The Research On Swimming Ability And Dynamics Of Typical Cage Aquaculture Fish

In this paper,the swimming ability and its kinetics of Larimichthys crocea,Sciaenops ocellatus and Sparus macrocephalus were studied.The research measured the endurance swimming ability and the critical swimming speed of Larimichthys crocea and juvenile fish,Sciaenops ocellatus and Sparus macrocephalus,respectively.The research also measured the impact of different temperatures on the swimming time of these three species of fish.Finally,the hydrodynamic characteristics of them were studied.The main results are as follows.In 45 cm/s flow velocity,the average endurance swimming time of juvenile Larimichthys crocea was only 12 min,while the time was 142 minutes and 30 seconds in 30 cm/s flow velocity.For 1-year-old Larimichthys crocea,the average endurance swimming time was 22 min in 60 cm/s flow velocity,and the time was 401 min in 45 cm/s flow velocity.The average critical swimming speed of juvenile Larimichthys crocea was 39.85 cm/s,and the critical swimming speed of 1-year-old Larimichthys crocea was 50.02 cm/s.The endurance swimming ability of Sparus macrocephalus was worse than that of Larimichthys crocea.Under the flow velocity of 0.8m/s,the average duration of swimming of the five test fish was only about 92 min.The endurance swimming time and the flow velocity of Sparus macrocephalus had a decreasing power function.The following formula was fitted by power function..The average critical swimming speed of Sparus macrocephalus was 44.51 m/s,which was smaller than that of Sciaenops ocellatus and Larimichthys crocea.Sciaenops ocellatus have a strong swimming ability.Even if the flow velocity was 1.0 m/s,the average endurance swimming time of Sciaenops ocellatus could reach to about 120 mins(2 hs).The average endurance swimming time and the flow velocity of Sciaenops ocellatus showed a decreasing power function,R2=0.944.The fitting formula was.The average critical swimming speed of Sciaenops ocellatus was also fast and it was 101.07 cm/s.The water temperature had a significant effect on the endurance swimming time of Sciaenops ocellatus.At 8oC,The endurance swimming time was only 43 mins,and at 18oC,the time increased to 108 mins.Then with the temperature increased,the time decreased.when the water temperature reached to26oC,the endurance swimming time of Sciaenops ocellatus was about half of the time at 18oC.In the similar conditions,Black seabream(Sparus macrocephalus)have larger cross-sections than Red Drum and Large yellow croaker,but the water resistance coefficient of the threes are not much difference between them.Therefore,from the dynamic point of view,in the process of swimming,the same weight to black porgy has a greater high water resistance than Sciaenops ocellatus and large yellow croaker,consume more energy.