• Korean Journal of Fisheries and Aquatic Sciences
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• v.22 no.5
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• pp.317-331
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• 1989

Chaenogobius laevis inhabit brackish waters. Adult male protects egg mass laid under the stones. The egg with small oil globule varied from 3.40 to 4.04 mm in diameter. When water temperature is $22.0\~23.0^{\circ}C$, larvae hatched about 113 hours after fertilization. The newly hatched larvae reared for 33 days grow up to 12.10 mm in total length and developed to the jevenile. When larvae length attained about 8.0 mm, jaw bones were more rapidly ossified than vertebrae and cranium.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.6
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• pp.501-507
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• 2000

Distribution and habitat characteristics of Zostera (Zosteraceae) in the eastern coast of Korea were examined along with plant monohology, sediment composition and physicochemical factors of seawater from June 1998 to July 2000, The results showed that three species, Zostera marina, Z. asiatica and Z, caespitosa were found in specific habitats. The depth of habitat for Z. asiatica was deeper ($8.5{\~}15.0 m$) than that of Z. marina ($1.3{\~}5.6 m$) and Z. caespitosa ($3.2{\~}5.2 m$). Z. marina beds were observed at brackish-water, port and inner bay with the sediment type of sand or muddy sand. Habitats of Z. asiatica were restricted to the open bay with the sediment type of sand, Zostera have been described with regard to different growth forms of vegetation, flowering shoot and life history. Vegetation and flowering shoot length varied significantly with habitats; values ranged $66.8{\~}110.0 cm$ and $128.0{\~}217,8 cm$, respectively. Morphology of Z. marina varied with water depth and different substrates. Morphological characteristics of Z. asiatica showed a new phenotype at the deeper water depth. Vegetation and flowering shoots of Z. caespitosa were not significantly different between study sites (values ranged from 64.9 cm to 70.3 cm). Nutrient concentrations of seawater were higher at southern part than at middle part of the eastern coast of Korea. Distribution of Zostera in the eastern coast of Korea was dependent upon differences in water depth and habitat environments, by which affected the morphological differences were affected.

• The Korean Journal of Malacology
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• v.19 no.2
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• pp.117-124
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• 2003

Reproductive cycle and sex ratio of the marsh clam Corbicula japonica, a oviparous clam, were investigated monthly by histological observation. Samples were collected in brackish water of Namdae stream on the east coast of Korea from November 2000 to October 2001. It was able to devide the reproductive cycle of this species into five successive stages; early active (April to June), late active (May to June), ripe (June to August), partially spawned (June to September), spent (September to January) and resting stage (February to April). The spawning period was from July to September, and the main spawning occurred between August and September when seawater temperatures reached above 26$^{\circ}C$. Mature eggs of Corbicula japonica were 60-70 ${\mu}m$ in diameter. The sex ratio of individuals over 10.1 mm in shell length was about 1:1 (x$^2$ = 1.22, p > 0.05).

• Parasites, Hosts and Diseases
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• v.26 no.4
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• pp.263-274
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• 1988

Recent patterns of infection with digenetic larval trematodes in fresh- water and brackish-water ask were studied in three locations of the river Taewha during the period from April to October, 1988, and compared with the data reported previously in the same river, 0(16 species of fish examined, the encysted larvae of Cyathocotyle orientalis were found most frequently from 9 species of fresh.water fish. The metacercariae of Echinochasmus sp. , Metacercaria hasegawai and Metagonimus yokogawai were found from 8 species, those of Clonorchis sinensis from 7 species, and Exorchis oviformis and Metorchis orientalis from 5 species of fish. The infection rates of fish with C. sinensis metacercariae were not lower than those reported in 1980, whereas their intensity of infection was found lowered in 3 species, Ccreobagrus brevicorpus, Gnathopogon atromaculatus, and Funtungia herzi. The infection rates of 3 species of fish with M. yokogawai metacercariae were lower than the results in 1982, while the rate was higher in 2 species, Zacco platypus, and Z. temmincki, and rather stationary in Flecoglossus altivelis. The intensity of infection in several species of fish appeared rather higher than in 1980. The encysted larvae of C. orientalis, Echinochasmus sp., E. oviformis and Metacercaria hasegawai showed variations in infection rates of fish in 1980 and in the present study. It was found that the rate of infection with digenetic larval trematodes in fresh- water fish was still relatively high in the river Taewha, and the metacercarial burden in the fish varied greatly by different fish in 1980 and in the present study.

