• Korean Journal of Ichthyology
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• v.17 no.2
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• pp.123-130
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• 2005

The ichthyofauna of Lake Cheongpyeong was investigated from April 2003 to November 2004. During the surveyed period 31 species belonging to nine families were collected. Dominant species in numbers was Hemibarbus labeo (relative abundance: 29.9%), subdominant was Acanthorhodeus gracilis (22.8%). Erythroculter erythropterus (14.6%) and Cyprinus auratus (6.3%) were also numerous. There were nine Korean endemic species belonging to three families, including Acheilgnathus yamatsutae. We need close observation on population fluctuations of Micropterus salmoides, an exotic carnivorous fish from North America, and Hemibarbus labeo and Erythroculter erythropterus, the dominant species by biomass in Lake Cheongpyeong.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.9 no.2
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• pp.51-63
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• 2004

Appearance of cold water in the coastal area off Ulsan-Campo, Southeastern coast of Korea, during summer has been well observed. To see the effect of this cold water on zooplankton distribution, we have collected zooplankton at 4 to 8 sites in the near coast as well as off coast for three times about two weeks of interval from July to August, 2001. Appearance of cold water was confirmed and total of about 195 zooplankton taxa were identified. Both the numbers of taxa appeared and zooplankton abundances did not show significant difference among the three sampling periods. On the other hand, the numbers of taxa appeared were generally greater in off coastal area while zooplankton abundances were greater in the near coastal area. These two variables showed different relationship with seawater temperatures. That is, the numbers of taxa appeared showed positive correlation with seawater temperatures (p<0.05) but abundances showed no significant relationship (p>0.05) with seawater temperatures of which variations were comparable with seasonal variations. It was postulated that the upwelling induced appearance of cold water enriched the nutrients, enhanced phytoplankton production and then provided better food conditions for smaller zooplankton in the near coastal part of this study area. In this context it was postulated that zooplankton distribution in the upwelling area might be controlled by food condition rather than seawater temperatures in spite of the large temperature variations caused by the appearance of cold water.

• Korean journal of applied entomology
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• v.32 no.2
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• pp.218-221
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• 1993

Sensitivities of insecticides and their seasonal variation were investigated against Myzus persicae. Some aphicides such as malathion were not effective on Myzus persicae in Chinese cabbage field. Difference of seasonal sensitivity was from I time to 16 times.

• Journal of Wetlands Research
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• v.17 no.3
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• pp.264-272
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• 2015

Understanding bird status is essential for the systematic and sustainable management of the Nakdong River Estuary, taking into consideration the relationship between ecosystems and the bird species. In this study, bird status in the Nakdong River Estuary Bird Sanctuary prior to the Four Major Rivers Project was analyzed using the bird monitoring data (2003-2011) from surveys conducted by the Busan Development Institute. The high percentage of winter visitors in terms of both species diversity (38.36%) and individual bird numbers (63.14%) suggest that the Nakdong River Estuary is an important wintering site for migratory birds. Cumulative numbers of individual birds were higher in Myungji (208,601), West Nakdong River (202,444), Eulsukdo (153,232), and Baekhap Doyodeung (150,595). The total numbers of migratory species were higher in Eulsukdo (171), Ilungdo (124), Myungji (132), and Samrak (121). Among the 232 species found in the Nakdong River Estuary, Anas platyrhynchos (17.71%) was the most common species, followed by Anas poecilorhyncha (8.85%), Larus crassirostris (6.48%), Anser fabalis (6.09%), Anas penelope (5.16%), and Calidris alpina (4.22%). Most bird taxa, except shelducks, showed annual fluctuations in individual numbers, with increasing frequency during survey periods. Of these, cormorants, swans, and gulls showed higher fluctuations than other taxa. Swans decreased drastically in numbers in 2007-2008 and 2009-2010 compared to previous years. Shore birds, gulls, wagtails, and other forest birds were also less common in 2010-2011. These results suggest that there were some environmental changes that might have affected the birds in the Nakdong River Estuary. Overall, the results suggest that habitat types affect the distribution of dominant species.

