Delivery of hatching larvae to estuaries by an amphidromous river shrimp: tests of hypotheses based on larval moulting and distribution
Delivery of hatching larvae to estuaries by an amphidromous river shrimp: tests of hypotheses based on larval moulting and distribution
复制标题
双性河虾将孵化幼虫运送到河口：基于幼虫蜕皮和分布的假设检验
DOI：
10.1111/j.1365-2427.2009.02244.x
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
R. Bauer
中科院分区：
文献类型：
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作者：
N. Rome;S. L. Conner;R. Bauer
摘要1.两栖虾生活和繁殖在淡水河流和溪流中，但它们的幼虫需要在海水中发育。幼虫可能会在上游孵化，然后漂到海里，尽管在一些物种中，雌性在幼虫被释放之前已经迁移到海岸。在这里，我们测试的相对重要性，幼虫漂流和雌性迁移的沼虾（十足目：长臂虾科）在美国路易斯安那州的密西西比河的分流。新孵化的幼虫（第1阶段）是不摄食的，如果没有遇到盐水，就不会蜕皮到第2阶段（第一次摄食阶段）。在实验室中进行析因实验，以测试（i）在不同盐度的水中暴露和维持之前阶段1幼虫在淡水中花费的时间对蜕皮至阶段2的影响。幼虫保持在淡水中的1或3天，然后改变到盐水在6或10 ppt显示出更大的频率蜕皮比那些保持更长的时间（5天）在淡水中或改变到更少的盐水（2 ppt）。非蜕皮幼虫在孵化后11天内死亡或濒死。3.在c河的两个地点用浮游生物拖曳物测量了第1阶段幼虫的相对丰度。相隔150公里，一个靠海，一个逆流而上。近海域的幼虫丰度明显高于上游。4.结果表明，在不同的温度下，M.在到达足够咸的水以刺激蜕皮到第一摄食阶段之前，俄亥俄鱼在淡水中漂流的时间有限。雌性迁徙可能在从距离海洋很远的大型大陆河流系统中运送无游物种的幼虫方面发挥重要作用，而在生活在短溪流中的物种中，仅幼虫漂流可能就足够了，就像在许多小型山区热带岛屿中发现的那样。
SUMMARY 1. Amphidromous shrimps live and breed in freshwater rivers and streams, but their larvae require development in sea water. Larvae may hatch upstream and then drift to the sea, although in some species females have been reported to migrate to the coast before larvae are released. Here, we tested the relative importance of larval drift and female migration in Macrobrachium ohione (Decapoda: Palaemonidae) in a distributary of the Mississippi River in Louisiana, U.S.A. 2. Newly hatched (stage-1) larvae are nonfeeding and will not moult to stage 2 (first feeding stage) without encountering salt water. A factorial experiment was conducted in the laboratory to test the effects on moulting to stage 2 of (i) time spent by stage-1 larvae in fresh water before (ii) exposure to and maintenance in water of different salinity. Larvae kept in fresh water for 1 or 3 days before a change to saline water at 6 or 10 ppt showed a greater frequency of moulting than those kept for longer (5 days) in fresh water or changed to less saline water (2 ppt). Non-moulting larvae died or were moribund within 11 days of hatching. 3. The relative abundance of stage-1 larvae was measured with plankton tows at two locations in the river c. 150 km apart, one near the sea and one upstream. Larval abundances near the sea were significantly greater than those upstream. 4. The results indicate that hatched larvae of M. ohione have a limited period in which to drift in fresh water before reaching water sufficiently saline to stimulate moulting to the first feeding stage. Female migrations may play an important role in delivering larvae of amphidromous species from large continental river systems in which distances to the sea are great, while larval drift alone may be sufficient in species living in short streams, like those found in many small mountainous tropical islands.