• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.3
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• pp.429-436
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• 1998

A bacteriological study of sea water and oyster in Charan Bay was conducted to evaluate sanitary conditions of the bay and compliance of waters with the recommended bacteriological criteria for the designated area of shellfish cultivation, The Samples were collected at 23 sampling stations(Fig. 1 and Fig. 2) estaslished once a month from January 1997 to December 1997, During the study period, temperature ranged from 4.7 to $25.6^{\circ}C$, transparency ranged from 3.3 to 6.2m chemical oxygen demand ranged from 1.67 to 2.18 mg/$\ell$, dissolved oxygen demand ranged from 5.4 to 10.0 mg/$\ell$ dissolved nitrogen ranged from 1.65 to 7.88 $\mu$g-at/$\ell$, phosphate ranged from 0.15 to 1.16 $\mu$g-at/$\ell$, Chlorophylla-a ranged from 0.95 to 12.69mg/$\ell$. The coliform group and fecal coliform MPN's of sea water were ranged from <1.8$\~$l,600 and <1.8$\~$540, respectively. The coliform group and fecal coliform MPN's of oysters were ranged from <18$\~$16,000 and <18$\~$1,400, respectively. The viable cell counts in oyster ranged from $1.5\times10^2$ to $7.5\times10^3$. The bacteriological criteria of sea water in shellfish growing area should be less than 70 per 100 ml of sea water for median value of coliform MPN, and below $10\%$ of the samples which contain over than 230 for coliform MPN or over than 43 for fecal coliform MPN. The sea water from 432 samples were complied water coliform criteria recommended for designated shellfish growing area. The coliform group, fecal coliform, classification of coliform group with IMViC reactions and pathogenic vibrios were analyzed. During the study period, infectious bacteria such as Vibrio cholerae, Salmonella sp, and Shigella sp, were not detected from the samples, but detection ratios of Vibrio parahaemolyticus and Vibrio vulnifirus were $7\~17\%$ in summer months.

• Korean Journal of Environmental Agriculture
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• v.35 no.4
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• pp.286-293
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• 2016

BACKGROUND: 18% of difenoconazole+iminoctadin triacetate microemulsion (3%+15%) formulation were mixed and sprayed as closely as possible to normal practice on the ten of farms located in the Youngju of South Korea. Patches, cotton gloves, socks, masks and XAD-2 resin were used to measure the potential exposure for applicators wearing standardized whole-body outer and inner dosimeter (WBD). This study has been carried out to determine the dermal and inhalation exposure to difenoconazole during preparation of spray suspension and application with a power sprayer on a grape orchard. METHODS AND RESULTS: A personal air monitor equipped with an air pump IOM sampler and cassette and glass fiber filter were used for inhalation exposure. The field studies were carried out in a grape orchard. The temperature and relative humidity were monitored with a thermometer and a hygrometer. Wind speed was measured using a pocket weather meter. All mean field fortification recoveries were between 97.3% and 119.6% in the level of 100 LOQ (limit of quantification) while the LOQ for difenoconazole was $0.025{\mu}g/mL$ using HPLC-UVD. The arms exposure to difenoconazole for the mixer/loader (0.0794 mg) was higher than other body parts (head, hands, upper body, legs). The exposure to difenoconazole in the legs for applicator (3.78 mg) was highest in the parts of body. The dermal exposure for mixer/loader and applicator were 0.02 and 2.28 mg on a grape orchard, respectively. The inhalation exposure during application was estimated as 0.02 mg. The ratio of inhalation exposure to dermal exposure was equivalent to 0.9% of the dermal exposure. CONCLUSION: The inhalation exposure for applicator indicated $18.8{\times}10^{-3}mg$, which was level of 0.9% of the dermal exposure (2.28 mg). Operator exposure (0.004 mg/kg bw/day) to difenoconazole during treatment for grape is calculated as 2.5% of the established AOEL (0.16 mg/kg bw/day).

