• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.5
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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.

• Journal of Korean Society on Water Environment
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• v.27 no.6
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• pp.776-783
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• 2011

In a natural water body, a useful ecotechnology to reduce standing crops of phytoplankton is to strengthen the top-down force of zooplankton. However, the predation of fish for zooplankton can make the force weak. This study was conducted to find out the effect of fish on the grazing pressure of zooplankton in the mesocosms established in a eutrophic stream (Kyongan Stream) from October to November in 2010. In the corral with fish, chlorophyll a concentration increased, and a small size cladoceran Bosmina longirostris was dominant. In the corral without fish, chlorophyll a concentration decreased along with the domination of a large cladoceran Daphnia galeata and a large copepod Eudiaptomus japonicus. The size-selective predation of fish appeared to miniaturize the zooplankton community, to narrow their food-size spectrum, and to weaken the top-down force.

• Korean Journal of Environment and Ecology
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• v.21 no.6
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• pp.506-514
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• 2007

Temporal and spatial distribution of fish community were investigated from September 2006 to April 2007 targeting the lagoon Youngrang, Korea. A total of 32 species belonging to 16 families were collected during the period, among which the species of primary freshwater fish accounted for 11 (34.38%), the species of peripheral freshwater fish for 18 (56.25%), and that of marine fish for 3 (9.38%) in collected fish community. As a result of taking a look at the transitional aspects of community by each surveyed station and period, it was found that when the 'Breaking-sandbar' occurred, there came a change in the composition ratio of the fish species according to their ecological characteristics. In addition, compared with the data obtained in the past with respect to the ichthyofauna of the lagoon Youngrang, it was found that the ratio of the primary freshwater species gradually decreased, while the peripheral freshwater and seawater species gradually increased according to the indraft of seawater. Thus, it was concluded that fish community in the lagoon seemed to go under transition in its spatio-temporal characteristics depending on the 'Breaking- sandbar.'

• Korean Journal of Ecology and Environment
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• v.41 no.4
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• pp.490-498
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• 2008

This study was to analyze fish composition and ecological indicator characteristics from eight sampling sites of Geum River, October 2007. Total number of family and species sampled were 9 and 40. The most dominant family was Cyprinidae (27 species, 85%), and then followed by Cobitidae, Odomtobutidae, and Gobiidae. Constancy values of Zacco platypus and Zacco temminckii were 1.00 and 0.30, respectively, and the relative abundance of Acheilognathus koreensis and Pseudogobio esocinus were greater than 5% of the total. The number of Korean endemic species sampled in this Geum River study was 7 family 19 species, which is 47.5% of total 40 species, and endangered species of Pseudopungtungia nigra and Gobiobotia brevibarba were only 0.5% of the total and these species were only distributed within the upstream regions. Exotic species, Micropterus salmoides, which is known as large-mouth bass, were observed in two sites of G3 and G7. Analytical results of fish community showed that community dominance index was 0.19, which is low, and the species evenness index (0.74), diversity index (2.03), and richness index (3.00) appeared high. These results indicate that structure of fish community is stable in the Geum River. According to various guilds analysis, the relative abundance of tolerant and omnivores at all sites were 40% and 47% of the total, respectively. This monitoring data may contribute changes of fish fauna and compositions in relation to habitat modifications and chemical water quality degradations in the future.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.2
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• pp.186-194
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• 2013

We compiled and analyzed long-term time-series data collected in Korea to evaluate changes in oceanographic conditions and marine ecosystems near Jeju Island ($33^{\circ}00^{\prime}-34^{\circ}00^{\prime}\;N$, $125^{\circ}30^{\prime}-127^{\circ}30^{\prime}\;E$) from 1981 to 2010. Environmental data included depth-specific time series of temperature and salinity that have been measured bimonthly since 1961 in water columns at 175 fixed stations along 22 oceanographic lines in Korean waters by the National Fisheries Research & Development Institute, and time series of estimated volume transport of the Tsushima Warm Current (TWC) and Korea Strait Bottom Cold Water (KSBCW) for the period from 1961 to 2008. We analyzed the species composition in terms of biomass of fish species caught by Korean fishing vessels in the waters near Jeju Island (1981-2010). Data were summarized and related to environmental changes using canonical correspondence analysis (CCA). The CCA detected major shifts in fish community structure between 1982 and 1983 and between 1990 and 1992; the dominant species were a filefish during 1981-1992 and chub mackerel from 1992 to 2007. CCA suggested that water temperature and salinity in the mixed layer and the volume transport of the TWC and the KSBCW were significantly related to the long-term changes in the fish community in the waters off Jeju Island. Fish community shifts seemed to be related to the well-established 1989 regime shift in the North Pacific. Further studies are required to elucidate the mechanisms driving climate change effects on the thermal windows and habitat ranges of commercial species to develop fisheries management plans based on reliable projections of long-term changes in the oceanographic conditions in waters off Jeju Island.

