• Korean Journal of Environmental Biology
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• v.17 no.2
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• pp.169-173
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• 1999

The present study was undertaken to survey the infection status of Metagonimus sp. metacercariae in freshwater fishes from Tong river located in Kangwon Province, a total of 178 freshwater fishes of 11 species were collected by a fish net and traps from the end of September to early October 1998. They were brought to the laboratory and examined under a stereomicroscope after artificial digestion with pepsin-HCI solution for one hour. Ten out of eleven species of freshwater fishes examined were found to contain metacercariae of Metagonimus sp. The most frequently infected fish was Liobagrus andersoni Regan 91.7% (11 of 12 fishes), followed by Gobiobotia breviburba Mori 75.0% (6 of 8 fishes), Zacco temmincki 66.2% (49 of 74 fishes), Cobitis koreensis Kim 50.0% (1 of 2 fishes), Microphysogobio longidorsails Mori 42.9% (9 of 21 fishes), Cobitis rotundicudata Wakiya et Mori 33.3% (2 of 6 fishes), Hemibarbus longirostris 33.3% (1 of 3 fishes), Pungtungia tenuicorpus 30.0% (3 of 10 fishes), Coreoleuciscus splenddus Mori 28.6% (4 of 14 fishes), Coreoperca herri Herzeanstein 11.1％ (1 of 9 fishes) respectively Metagonimus metacercariae was not found from Moroco kumgangensis Uchida of freshwater fish. The total number of Metagonimus sp. metacercariae was 81, 17, 216, 1, 14, 2, 1, 4, 10, 1, respectively. Infection rates of Metagonimus sp. in the five districts was shown as follows : Chongson-up Kyulam-ri 50.0% (12 of 24 fishes), Chongson-up Kasu-ri 34.0% (17 of 50 fishes), Shindong-up Unchi-ri 56.0% (14 of 25 fishes), Shingdong-up Kosong-ri 57.1％ (20 of 35 fishes), Shingdong-up Duckchon-ri 54.5% (24 of 44 fishes) respectively. Infection rate of freshwater fish was 48.9% (87 of 178 fishes) and from the results obtained in this survey, it was confirmed that freshwater fishes from Tong river was infected with metacercariae of Metagonimus sp.

• Korean Journal of Ecology and Environment
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• v.44 no.2
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• pp.203-213
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• 2011

Agriculture modern environments can vary due to factors such as land consolidation and ditch enhancement projects. But, these improvements projects can include cover-ing-up of irrigation ditches with concrete, increasing the drop between paddy field and drainage ditches, which might decrease the abundance and diversity of fish fauna around paddy fields. In this study, for the management of agrobiodiversity on fish in paddy fields, we installed a small-scale fishways between paddy fields and drainage ditches, and evaluated the effects on the eco-connection of the paddy fields, ditches and stream. Five fish species were recovered at the drainage ditches. The species exhibited characteristics spawning and growth based on the paddy field. The results indicate that the five fish species could ascend the paddy fields through the small-scale fishways. There are no difference of species numbers at ditches of environment-friendly agriculture paddy fields (A) and good agricultural practices (B) region, but individual numbers were higher at the B region. This result could be interpreted as indicating that ditch diversity was affected by positional properties rather than farming practices because the water flow and connection to adjacent stream of B region were better than A region. After ascertaining the fish species capable of ascending in a pre-survey of the drainage ditches, we set up small-scale fishways at the drop between paddy fields and drainage ditches. Three species of fish (Aphyocypris chinensis, Misgurnus anguillicaudatus, M. mizolepis) arrived at the paddy fields via small-scale fishways. The main movement time was from 18:00~24:00 and 00:00~06:00, indicating a preference for the night time period rather than the day period for migration. Concentrating the operation time from night to dawn seems prudent for effective management of small-scale fishways.

