• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.50 no.1
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• pp.30-38
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• 2014

Hydro-acoustic survey was carried out to investigate the spatial characteristics of fish distribution near two artificial reefs (AO: large octagonal semi-sphere and AC: combined custom built) having different types in Jeju marine ranching area. The survey system consisted of scientific echo sounder (EK60), DGPS system, and ECDIS (Mecys). Field survey was conducted on August and October 2012 with star survey and line transect survey line method, and species composition was investigated from gill net fishing survey. The acoustic signals from individual fishes and small fish schools were mainly recorded around AO, but large and strong signals from large fish school were mainly detected in the top layer of and the water column near AC. The echogram suggest that the fish aggregation for the two types of AO and AC exist the significant difference in fish species and spatial distribution pattern.

• Journal of Environmental Science International
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• v.29 no.1
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• pp.79-93
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• 2020

To determine the size distributions of water-soluble inorganic ionic species (WSIS) in roadside aerosols, sampling experiments were carried out in the urban roadside area of Jeju City on August 2018 and January 2019 by using the eight-stage cascade impactor sampler. The mass of roadside aerosols were partitioned at 57% in fine fraction, 36-37% in coarse fraction, and 6-7% in giant fraction, regardless of summer and winter. The mass concentrations of WSIS except for Na+ and SO42- in roadside aerosols were higher in winter than in summer. The size distributions of Na⁺, Mg²⁺, Ca²⁺ and Cl^- were characterized by bimodal types with coarse particle mode peaking around 3.3-4.7 ㎛ and 5.8-9.0 ㎛. The size distributions of NO₃^- and K⁺ shifted from a single fine mode peaking around 0.7-1.1 ㎛ in winter to bimodal and/or trimodal types with peaks around coarse mode in summer. SO₄^2- and NH₄⁺ showed a single fine mode peaking around 0.7-1.1 ㎛. The MMAD of roadside aerosols was lower than that of Na⁺, Mg²⁺, Ca²⁺ and Cl-. Based on the marine enrichment factors and the ratio values of WSIS and the corresponding value for sea water, the composition of roadside aerosols in Jeju City may be practically affected by terrestrial sources rather than marine source.

• Journal of Fisheries and Marine Sciences Education
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• v.24 no.5
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• pp.662-669
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• 2012

Bycatch and stranding of sea turtles from Jeju coastal water of Korea were monitered from 2008 to 2009. A total of 41 sea turtles, consisting of 12 greens (Chelonia mydas), 3 loggerheads (Caretta caretta), 1 hawksbill (Eretmochelys imbricata) and 25 unidentified species, were recorded and observed in those area. Reported stranding and bycatch reached to a peak in August. The largest number of bycatch occurred in the coastal waters around Aewol-eup located in northwest area of Jeju Island. Most of the bycatch were taken by set nets and gill nets, which prevailed over the fishing grounds in the coastal waters of the Jeju Island. It is suggested that an appropriate monitoring system be necessary to conserve endangered sea turtle species in Jeju of Korea.

• Geophysics and Geophysical Exploration
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• v.9 no.3
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• pp.231-240
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• 2006

A variety of geophysical well loggings have been conducted to investigate the geological characteristics for basaltic volcanic area in Jeju Island. Specially, there is no precedent case study using geophysical well loggings in Jeju Island. And so, the proper understandings for geological features of Jeju Island are the key to interpret geophysical well logs. Presently, seawater intrusion monitoring systems have been constructed for systematic development and conservation of groundwater resources. As the results of geophysical well loggings in this seawater intrusion monitoring boreholes, the responses of well logs for saturated zone have distinctly identified basalt sequences. In particular, neutron logging, gamma-gamma (density) logging, and resistivity logging have well exhibited the characteristics of lava flows and lithologic boundaries. In hyalocastite, porosity is high, and resistivity is low. Eventually, geophysical well logs are useful for securing sustainable development of groundwater in Jeju Island in that it has identified the characteristics of geological responses.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.58 no.1
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• pp.49-58
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• 2022

In September and October 2020, combined acoustic and trawl surveys were conducted in the northwestern sea of Jeju Island. In the survey area, a region, so called Jeju region, was designated to esimate the biomass of chub mackerel and jack mackerel using a trawl survey method and frequency difference method. In the September survey, the weight ratios of jack mackerel and chub mackerel to the total catch were 24.6% and 2.8%, respectively, and in the October survey, those ratios were 24.9% and 20.7%, which were used to calculate their biomass (trawl survey). Using the frequency difference range (-8 to -3dB) corresponding to two species in 120 and 200 kHz, their biomass was estimated (frequency difference method). As a result, the biomass of two species from the trawl method was 3252.3 tons in September and 5777.0 tons in October. The estimated biomass by the frequency difference method was 4926.6 tons in September and 7521.5 tons in October. It was the first trial to estimate the biomass of two species using the trawl and frequency differencing methods in South Korea although there were some differences between two methods. In addition, horizontal distributions of acoustic backscattering strength over the entire survey area were mapped.

