图们江马苏大麻哈鱼陆封型的生物学资料

BIOLOGICAL STUDIES ON LANDLOCKED MASU SALMON IN THE TUMEN RIVER

本文对628尾图们江马苏大麻哈鱼陆封型的一些生物学资料进行研究。结果表明鱼群由1—6龄组成,主要是2—4龄。我们首次发现雌鱼绝大多数个体(99.4%)终生不性成熟,性腺滞于Ⅱ期,故他们自繁能力极低。陆封型与洄游型关系密切。他们的产卵期与产卵场环境相同,前者雌雄比为1:1.7; 后者为8:1,前者雄鱼参与后者繁殖,其性比恰呈互补,主食落入水中的陆生昆虫。建议保护陆封型资源。

The landlocked masu salmon, Oncorhynchus masu (Brevoort), is one of the mostimportant fishes in Tumen River. Morphological and ecological studies were carried out in Sidaogou of the HungchunRiver, a tributary of Tumen River, in March to October 1977. Our specimens are parr. The males mature sexually in the landlocked condition,and develop into dark parr participating in the fertilization of eggs laid by the ana-dromous masu salmon in September and October. They are mainly of age 3, the smallestcollected being 84 mm. The females are not sexually matured throughout their life, though 2 out of 107specimens are found to be in the maturation stage V and female of 204 mm in lengthand 80. 7g in weight was recorded elsewhere from Mijiang, in having an individualabsdlute fecundity of 367. The two mature females collected measure 105 and 109 mmand weight 22.3 and 20.5 g respectively. Food ingested consists mainly of insects. Opercula were used for aging. One-year-old fishes measure on an average 83.5 mmin length, two-years-old 135. 1mm, five-years-o1d 167.8 mm.