Biology of the amphioxus, Branchiostoma belcheri in the Ariake Sea, Japan II.: Reproduction
Biology of the amphioxus, Branchiostoma belcheri in the Ariake Sea, Japan II.: Reproduction
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DOI：
10.2108/zsj.20.907
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发表时间：
2003-07-01
影响因子：
0.9
通讯作者：
Henmi, Y
中科院分区：
文献类型：
--
作者：
Yamaguchi, T;Henmi, Y
从1999年到2002年，我们调查了文昌鱼在日本有明海南部的繁殖情况。9月至12月性腺非常小或几乎没有，1月开始发育。性腺长度指数的变化表明，产卵开始于6月中旬，性腺已达到最大尺寸后。虽然大多数配子在第一次产卵时被挤出，但仍有一些留在性腺中。萎缩的性腺要小得多，但含有配子，第二次产卵发生在7月10日左右。目前还不清楚是否所有的成年人都产卵两次，但很大一部分人都这样做了。在第一次产卵后，雄性和雌性都失去了30%的体重。大多数一岁个体不产卵，成熟时的最小尺寸约为100毫米。20毫米。我们没有发现在非常大的个体中终止繁殖。性腺的平均数量在身体右侧（雄性26.2和雌性26.1）显著大于左侧（雄性24.0和雌性23.5）。我们在总共11184个样本中发现了两个雌雄同体。每一个都有四个或三个卵巢，总共有45或54个性腺。
We investigated the reproduction of the amphioxus Branchiostoma belcheri in the southern Ariake Sea, Japan, from 1999 to 2002. Gonads were very small or almost absent from September to December and began to develop in January. Changes in the gonad length index indicated that spawning began in mid June, after the gonads had attained maximum size. Although most gametes were extruded during the first spawning, some remained in the gonads. Shrunken gonads were much smaller but contained gametes, and the second spawning occurred around 10 July. It was unclear whether all adults spawned twice, but a large proportion of individuals did. After the first spawning, both males and females lost 30% of their body weight. Most one-year-old individuals did not spawn, and the minimum size at maturity was ca. 20 mm. We found no termination of reproduction among very large individuals. The average number of gonads was significantly larger on the right side of the body (26.2 in males and 26.1 in females) than on the left side (24.0 in males and 23.5 in females). We found two hermaphrodites in a total of 11, 184 specimens examined. Each had four or three ovaries among a total of 45 or 54 gonads.