• Parasites, Hosts and Diseases
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• v.27 no.1
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• pp.57-66
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• 1989

A scanning electron microscopic study was performed to observe the tegumental ultrastructures of Paragonimus iloktuenensis according to its developmental stages. The metacercariae were obtained from the liver of the brackish water crab, Sesarma dehaani. Juvenile and adult p. iloktsuenensis were recovered from the experimental rats on 2, 4 and 8 weeks after infection. The findings were summarized as follows: 1. The encysted metacercariae were charaeteristically gourd-shape, with their whole body surface beset with numerous spade-shape spines. The Barge, type II sensory papillae (non-ciliated round swellings) were arranged along the rim of the oral and ventral suckers, 11~12 and 6~8 in numbers respectively, 2. Two-week old juvenile worms, recovered chieay from the liver of the experimental rats, were slender in body shape: with their ventral sucker near the anterior one-third level. The distribution of tegumental spines was less dense than in the encysted metacercariae. The spines were with 1~2 pointed tips and 3~.4 longitudinal splits. Numerous ciliated knob-like, type I papillae were observed in both sides of the oral sucker, and 6 large, type If papillae were arranged along the rim of the ventral sucker. 3. Four week old worms, recovered from the thoracic cavity and/or lung parenchyme of the experimental rats, were thicker than wide in body configuration, and their ventral sucker was located near the anterior one.fourth level. The tegumental spines at ventral surface were grouped, each group with 3~5 aggregated ones. The type I and type II papillae (small-sired) were distributed chiefly around the rim of two suckers. 4. Adult (eight-week old) worms, recovered from the capsules in the lung parenchyme, were very stout, and covered densely with bearfoot like spines. At dorsal surface, cobblestone-like cytoplasmic processes were well-developed, with many tegumental spines embedded in them. It was observed in this study that the tegument of p. iloktsuenensis continued to change and differentiate as the worms grew to be adults.

• Journal of Wetlands Research
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• v.20 no.2
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• pp.181-189
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• 2018

This study was performed to analyze the dynamics and distributional condition of biological community and to support the basic information about the estuarine ecosystem management by using the intensively surveyed results by each taxon experts around Tamjin river. We analyzed the biological diversity, abundance, correlation among species, and ecological characteristics about 11 taxa groups including vegetation, fish, birds, mammals, etc. in the Tamjin river estuarine ecosystem. We classified vegetation types into 7 physiognomic types and 18 communities according to habitat conditions with the physical environments and salinity. In total, 1125 species including 9 species of endangered species were identified in research area. The species composition and distributional characteristics of each taxon were corresponded to the environmental characteristics of the estuarine ecosystem. Especially, the species diversity and distribution were clearly distinguished in the river according to the difference of the environmental factors such as flow rate, salinity, and soil. Despite the disturbance factors such as barrage and levees, the biodiversity and its distribution were evaluated to be high level under the current environmental conditions. However, loss or reduction of wildlife habitat due to reclamation, embankment, barrage installation and expansion of farmland has been identified as a major threat to the diversity and health of the local ecosystem. The results of this study can be used as a basic data to cope with various development pressure and damage crisis of the whole estuaries including Tamjin river.

• Microbiology and Biotechnology Letters
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• v.31 no.2
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• pp.95-102
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• 2003

Microalgae are a diverse group of photosynthetic organisms and abundant in every ecosystem in the biosphere. They are common in aqueous environments including marine, brackish and fresh waters and in some habitats that lack eukaryotic life such as some hot springs and highly alkaline lakes. Microalgal biotechnology that is focused on the microalgae-based production of a variety of useful materials such as pharmaceutical comfounds, health foods, natural pigments, and biofuels is considered as an important discipline with the development of biotechnology. In addition, the mass cultivation of microalgae can also contribute to improving the environmental quality by reducing the concentration of $CO_2$ which is one of major gases lead to global warming. Consequently, it seems that the microalgae can be used as an efficient, renewable, environmentally friendly source of high-value biomaterials such as chemicals, pigments, energy, etc. and the microalgal biotechnology will most likely represent a larger portion of modern biotechnology.

