| Connectivity of rivers is generally blocked because of the construction of dams. Thelife histories of migratory and semi-migratory fish are greatly changed, which was not onlyleading to the decrease of fish populations, but also due to the extinction of fish stockssection. The plight which fish faced can be eased by reasonable and effective fishwaydesign at a certain extent. Fishway also provides an exchange of species swim up anddown the channel. However, different fish with different characteristics can cause theproper untilization of fishway. Therefore the study of different fish swimmingcharacteristics will only provide the data bases for the successful fishway design.In this paper, the studies about swimming characteristics of five carps were conductedby two patent equipments from our research group (ZL201020136105.7andZL201320093505.8). Hydraulic characteristics were simulated in three kinds of verticalslot fishway using Fluent6.3. The paper contains the followings.1. Swimming ability and metabolism of silver carp were studied at150C,180C,210C,250C. The results have indicated that critical swimming speed (U crit) was increasingalong with the temperature (T,0C). And fitting equation is: Ucrit3.0730.149T(R2=0.983, P <0.005). It is illustrated that the swimming ability of silver carp was enhancedwith the temperature rises. Four speeds index were:1.41,1.31,1.60,1.80, were decreasingas temperature increases, indicating that the higher the temperature, the lower the energyuse efficiency.2. Swimming abilities of grass carp and black carp were researched under the slope0o,3o,6orespectively. Both were decrease with the slope increasing. Comparing two kinds ofcarp, as the slope raised by the0°to6°, critical swimming speed of black carp wasreduced to86.55percent of original, where the grass carp only reduced to79.40%. Blackcarp has a relatively better resistance.3. Four kinds of different previous activities cost (0.6/0.8/1.0/1.2U crit, in1hour)were measured at the18±1oC. The critical swimming speed was7.11±0.6BL/s in thecontrol group.U critwere7.25±1.35,6.33±0.60,6.26±0.80and5.60±0.42BL/s,respectively, at four kinds of activity cost states. The speed exponent is1.44,1.46,1.49and1.51, indicating that the efficiency become lower with the growth of the velocity duringactivity cost period. It is suggested that the continued swimming was not harmful to fish swimming capability when the swimming speed was lower than0.8U crit.4. The critical swimming speed was tested after one hour swim at0.6Vk,Ucritwere:5.96±0.11,6.04±0.19,6.37±0.17,4.74±0.30BL/s, respectively. It is indicated thatthe velocity of this level will have no effect upon fish swimming ability.5. Swimming ability of rock carp was studied in this part. The routine oxygenconsumption (RMR) was352.30±41.65mg/(kg.h) and maximum oxygen consumption canreach560.24±20.84mg/(kg.h). The critical swimming speed was8.03±0.16BL/s, andexcessive exercise oxygen consumption was115.22mg/kg. It is also eximined the repectswimming performance of rock carp subjected to twoU critseparated by30min. Therecovery rate was0.89±0.03. Comparing the relation between twoU crittests, the oxygenconsumption ofU crit-2was higher thanU crit-1at high flow rates. Rock carp’s swimmingability adapts to their migratory characteristics.6. Hydraulic characteristics in three kinds of vertical slot fishway were simulated byFluent6.3. It is found that the vertical slot fishway from side to side has similar velocitydistribution as other fishways, but more abundant flow field was existed in opposite sidevertical slot fishway, which will be good for juvenile and weaker fish. From comparison,fish passes efficiently in of vertical slot from side to side will be the best in three kinds ofvertical slot.This investigation will contribute to the basic science of fish swimming behavior andprovid the data required for the design of fishways. The fishways depending on special fishcould bring a better passing rate. |
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