Abstract: Darkbarbel catfish (Peletobagrus vachelli) is one of the major predatory fishes feeding on the eggs of Chinese sturgeon. In this paper, the wild darkbarbel catfish population (body length 14.34±5.16 cm, body mass 61.29±23.62 g) was collected from the lower reaches of Gezhouba  Dam, and a laboratory experiment was conducted to study the feeding preference, locomotion, and feeding circadian rhythm of the population under the conditions of natural day/night rhythm and water temperature 20.6 ± 0.5 ℃ and with the baits of earthworm (Pheretima sp.), commercial pellet, dried tofu, fish (Pseudorasbora parva), shrimp (Macrobranchium nipponense), and sweet potato, aimed to search for the countermeasures to reduce the predation of darkbarbel catfish on the eggs of Chinese sturgeon. No significant differences were observed in the percentages of the preference to the six kinds of baits, but the feeding rate of darkbarbel catfish on earthworm, fish, and shrimp was significantly higher than that on tofu, sweet potato, and commercial pellet. Under no bait addition, the locomotion level of the darkbarbel catfish could be defined as active period (18:00-22:00), subactive period (22:00-7:00), and non-active period (7:00-18:00), with significant differences among the three periods. Under bait addition, the locomotion level of the darkbarbel catfish could be defined as activity period (18:00-5:00) and non-activity period (5:00-18:00), with significant differences between the two periods. The feeding activity level of the darkbarbel catfish was classified into feeding period (17:00-5:00) and non-feeding period (5:00-17:00), with significant differences between the two periods. It was concluded that darkbarbel catfish preferred to feed earthworm, fish, and shrimp, and the locomotion and feeding rhythms of the darkbarbel catfish were of nocturnal, with the locomotion level disturbed by baits.

Key words: canopy height, instantaneous water use efficiency, short-term water use efficiency.,  , Platycladus orientalis forest