• Korean Journal of Environment and Ecology
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• v.34 no.2
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• pp.115-120
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• 2020

This study investigated the dominant species and the population variation of the ant species, an indicator species of biodiversity, to obtain basic data on the changes of population according to the future climate change. The survey period was from June to September 2013, and we investigated the distribution of ants by square irradiation method (10m × 10m) using traps. The survey in each altitude identified a total of 14 species of 11 genera in 3 subfamilies and collected 15,466 individuals. We confirmed the distribution of 4,548 individuals of 13 species at low altitude (700m), and the dominant species was Aphaenogaster japonica (49.9%). At the middle altitude (900m), we collected 9,129 individuals of 8 species, and the dominant species was Pheidole fervida (57.7%). At high altitude (1,100m), we identified 1,789 individuals of 10 species, and Myrmica kotokui (43.3%) was the dominant species. It was confirmed that Aphaenogaster japonica, Nylanderia flavipes, and Pheidole fervida were widely distributed throughout the altitudes.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.13 no.3
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• pp.13-22
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• 2010

본 연구는 칠면초의 분포역을 결정짓는 개체수의 변화와 성장 변화를 분석하고자 6개 조사역 18 Site에서 2006~2008년의 3년간 개체수 변화, 지상부길이 생장변화, 토양요인의 변화를 조사하였다. 칠면초의 개체수 변화는 간척으로 인한 해수유입의 급격한 감소가 저위 염습지의 수분공급이 원활하지 못한 환경을 조성하여 2008년도 8월 이후에 급격히 감소하는 영향을 나타냈다. 길이 생장변화 역시 강수, 해수유입 감소 등에 의한 탈염이 큰 영향을 미친 것으로 조사되었다. 특히 토양요인의 변화에서 칠면초의 개체수 및 길이생장에 $EC_{1:5}dS/m$가 가장 큰 영향을 미친 것으로 나타났다. 새만금 만경강 하구역 갯벌 염습지는 새만금 간척사업으로 인한 해수유입의 급격한 감소와 담수의 유량변화에 따른 수위변동 등의 환경요인에 의하여 간척사업이전 우점종인 칠면초의 분포역과 생장에 큰 영향을 미쳤다.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.2
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• pp.175-187
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• 1997

Benthic community structure was studied in Chinhae Bay during 3 years from June 1987 to May 1990, based on the samples from 12 stations on the seasonal, bimonthly or monthly basis (lim and Hong, 1994a, b). A total of 287 species was sampled with mean density of $1045.5\;ind./m^2$ and biomass of $98.48g/m^2$ during studyperiods. Of these species, there were 91 species of crustaceans $(31.7\%)$, 88 of polychaetes $(30.7\%)$, 56 of molluscs $(19.5\%)$, 22 of echinoderms and 30 of the micellaneous species. Polychaetes were density-dominant faunal group with a density of $824.7\;ind./m^2$, comprising of $18.6\%$ of the total density of the benthic animals. It was followed by molluscs with $14.62\;ind./m^2$ $($14.4\%\;of\;the\;total\;density)$ crustaceans with $50.5\;ind/m^2\;(4.6\%)$ and echinoderms with $13.4\;ind/m^2\;(4.6\%)$. Molluscs were the biomass-dominant faunal group with a mean biomass of $54.62\;g/m^2$. It was followed by polychaetes with $21.74\;g/m^2$ and echinoderms with $6.66\;g/m^2$. Based on community analysis, species richness, diversity and evenness showed decreasing trends toward the inner bay from outer stations, whereas dominance showed increasing. The three most dominant species Lumbrineris longifolia, Paraprionospio pinnata and Theora fragilis had densities over $40\%$ of the total density of benthic organisms in Chinhae Bay. Seasonal changes of benthic communities in the inner bay were high compared to those of the outer bay. It was mainly due to the occurrence of hypoxic condition in the inner area of the bay. Cluster analysis showed that the benthic community could be divided into four stational groups, that is, Group 1, the innermost area, which received the most heavy anthropogenic effects including seawage and waste water, Group II, the central area of the bay, Group III, the transitional area, Group IV, the mouth pan of the bay exposed to the open sea. The areal groups based on the environmental factors coincided with the zonal groups from the species composition. This fact suggests that the overall spatial distribution of macrobenthos in Chinhae Bay was controlled by the sediment organic carbon content of the bay.

