• KSBB Journal
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• v.18 no.3
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• pp.180-185
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• 2003

Glycosaminoglycans (GAGS was extracted from sea squirt, Styela clava with sodium phosphate at 105$^{\circ}C$ for 2 hr and deproteinized with trichloroacetic acid or hydrochloride. The GAGs obtained from tunic consist 41.7% crude carbohydrates, 31.8% crude protein, and 31.2% sulfate. It was mainly constituted of galactose, glucosamine, glucose, mannose, and glacrosamine. The prominent amino acid were phenylalanine, threonine, glutamic acid, and aspartic acid. Mineral contents was mainly constituted 3.0 mg% sodium, 1.6 mg% potassium, and 1.2 mg% phosphorus. Trichloroacetic acid, hydrochloride and 5-sulfosalicylic acid were used for deprotein of the GAGs. Effective volume for deprotein of crude GAGs were 5.0% trichloroacetic acid (w/v) and 10.0% HCI (v/v) treatment. The deproteinized GAGs contained 35.1%, 35.4% of protein and 22.0%, 18.5% of sulfate, respectively.

• The Journal of Fisheries Business Administration
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• v.25 no.2
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• pp.115-145
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• 1994

The objetives of this study are to find the economic feasibility of the polyculture and to give the economic information of the polyculture for aquaculture fishermen. The polyculture is defined as the rearing of several species together to make more efficient use of the growing space and the total ground environment. The economic feasibility analysis in the polyculture involves the profitability, the productivity, and the risk reduction effect. The results of the economic feasibility analysis in the polyculture are as follows; First, in the profitability analysis, the solid utilization of ground in the polyculture is more profitable than the monoculture. The profitability owing to the plane utilization of the ground in the polyculture is positioned between those of the monoculture of each speices. Second, in the productivity analysis, oyster and sea squirt are diminishing returns to scale. Third, the variation on the average rate of return in the polyculture products is smaller than that of the monoculture. Finally, the result of comparison between the polyculture and the monoculture shows that the polyculture in coastal area is more profitable and more efficient than the monoculture. Most of cultivating species are selective in their diet Thus, stocking different kinds of cultivating species will efficiently utilize space and food It seems that polyculture is more appropriate for those species that live in different ecological niches. We think that the production per unit of ground can be increased, and the fixed cost per unit of output be reduced, so the polyculture is more profitable than the monoculture. Based on the above results, we concludes that the polyculture is economically feasible when profitability and productivity are increased and simultaneously the variation of average rate of return in the polyculture is smaller than that of the monoculture.

• Journal of Convergence for Information Technology
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• v.11 no.4
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• pp.186-193
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• 2021

Ciona intestinalis and Ciona savignyi have been designated as hazardous species because they have caused great damages as they appeared in ports, ships, and farms in Korea in large amount. Therefore, in terms of using them, the possibility of use as cosmetic ingredients was examined. C. intestinalis and C. savignyi were treated with 70% ethanol to make an extract and then their antioxidant activity was measured. C. intestinalis and C. savignyi showed 71.80% and 21.40% of DPPH at 20mg/mL of extract, respectively. ABTS was 95.47% and 27.53%, while nitric oxide production inhibitory ability was 97.47% and 88.90%, respectively. Total phenol content was 0.081 and 0.041 mg gallic acid/mg extract, respectively. As a result, C. intestinalis showed somewhat higher antioxidant activity than C. savignyi. It is confirmed that these extracts are animal-derived antioxidants that can be used as cosmetic materials.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.2
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• pp.118-126
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• 1986