• Korean journal of applied entomology
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• v.62 no.3
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• pp.213-214
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• 2023

In a paper reporting the introduction and settlement of Anoplophora horsfieldii (Hope) into Jeju, it was found that Bactrocera dorsalis (Hendel) was misquoted as "it was introduced into the Jeju area and is currently being discovered." Fortunately, the sentence was quickly discovered and corrected to "it has the potential to be introduced to Jeju Island". Taking this as an opportunity, we would like to emphasize to researchers that it is necessary to verify very carefully when describing the domestic distribution of prohibited quarantine pests. Estimating by the cold stress index of the CLIMEX model, B. dorsalis was predicted to be unable to survive in Jeju in the winter of 2022-2023. However, in the winter of 2023, it was confirmed that the occurrence of A. horsfieldii was found to occur in the summer after overwintering at sub-zero temperatures, and it was judged to have succeeded in settling.

• Korean Journal of Medicinal Crop Science
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• v.22 no.4
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• pp.301-305
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• 2014

This study was carried out to investigate the vegetation and habitat environment of Sageretia thea which is distributed in Jeju island, Korea. Sageretia thea were mainly distributed to the west area in Jeju island. Soil pH and EC of Sageretia thea habitat were 5.8 and $0.34dS{\cdot}m^{-1}$. The contents of organic matter, available phosphate, exchangeable potassium, exchangeable sodium, exchangeable magnesium and exchangeable calcium were 15.27%, $13.6mgkg^{-1}$, $0.27cmol_+kg^{-1}$, $1.3cmol_+kg^{-1}$, $1.7cmol_+kg^{-1}$, $4.9cmol_+kg^{-1}$, respectively. Thirty one taxa including 25 families, 31 genus, 27 species and 4 varieties were identified surrounding Sageretia thea habitat. Specific plant species were 1 taxon in III grade, 1 taxon in I grade and 3 taxa in I grade.

• Journal of Ecology and Environment
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• v.44 no.1
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• pp.41-44
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• 2020

The Chinese many-toothed snake (Sibynophis chinensis) is an endangered species in South Korea. To determine its reproductive activity, here we captured a gravid S. chinensis from Mulyeongari Oreum Wetland Conservation Area, Jeju Island, on May 27, 2018, and reared it at Animal Taxonomy and Morphology Laboratory, Jeju National University, South Korea. The snake oviposited a clutch of six eggs between June 12 and 20, 2018, with an average size of 24.86 ± 1.36 mm in length and 9.86 ± 0.49 mm in width, which were artificially incubated at a constant temperature of 27 ℃. After incubating for 34-41 days, five of these six eggs successfully hatched. Average snoutvent length (SVL), tail length (TL), and body weight (BW) of hatchlings were 136.5 ± 5.17 mm, 47.76 ± 2.80 mm, and 1.66 ± 0.12 g, respectively. This study observed the reproductive activity of S. chinensis and characterized its eggs and hatchlings for the first time, providing valuable information for the long-term conservation plan of S. chinensis in South Korea.

• Journal of Environmental Science International
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• v.26 no.12
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• pp.1389-1397
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• 2017

In this study, we calculated the fixed-type Areal Reduction Factor (ARF) of the Hancheon River basin in Jeju Island, and compared the calculated ARF and the ARF of the four major river basins suggested by the Ministry of Land, Infrastructure and Transport. As a result, the maximum fluctuation ratios of ARF for the four major river basins calculated using area, frequency, and initial duration time were significant: 7.61% for the Hangang River basin; 12.69% for the Nakdonggang River basin; 8.09% for the Kumgang River basin; and 17.98% for the Yeongsangang River basin. In addition, the differences between the maximum and minimum value of ARF for the Hancheon River basin based on 48 hours was 2.13%, and it was smaller than the one for the four major river basins: 8.92% for the Hangang River basin; 11.41% for the Nakdonggang River basin; 8.87% for the Kumgang River basin; and 17.17% for the Yeongsangang River basin. The Yeongsangang River basin had the highest difference.

• Research in Community and Public Health Nursing
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• v.20 no.3
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• pp.277-284
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• 2009

Purpose: This study was to investigate depression prevalence and related factors of depression in Jeju Province. Methods: The study sample selected using randomized cluster sampling method, and the unit of cluster was 25 households. Data were collected from 1275 adults in 723 households through home visit interview. The response rate was 89.4%. The instrument used for measuring depression was CES-D, the cut-off score was 21. Data were analyzed using Chi-square test and logistic regression. Results: The prevalence of depression in Jeju was 18.1%. The significant differences were found with depression prevalence rate by the group of gender, age, inhabited area, marital status, educational status, monthly household income, life satisfaction, socioeconomic status, perceived health status, morbidity during last 2 weeks, perceived stress, perceived fatigue, participation in social activities, and family life satisfaction. The most predictive factors among those variables were perceived fatigue with 17.93 of odds ratio, family life satisfaction with 9.86 odds ratio, and perceived stress with 9.66 of odds ratio. Conclusion: The prevention and management of depression program development was suggested and mental health promotion program for the prevention of depression was suggested.