The Effect Of Exercise Training On Swimming Ability And Behavior Of Grass Carp

At present,ecological priority is the general trend,and the construction of ecological channel is the main trend of channel development in the future.However,the contradiction between channel regulation and fish habitat protection is becoming increasingly prominent.In order to strengthen the protection of the aquatic ecology of the Changjiang River,it is proposed to reconstruct and repair the fish habitat in the project section.There are some differences between the swimming ability of wild fish and cultured fish in the Changjiang River.In order to make the swimming ability of fish adapt to the habitat,this paper carried out the research on the swimming ability and behavior of fish by exercise training.In this paper,three groups of grass carp with L1(10-13cm),L2(13-16cm)and L3(16-20cm)body length were selected as the experimental objects.Through three weeks of exercise training in 0.05-0.7m/s water environment,based on a series of flume experiments,the critical swimming speed and preferred swimming speed were determined.In this paper,we compared and analyzed the critical swimming speed,preferred swimming speed and rheotaxis between the untrained group and the training group.The conclusions are as follows :(1)In this paper,the relationship between critical swimming speed and body length of Grass carp in the range of 10-20 cm body length was fitted.It was found that the body length of L1(10-13cm),L2(13-16cm)and L3(16-20cm)decreased by 24.5%,23.7% and 22.4%,26.3%,23.6% and 21.6% respectively.The results showed that the critical swimming speed of grass carp was decreased by exercise training,but the linear relationship between critical swimming speed and body length was not changed by sports training.The absolute critical swimming speed increased with the increase of body length,while the relative swimming speed decreased with the decrease of body length.(2)The results show that the preferred swimming speeds of L1(10-13cm),L2(13-16cm)and L2(16-20cm)in untrained group are 0.25-0.32m/s,<0.32m/s,<0.25m/s,respectively.The preferred swimming speeds of training group are 0.25-0.32m/s,<0.25m/s,<0.25m/s,respectively.The preferred swimming speeds of untrained group increase by 16.4%,30.9% and 41.7% within the flow velocity range of< 0.25m/s in 24 h,while those of training group increase by 27.9%,49.9% and 41.7%respectively 54.4%。The results show that the preferred swimming speeds of L1(10-13cm),L2(13-16cm)and L2(16-20cm)in untrained group are 0.25-0.32m/s,<0.32m/s,<0.25m/s,respectively.The preferred swimming speeds of training group are 0.25-0.32m/s,<0.25m/s,<0.25m/s,respectively.The preferred swimming speeds of untrained group increase by 16.4%,30.9% and 41.7% within the flow velocity range of< 0.25m/s in 24 h,while those of training group increase by 27.9%,49.9% and 41.7%respectively 54.4% 。 The results showed that the exercise training reduced the swimming speed of L2(13-16cm),but increased the speed of Grasscarp’s transfer to low velocity and the preference for low velocity in the range of 10-20 cm,and did not change the tendency of Grasscarp swimming speed with the increase of body length.(3)Through the analysis of the video,it is found that exercise training can enhance the flow rate of grass carp,increase the number of recoil and the proportion of static countercurrent at high flow rate,and reduce the frequency of tail swinging and the flow rate of motion path selection.The results show that the grass carp is more sensitive to the change of flow velocity,and will adjust the flow behavior according to the different water flow,and prefer to move in the path of low flow velocity and stay in the environment of low flow velocity,which can resist the impact of water flow with lower energy consumption.(4)Through the analysis,the results show that there are differences in swimming ability between trained and untrained Grass carp.The results show that the swimming ability of Grass carp will be affected by the water velocity of different living environment,and the swimming ability of wild fish in Changjiang River is also different from that of fish in still water,which can provide reference value for other researchers in the research on the adaptability of fish swimming ability and habitat.(5)This paper puts forward that Grass carp is more sensitive to flow velocity through exercise training,can avoid high flow velocity and swim with low energy consumption,which is helpful to improve survival rate when releasing in the field,and puts forward the relationship between critical swimming speed,preferred swimming speed and body length of grass carp,which provides powerful data support for fish habitat construction and restoration,and provides feasibility for ecological channel construction.