영평천에 서식하는 새미 Ladislabia taczanowkii (잉어과)의 개체군 생태

초록

Population ecology of Ladislabia taczanowskii was investigated at upper part of Yeongpyeong stream in Korea form May to September, 2011. The habitat of L. taczanowskii was low water temperature, which was not higher than 22℃, and stream form was Aa type. In addition, the substrate structure of habitat was mostly in the boulder and cobble bottoms with water velocity of 0.2-0.9 m/s and water depth was 0.20-0.70 m. The cohabitation species of fishes were Coreoleuciscus splendidus (3.5%), Rhynchocypris oxycephalus (5.8%), Zacco Koreanus (47.9%), Orthrias nudus (2.9%), Misgurnus anguillicaudatus (0.5%), Liobagrus andersoni (1.0%) and Cottus koreanus (5.8%). The total length in the population indicated that below 52 mm group is one year old, 52-79 mm group was two years old, 80-95 mm group is three years old and the 95mm longer group is regarded over four years old. Males and females were become sexually mature at sizes longer than 80 mm total length and this result indicated that sexually maturated individuals appeared over the three years of age. The prosperous spawning season was June with the water temperature in the range 19.5-21.1℃. Nests were built up at a water depth of 0.5-0.6 m, a current velocity of 0-5 cm/s and the bottom structure consisted of gravel and sand. The average number of eggs in the ovary was 699. L. taczanowskii was omnivore and consumed attached algae and aquatic insects. The main prey materials were Bacillariophyta, Chironomidae and Psychomyiidae. However, before the breeding season, L. taczanowskii consumed large number of aquatic insects such as Chironomidae and Psychomyiidae. On the other hand, after the breeding season, its main prey was Bacillariophyta.