• The Korean Journal of Ecology
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• v.24 no.1
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• pp.45-50
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• 2001

The fish fauna of the Buan Dam, Chollabuk-do, Korea which was constructed in 1995 was surveyed in 1994 and 1998. 14 fish species were collected in the Buan Dam and 19 species were recognized in the brackish waters along the lower course of the dam in 1998. It was remarked that the dominant species in the dam has been changed dramatically from Zacco platypus and Z. temmincki to Pseudorasbora parva and Squalidus gracilis majimae within the three years after the dam construction. And also the number of Carassius auratus and Sirulus asotus were gradually increased in the dam. However, lksookimia pumila, the threatened fish species of Korea, was decreased sharply and restricted conspicuously by fragmentation of the habitat. The positive strategies should be considered for the species conservation of lksookimia pumila in the Buan Dam.

• Journal of Ecology and Environment
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• v.38 no.3
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• pp.307-318
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• 2015

The objectives of this study were to identify multi-level stressors from blood biomarkers to community-level bioindicators and diagnose the stream ecosystem health in polluted streams. Blood chemistry such as total protein ($T_{Pro}$), blood urea nitrogen ($B_{UN}$), total cholesterol ($T_{Cho}$) and $A_{lb}$umin ($A_{lb}$) were analyzed from sentinel fish tissues; the functions of kidney, gill and liver were significantly decreased in the impacted zone ($I_z$), compared to the control zone ($C_z$). Histopathological analysis showed that fish liver tissues were normal in the $C_z$. Fish liver tissues in the $I_z$, however, showed large cell necrosis and degeneration and also had moderate lobular inflammation and inflammatory cell infiltration of lymphocytic histocytes. Species biotic index (SBI) at species level and stream health assessment (SHA) at community level indicated that chemical impacts were evident in the $I_z$ (ecological health; poor - very poor), and this was matched with the blood tissue analysis and histopathological analysis. The impairments of the streams were supported by water chemistry analysis (nitrogen, phosphorus). Tolerance guild analysis and trophic guild analysis of fish were showed significant differences (P < 0.01) between $C_z$ and $I_z$. Overall, multiple parameter analysis from biomarker level (blood tissues) to bioindicator level (community health) showed significantly greater impacts in the $I_z$ than $C_z$. This approach may be effective as a monitoring tool in identifying the multilateral and forthcoming problems related to chemical pollution and habitat degradation of stream ecosystems.

• Korean Journal of Ecology and Environment
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• v.42 no.4
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• pp.422-431
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• 2009

This study was to provide basic data for aquatic ecosystem research using fishes. Field sampling was carried out at five selected sites of Gap Stream, and fish samples, especially for a selection of sentinel species were collected three times in June, September, and October 2007. We analyzed total length distribution of Zacco platypus in relation with the season and the sampling sites, and then compared with total body weight, condition factor (K), and age distribution of the fish. The fish population data were compared with physico-chemical water quality, obtained from the Ministry of Environment, Korea. Water quality analysis showed a significant nutrient enrichment, based on total nitrogen (TN) and total phosphorus (TP), and organic matter pollution, based on biological oxygen demand (BOD) and chemical oxygen demand (COD) in the Site 5, which is directly influenced by wastewater disposal plant (WDP). Population analysis of the sentinel species showed that the total number of individuals, age distribution, and the population size-structure were influenced by the effluents from the WDP, and that reproductive failure of young-age population were evident in Site 5. According to the relation analysis of total weight to K, the disturbed population was mainly attributed to combined effects of habitat modifications and chemical degradations. Regression analysis of K values against water quality parameters showed significant (p<0.05) positive relations with nutrient and organic matter contents. Our data suggest that the population structure using a sentinel fish species reflected the ambient water quality in the stream and that diagnosis of aquatic ecosystem health using Z. platypus population may be practical for water resource and ecosystem conservations.

• Korean Journal of Ichthyology
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• v.31 no.4
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• pp.241-248
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• 2019

The freshwater fish fauna for the whole water system of Geogeumdo Island was surveyed at a total 10 sites from March 2018 to February 2019. During the surveyed period, 13 species belonging to 5 families and 4 orders were collected. Cyprinidae (68.84%) and Gobiidae (18.21%) were the dominant family, and the dominant species was Zacco temminckii (53.71%), and the subdominant species was Rhynchocypris oxycephalus (10.78%). Kichulchoia brevifasciata (1.27%) that endangered species were found in this study, but the habitat was confirmed in one site in Sinpyeongcheon compared to previous literature. Three endemic species of Korea were found in this island such as Iksookimia hugowolfeldi (5.07%), Liobagrus somjinensis (2.99%) and K. brevifasciata (1.27%). According to analysis of fish community structure based on average diversity, evenness index, dominance and richness indices in Geogeumdo Island were 1.666, 0.649, 0.645 and 1.713, respectively.