• The Korean Journal of Malacology
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• v.28 no.2
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• pp.91-99
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• 2012

Corbicula japonica, belonging to Other Veneroida Family Corbiculidae, was distributed in the freshwater and brackish rivers, where was a sandy and shallow depth. Catch of C. japonica in the Seomjin River occupied at a large portion of the catch in Kyungnam Province, which was about 30% of total catch in Korea. C. japonica has little studied on biomass, scientific resources assessment and management, because of inaccurate catch report data in the Seojin River. In this study, we conducted scientific and systematic approaches under data limited situation with application of the potential fishery yield system for sustainable fisheries resources management. Estimation system of the potential fishery yield was consisted of 5 tier system. We have used to tier 1 and 2 which were demanded higher level of information than the other tiers. The potential fishery yields were estimated 77.66ton for tier 1 using commercial fishery-dependent data, and 129.82ton for tier 2 with fishery-independent survey data.

• Korean Journal of Environmental Biology
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• v.31 no.4
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• pp.402-410
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• 2013

In this study, to identify ichthyofauna of the Seomjin River, which has no barrage at estuary, and to estimate effect of estuary barrage, fish sampling was conducted at 16 study sites in mainstream of the Seomjin River from 2010 to 2012. A total of 54 species classified into 17 families were collected. Cyprinidae was the dominant family and Zacco platypus (relative abundance, RA: 47.8%) was identified as the dominant species. In total, 17 Korean endemic species (31.5%) were collected, and it is higher than the average endemic rate of Korean peninsula (22.5~25.9%). Although the relative abundance of exotic species (1.1%) was low, it is higher than the past studies (2002: 0.0%, 2009: 0.4%). Dominance index of freshwater region (St.4~St.16) was relatively higher than estuary (St.1~St.3), because Z. platypus showed high relative abundance at freshwater region. But diversity and evenness index showed contradictory results, as estuary was higher than freshwater region. The ratios of sea fish, peripheral freshwater fish and economic fish, and diversity index are higher than the Nakdong River, the Yeongsan River and the Geum River. In conclusion, to conserve the value of the Seomjin River ichthyofauna, continuous monitoring is necessary.

• Parasites, Hosts and Diseases
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• v.36 no.3
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• pp.155-162
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• 1998

Two endemic foci of heterophyid infections were discovered in coastal villages of Puan-gun. Chollabuk-do, and Sachon-gun. Kyongsangnam-do, Korea. Fecal examina- tions were performed on 153 inhabitants of Puan-gun and 138 of Sachon-gun, using cellophane thick smear and formalin-ether sedimentation technique. The helminth egg and/or protozoan cyst positive rate was 21.5% (33/153) in Puan-gun and 39.1% (54/138) in Sachon-gun. In Puan-fun, the egg Positive rate of heterophyids was the highest, 17.6%, and that of other parasites was 0.7-2.6% by parasite species. In Sachon-gun, that of heterophyids wa's 18.8%, followed by Clonorchis sinensis (12.3%). and other parasites (0.7-5.OBEI . Twenth-two (Puan-gun) and six (Sachon-gun) heterophyid egg Positive cases were treated loth praziquantel, and adult flukes were collected from their diarrheic stools. A total of 3,284 adult flukes of Heterophyes nocens was collected from all of the 22 patients treated in Puan-gun (3-778 individually) , and other trematodes were also collected from 2- 15 patients; Ftgidiopsis sumac, Stellcntchcsmus JcEcctus, Metogoninus Wokogaupci, M. miyntci, Stictodora Juscnta, Heterophwopsis continua, Acnnthopcrwphium kurognmo, and GWmnophaELoines seoi. In Sachon-gun, M. yokognwci (3,007 specimens), H. nocens (120), aud S. falcatus (46) were collected from 5 of 6 treated patients, and H. continuo and 5. tan each from one patient. The present study revealed that heterophyid flukes, especially If. nocens and M. Wokofowai, are prevalent in the southern and western coastal areas of Korea where fresh and/or brackish water fishes are popularly eaten raw.