• Korean Journal of Environmental Biology
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• v.38 no.1
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• pp.1-15
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• 2020

This study was conducted to determine whether invasive muskrats settle in the natural ecosystem of Korea. The study also aimed to provide information on the selection of target areas, basic behavioral characteristics, and habitat use-related data, all of which are essential for effective management strategy establishment and site management. To this end, a trend in international muskrat management was identified to examine the management direction according to the settlement stage. We also secured the location of 72 domestic farmers and classified five regions in Gyeonggi-do, Chungcheongnam-do, Gyeongsangbuk-do, and Sejong Special Self-governing City into regions with high potential for natural leakage to raise the need for a quick survey. We determined that muskrats successfully settled in the natural ecosystem of Korea, based on the fact that we consistently identified a muskrat habitat at the same point for three years, from 2016 to 2018, the age of the captured population was estimated to be 1.2 years, and there had been no additional make-up factors near the habitat since 2012. The muskrats that settled in Korea showed a small home range of 0.0027 ㎢ (MCP 95%) and were estimated to show regular mobility before Spring and Autumn. Also, the areas where the muskrat habitat was observed had a high level of habitat environment disturbance and their ecological and food intake characteristics reflected that disturbance. Muskrat traces were high in hydrophyte vegetation, which can be used as a hideout in open waters and where the growth of both floating leaved plants and floating plants are prevalent. Since international invasive muskrats have already settled in the domestic ecosystem and there is concern about their proliferation in the future, the government must consider a preemptive response and scientific management.

• Journal of The Korean Society of Grassland and Forage Science
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• v.37 no.1
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• pp.28-34
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• 2017

A new naked oat cultivar, 'Jungmo2005'(Avena nuda L.), was developed for food and forage use by National Institute of Crop Science, RDA in 2010. It was derived from a cross between $F_1$['Early80'/'Gwiri33'] and $F_1$['Early80'/'Gwiri23']. 'Early80', a covered oats, has early heading and high yielding, while 'Gwiri23' of covered type and 'Gwiri33' of naked type has early heading with large-size grain. 'Jungmo2005' has the characteristics of narrow and long leaves of pale green color, middle diameter culm of yellow color and medium grain of whitish yellow color. Cultivar 'Jungmo2005' had 2 days earlier heading date (May 9) than the check cultivar 'Seonyang' (May 11) in field condition. The 'Jungmo2005' showed better winter hardiness than that of the check cultivar, and similar to the check cultivar in respect to lodging resistance. The 'Jungmo2005' had 105 cm of culm length, 21.5 cm of spike length, 658 spikes per $m^2$, 82 grains per spike, 23.3 g of 1,000-grain weight, and 622 g of test weight. The grain yield of 'Jungmo2005' was averaged $3.38MT\;ha^{-1}$, which was 6% higher than that of the check. Average forage fresh and dry matter yield of 'Jungmo2005' harvested at milk-ripe stage were 44.8 and $12.6tone\;ha^{-1}$, respectively, compared with 47.5 and $12.5tone\;ha^{-1}$ of the check. The protein content of the 'Jungmo2005' was similar to the check (7.6% and 7.5%, respectively), while ADF (28.6%) and NDF (51.5%) were lower than the check (31.4% and 57.0%, respectively). TDN content and RFV were higher than those of the check (66.3%, 120.3 and 64.1, 105.2, respectively). 'Jungmo2005' is recommended for fall sowing cropping only in the south area where daily minimum mean temperatures are averaged higher than $-4^{\circ}C$ in January, and it should not be cultivated in mountain areas, where frost damages is likely to occur. The areas would do better only to sow in spring season.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.2
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• pp.272-277
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• 1998

Filtering rates of two farming ascidians Styela clava and S. plicata, and of a farming mussel Mytilus edulis were experimentally investigated with reference to effects of water temperature and size. Absorptiometric determinations of filtering rates were carried out in a closed system with experimental animals being decreased indicate dyes neutral red. Optical density (OD) of 440 nm in path length 22 mm cell used as the indication of food particles absorption was appeared directly in proportion with the concentration of neutral red dyes. The filtering rate F is calculated by Kim's equation $F\;=\;V(1-e^{-z})$, where V is the water volume ($\ell$) in the experimental jar, and Z is the decreasing coefficient of OD as meaning of instantaneous removal speed as In $C_t\;=\;In\;C_{o}-Z{\cdot}t$, in this formula $C_t$ is OD at the time t. Filtering rate of S. clava increased as exponential function with increasing temperature while not over critical limit, and the critical temperature for filtering rate was assumed to be between $28^{\circ}C$ and $29^{\circ}C$. In case of S. plicata, the critical temperature was to be below $13^{\circ}C$, and through the temperature range $15\~25^{\circ}C$ appeared a little difference in level even though with significant. M. edulis was not appear any significant effects by water temperature less than $29^{\circ}C$. The model formula derived from the results is as below, where F is filtering rate (${\ell}/hr/animal$), T is water temperature ($^{\circ}C$), and DW is dry meat weight (g) of experimental animal. $$S.\;Clava;\;F\;=\;e xp\;(0.119\;T-4.540)\;(DW)^{0.6745},\;T<29^{\circ}C$$) $$S.\;plicata;\;F\;=\;e xp\;(A_t)\;(DW)^{0.5675},\;(13^{\circ}C $$[A_t =-8.56+0.6805\;T-0.0153\;T^2]$$ $$M.\;edulis;\;F\;=\;0.3844\;(DW)^{0.4952},\;<29^{\circ}C$$)

