Spawning, fertilization, and larval development of Potamocorbula amurensis (Mollusca: Bivalvia) from San Francisco Bay, California
Spawning, fertilization, and larval development of Potamocorbula amurensis (Mollusca: Bivalvia) from San Francisco Bay, California
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发表时间：
2000-10
期刊：
影响因子：
0.7
通讯作者：
M. Nicolini;D. L. Penry
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作者：
M. Nicolini;D. L. Penry
在 15°C 下，山眼子发育到直铰幼虫阶段的时间为 48 小时。受精后 17 至 19 天，山菝葜的壳长约为 135 J1m。我们对山梨幼虫发育时间的观察支持了早期研究人员的假设，即其最初引入旧金山湾的路线是通过跨太平洋货船在压载水中运输的ve1iger幼虫。山葡萄幼虫期相对于旧金山湾水团停留时间的长度表明，足以允许从北湾到南湾种群的大量扩散，这与之前的观察结果一致，即旧金山湾山葡萄种群之间的遗传分化较低。山菝葜在各个发育阶段都具有明显的广盐性。产卵和受精可以在5至25 psu的盐度下发生，并且卵子和精子各自可以耐受盐度至少10-psu的增加或减少。 2 小时龄的胚胎可以耐受 10 至 30 psu 的盐度，到 24 小时龄时，它们可以耐受与成年蛤相同的盐度范围（2 至 30 psu）。山毛榉幼虫能够耐受盐度大幅变化的能力表明，它们在不完全的海洋压载水交换以及随后排放到各种盐度的接收水域中生存的强大潜力。 Potamocorbula amurensis (Schrenck, 1867) 于 1986 年首次从东亚河口引入旧金山湾，其数量在海湾所有地区急剧增加 (Carlton et al. 1990)。它已经取代了以前的底栖群落的一些成员（Nichols 等人，1990 年），现在是海湾某些地区的主要组成部分（Nichols 等人，1990 年；Alpine 和 Cloern，1992 年）。旧金山湾内山葡萄的高种群密度、个体和种群的快速增长率及其利用变异的推断能力1 这项工作得到了美国国家科学基金会授予 D. Penry 的 Alan T. Waterman 奖的支持。稿件于 2000 年 1 月 28 日接受。 2加州大学伯克利分校综合生物学系，加利福尼亚州 94720-3140（电话：510643-5915；传真：510-643-6264；电子邮件：dpenry@socrates.berkeley.edu）。 3当前地址：美国地质调查局，Placer Hall, 6000 J Street, Sacramento, California 98519。丰富的食物资源（例如浮游植物、细菌、碎屑、幼虫）（Alpine 和 Cloern 1992、Werner 和 Hollibaugh 1993、Kimmerer 等人 1994）表明它已成为碳中重要的消费成分和营养循环 湾（Hollibaugh 和 Werner 1991）。因此，了解山龙的生活史对于了解旧金山湾种群的生态至关重要。大多数对旧金山湾山鼠尾草的研究都集中在成虫身上。实地研究表明，一些山鼠种群全年产卵，新定居的蛤在几个月内即可繁殖（Parchaso 1995），但除此之外，关于旧金山湾山鼠早期生活史阶段的繁殖、发育或生存的信息很少。我们在实验室中诱导山葡萄产卵，并在此描述了从受精到定居的发育过程。
In Potamocorbula amurensis time for development to the straight-hinge larval stage is 48 hr at 15°C. Potamocorbula amurensis settles at a shell length of approximately 135 J1m 17 to 19 days after fertilization. Our observations of timing of larval development in P. amurensis support the hypothesis of earlier workers that its route of initial introduction to San Francisco Bay was as ve1iger larvae transported in ballast water by trans-Pacific cargo ships. The length of the larval period of P. amurensis relative to water mass residence times in San Francisco Bay suggests that it is sufficient to allow substantial dispersal from North Bay to South Bay populations in concordance with previous observations that genetic differentiation among populations of P. amurensis in San Francisco Bay is low. Potamocorbula amurensis is markedly euryhaline at all stages of development. Spawning and fertilization can occur at salinities from 5 to 25 psu, and eggs and sperm can each tolerate at least a lO-psu step increase or decrease in salinity. Embyros that are 2 hr old can tolerate salinities from 10 to 30 psu, and by the time they are 24 hr old they can tolerate the same range of salinities (2 to 30 psu) that adult clams can. The ability of P. amurensis larvae to tolerate substantial step changes in salinity suggests a strong potential to survive incomplete oceanic exchanges of ballast water and subsequent discharge into receiving waters across a broad range of salinities. Potamocorbula amurensis (Schrenck, 1867) was first introduced to San Francisco Bay in 1986 from estuaries in eastern Asia, and its numbers have increased dramatically in all regions of the bay (Carlton et al. 1990). It has displaced some members of the previous benthic community (Nichols et al. 1990) and is now a dominant component in some areas of the bay (Nichols et al. 1990, Alpine and Cloern 1992). The high population densities and rapid individual and population growth rates of P. amurensis within San Francisco Bay and its inferred ability to exploit a vari1 This work was supported by the Alan T. Waterman Award from the National Science Foundation to D. Penry. Manuscript accepted 28 January 2000. 2Departrnent of Integrative Biology, University of California, Berkeley, California 94720-3140 (phone: 510643-5915; fax: 510-643-6264; E-mail: dpenry@socrates. berkeley.edu). 3Current address: U.S. Geological Survey, Placer Hall, 6000 J Street, Sacramento, California 98519. ety of food resources (e.g., phytoplankton, bacteria, detritus, larvae) (Alpine and Cloern 1992, Werner and Hollibaugh 1993, Kimmerer et al. 1994) suggest that it has become an important consumer component in carbon and nutrient cycling in the bay (Hollibaugh and Werner 1991). Understanding the life history of P. amurensis is therefore central to understanding the ecology of populations in San Francisco Bay. Most research on P. amurensis in San Francisco Bay has focused on adults. Field studies indicate that some populations of P. amurensis spawn throughout the year and that newly settled clams become reproductive within a few months (Parchaso 1995), but beyond that there is little information on reproduction, development, or survival of early life history stages of P. amurensis in San Francisco Bay. We have induced P. amurensis to spawn in the laboratory and here describe development from fertilization through settlement.