Microhabitat Segregation of Sand-dwelling Fish in the Naeseong Stream, Korea

초록

Naeseong Stream as a tributary of Nakdong River has conserved the unique structure and function of a typical sand-bed stream ecosystem. It is predicted that the fish assemblage will be changed in downstream stretches of the Yeongju Dam which is under construction and will operate soon upstream of the Naeseong stream. To predict the change of fish habitat in physical environment of the Naeseong stream, we calculate the habitat suitability index (HSI) of fish which prefers sand-bed. Selected fish are pseuchgobio esocinus, gobiobotia nakdongensis and cobitis hankngensis. We are sampling fish, bed materials, velocity and water depth in the nine study sites in downstream of the dam in the Naeseong Stream. Suitable habitat ranges of three sand-dwelling fish were differentiated; water velocity 0.2 ? 0.4m/s, 0.4 - 0.6 m/s and 0 - 0.3 m/s, water depth 0.20 - 0.30 m, 0.17- 0.21 m and 0.18 - 0.30 m, the median diameter of substrate particles (D5o) 1.0 - 1.5 mm, 1.3 一 1.5 mm and 1.1 - 1.4 mm in P. esocinus, G. nakdongensis and c. hanlaigensis, respectively. The simulated results of physical habitats in each species showed that their microhabitats were segregated in a sand stream. In conclusion, fish habitat could be predictable according to calculated HSI in changed rate of flow after construction of Yeongju Dam in the downstream of the Naeseong stream. This research was supported by a grant (12-TI-C02) from Advanced Water Management Research Program funded by Ministry of Land Infrastructure and Transport of Korean government.