• Korean Journal of Environment and Ecology
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• v.29 no.3
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• pp.391-400
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• 2015

In order to investigate the distribution and species composition of fish in shallow wetlands that might be affected by environmental factors, we investigated the physicochemical parameters, macrophytes biomass, and fish assemblage in 24 shallow wetlands in South Korea from May to June, 2012. In this study, a total of 20 fish species were identified, and Cypinidae were found to be the most dominant species. Physicochemical parameters and macrophyte biomass were different in the survey sites, and macrophytes biomass, in particular, showed a positive relationship with fish abundance in stepwise multiple regression (df=1, F=32.00, P=0.001). According to the result of the cluster analysis between survey sites, the survey sites were divided into three groups in accordance with species composition of fish in relation to macrophytes biomass. In the wetlands of the first group, Lepomis macrochirus which belongs to Centrarchidae was found to be dominant and other fish assemblages were hardly seen. In the second group, unlike the first group, Carassius auratus that belongs to Cypinidae was found to be dominant. In the third group, Lepomis macrochirus was found to be as dominant as the first group but various other fish species appeared. Where there was abundance of the main food sources (i. e. zooplankton) of fish in the survey sites, there were more diverse macrophyte biomass. Consequently, it is proven that macrophytes strongly affect the species composition and abundance of fish, and high biomass of macrophytes support high assemblage of fish. Based on these results, we recommend establishing diverse aquatic macrophytes communities when restoring or creating wetlands to assure high diversity of fish species that use macrophytes as their habitat.

• Korean Journal of Environment and Ecology
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• v.29 no.3
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• pp.333-343
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• 2015

This research aims at identifying the goshawk's possible and replaceable breeding ground by using the MaxEnt prediction model which has so far been insufficiently used in Korea, and providing evidence to expand possible protection areas for the goshawk's breeding for the future. The field research identified 10 goshawk's nests, and 23 appearance points confirmed during the 3rd round of environmental research were used for analysis. 4 geomorphic, 3 environmental, 7 distance, and 9 weather factors were used as model variables. The final environmental variables were selected through non-parametric verification between appearance and non-appearance coordinates identified by random sampling. The final predictive model (MaxEnt) was structured using 10 factors related to breeding ground and 7 factors related to appearance area selected by statistics verification. According to the results of the study, the factor that affected breeding point structure model the most was temperature seasonality, followed by distance from mixforest, density-class on the forest map and relief energy. The factor that affected appearance point structure model the most was temperature seasonality, followed by distance from rivers and ponds, distance from agricultural land and gradient. The nature of the goshawk's breeding environment and habit to breed inside forests were reflected in this modeling that targets breeding points. The northern central area which is about $189.5 km^2$(2.55 %) is expected to be suitable breeding ground. Large cities such as Cheongju and Chungju are located in the southern part of Chungcheongbuk-do whereas the northern part of Chungcheongbuk-do has evenly distributed forests and farmlands, which helps goshawks have a scope of influence and food source to breed. Appearance point modeling predicted an area of $3,071 km^2$(41.38 %) showing a wider ranging habitat than that of the breeding point modeling due to some limitations such as limited moving observation and non-consideration of seasonal changes. When targeting the breeding points, a specific predictive area can be deduced but it is difficult to check the points of nests and it is impossible to reflect the goshawk's behavioral area. On the other hand, when targeting appearance points, a wider ranging area can be covered but it is less accurate compared to predictive breeding point since simple movements and constant use status are not reflected. However, with these results, the goshawk's habitat can be predicted with reasonable accuracy. In particular, it is necessary to apply precise predictive breeding area data based on habitat modeling results when enforcing an environmental evaluation or establishing a development plan.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.9 no.3
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• pp.155-162
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• 1976

