外来種アメリカザリガニの駆除に用いるペットボトル製トラップの検討

抄録

To examine the effectiveness of different colored bottle traps for capturing an invasive crayfish Procambarus clarkii introduced from North America, we conducted two experiments (Experiments 1 and 2) in two ponds (the Onibasu and Raku-u-sho) in the Handayama Botanical Garden, Okayama, Japan. A set of traps consisted of three different colored bottles (black, white, and transparent). In Experiment 1, we compared the numbers of crayfish captured in different colored bottles; we set the three colored bottle traps with artificial bait at 10 stations in the Onibasu pond in the late afternoon and retrieved them early the following morning. In Experiment 2, we examined the difference in the numbers of crayfish captured during the day and at night; we set the same three colored bottle traps at 10 stations in the Raku-u-sho pond during the daytime and at nighttime and retrieved them in the late afternoon and early the following morning, respectively. In Experiment 1, there were multiple individuals in all of the traps, indicating that the plastic bottles were effective in capturing P. clarkii. The number of P. clarkii captured was significantly higher in the white and transparent traps than in the black traps. In Experiment 2, significantly more P. clarkii were captured at nighttime than during the day. The number of P. clarkii captured was not significantly different between the three colored bottles during the daytime. However, compared to the black traps, the white traps were significantly more effective in catching P. clarkii, but the effectiveness of the transparent traps was not significantly different from that of the black and white traps. Our results indicate that white or transparent plastic bottle traps were the most effective, especially at nighttime, for capturing invasive P. clarkii.