Author(s): Taiki Hotta; Yuichi Kayaba
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Keywords: No Keywords
Abstract: Excessive addition of sediments from dams to the downstream river might affect the habitat of riverine organisms. In this study, a selection experiment was conducted on a grazing fish, the ayu. Preference of the fish for different exposure heights -- 2,5, and 10 cm -- of stones as a feeding habitat was examined in a large experimental flume. The ayus fed on the algae attached to the stones of exposure height 5 and 10 cm more frequently than on the stones of height 2 cm. Furthermore, the fishes left longer bite marks on the stones of height 5 and 10 cm than that on the stones of height 2 cm. These results suggest that the ayus prefer the stones of exposure height not less than 5 cm to feed on the algae more efficiently.
Year: 2018