• Journal of Practical Agriculture & Fisheries Research
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• v.21 no.2
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• pp.27-33
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• 2019

The purpose of this study was to compare the storage and post-storage changes of Cheorwon onions and onions for each region. Onion is a perennial plant belonging to the lily family. It is native to Persia of Southwest Asia. It is cultivated much in the temperate regions of the world. Cheorwon area is inland, but it has high continental climate due to its high altitude. Therefore it is said that the onion cultivated in this region has higher sugar content and higher taste than onion grown in southern region. Although the results of onion storage experiments in Cheorwon, Muan, Buan, and Changnyeong regions did not show much difference in weight, width, and height measurements before and after storage, Brix was reduced by approximately 1-2 brix. Before and after storing in each region, Brix was the highest in Cheorwon, Changnyeong, Buan, and Muan, and after saving, onions in Cheorwon were the same order. After each region was stored, the results showed that Cheorwon (112.3g), Muan (106g), Buan (102.1g) and Changnyeong (92.6g) had the highest hardness. Cold storage tests show that onions contain the least amount of corruption in paper boxes, while Cheorwon onions have the lowest level of corruption in other areas.

• Applied Microscopy
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• v.45 no.4
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• pp.254-258
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• 2015

A histological study on the retina of Misgurnus anguillicaudatus was carried out by light microscopy and scanning electron microscopy as part of getting information about relation between its habitat and visual cells. The visual cells of the retina in M. anguillicaudatus, a bottom-dwelling freshwater pond loach in stagnant or slow waters such as swamps, reservoirs and paddy fields, consists of double cones and large rods. The cones form a row mosaic pattern in which the partners of double cones are linearly oriented with a large rod. In a double cone, the two members are unequal such that one cone may be longer than the other.

• Animal cells and systems
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• v.11 no.2
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• pp.155-160
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• 2007

The skin of the Korean bullheads, Pseudobagrus brevicorpus and P. koreanus, is composed of epidermis, dermis and subcutis. The epidermis has three layers, the outermost layer, middle layer and stratum germinativum. The epidermis consists of two types of gland cells, an unicellular mucous cell of sulfomucin and a large club cell having sometimes two nuclei. The epidermis has numerous intraepithelial blood vessels in P. brevicorpus but not at all in P. koreanus. Lymphatic spaces containing lymphocytes are well developed in mainly the stratum germinativum. The dermis lacks scales and consists mostly of bundles of coarse collagen fibers. The collagen bundles are arranged in parallel to each other in the dorsum and lateral region toward the dorsum, but vertically at intervals in the abdomen and lateral region toward the abdomen. Considering this unique skin structure, the two species are likely to exercise cutaneous respiration as a dual respiratory system to overcome hypoxic conditions which frequently occurs in their habitats.

• Journal of Wetlands Research
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• v.5 no.1
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• pp.1-13
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• 2003

Conservation of wetlands are important because wetlands are hatcheries for fishes and habitat for migratory birds and mammals. Wetlands also function as a filter for polluted water and material and transition zone for harboring numerous species of plants and animals. This paper reviewed the importance of wetland conservation and policy on management of wetlands in Korea. Wetland Conservation Act(1999) and Maritime Management Act(1999) are two legislation for conservation of wetlands. Wetland Conservation Act is issued by both Ministry of Environment and Ministry of Maritime Affairs and Fisheries. The definition of wetlands are so diverse, but this paper categorized wetlands as both natural and man-made lakes, mud flat areas and inland wetlands. Management application was considered for each wetland categories.

• Journal of Marine Life Science
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• v.3 no.1
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• pp.9-21
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• 2018

This study investigated cytogenetic and hematological and histological characteristics between diploid and spontaneous triploid on Cyprinidae (Crucian carp, Carassius auratus; crucian carp, C. cuvieri and common carp, Cyprinus carpio) in four major rivers of Korea. In our results, DNA contents of triploid Cyprinidae were 50% more than those of diploid Cyprinidae. Also, erythrocyte size of triploid Cyprinidae was 50% larger than those of diploid Cyprinidae. In all sampling rivers, sex ratios of C. auratus were biased to female, and especially, triploid groups of C. auratus were all female groups (p<0.05). In principle, sex ratios of C. cuvieri and common carp were equivalent between male and female.

• Journal of fish pathology
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• v.24 no.2
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• pp.161-166
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• 2011

The metacercariae of Clinostomum complanatum (Rudolphi, 1814) were isolated in the whole body muscle of wild freshwater fish, spotted barbel gudgeon (Squalidus multimaculatus Rosoya et Jeon) from the local river in Yeongdeok, Gyeongsangbuk-do, Korea. The infected fish with bumpy body surface by "yellow grub" showed erratic swimming behavior and some fish were died. The isolated excysted metacercariae were tongue shaped and 2.85~5.89 mm ${\times}$ 0.8~1.99 mm in size. 1~98 metacercariae were isolated in individual fish and mean infection intensity was 25. All examined adult spotted barbel gudgeon sizing 7 cm in body length were infected. This is the first report of disease outbreak and mortality caused by C. complanatum infection in wild freshwater fish in Korea.

