報告書番号

V08042

タイトル（和文）

飼育実験によるカワヒバリガイの生存可能水温の解明

タイトル（英文）

Study of water temperature effect on survival of golden mussel (Lymnoperna fortunei) under rearing experiment

概要 （図表や脚注は「報告書全文」に掲載しております）

飼育実験により，カワヒバリガイの水温に対する生残率の変化を確かめた。その結果，5℃～35℃の範囲では，20日間の短期的な温度影響は受け難いが，長期になると高温（35℃）において生残率が低下することが明らかになった。さらに，300日を越える長期の低温に曝露した場合，生存率が50％に低下したが，その後の昇温を経験しても32％の個体が生残した。以上のことから，カワヒバリガイの生存可能水温は5～30℃であり，長期低水温とその後の急激な昇温に対する耐性も有することが明らかになった。

概要 （英文）

Golden mussel (Lymnoperna fortunei) is one of the most problematic invasive species in the freshwater intake system in Japan. There is little information on the temperature adaptability or tolerance of this species, except for the field observation data. In this study, we initially developed techniques to grow the mussel under laboratory conditions including available food organisms, and then examined the effect of temperature on the survival. The mussel was able to take the freshwater diatom (Cyclotella sp.) and the green algae (Chlorella sp.) as food, however, the former is considered to be more appropriate based on the survival rate, the growth of shell length, and carbon stable isotope ratio of the tissue. Survival rate was independent on the temperature range from 5 to 30degree C, and was much lower at 35degree C in 114-day rearing experiment, although 5 to 35degree C did not affect the rate during initial 20 days. Half of mussel died after 309 days rearing at 5 C. Then the temperature was raised to 15degree C by 2degree C per day, and 32% of the mussel survived after 20 days rearing period at 15degree C. These results suggest that golden mussel can survive under wide range of temperature, and is able to inhabit in most lakes and ponds in Japan.

報告者

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