• Korean Journal of Ecology and Environment
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• v.38 no.3 s.113
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• pp.289-296
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• 2005

The fish fauna and community structure at 20 stations in streams of the Mt. Biseul were investigated from June 2003 to May 2004. During the study period, 29 species, 25 genera belonging to 9 families were collected. Cyprinid fish occupied 48.3% (14 species) and cobitid fish had 13.8% (4 species). Six species (22.2%) were korean endemic and two species of Micropterus salmoides and Lepomis macrochirus were exotic. It was found that the population density of carnivorous fish (Opsariichthys uncirostris amurensis) increased in the lower-reach of small streams in the Mt. Biseul area since it had been introduced from the other native rivers in the middle 1990s. As the result of analyzing fish community in the surveyed area, the species diversity ranged from 0.553 to 1.023. The findings showed that the Geumpo, Chacheon and Hyeonpung streams had higher species diversity indicies of 0.936 ${\sim}$ 1.023 than the Sincheon and Gisegok streams with 0.553 ${\sim}$ 0.727.

• Proceedings of the Korea Society of Environmental Biology Conference
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• 2002.05a
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• pp.67-67
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• 2002

• Korean Journal of Environmental Biology
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• v.22 no.3
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• pp.446-455
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• 2004

The ichthyofauna and community structure in Hongcheon river, Korea, was investigated from April to October 2002. During the surveyed period, 52 species belonging 11 families were collected. There were 23 Korean endemic species (44.23%), including Rhodeus uyekii, Acheilognathus signifer, A. yamatsutae, Coreoleuciscus splendidus, Koreocobitis rotundicaudata and Silurus microdorsalis. Dominant species were Zacco platypus (20.38%), and subdominant species were Z. temmincki (19.62%). Also, Rhynchocypris oxycephalus (8.45%), Pungtungia herzi (8.01%), C. splendidus (6.63%) were numerous. Of the 6 introduced fishes in Hongcheon river Carassius cuvieri, Lepomis macrochirus and Micropterus salmoides were originated from foreign countries but Anguilla japonica, Gymnogobius urotaenia, Rhinogobius giurinus were introduced from other native river systems. According to the fish distribution, the fish community of Hongcheon river was divided into 4 groups by principle component analysis (PCA).

• Korean Journal of Ecology and Environment
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• v.46 no.2
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• pp.154-165
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• 2013

The species composition of the fish community was studied in four streams where fish kills have previously occurred in recent years; Worun Stream, Seo Stream, Jangnam Stream, and the Anyang Stream. The number of fish species varied from 22 to 86% compared to the number of fish species pre-fish kill. The recovery of fish populations in the streams seems to be determined by water quality and the presence of artificial structures in the streams. The Jangnam Stream, where alkaline pH caused a fish kill, showed a high recovery of fish species due to improvements in water quality. Anyang Stream had a low number of species, possibly because dissolved oxygen concentrations were intermittently low. Artificial structures in streams had a negative impact the recovery of fish species, particularly for benthic fish species. It appears that fish populations can recover rapidly when water quality improves or the movement of fish community is unimpeded. However, water quality and artificial structures in many streams in Korea still present adverse conditions for fish survival, deterring the recovery of fish populations. To conserve fish populations in streams, habitat all owing unimpeded movement for fish and controls on pollutant inputs are needed.

• Journal of Environmental Science International
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• v.21 no.11
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• pp.1361-1369
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• 2012

A biological assessments of fish community structure were carried out in the lower reach of Seomjin River from May 2009 to November 2010. The collected fish from the six surveyed sites were 63 species belonging to 24 families, and 10 orders. Although species was different depending on sites, the numbers of individuals were not shown significance on sites. Locational dominant species were different. For example, the dominant species on May were Zacco platypus at W-1, Zacco temminckii at W-2, Acanthogobius flavimanus at W-3 and W-4, and Leiognathus nuchalis at W-5 and W-6. There is no seasonal differences in species. Species diversity was the best up to 2.64 on May at W-1 from 1.33 on November at W-6. As a result of an analysis about environmental factors for the numbers of fish species and individuals in each surveyed sites, the most effective groups were DO, BOD, and COD. The proportional difference was high on May than November between transient and asymptotic projections for population size and population growth rate for simulations starting at the current or theoretical stage distribution.