• 한국수산과학회지
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• 제53권5호
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• pp.761-772
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• 2020

In order to study about species composition and community structure of fish in the coastal water off Boryeong were investigated from January 2018 to December 2019. A total of 10,863 individuals of 87 species of 44 families were collected. The dominant species were Liparis tanakai accounted for 19.8 percent of the total with Amblychaeturichthys hexanema and Collichthys niveatus accounted for 12.4 percent and 11.0 percent of the total number. A cluster analysis based on the Bray-Curtis similarity revealed that the fish community divided into two groups, According to season. The fish species that appeared summer and autumn were mainly migratory, while the fish species that appeared in spring and winter were mainly resident species. Fish caught by stow net had a high percentage of immature fish. It presented that coastal water off Boryeong is located an important spawning and nursery for fisheries resource.

• Journal of Ecology and Environment
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• 제48권1호
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• pp.32-48
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• 2024

Background: Longitudinal connectivity in river systems strongly affects biological components related to ecosystem functioning, thereby playing an important role in shaping local biodiversity and ecosystem health. Environmental DNA (eDNA)-based metabarcoding has an advantage of enabling to sensitively diagnose the presence/absence of species, becoming an efficient/effective approach for studying the community structure of ecosystems. However, little attention has been paid to eDNA-based biomonitoring for river systems, particularly for assessing the river longitudinal connectivity. In this study, by using eDNA we analyzed and compared species diversity and composition among artificial barriers to assess the longitudinal connectivity of the fish community along down-, mid- and upstream in the Hotancheon from the Geum River basin. Moreover, we investigated temporal variation in eDNA fish community structure and species diversity according to season. Results: The results of species detected between eDNA and conventional surveys revealed higher sensitivity for eDNA and 61% of species (23/38) detected in both methods. The results showed that eDNA-based fish community structure differs from down-, mid- and upstream, and species diversity decreased from down to upstream regardless of season. We found that there was generally higher species diversity at the study sites in spring (a total number of species across the sites [n] = 29) than in autumn (n = 27). Nonmetric multidimensional scaling and heatmap analyses further suggest that there was a tendency for community clusters to form in the down-, mid- and upstream, and seasonal variation in the community structure also existed for the sites. Dominant species in the Hotancheon was Rhynchocypris oxycephalus (26.07%) regardless of season, and subdominant species was Nipponocypris koreanus (16.50%) in spring and Odontobutis platycephala (15.73%) in autumn. Artificial barriers appeared to negatively affect the connectivity of some fish species of high mobility. Conclusions: This study attempts to establish a biological monitoring system by highlighting the versatility and power of eDNA metabarcoding in monitoring native fish community and further evaluating the longitudinal connectivity of river ecosystems. The results of this study suggest that eDNA can be applied to identify fish community structure and species diversity in river systems, although some shortcomings remain still need to be resolved.

• 생태와환경
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• 제40권4호
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• pp.546-552
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• 2007

The objectives of this study were to analyze fish compositions, based on trophic guilds and tolerance guilds and determine community characteristics structure at five sampling sites of Yeongsan Lake during July 2006-May 2007. Total number of species sampled was 30 species and the number was 1350. Cyprinidae (77%) and Centrarchidae (15.7%) dominated the community and then followed by Cobitidae(2.7%), Gobiidae(2.4%), Mugilidae (0.5%), and others (0.1%). The relative abundance of tolerant and omnivore species at all sites was 63% and 77% of the total, respectively, suggesting an ecological degradations in the Lake. Exotics species such as large mouth bass (Micropterus salmoides), which is a top-carnivore in the water distributed at all sampling sites, implying that ecological disturbance was severe based on previous reference of US EPA (1991). Also, we found external anomalies such as external deformities, bleeding and tumors and not found migratory fish. Analysis of fish community structure showed that species diversity index and richness index was the highest in Site 1 and the dominance index was the highest in Site 2. In this study, high proportions of tolerant species and omnivore species, widespread exotic species, and frequent observations of abnormal fish. Such problems may be directly or indirectly associated with high nutrient enrichments and the reduced flow velocity by the dam construction. The ecosystem restoration by dam removal or removal of exotic top-carnivore fish may be one of the best strategies for better lak management.