• Korean Journal of Ecology and Environment
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• v.43 no.2
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• pp.288-297
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• 2010

This study was to evaluate the ecological stream health through the Multimetric Fish Assessment Index (MFAI) along with fish fauna analysis based on the tolerance and trophic guilds at Miho stream in 2008 and 2009. Also, we analysed total mercury concentration in fish tissues to examine heavy metal contamination. Total sampled fish were 40 species and 2,557 individuals and Zacco platypus was the most dominant with 35% relative abundance. It was sampled with 11.4% RA for Korean endemic species (10 species 291 individuals) less than average RA 39.3% for the Geum river watersheds. According to the tolarance guild analysis, tolerant species was more dominant with 58.9% RA (15 species, 1,507 individuals) than sensitive species with 6.6% RA. Trophic guild analysis also suggested that omnivores were more dominant (60.5% RA) than insectivores (31.5% RA). Riffle-benthic species was also sampled with 7.7% RA. Ecological stream health based on the MFAI were averaged 25.3 (n=3) with fair-poor condition in 2008 and also 26.3 (n=3) with fair condition in 2009, just slightly increased than 2008. Qualitative habitat evaluation index was averaged 134 (n=3) with fair condition but most of sites had sediment accumulation that reflected substrate degradations proceeding. From the result of total mercury accumulation in fish tissues, kidney and liver tissues showed the highest but the lowest for gill tissues. Overall mercury concentration were not exceed the national standards by Korean Federation of Drug and Administration (KFDA). Consequently, our result could correspond with the characteristics of Miho stream where point sources such industrial complexes and wastewater treatment plant widely distributed around the stream along the gradient of up and downstream.

• Korean Journal of Food Science and Technology
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• v.32 no.3
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• pp.550-563
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• 2000

This study was carried out in order to elucidate the fundamental data on the taste compounds between wild and cultured fishes produced on Chungmu and Wando at the southern coast areas of Korea. For this purpose, the food components of cultured fishes such as red sea bream Pagnus major, Sebastes pachycephalus and flounder, Paralichthys olivaceus being spot lighted for the main sea fish, the staple food and high economic fish were investigated and compared with those of the wild ones. There was a little appreciable difference in the proximate compositions of all the species from localities between wild and cultured fishes. But according to the growing conditions, wild fishes were higher in moisture contents and lower in crude lipid content than those of cultured fishes and little difference was seen in protein and ash contents between the two. With regard to the nucleotides and their related compounds, i.e. ADP, IMP and inosine were detected but ATP and hypoxanathine were not from them. On the other hand, there were little difference in the total taste compounds of all the species from localities and the growing conditions between wild and cultured fishes. But all the species were higher in IMP content. The total of seventeen amino acids were detected in samples. The highly contents of glutamic acid, lysine, aspartic acid, proline, leucine, alanine, valine and alginine were showed and less low contents of cystein, histidine, methionine, tyrosine and phenylalanine were detected. The total amino acids of the others were much alike in that composition. Little difference was seen from localities and the growing conditions between wild and cultured ones. The free amino acids were much alike in that composition of all the species. There was little difference in the free amino acid compositions all the species from localities and the growing conditions between wild and cultured fishes. But taurine was dominant, showing from 39% to 65% of the free amino acid content and it is followed by hydroxyproline, lysine, alanine and glycine in other. There were differences in the organic acid compositions of all the species from localities and the growing conditions between wild and cultured fishes. In addition, cultured fishes were more abundant in the total organic acid compositions than those of wild ones.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.24 no.5
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• pp.273-288
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• 1991

To elucidate the physiological and biochemical differences between chondrichthyes and osteichthyes, the properties of the specific digestive enzymes in cat-shark, Cephaloscyllium umbratile, and mackerel, Scomber japonicus, were studied. Homogenous trypsin proved through the disc-electrophoresis, SDS-PAG electrophoresis and gel filtration was obtained from the pancreas of cat-shark by $50-70\%$ saturated ammonium sulphate fractionation, DEAE-Sephadex A-50 column chromatography, benzamidine-Sepharose 6B affinity chromatography and Sephadex G-75-120 gel filtration. Two types of trypsins were also obtained from the pyloric caeca of mackerel by $30-70\%$ saturated ammonium sulphate fractionation and the slightly modified procedure from the method adopted in the purification of cat-shark trypsin. The two trypsins, designated trypsin A and B, were proved their homogeneity by disc- and SDS-PAG electrophoresis and gel filtration. The molecular weights of the trypsins were estimated to be 31,700 for cat-shark trypsin, 30,000 for mackerel trypsin A and 29,000 for mackerel trypsin B by SDS-PAG electrophoresis, but those were estimated to be 21,500 for cat-shark trypsin, 23,700 for mackerel trypsin A and 21,500 for mackerel trypsin B by gel filtration. The trypsins exhibited their optimum conditions at pH 9.0 and on temperature ranged from $45^{\circ}C\;to\;50^{\circ}C$ for cat-shark, and at pH 8.0 and a temperature of $50^{\circ}C$ for mackerel trypsin A and B, respectively. The cat-shark trypsin was stable at pH 10.0 and the temperature below $10^{\circ}C$, whereas the mackerel trypsin A and B, were stable in the range over pH 7.0 to pH 9.0 below $10^{\circ}C$ and at pH 8.0 below $35^{\circ}C$, respectively. The mackerel trypsins were severely inhibited by some heavy metal ions such as $Ag^{2+},\;Cu^{2+}\;and\;Hg^{2+}$ compared to cat-shark trypsin. All of the enzymes were also inhibited by antipain, leupeptin, TLCK(tosyllysine chloromethyl ketone) and SBTI(soybean trypsin inhibitor) remarkably. The inhibitory effects of PMSF(phenylmethane sulphonylfluoride), DFP(diisopropyl fluorophosphate) and benzamidine were indicated that these enzymes belong to serine-proteases.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.5
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• pp.439-477
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• 2000

