Impacts of invasive crayfish (Pacifastacus leniusculus) on endangered freshwater pearl mussels (Margaritifera laevis and M. togakushiensis) in Japan
Impacts of invasive crayfish (Pacifastacus leniusculus) on endangered freshwater pearl mussels (Margaritifera laevis and M. togakushiensis) in Japan
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DOI：
10.1007/s10750-013-1665-8
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发表时间：
2013-12-01
期刊：
影响因子：
2.6
通讯作者：
Akiyama, Yoshihiro B.
中科院分区：
文献类型：
--
作者：
Machida, Yoshiyasu;Akiyama, Yoshihiro B.
外来入侵小龙虾 Pacifastacus leniusculus 被认为对淡水珍珠贻贝 Margaritifera laevis 和 M. togakushiensis 有害。它也经常在日本的贻贝栖息地定居。为了测试外来小龙虾对贻贝的负面影响，我们在体外评估了信号小龙虾对淡水珍珠贻贝的捕食影响。我们针对不同尺寸的贻贝（根据壳长分为四类：10、30、50 和 70 毫米）测试了贻贝的成活/受伤率与小龙虾捕食之间的关系。小龙虾在破壳后选择性地以 10 毫米级贻贝的肉为食。所有大小级别的贻贝的壳边缘都会被小龙虾损伤。结果还表明，小龙虾对 50 毫米规格的贻贝伤害尤为严重。这一观察结果可归因于该贻贝尺寸是小龙虾可以有效容纳的最合适的贝壳尺寸（甲壳长度为 29.56-37.73 毫米）。这项研究表明，入侵小龙虾的存在会破坏贝壳边缘和/或杀死贻贝，从而减少淡水珍珠贻贝的数量。入侵小龙虾的负面影响不仅减少了贻贝数量，还可能限制贻贝的补充、生长和繁殖。
The invasive alien crayfish Pacifastacus leniusculus is considered harmful to freshwater pearl mussels Margaritifera laevis and M. togakushiensis. It also often colonises mussel habitats in Japan. In order to test the negative effects of alien crayfish on mussels, we evaluated the predation impact of signal crayfish on freshwater pearl mussels in vitro. We tested the relationship between the survival/injury rates of mussels and crayfish predation with respect to different sizes of mussels (four classes based on shell length: 10, 30, 50 and 70 mm). Crayfish selectively fed on the flesh of the 10-mm size class mussels after breaking their shells. The shell margins of mussels in all size classes were injured by crayfish. Results also showed that crayfish particularly injured the 50-mm size class of mussels. This observation could be attributed to this mussel size being the most suitable shell size (29.56-37.73 mm in carapace length) that the crayfish can effectively hold. This study shows that the presence of invasive crayfish reduces freshwater pearl mussel populations by damaging the shell margins and/or killing the mussels. This negative impact of invasive crayfish not only decreases the mussel population but could also limit mussel recruitment, growth and reproduction.