• Fisheries and Aquatic Sciences
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• v.5 no.1
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• pp.59-63
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• 2002

Swim up fry of the Nile tilapia, Oreochromis niloticus, were fed 0 or 60 mg l7-methyltestos­terone (MT) per kg feed for 30 days. Fish that had been fed 0 or 60 ppm MT for the first 30 days were subsequently fed a commercial diet for 56 weeks to evaluate growth, survival, sex ratio, body composition, gonadosomatic index and the total edible portion. Mean body weight of MT treated group and untreated group were 1.7 g and 1.1 g, respectively at the end of the treatment for 30 days $(P<0.05)$. The experiment was terminated after a total of 60 weeks, the mean body weight of the MT treated population was 1,016 g and that of the untreated population was 762g $(P<0.05)$. However, the final mean body weight of untreated males (l, 086g) was not significantly different from treated males (l,016 g), but the mean body weight of the female group was 512 g. Therefore, the reason for the lower mean body weight of the untreated group was entirely due to stunted females. The percentage fillet yield of MT treated fish$(34.6\%)$ was not significantly different from that of the untreated males $(34.4\%)$, but the untreated females were lower than those of both treated and untreated male groups $(32.4\%)$ (P<0.05). There were no significant differences in the percentage of the all edible portion (AP) between MT treated and untreated males, but females were lower than males. Females are smaller fish in size and the gonads are larger in proportion which were discarded along with the intestine this explains the observed difference. Total biomass of the two groups were 134.8kg and 104.5kg per $m^3$, respectively. The proportion of fish reaching a marketable size of over 800 g in body weight within 14 months were $78\%$ in the MT treated group and $41\%$ in the untreated group.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.2
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• pp.414-421
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• 2015

This study was conducted to investigate the effects of Spirulina level in the diet on growth and skin color of red- and white-colored fancy carp Cyprinus carpio var. koi at different feeding periods. Five experimental diets (designated as Con, S5, S9, S13 and S17) were prepared to contain 0, 5, 9, 13 and 17% Spirulina. Each experimental diet was fed to two replicate groups of fish (6.6 g/fish) to visual satiation three times a day for 12 weeks. Weight gain and feed efficiency of fish were not affected by dietary Spirulina level. The values of redness ($a^*$), lightness ($L^*$) and yellowness ($b^*$) of the fish skin were influenced by dietary Spirulina level at different feeding period. The $L^*$ value of skin in the fish fed S9, S13 and S17 diets tended to decrease with feeding period. The skin $a^*$ value of the fish increased significantly with feeding period and dietary Spirulina level. The skin $a^*$ value of the fish fed the diets containing 5-17% Spirulina was higher than that of fish fed control diet at 6 and 12 weeks of feeding. The skin $a^*$ value and total carotenoids of the fish fed the S17 diet was the highest among groups. Based on the results of this study, it can be concluded that dietary inclusion of Spirulina powder could increase the skin redness of red- and white-colored fancy carp.

• Journal of fish pathology
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• v.14 no.1
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• pp.3-10
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• 2001

The present study was to obtain a basic research data about medicinal herbs by screening in vitro antimicrobial activity and the production of superoxide anion($O_2^-$) from the head kidney phagocytes of olive flounder, Paralichthys olivaceus. The following fourteen kinds of medicinal herbs extracted by boiling water were used : Gosam, Gwijeonu, Gujeolcho, Bagha, Bangpung, Yeongyo, Yagssug, Jiyu, Sambaegcho, Samjiguyeobcho, Sangbaegpi, Sohwehyang, Pyeonchug, Palgag. Antimicrobial activity against fish pathogenic bacteria, Listonella anguillarum, Vibrio sp., Vibrio alginolyticus, Edwardsiella tarda, Streptococcus sp. and Lactococcus garvieae, and the production of superoxide in kidney macrophage of olive flounder were examined by disk method and nitroblue tetrazolium(NBT) reaction, respectively. Among the tested herbs, Yagssug showed the highest antimicrobial activity against those fish pathogenic bacteria and stimulation of $O_2^-$ production.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.16 no.4
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• pp.368-378
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• 1983

The community structure of intertidal benthic marine algae were studied seasonally at Odongdo, southern coast of Korea, from June 1982 to May 1983. Algal coverage in $50{\times}50\;cm$ quadrat were recorded for each species by line transect method. The vertical zonation investigated by line transects is recognized into three groups : Upper, middle, and lower zones. The representative species are Gelidium divaricatum, Enteromorpha linza, Porphyra yezoensis, Scytosiphon lomentaria, Blidingia nana, Ectocarpus confervoides in the upper, Ulva pertusa, Chondria crassicaulis in the middle, and Sargassum sagamianum, S. thunbergii, Undaria pinnatifida, Gelidium amansii and various other red algae in the lower zone. The number of algal species and coverage were generally highest in April and lowest in August. Species which appear dominant at least once a year were all of the spring type and the others were autumn type. According to the cluster analysis by similarity index community coefficient(SICC) among 5 transects, the algal communities are divided into two groups, i. e. open-sea group and inland-sea group.