• 수산경영론집
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• 제36권2호
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• pp.25-52
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• 2005

Since late 1990's, the Fish Aquiculture Households belong Fishing Community have been faced very serious pressure of management. The surface factors of this situation have been understood to overproduction and too much imports from China, but basic factor was caused structural problem, that is considered small scale production system. Then, We should enlarge scale of the Fish Aquiculture Households belong Fishing Community to overcoming profitability aggravation. To the Enlargement of Scale, We should consider to change the regime of Fishing Community that means two practical programs. First, it need to enlarge the scale of Fishing Community than now, and Second, it need to incorporate the Fishing Community for exclusive Management of Fish Aquiculture Rights.

• 한국수산과학회지
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• 제47권5호
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• pp.659-666
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• 2014

Our aim was to compare the community structure of fish in the coast of Wando Island between 2001 and 2013. Using a gape net with wings, we collected 61 taxa, wherein the most dominant species was Engraulis japonicus. The sea temperature in the middle layer of the survey station in 2001 (after June) was obviously higher than that in 2013, which was < $20^{\circ}C$. Except for Thryssa kammalensis in 2013, the log transformed individuals of seven dominant species, selected using a SIMPER (similarity-percentages procedure) analysis, decreased. Decreases in the individuals of Gobiidae spp., the warm-water species Trichiurus japonicus and Conger myriaster, and the migratory species Syngnathus schlegeli, Setipinna taty and Sardinella zunasi, which arrive in the southern coastal waters of Korea during summer-autumn, could be due to decreasing sea temperature in 2013. Thus, fish species diversity, estimated from rarefaction and k-dominance curves, declined in the coastal waters of Wando Island from 2001 to 2013, resulting in a significant difference in fish community structure.

• 한국수산과학회지
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• 제49권5호
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• pp.701-710
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• 2016

We examined the inter-annual changes in the community structure of fish in the Yeosu coast during the spring fishing period (May June) from 2008 to 2015. Using a both sides fyke net, we collected 74 taxa, of which the dominant species was Trachurus japonicus. In the years 2009-2010 and 2015, when the relative abundance of T. japonicus decreased, the fish species diversity increased, as estimated from the rarefaction curve and beta-diversity, resulting in a significant difference in the fish community structure between two year groups: one comprising 2009-2010 and 2015 and the other comprising 2008 and 2011-2014. T. japonicus may be a keystone species that plays a critical role in temporal changes in the community structure of fish caught by fyke nets along the southern coast of Korea. Obvious modes in the length-frequency of T. japonicus smaller than fork length (FL) 10 cm were observed continually during the study, while the frequency of T. japonicus bigger than FL 15 cm declined rapidly after 2010. The new recruitment of smaller T. japonicus before and after 2010 appeared beginning in June and May, respectively.

• 한국수산과학회지
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• 제43권5호
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• pp.510-520
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• 2010

This study investigated the community structure and seasonal variation of the fish assemblages on Jangbong tidal flat, Incheon, Korea. Fish were collected monthly using a small otter trawl from November 1999 to January 2001. Thirty-six fish species were recorded, with a mean density of 185 individuals and biomass of 2,594.3 gWWt. The most abundant species by number were Johnius grypotus (23.7%), Acanthogobius hasta (17.8%), and Cynoglossus joyneri (10.7%), while the dominant species by catch weight were Acanthogobius hasta (21.2%), Sebastes schlegeli (16.2%), J. grypotus (14.0%), and C. joyneri (10.8%). Cluster analysis and non-metric multi-dimensional scaling (nMDS) were applied to assess the seasonal fluctuation in the fish assemblages. Based on the result of the cluster analysis and nMDS ordination, the faunal group could be divided into cold- and warm-water specialist groups. The cold-water specialists included A. hasta, Acanthogobius luridus, Triaenopogon barbatus, Tridentiger trigonocephalus, and Liza haematocheila. The warm-water specialists were J. grypotus, C. joyneri, S. schlegeli, and Hexagrammos otakii. In conclusion, the community structure showed a distinct seasonal trend, which seemed to be related to the seasonal fluctuations in water temperature.

