheries processing industry have shown a decreasing trend in recent years. This reflects the reality that intermediate inputs are gradually being replaced by imports from domestic production due to the expansion of market opening and the depletion of fishery resource. In the future, it is necessary to prepare a strategy to increase the value-added productivity of the fisheries processing sector and foster it as an export industry.

• 수산경영론집
• /
• 제26권1호
• /
• pp.55-77
• /
• 1995

This study analyzed the structure of imported fisheries, focusing especially on the following factors of live fisheries import : First of all, it is confirmed that the import of live fisheries expands when domestic production decreases. To put it concretely, the structure of domestic live fish supply is based upon the production of aquaculture, the shift from export to domestic use, and imported live fisheries. These all coexist, expand, and grow together. Secondly, the structure of the consumer's market - the background of expanding and growing live fisheries-is currently diversifying with quality and quantity from a local area consumer system based upon regional markets, to a wider ranged system based upon the food industry and retailing market. The existence of the consumer markets is premised upon a stable supply structure, in terms of material and price. Thirdly, in terms of trade policy, control of imports instantly reduces import goods. But it is reasonable to say that there is not any logical effectiveness of denying the stable growth of low market capital under the background of strong consummer expansion. Fourthly, the attitude of the import related managener organization is directly related to the degree to which it is connected to live fish import. It is demanded that such a managing organization possess suitable facilities, specializaed knowledge, and management skill of live fisheries. So it is predicted that newly introducing the importing of live fisheries is not simple. It indirectly shows that the capital which relates to live fisheries are connected with the importing og live fish fisheries.

• 한국수산과학회지
• /
• 제52권2호
• /
• pp.173-179
• /
• 2019

We investigated the ecological characteristics and proximate composition of Muraenesox cinereus off the southern coast of Korea. Anal length distribution, sex ratio, condition factor of M. cinereus individuals caught by costal complex (longline) fisheries were investigated from June to October 2018. The mean anal length was 23.5 cm, which was less than $L_{50}$, indicating that the individuals were mostly immature. Sex ratio is 9:1, we captured 382 females and 29 males, which produced a significantly different ratio (P<0.05). Condition factor remained constant over the study period. The proximate composition of M. cinereus individuals was analyzed from July to October 2018. No significant differences in moisture, crude lipid, crude protein, and ash content were observed between individuals caught in summer and those caught in fall.

• 한국수산과학회지
• /
• 제42권6호
• /
• pp.621-627
• /
• 2009

In order to standardize the juvenile abalone rearing technique, we selected sample farms by region in East, West and South coasts of Korea and Jeju island. We also have reviewed previous literature and visited farms to survey on the management of abalone juvenile production, spawning, hatching and so forth. Results of investigation are as follows: The light colors of tanks for larvae breeding are good for a frequent examination of larvae behaviour changes during the breeding period. The tank for the abalone juvenile production is a rectangular form in general and its size should amount to 3.5 m in length and 1.2 m width. It also should be built with proper drainage. The best age and size of adult for juvenile production are 3-6 years old individuals, with 9-12 cm separate burial and 125-150 g average weight. To induce spawning, the use of the exposure on air and ultraviolet ray together was the most effective. The density of larvae by plate should be 150-300 individuals and the proper stocking density was est imated and amount to 10-30 individuals. It has been shown that a correlation between water surface size($X_1$) and number of plates ($Y_1$), when producing abalone juveniles, is quite high and it is described by equation $Y_1=138.88X_1-5,736.8\;(R^2=0.9028)$. In addition, it has also been shown that a correlation between production of abalone juveniles ($Y_2$) and number of plates ($X_2$) is high and it is described by equation $Y_2=4.554X_2+12,493\;(R^2=0.8818)$. In Jindo region where a mass production of juveniles abalone has been done, it was shown, that a correlation between rearing water surface size ($X_3$) and production of juveniles abalone ($Y_3$) is very high and this relationship was described by the equation $Y_3=747.03X_2+94,359(R^2=0.9809)$. It has also been shown that a correlation between water surface size ($X_4$) and production of abalone juveniles ($Y_4$) in nationwide is high and the relationship between this variables was described by equation $Y_4=635.85X_4+99,923\;(R^2=0.9020)$.