Comparison of Maximum Swimming Speed and Critical Swimming Speed Between Yellow Catfish and Crucian Carp in Yuanshui River
In order to analyze the ecological adaptability of flowtaxis characteristics of fish and provide basic data for the conservation of fishery resources in the waters in the Dongting River system,the critical swimming speed(Ucrit)and maximum swimming speed(Umax)were determined in yellow catfish Pelteobagrus nitidus with body length of(13.94±1.85)cm and crucian carp Carassius auratus of(12.28±1.42)cm in a self-made fish movement test tank by increasing flow-velocity method by an external frequency converter adjusting the motor power and changing the speed of the propeller with different flow velocities and the relationships between Ucrit,and Umax and body length of the two fishes were analyzed at water temperature of(20.0±1.5)℃ and room photoperiod.The maximum swimming speed(Umax,cm·s-1)and the relative maximum swimming speed(Umaxr)[(=Umax/BL(body length),BL·s-1)]was measured when the initial flow-velocity of 1 BL/s in the experiment was increased by 2 cm·s-1 every 15 s until the fish become tired and stopped swimming at the barrage for 20 s.The critical swimming speed(Ucrit)is defined as the fact that the flow velocity as slowly increased to 60％Ucrit,and after the test fish continued to swim for 15 min,the Ucrit was increased by 15％,and then continued to increase the flow velocity in this way until the test fish became exhaustion without longer swim again.Record the motor frequency at this time and move the test fish out of the observation area and put it into the rest area,record the morphological parameters of the test fish and the swimming time before the exhaustion,and calculate the critical swimming speed Ucrit and the relative critical swimming speed(Ucritr,BL·s-1).The results showed that the yellow catfish had the absolute Ucrit of(39.21±3.41)cm·s-1 and the relative Ucrit of(2.83±0.15)BL·s-1.Their absolute Umax and relative Umax were(28.96±3.44)cm·s-1 and(2.08±0.04)BL·s-1,respectively.Crucian carp had the absolute Ucrit of(40.78±2.15)cm·s1,the relative Ucrit of(3.34±0.23)BL·s-1,absolute Umax of(39.67±3.14)cm·s-1 and relative Umax of(3.24±0.14)BL s-1,According to the results,the linear and nonlinear models between Uit,and Umax and body length were significantly correlated(P＜0.05).The paired T test showed that there were very significantly higher Umaxr and Ucritr in crucian carp than those in the yellow catfish(P＜0.01),without significantly different in Ucrit(P＞0.05).These findings provide corresponding support for understanding of the physiological and ecological adaptation mechanism of different fishes and for the design of fish passing facilities.
万方数据
维普