Forty one samples from thirty three species of algae (19 from 15 species of Rhodophyceae, 18 from 14 species of Phaeophyceae, 3 from 3 species of Chlorophyceae, and 1 of marine Phanerogams) collected from several locations on the east, west and south coast of Korea, were analyzed for their contents of crude protein, fat, cellulose, ash, nitrogen free extract, amino nitrogen, and total amino acids. For the examination of extractability of algal protein with water, 4 species of algae, Sargassum thunberggi, Grateloupia filicina, Phyllospadix japonica, and Sargassum confusum, were analyzed. And the effect of some precipitation treatments for isolation of algal protein was also tested. As a matter of fact, Rhodophyceae showed high content in crude protein and low in crude fat while the case was opposite for Phaeophyceae and Chlorophyceae. Refering to the content of crude protein and total amino acids, the recommendable algae for protein sources were Sargassum thunbergii, Acrosorium flabellata, Phacelocarpus japonicus, Laurencia okamurai, Laurencia intermedia, Grateloupia filicina, Chondrus ocellatus, Gloiopeltis furcata, Gigartina tenella, Dictyota dichotoma, and Scytosiphon lomentaria. Methanol treatment appeared most effective in precipitation isolation of protein from water extracts whereas pH control method did not so beneficial. The precipitation rate of protein was particularity higher in the extract of Sargassum confusum ana the lowest was makted from the extract of Sargassum thunbergii.

• Korean Journal of Breeding Science
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• v.41 no.1
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• pp.56-60
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• 2009

A new naked oat cultivar Daeyang (Avena sativa L.) was developed by Department of Rice and Winter Cereal Crop, NICS, RDA in 2007. It was derived from a cross between 'FLX446-1-84-Q1'. and 'SO92004-B-3-3-5-7'. The FLX446-1-84-Q1, a naked oat cultivar from USA, is early heading and has good seed quality, while the SO92004-B-3-3-5-7, a covered oat breeding line, has a high yield with large grain. Subsequent generations were handled in a bulk method and pedigree selection program, and the SO97013-B-16-4 was selected based on agronomic performance in 2001. The line showed both high yield and good husking rate of seed in the yield trial tested at Suwon from 2002 to 2003, being designated as Gwiri51. The Gwiri51 was subsequently evaluated for winter hardiness, earliness, and yield in four locations, Gimje, Iksan, Jeongeup, and Jinju, from 2004 to 2007 and was designated as "Daeyang" and released. Its heading date was May 8 and maturing time was June 14 in a paddy field condition. The new cultivar Daeyang had 97 cm of culm length and 25.2 cm of spike length, 644 spikes per $m^2$, 65 grains per spike, 30.3 g of 1,000-grain weight, and 635 g of test weight. Daeyang showed better winter hardiness than that of the check cultivar 'Sunyang', and similar seed quality to the check cultivar in respect to percent content crude protein and $\beta$-glucan. However, it showed higher husking rate than the check cultivar. Grain yield of Daeyang in the regional yield trial for 4 years were averaged 4.18 MT $ha^{-1}$, which was 20% higher than that of the check cultivar Sunyang. Fall sowing cropping is recommended only in a south area where daily minimum mean temperatures are averaged higher than $-4^{\circ}C$ in January, and should be excluded in mountain area where frost damage is presumable.

• Journal of Korean Society of Forest Science
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• v.108 no.3
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• pp.429-439
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• 2019

The objectives of this study were to gauge the extent of the forestry business through establishing the definition of forestry industry from the perspective of economic convergence and to analyze key components that affect each growth phase of a forestry business entity by classifying them. A total of 1,397 "sixth-sector industry" management entities were certified by the Ministry of Agriculture, Food, and Rural Affairs in South Korea from 2012-2017. Of these, 259 (18.5%) were in the forestry sector. In this study, the 259 forestry management entities were further classified into three phases based on sales distribution: entrance, development, and maturity. The entrance phase (<100 million KRW), development phase (>100 million and <1 billion KRW), and maturity phase (>1 billion KRW) constituted 33.2%, 55.4%, and 12.4% of the total 259 entities, respectively. The results showed that most of the management entities were either in the entrance or development phases, and only a small portion was in the maturity phase. To identify the key variables that affect each of the phases, chi-square analysis was used. We designed the "sixth-sector industry" type as an independent variable, whereas selected region, business organization, manager age group, forest product, processing type, and service type were designated as dependent variables. The results of the analysis showed that the processing and service types influenced all three developmental phases. Moreover, as the phase advanced, processing type showed a higher proportion of health-functional ingredients, such as powder or extract from forest products, which enable to develop and produce a variety of products. Service type also changed from simple experience to integrated experience tourism and finally to tourism education. Distribution and sales channel also turned out to be a significant factor during the development phase. This study provides the basic information needed to guide government support in the implementation of a formal forestry business through convergence as well as to increase the efficiency of business management.