Abstract
Ecological characteristics of Orthrias nudus from the Eoron Stream, Gangwon-do, Korea were investigated from January to December 2009. O. nudus inhabits mainly riffles of the upstream and mid-upstream stretches of Eoron Stream, which were composed of boulder and cobble bottoms. The current velocities in these habitats were 0.42~1.34 m/sec and depths were 15~46 cm. The sex ratio of female to male was 1 : 0.98. It is presumed that the spawning season is from April to June when water temperatures were $15{\sim}19.2^{\circ}C$. Sexually mature individuals appeared to be over one year of age. Frequency analysis of total length indicated that the group 58~99 mm in total length is represented by one-year-old individuals, and the group over 100 mm by two-year-old individuals. The average number of eggs in the ovaries was estimated as 4,119 per mature female. Stomach contents of O. nudus were composed of aquatic insects such as Ephemeroptera, Trichoptera and Diptera.
대륙종개는(Orthrias nudus)의 생태적 특성을 연구하기 위해 2009년 1월부터 12월까지 어론천에서 조사하였다. 본 종은 하천 중 상류에서 상류역 여울에 걸쳐 분포하며 하상구조는 주로 큰 돌과 작은 돌로 이루어져 있었다. 서식지 수심은 15~46 cm 이었고 유속은 0.42~1.34 m/sec 상태를 유지하고 있었다. 성비는 1:0.98이었고 산란시기는 4~6월이며 산란기 수온은 $15{\sim}19.2^{\circ}C$이였다. 만 1년생 이상부터 성적 성숙이 이루어지기 시작하였다. 전장이 58~99mm의 집단은 만 1년생, 100 mm의 이상은 만 2년생으로 추정된다. 포란수는 평균 4,119개 이었고 먹이생물은 수서곤충인 하루살이목(Ephemeroptera), 날도래목(Trichoptera), 파리목(Diptera) 등이 있다.