Seasonal variation in species composition of fishes in the eelgrass bed in Angel Bay of the southern coast of Korea was determined using monthly samples by a beam trawl from April 1998 to March 1999, A total of 39 species, 2,065 individuals and 8,930 g of fishes were collected during the study period. The fish were composed of the small-sized resident species and the juveniles of Leiognathus nuchalis, Pholis nebulosa, Spgnathus schlegeli and Sebastes ineinis predominated in abundance, accounting for $60{\%}$ of total number of individuals. The number of species and biomass were low from December to March when the water temperature was low, The biomass increased by the catch of a large number of L. nuchalis and S. inemis in April and May when the eelgrass grew fast. The fish numbers decreased in June and July when the adults of the resident species declined after the spawning. A large number of juveniles which had released in spring occurred in August. The biomass of fish decreased from September, and a few number of fish were collected in winter. Species were grouped into four by cluster analysis: the warm season group including P. nebulosa, S. schlegeli and L. nuchalis, the cold season group including Chaenogobius heptaoanthus and Platycephalus indieus, the group of fish species occurred during the growing season of eelgrass such as P. couoides, S. inermis and P. perooides, and the group of fish species occurred during decaying season of eelgrass such as S. cirrhifer and H. coronatus. Principal component analysis indicated that seasonal variation in species composition was determined by the water temperature and standing crops of eelgrass.

• Korean journal of food and cookery science
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• v.6 no.3 s.12
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• pp.43-50
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• 1990

Distribution of amino acids and related compounds in the muscle extract of seven species of right-eye flounder (spotted halibut, slime flounder, marbled sole, sand flounder, stone flounder, frog fleunder and bastard halibut) were studied. The effect of heat treatment on quantitative change in the composition of amino acids and related compounds in the extract of sand fleunder muscle was also investigated since the sand flounder has much Ex-nitrogen in the extract of the muscle. The content of crude protein and that of pure protein were in the range of $17.54{\sim}19.99%$ and $15.63{\sim}17.95%$, respectively. Among the extracts of the seven fish muscle, stone flounder showed the highest content of Ex-nitrogen(2.12%). In the muscle extracts of the seven fish taurine was abundantly contained $(29.4{\sim}56.9%)$, and followed alanine $(6.6{\sim}10.4%)$ and glycine $(1.6{\sim}16.7%)$. The compositions of amino acids and related compounds were characterized by the existence of phosphoethanolamine, ${\alpha}-aminoadipic\;acid$, DL-allocystathionine, ethanolamine and ornithine. The experiments on amino acids and related compounds of the muscle extract of sand flounder with reference to heating time and temperature were resulted in that the amount of taurine, tyrosine, leucine and alanine were increased with the heating time at $100^{\circ}C$, whereas that of lysine, histidine, ${\alpha}-aminoadipic\;acid$ and proline were decreased with prolonged heating time. When heating temperature was changed from $90^{\circ}C$ to $130^{\circ}C$ for 60 min, the contents of taurine, alanine and leucine were increased, while that of histidine, lysine and aspartic acid were decreased.

