Research On Swimming Ability Of Takifugu Rubripes

Takifugu rubripes with its unique economic and scientific value and increasingly concerned about people,has become one of the characteristics of Chinese aquaculture varieties,is an important export of economic fish.Although the coastal areas of the Takifugu farming scale continue to expand the low survival rate is still difficult.The level of swimming ability is an important indicator of the health of fish.Therefore,this study studied the effects of temperature,salinity,body length and starvation on the critical velocity of Takifugurubripes,swimming time and the impact of the burst speed,aimed at the puffer swimming ability research and farming to provide scientific basis for the data and reference materials.Main research results:(1)The absolute critical velocity of the puffer is 25.36 ± 1.02 ~ 46.11 ± 1.81 cm s-1 at each temperature(15 ?,21 ?,25 ?,30 ?).When the water temperature is between 15 ? and 30 ?,the absolute critical velocity increases with the increase of temperature,and the absolute critical velocity(Ucrit,cm s-1)and the temperature(t,?)The relationship can be fitted with a second polynomial of Ucrit =-0.032t2 + 2.3434 t + 4.4949,R2 = 0.9974(P <0.01).(2)The absolute critical velocity of puffer was 8.85 ± 1.41 ~ 39.79 ± 1.72 cm s-1,and the relative critical velocity was 8.70 ± 0.42 ~ 6.94 ± 0.26 BL s-1.When the body length is in the range of 3cm ~ 6cm,the absolute critical velocity increases with the increase of body length,while the relative critical velocity tends to decrease gradually with the increase of body length.The relationship between body length(L,cm)and absolute critical velocity(Ucrit,cm s-1)can be fitted with a quadratic polynomial of Ucrit =-0.6988L2 + 11.103L-5.4118 R2 = 0.9898,body length(L(Ucrit ',BL s-1)can be fitted with a quadratic polynomial of Ucrit' = 0.0238L2-0.7488 L + 9.6786,R2 = 0.9942(P <0.01).(3)The absolute critical velocities of the red puffer were 38.16 ± 1.24,38.17 ± 1.89,37.72 ± 0.73 and 37.24 ± 2.04 cm s-1,respectively,for each salinity group(5 ‰,10 ‰,20 ‰,32 ‰ and 40 ‰)the absolute critical velocity of puffer is not significantly changed with salinity.(4)The absolute critical velocity of the puffer was 95.24 ± 2.04 ~ 27.67 ± 1.24 cm s-1 after starvation(1,3,6,and 9)days.The relationship between the number of hunger days(d,d)and the critical velocity(Ucrit,cm s-1)can be fitted with a quadratic polynomial of Ucrit =-0.0292d2-0.23 d + 31.85,R2 = 0.8053(P <0.01).(5)The swimming time of the puffer at the flow rate of 34.61 cm s-1 was 4.12 ± 1.77 ~ 19 ± 23.72 min in the temperature range(15 ?,20 ?,25 ?).The relationship between the temperature(T,?)and the swimming time(t,min)can be fitted with the quadratic polynomial of t =-0.1567T2 + 7.8033 T-77.6,R2 = 1(P> 0.05).The swimming time of the flow rate is increasing with the temperature increasing.(6)The swimming time of the puffer at the flow rate of 34.61 cm s-1 was 42 ± 25.46,29.17 ± 26.50 and 19 ± 23.72,respectively,in the salinity range of 10 cm,20 ‰,32 ‰ and 40 ‰.,51.50 ± 17.25 min.The swimming time of the flow rate did not change with the salinity.(7)The burst speed of puffer was 1.3 ± 0.2 ~ 2.93 ± 0.23 m s-1 in the range of 6cm body length(15 ?,20 ?,30 ?).The relationship between the temperature(T,?)and the burst speed(Uburst / m s-1)can be fitted with the quadratic polynomial for Uburst =-0.0082T2 + 0.4882T-4.3213,R2 = 1,(P <0.01).(8)The burst speed of puffer in the body length range of(3cm,4cm,5cm,and 6cm)is 1.6 ± 0.1 ~ 3.05 ± 0.41 m s-1.The relationship between body length(L,cm)and outbreak velocity(Uburst / m s-1)can be expressed by quadratic polynomial as Uburst =-0.0764L2 + 1.1751L-1.2424,R2 = 0.9992(P <0.01).(9)The burst speed of the puffer at the salinity range of 5 ‰,10‰,20 ‰,32 ‰ and 40 ‰ was 2.30 ± 0.40,2.64 ± 0.19,2.32 ± 0.41,3.05 ± 0.42,2.65 ± 0.37 m s-1..Burst speed did not change with the salinity.Research indicates:(1)In the case of the same environmental conditions,the temperature and body length are positively correlated with the swimming ability of Takifugu rubripes.(2)The change of acute salinity has no significant effect on the swimming ability of Takifugu rubripes.(3)Hunger will seriously reduce the critical swimming speed of Takifugu rubripes.