• Korean Journal of Environment and Ecology
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• v.22 no.3
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• pp.301-308
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• 2008

We conducted the survey about the avian fauna, population, community and correlation between avian population and densities of the fallen rice grain in Cheonsu reclaimed area(Ganwol and Bunam Lake and reclaimed land) from Oct. 2006 to Mar. 2007. Total surveyed species number was 142 species, sum of maximum count of each species was 362,797 individuals, sum of average count of each species was 84,818 individuals. Comparing with early and late wintering season, number of species was stable in each survey time, but total population was decreased as the season progressed. Dominant species were Bean Geese Anser fabalis, Baikal Teals Anas formosa, White-fronted Geese Anser albifrons, Mallards Anas platyrhynchos and Pintails Anas acuta. Population fluctuation of the Bean Geese Anser fabalis, Baikal Teals Anas formosa, Mallards Anas platyrhynchos, PintailsAnas acuta was decreasing, but population of the White-fronted Geese Anser albifrons was stable. Number of species, total population were not significantly different among Ganwol, Bunam and Cheonsu Bay. Survey period was significantly correlated with species diversity and population in each area, and most community indices of each area were shown significant correlation. The density of the fallen rice grain was significantly different between the harvested rice paddy by big harvesting machine and small harvesting machine. Density of the fallen rice grain in stubble collected area was significantly different with area of stubble not collected. Density of the fallen rice grain was drastically decreased in the middle of wintering season, but not significantly different between Dec. 2006 and Feb. 2007. Avian population was strongly correlated with number of fallen rice grain in the same period.

• Korean Journal of Environmental Biology
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• v.38 no.4
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• pp.667-677
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• 2020

This study was conducted to investigate the fish fauna and characteristics of the Carassius auratus population in the Boryeong Reservoir in Chungcheongnam-do from October 2017 to June 2018. The collected fish were identified as 3,506 individuals of 15 species from a total of nine families. The dominant and subdominant species were H. nipponensis with 1,706 (48.6%) individuals and C. auratus with 1,021 (29.1%) individuals, respectively. The biomass of C. auratus (246,130g), P. fulvidraco(50,610g), C. cuvieri (14,730 g), S. asotus (11,560 g), and C. carpio (10,930 g) was analyzed. The results of the community analysis showed a dominant index value of 0.87 (±0.2), a diversity index value of 0.78 (±0.5), an evenness index value of 0.47 (±0.2), and a richness index value of 0.99 (±0.5). The length-weight analysis of C. auratus showed a regression coefficient b of 3.06, and a condition factor (K) of 0.0004 with a positive slope. The frequency distribution of the total length analysis of the C. auratus population inhabiting the Boryeong Reservoir showed a high distribution of lengths between 140-160 mm and a low distribution between 230-280 mm. The normalized difference water index (NDWI) was analyzed over the Boryeong Reservoir water surface from 2013 to 2014 using Landsat 8 channel data. The areas where the NDWI was decreased were located at the inflow site of Ungcheon Stream.

• Korean Journal of Environmental Biology
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• v.24 no.4
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• pp.372-379
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• 2006

In order to study temporal fluctuation and ecological characteristics of Noctiluca scintillans, its abundance was investigated in correlation with water temperature, salinity, precipitation, chlorophyll a concentration and copepods abundance in the coastal waters of Incheon from January 1999 to December 2000. N. scintillans was seasonally abundant during spring and autumn with temperature ranging from 10.3 to $21.5^{\circ}C$, but depleted in winter and summer. Low temperature below $4.5^{\circ}C$ in winter and low salinity due to high rainfall in summer led N. scintillans to disappear. A Cross Correlation Analysis (CCA) showed that chlorophyll a concentration was positively correlated with abundance of N. scintillans at the time lags of 10 days. This suggests that phytoplankton may be a contributing factor for increasing abundance of N. scintillans. During spring, eggs of Acartia hongi were found in 2.9 to 21.1% of individuals of N. scintillans. It was deduced that 1.2 to 49.5% of the eggs produced by A. hongi was preyed upon by N. scintillans. Therefore, N. scintillans may control the population size of initial developmental stage of A. hongi in the costal waters of Incheon.