| 要旨トップ | 目次 | 日本生態学会第68回全国大会 (2021年3月、岡山) 講演要旨
ESJ68 Abstract


一般講演(ポスター発表) P2-248  (Poster presentation)

淡水性二枚貝カワシンジュガイの再生産規定要因の解明―宿主の生息環境にも着目して―
Factors affecting recruitment failure of freshwater mussel (Margaritifera laevis): Gaps of habitat preference between juvenile mussel and host fish

*川尻啓太(北海道大学), 石山信雄(北海道立総合研究機構), 三浦一輝(斜里町立知床博物館), 照井慧(ノースカロライナ大学), 末吉正尚(土研・自然共生研究セ), 中村太士(北海道大学)
*Keita KAWAJIRI(Hokkaido Univ.), Nobuo ISHIYAMA(Hokkaido Research Organization), Kazuki MIURA(Shiretoko Museum), Akira TERUI(UNC Greensboro), Masanao SUEYOSHI(ARRC), Futoshi NAKAMURA(Hokkaido Univ.)

 Freshwater mussels, Unionoida, are endangered across the globe due to recruitment failures. In the present study, we investigated the relative effects of biotic (host fish density) and abiotic factors (water depth, fine sediment, water temperature, water quality) on the recruitment success of Margaritifera laevis in Hokkaido, northern Japan. We additionally examined factors regulating the density of host fish, Oncorhynchus masou masou. Statistical analysis revealed that the proportion of juvenile mussels had a unimodal relationship with the host fish density, which was the most influential factor among candidate variables. The positive effects of host fish may be attributable to the increased infection rate. One possible reason for the negative correlation at high density is the reduction of larval growth associated with the low host fish's body condition. We also found that the host fish density was negatively affected by nutrient enrichment, which was caused by farmland expansion. Our results suggest that mitigations of water quality degradation should be preferentially conducted to recover the host fish density and improve mussel recruitment. While fish stocking is widely used to enhance salmon production, conservation practitioners should be aware that excessive host densities can potentially disturb mussel recruitment.


日本生態学会