Abstract: Japanese dace（Leuciscus hakonensis）,the only anadromous member in the family of Cyprinidae,is found at the coast of Pacific in Asia.The main ecological characteristics including body length,body weight,age,growth and fecundity,gonado-somatic index,and condition factor in spawning migration period were evaluated by the 890 samples collected in Suifen River in 2009.The broodstock migrating to the upstream were found to spawn in Suifen River three times,from mid-march to the beginning of April,from middle to the end of April,and in May.The spawning fish showed golden in body color in the first spawn,silver in body color in the second spawn,and deep color in the third spawn.There were different sex ratio,gonado-somatic index,and condition factor in spawning population,the second batch being the main predominant reproductive population.Some measurements to protect the proliferation of this fish were proposed based on the main ecological characteristics here.

Key words: Suifen River, Leuciscus hakonensis, reproductive population, ecology, resource conservation