• Journal of Korean Society on Water Environment
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• v.29 no.6
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• pp.746-753
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• 2013

The aim of this study was to evaluate artificial fish shelter, which was known to increase prey survival and expand habitat space to improve species diversity and fish communities in a freshwater ecosystem. The experiment was performed at an outdoor test-bed for three months from 2011 by comparing the responses to adjustments in the volume of the artificial patch (juvenile fish shelter, JFS) in the control and experimental groups. Analysis of the environmental conditions over two periods (Period1 ~ 2) showed minor differences in the physichemical characteristics of water quality, phytoplankton, and zooplankton biomass, thus, allowing comparative analysis of feeding ecology. However, high water temperature conditions in Period1 ($25.6{\pm}2.0^{\circ}C$), affected the predation activity of the piscivorous fishes, Coreoperca herzi (C. herzi, size $89{\pm}4mm$). Survival rates of the prey fishes, Rhynchocypris oxycephalus (R. oxycephalus, size $29{\pm}1mm$), improved as the patch volume increased and were higher than those of the control group by 35.9 ~ 46.7%. Analysis showed that JFS reduced the chances of predator-prey encounter, and thereby minimized prey vulnerability.

• Journal of Korean Society of Disaster and Security
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• v.16 no.4
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• pp.109-121
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• 2023

Squr dikes in rivers can enhance various ecological environments, contributing to the improvement of the river's environmental functions. However, the alterations in flow caused by squr dikes not only enhance environmental functions but can also have adverse effects. Therefore, this study aimed to analyze the flow changes induced by the installation of squr dikes through flume experiments and assess their impact on fish habitats. Key factors in the fish habitat environment include flow velocity, turbulence kinetic energy, and recirculation zones. Among these, particular emphasis was placed on examining turbulence kinetic energy and recirculation zones. Experimental conditions were set by varying the interval and submergence of the squr dikes, resulting in a total of eight experimental cases. The results revealed that shorter interval and lower submergence of the squr dikes led to increased turbulence kinetic energy and recirculation zone sizes, significantly impacting fish habitats.

• Journal of Environmental Health Sciences
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• v.44 no.3
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• pp.259-266
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• 2018

Objectives: Considered the "national fish" in Korea, the walleye pollock (Gadus chalcogrammus) has disappeared in the East Sea (Sea of Japan), a main habitat and fishing ground for the species. The reason for the disappearance is still a matter of controversy. This study was performed to investigate the long-term relationship between the walleye pollock catch and various meteorological and oceanographic factors in these waters. Methods: Fishery data on walleye pollock and data on meteorological and marine environmental factors over the 30 years (1981-2010) were obtained from the official national database. Time series analysis and correlation and regression analyses were performed to study the relationships. Results: Both air temperature and sea surface temperature in the East Sea rose over these 30 years, and the latter became more prominent. Salinity and dissolved oxygen showed a tendency to decrease while concentrations of nutrients such as nitrite nitrogen and nitrate nitrogen showed an increasing tendency. Sea surface temperature, air temperature, atmospheric pressure, and wind grade were negatively correlated with the catch size of walleye pollock (p<0.05), but salinity was positively correlated (p<0.001). Conclusion: The results of this study indicate that climate change, especially ocean warming, affected the habitat of walleye pollock. The results also indicate that lower sea surface and air temperatures, milder wind grade, and higher salinity were preferred for the survival of the fish species. It is necessary to pay attention to changes of the ocean ecosystem in terms of environmental pollution as well as seawater temperature.

