EFFECTS OF FLOW RATE ON SWIMMING STATES AND ACTIVITY METABOLISM IN JUVENILE HYBRID STURGEON

In order to study the effects of flow rate on swimming performance and activity metabolism, discuss the relationshipbetween swimming states, rheotaxis frequency, tail beating frequency and oxygen consumption rate, the effectsof different flow rates (0.0, 0.1, 0.3, and 0.5 m/s) on swimming states and in juvenile hybrid sturgeon (Huso duricusGeorgi♂×Acipenser schrencki Brandt♀), weight of (56.10±4.95) g and body length of (21.08±0.27) cm, were studied.The experimental temperature was 26℃ and the instrument for measuring swimming behavior and activity metabolismwas used. The results showed that swimming states of juvenile hybrid sturgeon were apparently affected by flow rate.With increasing water velocity, the proportion of behavior of swimming forward or keeping stable decreased. Whiletime proportion of behavior of moving backward or swimming downstream increased. Rheotaxis frequency, tail beatingfrequency and oxygen consumption rate of juvenile hybrid sturgeon, peaking at 100%, (2.53±0.34) Hz and(490.99±164.59) mg O2/(kg·h) of each sampling time, at the flow rate of 0.3 m/s were higher than those at the flow rateof 0.0 m/s. Compared to the parameters at the flow rate of 0.3 m/s, though rheotaxis frequency of fish kept stable by100% at the flow rate of 0.5 m/s, oxygen consumption rate was increased by 21.86%, while tail beating frequency wasdecreased by 6.7%. There were linear correlations between tail beating frequency and rheotaxis frequency, while therewas no correlation between tail beat frequency and oxygen consumption rate. Rheotaxis frequency, tail beating frequencyand oxygen consumption rate exhibited different trends with the experimental time. Rheotaxis frequency keptstable, while tail beating frequency decreased with the experimental time. Oxygen consumption rate increased and themaximum appeared in the 9h, then the index decreased and maintained stable. The results showed that swimming stateof juvenile Hybrid sturgeon was apparently affected by flow rate, while the relations between tail beat frequency whichreflects exercise intensity and oxygen consumption rate were influenced by swimming states, meanwhile it also relatedto the time changes of the characteristic of exercise metabolism.