Spawning activities and physical characteristics of the spawning ground of Lethenteron reissneri at the headstream of the Himekawa River, central Japan
Spawning activities and physical characteristics of the spawning ground of Lethenteron reissneri at the headstream of the Himekawa River, central Japan
复制标题
日本中部姬川河源头的Lethenteron reissneri产卵场的产卵活动和物理特征
DOI：
10.1007/s102280200022
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发表时间：
2002
影响因子：
1.2
通讯作者：
M. Takayama
中科院分区：
文献类型：
--
作者：
M. Takayama
据估计，姬川河源头的远东七鳃鳗的产卵期为3月中旬至5月下旬，产卵活动高峰期为4月初至5月初。一九九九年的性别比率（男女比例）介乎1:1 .5至1:1 . 3（平均1:1 .8），而二零零零年则介乎1:1 .8至1:1 .4（平均1:1 .4）。在观察到的90%的产卵巢中，雄性数量超过雌性。产卵期产卵巢的建造面积有向上游移动的趋势。巢建在水深5 ~ 70 cm、流速10 ~ 30 cm/s、卵石直径5 ~ 20 mm的基质上。Lethenteron reissneris在与petromyzon marinus相似的基质上筑巢，但筑巢点较浅，且在水流较慢的地区。
The spawning period of the Far Eastern brook lamprey,Lethenteron reissneri, in the headstream of the Himekawa River is estimated to be between mid-March and late May with the peak of spawning activity between early April and early May. The sex ratio (female:male) in 1999 ranged from 1 : 2.5 to 1 : 3.0 (mean 1 : 2.8) and in 2000 from 1 : 0.8 to 1 : 4.0 (mean 1 : 2.4). In >90% of the observations of spawning nests, males outnumbered females. The construction area of spawning nests tended to shift upstream during the spawning period. The nests were constructed at water depths between 5 and 70 cm, water velocity between 10 and 30 cm/s, and on substrate with pebbles of 5–20 mm in diameter.Lethenteron reissnericonstructed nests on substrate similar withPetromyzon marinus, but at shallower points and in areas with a slower water velocity.