ABUNDANCE AND FRESH-WATER MIGRATIONS OF THE ANADROMOUS PARASITIC LAMPREY, LAMPETRA-TRIDENTATA, IN A TRIBUTARY OF THE FRASER-RIVER, BRITISH-COLUMBIA
ABUNDANCE AND FRESH-WATER MIGRATIONS OF THE ANADROMOUS PARASITIC LAMPREY, LAMPETRA-TRIDENTATA, IN A TRIBUTARY OF THE FRASER-RIVER, BRITISH-COLUMBIA
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DOI：
10.1139/f91-151
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发表时间：
1991-07-01
影响因子：
2.4
通讯作者：
LEVINGS, CD
中科院分区：
文献类型：
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作者：
BEAMISH, RJ;LEVINGS, CD
在1984-85年至1987-88年期间，从尼古拉河迁移出的中国七鳃鳗幼鱼估计约为176000、19000、90000和102000只;与此同时，约有749 000、909 000、920 000和605 000头4岁和5岁的大型阿摩尼亚鱼离开了河流。 9月开始有年轻人移徙，3月中旬至5月中旬移徙人数最多。 Ammococoterm的表现类似，但运动持续全年。 大多数幼成虫在4 ~ 5岁时变态，5 ~ 6岁时洄游入海。 尼古拉河中的七鳃鳗何时到达盐水还没有确定;从3月到7月，三齿鱼从弗雷泽河进入格鲁吉亚海峡。 成熟的成虫于8月首次从海洋返回尼古拉河，当时河水水位最低。 这是首次对该虫的幼成虫丰度进行估计。在弗雷泽河流域的任何一条河流中都有三齿龙。 非常大量的年轻成年人和老年ammocococoalies离开尼古拉河表明，寄生七鳃鳗是丰富的弗雷泽河，他们可能是一个共同的捕食者的商业重要鱼类。
The migration of young adult Lampetra tridentata out of the Nicola River during 1984-85 through 1987-88 was estimated to be approximately 176 000, 19 000, 90 000, and 102 000; at the same time, approximately 749 000, 909 000, 920 000, and 605 000 large ammocoetes, age 4 and 5 yr, left the river. Migration of young adults started in September, with the largest number migrating from mid-March to mid-May. Ammocoetes behaved similarly except that movement continued throughout the year. Most young adults metamorphosed at age 4 or 5 and were age 5 or 6 when they migrated to sea. It was not determined when lamprey from the Nicola River reached salt water; however, L. tridentata entered the Strait of Georgia from the Fraser River from March until July. Maturing adults first returned to the Nicola River from the ocean in August when water levels in the river were at their lowest. This is the first estimate of abundance of young adult L. tridentata in any river in the Fraser River drainage. The very large number of young adults and older ammocoetes leaving the Nicola River indicate that parasitic lamprey are abundant in the Fraser River and that they are potentially a common predator of commercially important fishes.