Vibrio vulnificus is a recently recognized halophilic organism that nay cause serious human infections. Patients infected with V. vulnificus often have a history of exposure to the sea, suggesting that the organism may be common inhabitant of marine environment. The purpose of this experiment is to investigate the distribution and bacteriological characteristics of V. vulnificus. The strain used in this experiment was isolated from sea water and sea products such as common octopus (Octopus variabilis), ark shell (Anadara broughtonii), blue crab (Ericheir japonica), and sea squirt (Synthia roretzi) collected in Pusan area from July to October in 1985. V. vulnificus was frequently isolated in August when temperature of sea water was around $26^{\circ}C$ and rarely isolated in October when temperature of sea water was around $18.5^{\circ}C$. The distinctive biochemical characteristics of V. vulnificus were ONPG hydrolysis positive and fermented lactose and not grown in peptone water contained $8\%$ NaCl. The optical density at 660 nm of the growth of V. vulnificus was reached maximum level after 8 hours of culture at $35^{\circ}C$ in brain heart infusion broth but that of V. vulnificus was little increased at $15^{\circ}C$ for 14 hours. Optimum temperature and pH for the growth of V. vulnificus were around $35^{\circ}C$ and 8.0. The specific growth rate and the generation time of V. vulnificus isolated from the samples were $1.21\;hr^{-1}$, 34 min at $35^{\circ}C$ and $0.61\;hr^{-1}$, 69 min at $25^{\circ}C$, respectively. V. vulnificus did not grow on eosin-methylene-blue agar, salmonella-shigella agar, deoxycholate agar but grew well on Endo agar, xylose-lysine-deoxycholate agar and hektoen enteric agar. On Endo agar, the colonies of V. vulnificus were red and achieved a diameter of 2 to 4 mm as a feature enabling differentiation of V. vulnificus from other Vibrio spp. V. vulnificus grow well on TCBS agar forming green colonies. V. vulnificus refrigerated at $4^{\circ}C$ exhibited a linear decline of its viablity as 1 log cycle in every 16 hours storage, while V. vulnificus freezed at $-18^{\circ}C$ almost became extinct.

• Journal of the Korean Society for Marine Environment & Energy
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• v.14 no.3
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• pp.154-162
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• 2011

Seawater quality was investigated each month at 30 stations near Tongyeong, South Korea, to provide data for the effective use of coastal fisheries and the reduction of economic damage to marine products. Water temperature was lowest in January and highest at the end of August. Neither extremely low water temperature below $4^{\circ}C$ nor fish damage caused by low water temperature was observed. Salinity ranged from 24.04 to 34.39 psu in the surface layer and from 29.92 to 34.39 psu in the bottom layer. The minimum salinity, attributable to rainfall events, was observed in July; salinity increased to high of about 34 psu in November. Low dissolved oxygen (DO), below 4 mg/L, was observed at Wenmun and Buksin Bays during May to October. Concentrations of $NO_2$-N, $NO_3$-N, and $PO_4$-P were low from March to September and high from October to February. Transparency was 6 m on average and was high in Wenmun Bay. Chemical oxygen demand (COD) and chlorophyll a (Chl. a) were high during summer, when the water temperature was high. With cluster analysis based on environment factors related to water quality, the study area could be divided into three main sea areas: Buksin Bay, coastal seawater, and offshore seawater. Buksin Bay was characterized by low salinity, high DO and Chl. a, and high transparency in the surface layer and by low DO and high $NH_4$-N in the bottom layer. Offshore seawater had high salinity and $NO_3$-N and low Chl. a concentration. In summer season that oyster need lots of phytoplankton, $NO_3$-N and Chl. a concentrations at this study area were low compare to Gwangy-ang and Gamak Bays. In winter, a sea squirt swallow much more than other season, the Chl. a concentrations were also low than Gwangyang and Gamak Bays.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.13 no.2
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• pp.57-64
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• 1980

Seed tunicates of Halocynthia roretzi (v. DRASCHE) which were artificially settled in Chungmu area were transplanted to Seonyudo and Eochungdo to know the feasibility of the tunicate culturing in the western coast of Korea. From April 1978 to March 1979, the growth of the transplanted tunicate in the two area was compared and analyzed in reference to the ecological factors. At the time when the seeds were transplanted, the mean body height of Halocynthia roretzi(V. DRASCHE) was 1.84 mm, body breadth 1.42 mm, and the body weight 15.0 mg. After 333 days the mean body height was 10.77 mm, body breadth 6.75 mm, and body weight 201 mg in Seonyudo area. In Eochungdo area the mean body height was 13.5 mm, body breadth 11.51 mu and body weight 880 mg. According to above results, it is possible to culture the seeds in Eochungdo area. Salinity $(29.2-32.0\%_{\circ})$ was favorable, water temperature $(6.8-26.8^{\circ}C)$ was not a critical factor, but the growth of the tunicate was affected by the high temperature$(over\;25.0^{\circ}C)$ in July. Transparency lower than 1.0 m seriously affects the growth of the tunicate, and it was one of the important factors inhibiting the growth of the tunicate. Seonyudo area was found out to be inadequate for the culture of the sea spuirt Halocynthie roretzi because of the retarded growth in body breadth and weight while showing extended growth in body length then leading to higher mortality owing to large amount of silting and fouling of the colonial tunicate, Didemnum (didemnum) moseleyi.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.6
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• pp.1162-1168
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• 2000

