• Korean Journal of Ichthyology
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• v.10 no.1
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• pp.67-76
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• 1998

The ichthyofauna and the structure of fish community were surveyed from April to November 1997 at eighteen stations in the Yonggang river which is a first tributary located at the middle reach of the Nakdong river system. During the surveyed period, 32 species belonging to ten families were collected. Of them cyprinid fish occupied 53.1% (17 species) and cobitid fish 15.6% (5 species). Thirteen species (40.6%) were known as Korean endemic species. Dominant species were Zacco temmincki (32.78%) and Moroco oxycephalus (15.10%). Zacco platypus, Pungtungia herzi. Niwaella multifasciata, and Odontobutis platycephala were common species. Rare species which occupied less than 0.1% of total individuals were Lampetra reissneri, Pseudorasbora parva, Squalidus chankaensis tsuchigae, Microphysogobio koreensis, Gobiobitia naktongensis, Cobitis rotundicaudata, Nemacheilus toni, Silurus asotus, Silurus microdorsalis, Siniperca scherzeri, and Oreochromis niloticus. A tendancy were shown in regional distribution that Moroco oxycephalus dominated in upper stream, Zacco temmincki and Moroco oxycephalus in mid - upper stream, Zacco temmincki and Niwaella multifasciata in mid - lower stream, and Zacco platypus and microphysogobioid fishes in lower stream. St. 11 which located in mid- reach of Yongam stream and St. 15 and 18 which located in main stream had the most stable and diverse community structure, but St. 1, 5, and 7 were unstable and the simplest community structure.

• Korean Journal of Ecology and Environment
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• v.44 no.2
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• pp.226-238
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• 2011

Ichthyological fauna and community structure were surveyed in the Naeseong Stream around the planed Yeongju Dam, Yeongju City, Gyeongsangbuk-do from April 2007 to October 2009, During the survey period, 27 species (25 genera, 10 families) were collected. Cyprinid fish comprised 63.0% (17 species) and cobitid fish comprised 7.4% (2 species). Ten of the 27 species (37.0%) were endemic species. The dominant and subdominant species based on the number of individuals was Zacco platypus (43.2%) and Zacco koreanus (15.8%), respectively. Introduced from the other native rivers and exotic fish were Opsariichthys uncirostris amurensis, Leiocassis ussuriensis, and Micropterus salmoides (11.1%). The declining population density of Zacco koreanus and its subdominant status represents a change, since, up until the mid 1990's, it was widely distributed throughout the area and was the dominant species. The distribution area of Zacco koreanus decreased in size; by 2009, it no longer inhabited the lower reaches of the Naeseong Stream. On the other hand, Zacco platypus remained the dominant species throughout the area, except for the upper-reaches of the water-course. Gobiobotia naktongensis inhabited all areas of Naeseong Stream, which mainly has a sandy bottom. Analyses of the fish community revealed species diversity, even-ness and dominant indices were 0.881, 0.615, and 0.230 respectively. These results showed that the main river, in which the water width and flow are abundant and which has various habitats, has a higher species diversity (0.829) than the tributary (0.735).