Study On The Upward Behavioral Characteristics Of Juvenile Silver Carp In Vertical Slot Fishway

As an important part of aquatic biological organisms,fish occupy an important position in river ecosystems.In order to make up for the impact of water conservancy facilities on fish spawning,fishway came into being.Through reasonable fishway design,the ecological physiology of the fish target can be clearly defined,which can help the fish to track fisheries successfully and be conducive to the restoration of a good state of the river’s ecological environment.It is important for the conservation of biodiversity and the diversity of ecosystems.On the basis of reading a large amount of literature,this study summarized domestic and foreign scholars’related fishway research and construction experience and relevant fish behaviorstudy,explored the kinetic energy metabolism process of Juvenile Silver Carp in laboratory conditions.A physical model test and a numerical simulation method were combined to analyze the hydraulic characteristics under the vertical slot fishway,and the relationship between the swimming behavior and the hydraulic characteristics of the target fish in the fishway was investigated.The main work of the study was as follows:1)The behavioral characteristics of Juvenile Silver Carp during exercise were studied through a flume experiment.Combined with the changes in energy metabolism during exercise,the oxygen consumption rate and the fish tail frequency under forced conditions were fitted equation:MO₂=318.3+1.04TBF^2.87（R²=0.99）,Oxygen consumption rate increases with the TBF.The fitting equation obtained oxygen consumption rate（TBF=0）under relatively stationary conditions is 318.3 mg O₂ kg^-1h^-1,which is similar to the measured standard metabolic rate（284.47±30.75）mg O₂ kg-¹h^-1 under the experimental conditions.Under the conditions of spontaneous movement,the TBF and the rate of the oxygen consumption rate change over time have a periodic trend,but the overall exercise capacity has decreased slightly with time.2)Based on the data of body weight and swimming speed of Juvenile Silver Carp under experimental conditions,the bioenergy model of Juvenile Silver Carp was deduced by AMR=10.39M^0.12U^0.39（R²=0.95,P<0.001）.In actual projects,depending on the target of the fish,it is often necessary to match the design of different hydraulic parameters.Through the establishment of the interspecies biological energy model,it is possible to provide the metabolic data of different fish targets for the engineering design.3)A fish test was conducted on 90 Juvenile Silver Carp in the vertical slot fishway model.The experimental results showed that the flow rate of Q=0.45 m³/s was greater than that of other operating conditions,and the flow disturbance was also relatively high.At the same time,it was found that the fish body would show certain prevailing behavior during the retrogression process.In order to better realize the fish pass fish efficiency,an additional bunker or water supplement hole may be added at the position of the inlet of the vertical joint fish pass to enhance energy dissipation.4)In the present study,the limit of exercise capacity of Juvenile Silver Carp was actually in the range of cross-sectional average flow velocity values of 0.28-0.35m/s.When the flow rate in fish passes exceeds this range,the fish body adjusts the migration path by tking a rest area to the fish pond.Spearman’s correlation analysis was used to study the correlation between migrating time and hydraulic factors of carp.Under the three conditions,the time of retrogression and the flow rate of carp were correlated（p<0.001）,in which q=0.3m³/s.In the situation,the correlation coefficient R has the largest value.Compared with the flow rate,the turbulent energy had a more significant effect on the fish’s retrogression time,and the R values were all greater than 0.7,indicating that the turbulent kinetic energy in the hydraulic factors had a more direct effect on the fish movement behavior in fish tracing.5)Using flow-3d numerical simulation software to simulate the internal hydraulic characteristics of vertical slot fishway,finding that lower layers of water provides a better condition for fish tracing back.According to the hydraulic characteristics of the fishway simulation,with reference to other theoretical studies,two feasible upward paths of A and B are given,along with the resistance and energy consumption,and the migration process along the route is discussed.The calculation results show that the A-path can provide better hydraulic conditions for the migration of Juvenile Silver Carp compared with the B-path,and benefit the migration of juvenile juveniles.