• Korean Journal of Ichthyology
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• v.30 no.3
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• pp.161-166
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• 2018

The olfactory organ of Korean endemic fish Microphysogobio yaluensis are described anatomically and histologically, focused on relationship to its habitat and ecology. The paired olfactory organs are located at the dorsal snout, and externally consist of two semicircular nostrils and single nasal flap. They internally have rosette structure with 22 to 24 units of lamellae and the raphe inside the olfactory chamber. The lamella is made up of the sensory and the non-sensory epitheliums. The sensory epithelium has olfactory receptor neurons, supporting cells and basal cells whereas the nonsensory epithelium has stratified epithelial cells, ciliated non-sensory cells and mucous cells with acidic and neutral mucins. These structures might be considered that M. yaluensis has the olfactory organ which corresponds to the high sensitivity for its habitat and ecology, and is usable as a taxonomic key.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.485-485
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• 2022

본 연구에서는 낙동강 수계에서 어류의 수생태 건강성이 악화된 지점, 장기간 수질이 악화되거나 수위가 저하된 지점, 보호종이 지정된 지점을 중심으로 어류 서식지적합도지수(Habitat Suitability index, HSI)를 산정하였다. 현장조사는 하천유량이 감소하는 4월부터 6월 사이 총 4회 실시하였고, 투망과 족대를 이용해 어류 채집하였다. 어류의 서식지 특성 조사를 위해 채집 지점에서 수심, 유속, 하상재료를 조사하고 기록하여 엑셀 자료를 구축하였다. 본 연구에서는 실제 하천 단면의 물리적 특성을 잘 반영할 수 있는 WDFW(Washington Dept. of Fish and Wildlife) 방법을 이용하여 어류 서식처적합도지수를 산정하였다. 낙동강 수계 10개 지점에서 실시한 어류 조사 결과는 전체 9과 35종 2,227개체이다. 낙동강 수계 10개 지점의 대표어종을 선정하기 위해 법정보호종, 유영성종, 고유종, 기타 중요종을 검토한 다음 각 지점별 대표어종, 대리어종, 유사어종 등을 산정하였다. 낙동강 수계 전반에 걸쳐 피라미가 우점종으로 조사되었으며, 낙동강 상류지역에는 모래무지, 하류에는 수수미꾸리와 유사한 종의 출현빈도가 높은 것으로 나타났다. 낙동강 전역에 걸쳐 서식하고 있는 피라미는 가능한 대표어종에서 제외하고, 보호종과 고유종을 중심으로 대표어종을 선정하였다. 그 결과 낙동강 상류 내성천 합류전 지점에서는 피라미, 내성천에서 참마자, 위천에서 참몰개, 갑천에서 돌고기, 황강에서 모래무지, 금호강에서 돌마자, 밀양강에서 쉬리. 남강에서 피라미, 형산강에서 참갈겨니, 태화강에서 피라미로 대표어종을 각각 결정하였다. 다음으로 각 지점별 대표어종에 대한 수심, 유속, 하상재료 조사 자료를 이용해 대표어종에 대한 서식지적합도지수를 산정하였다. 최근 갈수기 유량 감소로 생태계가 위협받는 기간이 증가하고 있다. 하천의 정상적인 생태기능 유지를 위한 최소한의 유량이 필요하고, 이를 확보하기 위한 노력이 요구된다. 어류의 서식지적합도지수를 활용해 갈수기 어류 서식에 필요한 최소한의 유량을 결정하거나, 수생태계 복원을 위한 기초자료로 활용성이 높을 것으로 판단된다.

• Korean Journal of Environment and Ecology
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• v.11 no.1
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• pp.100-110
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• 1997

To clarify the structure and function of ecosystem and establish the method for the conservation of biodiversity and community analysis at Soksacheon and Gyebangcheon, the authors surveyed the aquatic environment and freshwater fish fauna at 13 stations from July, 1995 to June, 1996. Collected 1,908 individuals were belong to 20 Species, 4 Oredr, 1 Suborder, 6 family, 7 Subfamily. The detail results are as follows. 1. It was confirmed that most of the surveyed stations were mountain valley of river type Aa, Ab. River structures were mixed with pebble, sand, rock and water quality of Soksacheon were pH(7.41), [COND.(0.051), TURB.(10.00), DO(8.66), W.T.(15.4)] and Gyebangcheon were pH(7.44), [COND.(0.097), TURB.(21.59), DO(9.35), W.T.(15.4)]. 2. Among them, 18 species were primary freshwater fishes(99.98%) and 2 species of pheripheral freshwater fishes(0.02%). 12 species(60%) of them were endemic species of Korea and they were Moroco kumgangenesis, Microphysogovio longidorsalis, Cobitis rotundicaudata, Misgurnus anguillicaudatus, Coreoleucisus splendidus, Cobitis longicorpus, Oncorhynchus masou ishikawai, Brachymystax lenok, Hemibarbus longirostris, Silurus microdorsalis, Cobitis koreensis koreensis and Hemibarbus mylodon. 3. Dominant species were Moroco kumgangenesis(46.85%) and Zacco temmincki(27.35%).