1. Dept. of Civil and Environmental Engineering, Tohoku Univ., 6-6-06 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579, Japan.
2. Dept. of Fisheries and Wildlife, 303 Manly Miles, Michigan State Univ., East Lansing, MI 48824 (corresponding author).
3. Dept. of Fisheries and Wildlife, 13 Natural Resources, Michigan State Univ., East Lansing, MI 48824.