• 한국수산과학회지
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• 제48권5호
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• pp.776-782
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• 2015

We examined the community structure of fish off the coast of Jindo Island in response to a cold water appearance in the southwestern sea of Korea each August between 2013–2015. Using a gape net with wings, we collected 31 taxa during the study period, wherein the most dominant species was Engraulis japonicus. Collichthys lucidus and Neosalanx andersoni, which are mainly distributed in the western sea of Korea, increased in abundance and were dominant in August 2013, possibly due to the apparent intrusion of cold water (< 19°C) from offshore into the coastal waters of Jindo Island. Meanwhile, Scomberomorus niphonius and Sardinella zunasi, which are known as warmwater migratory species, increased in abundance and were dominant in August 2015, likely influenced by the warmer water (> 20°C) at the coast, which resulted in a noticeable lessening of the cold water in the study area. However, no significant differences were observed in fish community structure in the month of August between 2013–1015. This implies that the small-scale spatial and temporal variations in the cold water had limited effects on the fish community structure, even though the abundances of several dominant species varied in the coastal waters.

• 한국수산과학회지
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• 제33권1호
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• pp.1-8
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• 2000

본 조사는 1995년 8월부터 1996년 2월까지 계절별로 3차례에 걸쳐 통영주변 가두리 밑의 환경 및 저서동물 군집조사를 통해 가두리 운영에 따른 저서생물 군집구조의 변화를 알아보기 위해 실시되었다. 조사지역의 가두리 밑은 주변 해역과 유사한 퇴적상과 용존산소량을 나타낸 반면 높은 유기물 함량을 나타냈다. 종 수의 경우 가두리 밑이 대조구에 비해 적었지만 서식밀도에서는 현저히 높게 나타났다. 가두리 밑의 경우 Capitella capitata 와 Nebalia bipes등이, 대조구의 경우 Lumbrineris longifolia와 Amphioplus sp.가 우점 종을 나타냈다. 특히 가두리 밑에서는 Asterina pectinifera와 Asterias amurensis 등 표서성 초대형저서동물의 서식밀도가 높게 나타났다. 다양도에서 가두리 밑은 계절적인 차이를 보인 반면, 대조구는 차이를 나타내지 않았다. 군집구조에서 가두리 밑과 대조구는 상이한 구조를 나타냈다. 본 조사결과 가두리 양식은 유기물 증가와 시설물에 의한 유해 패각 가입 등 생물학적 영향에 의해 가두리 밑 저서환경과 저서동물 군집구조에 영향을 미치는 것으로 나타났다.

• Ecology and Resilient Infrastructure
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• 제4권1호
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• pp.34-43
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• 2017

낙동강의 지류하천인 내성천은 전형적인 모래하천으로 고유한 생태계의 구조와 기능을 가지고 있다. 그러나 2016년부터 운영되고 있는 영주댐에 의하여 내성천의 댐 하류에서 하상의 변화와 이에 따른 어류상의 변화가 예상된다. 본 연구에서는 2014년부터 2016년까지 모래하천인 내성천에서 어류의 서식환경, 생물상 및 군집구조의 변화를 모니터링하기 위하여, 공사중인 영주댐 하류와 대조지소로서 서천에서 하천 환경을 조사하고 어류를 채집하였다. 내성천에 영주댐이 축조되기 시작하면서 댐 직하류에서 하상 재료의 입경 크기가 증가하였다. 영주댐이 운영되기 전 내성천에서는 피라미가 우점하였고, 조사지점에 따라서 끄리, 쉬리, 참마자, 모래무지가 아우점하였다. 내성천에서는 모래 하상에서 특이하게 서식하는 누치, 참마자, 모래무지, 흰수마자, 기름종개, 대동갱이가 발견되었다. 내성천의 영주댐 하류에서 어류 군집는 하상 재료의 입경에 따라서 돌마자, 쉬리, 꺽지 등의 자갈 하상 어종 출현 군집과 누치, 기름종개, 흰수마자 등의 모래 하상 어종 출현 군집으로 구분되었다. 또한 이들 군집은 영주댐 건설 이후에 시간이 경과함에 따라서 점차 모래 하상 어류 군집에서 자갈 하상 어류 군집으로 변하는 경향이었다. 그러므로 영주댐 하류 하천에서 환경과 어류상의 변화를 지속적으로 모니터링하여 모래하천의 생태계 보전을 위한 기초자료를 확보하여야 할 것으로 생각된다.