This study was designed to determine the seafood prcference of the 480 elcmentaty school children in Pusan. The survey was conducted from February 8 to February 22 in 2000. The correlation between nutrition knowledge and dietary attitude is highly significant. However there were no differences in nutrition knowledge and dietary attitude berween male and frmale students. Children's prefercnce is high in laver, crab, common squid, mackerel, hair tail, shrimp, but is low in oyster, warty sea squirt and salt-fermented seafood. The factors affected on the intake frequcncy of seafood and preference were dietary attitude of the children, cducation level of the mother and recommendation of the mother. Children's opinion on the intake of seafood was influenced by their nutrition knowledge and dietary attitude and the recommendation of the mother. Eating frequcncies of the seafood were not influenced by sex, family type, monthly food expenditure and dietary attitude of the mother.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.2
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• pp.125-130
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• 2001

Experimental culture of Halocynthia roretzi was carried out near coast by Wolsung from January to August 1997 to investigate accumulation of heavy metals (Cd, Pb and Cu) by H. roretzi, Water temperature, salinity, pH and Suspended Particulate Matter (SPM) were $10.7\sim25.2^{\circ}C$, $33.0\sim34.6\%_{\circ},\;8.25\sim8.49\;and\;3.84\ksim7.92\;mg/L$, respectively, The heavy metal accumulation in H. roretzi was in the order of Cu>Pb>Cd. Heavy metal concentrations in the organs showed following order; Gill${\geq}Viscera{\gg}$Gonad>Muscle>Mantle for Cd, $Gill{\geq}Viscera{\gg}$ Gonad> Muscle$ {\geq}$Mantle for Pb and Viscera>Gill${\gg}$ Gonad>Muscle>Mantle for Cu.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.1
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• pp.71-76
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• 2002

To understand the effect of heated effluent from a nuclear power plant on marine organism, experimental culture of Halocynthia roretzi was carried out at heated effluent of Wolsung nuclear power plant from January to December 1996. Temperature was $11.2\~27.9^{\circ}C$ and salinity was $32.54\~34.59\%_{\circ}$ during the culture period, The Growth of H. roretzi on lower area of Bonggil-ri (St. 1) was not normal in height, breadth and weight due to heated effluent. Daily growth rate (DGR) of H. roretzi about Kampo area (St, 4) was significant other station, and St. 1 was significant from other station except St. 4, Mytilus edulis was major fouling organism (over $90\%$) that were M. edulis, Dideninum moseleyi, Styela clava in experiment culture farm. St. 1 was higher (mean 143 individual) and St. 4 was lower (mean 56 individual) appearance attached of M. edulis. Growth of H. roretzi reduced when attached number of M. eduiis was increased, because correlation between DGR and number of M. edulis was negative.

• Korean Journal of Environmental Biology
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• v.31 no.3
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• pp.204-212
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• 2013

This study analyzed the occurrence of tunic softness, survival rate, metabolic rate and histopathologic changes arising from the effect of hypoxic environment in order to find the causes of occurrences of tunic softness, which manifests as the key phenomenon of mass mortality of Halocynthia roretzi. Regarding the survival of H. roretzi with reduction in dissolved oxygen, all the entities died on the 4th day of exposure to the dissolved oxygen concentration of $2mg\;L^{-1}$ while 50% mortality was observed on the 5th day of exposure to the dissolved oxygen concentration of $3mg\;L^{-1}$. Therefore the 5 days-$LC_{50}$ was found to be $3.55mg\;L^{-1}$ (1.86~$4.96mg\;L^{-1}$). However, occurrence of tunic softness was not observed during the period of exposure to low oxygen concentration. The oxygen consumption rate significantly decreases at the dissolved oxygen concentration of less than $5mg\;L^{-1}$ in comparison to the control group. Therefore, it is presumed that H. roretzi controls the respiration rate for prescribed period of time when exposed to hypoxic environment. Regarding the histopathologic changes in the gill, digestive gland and cyst of H. roretzi due to hypoxic environment, necrosis of epithelial layer, in filtration of blood cells, and condensation of nucleus that compose each of the organs were observed. Regarding morphological changes, the decrease in volume with shrinking of the tunic, discoloration of the internal organs and necrosis of gill and hepatopancreas were observed.