• Journal of Aquaculture
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• v.8 no.1
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• pp.31-46
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• 1995

Gonadal maturation and annual reproductive cycle in ovoviviparous oblong rockfish, Sebastes oblangus on the basis of monthly gonadosomatic indices (GSI), hepatosomatic indices (HSI) and histological observations of gonadal tissues. GSI values of female were in a wide range from $0.l5\pm0.0l\;(July)\;to\;58.54\pm3.86$ (December) and began to increase in August and reached the maxium in December, then decreased rapidly thereafter. Male GSI values were in a range from $0.08\pm0.03$ (July) to $1.55\pm0.27$ (September) and began to increase rapidly in July and reached the maximum in September, then decreased gradually, thereafter. Female HSI was in a range from $0.89\pm0.12$ (December) to $3.73\pm0.15$ (October), and male's was from $2.09\pm0.76$ (October) to $3.62\pm0.48$ (August). HSI reached the maximum values one or two months before GSI reached their maxium values in both sex, and then decreased rapidly thereafter. Mature oocytes began to appear in late October as being oocytes began to mature in August, and the type of oocyte development is categorized in the roup-synchronous oocyte development'. Ovulation and fertilization of ripe oocytes occurred in November, and hatched larvae were born from December to January. Maturation of testis was progressed in short term from August to October and spermatozoa were released in October. Sperm balls consisted of many spermatozoa were preserved in ovarian cavity of female after copulation. These results may suggest that the annual reproductive cycle of oblong rockfish could be divided into the following successive stages: growing (August and September), mature (September and October), gestation (November and December), parturition (December and January) and resting (February to July) in female, and growing (August and September), mature (September and October), copulation (October) and resting (November to July) in male.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.44 no.2 s.314
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• pp.37-46
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• 2007

In this paper, we propose technologies for enhancing the immersive realization of virtual objects in AR-based product design. Generally, multimodal senses such as visual/auditory/tactile feedback are well known as a method for enhancing the immersion in case of interaction with virtual objects. By adapting tangible objects we can provide touch sensation to users. A 3D model of the same scale overlays the whole area of the tangible object so the marker area is invisible. This contributes to enhancing immersion. Also, the hand occlusion problem when the virtual objects overlay the user's hands is partially solved, providing more immersive and natural images to users. Finally, multimodal feedback also creates better immersion. In our work, both vibrotactile feedback through page motors, pneumatic tactile feedback, and sound feedback are considered. In our scenario, a game-phone model is selected, by way of proposed augmented vibrotactile feedback, hands occlusion-reduced visual effects and sound feedback are provided to users. These proposed methodologies will contribute to a better immersive realization of the conventional AR system.

• Korean Journal of Ichthyology
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• v.26 no.2
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• pp.99-111
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• 2014

Community structure of fish and inhabiting status of natural monument and endangered species, Cobitis choii were investigated in the Baekgok Stream, a tributary of the Geum River drainage system of Korea from May to November 2012. Ten-15 fish species inhabited upper stream (St. 1~St. 3) with a Aa or Aa-Bb river type composed of mostly pebble and cobble bottoms. 15~21 species did middle stream (St. 4~St. 5) with Aa or Aa-Bb type composed of mostly cobble, boulder and pebble bottoms. Nine species did Reservoir Baekgok (St. 6) with composed of mostly mud bottoms, and Seven species did Reservoir Baekgok outflow (St. 7) with Aa-Bb type composed of mostly boulder and cobble bottoms. And 20~23 species did lower stream (St. 8~St. 9) with a Bb-Bc type composed of mostly cobble and sand bottoms. A total of 35 species belonging to ten families were found in the stream during the survey. The dominant species were in the order of Zacco platypus (34.7%), Pungtungia herzi (9.4%) and Microphysogobio yaluensis (9.0%). Other abundant species included Tridentiger bifasciatus (8.2%), Pseudogobio esocinus (5.9%), Carassius auratus (4.6%), Squalidus chankaensis tsuchigae (3.7%), Rhinogobius brunneus (3.0%). Among residing species, ten (28.6%) species were endemic to Korea, one (Cobits choii) was endangered, and two (Micropterus salmoides and C. cuvieri) were non-indigenous. Natural monument and endangered species, C. choii were only inhabited St. 5, and they are inhabited 30~100 cm in water depth, sand bottom and slowly velocity. Using the mark-recapture method, populations were estimated at $7,838{\pm}6,290$ individuals. Age group in May estimated from total length indicated that the 38~45 mm group is 0 year old, the 46~60 mm group is 1 years old, the 61~80 mm group is 2 years old, and the 81~93 mm group is more than 3 years old. Condition factor (${\times}10^5) was 0.36~0.39 and 0.35~0.38 for female and male, respectively, and they are 13.5% were infected with parasites (digenea). We are discussed the health status, threats and conservation strategies of C. choii in the Baekgok Stream.