Environmental Characteristics Of High-saline Shrimp Culture Ponds And The Effects Of Temperature And Salinity On Shrimp Litopenaeus Vannamei

There are a large number of high-salt water bodies in China,which are widely distributed in 19 provinces,municipalities and autonomous regions in China.In recent years,in these waters,in addition to drying salt,extracting bromine,and performing Artemia fishing production,some high salt water bodies have also been utilized as culture of shrimp Litopenaeus vannameii.L.vannamei has become the main cultured species in China because of its advantages such as short culture cycle,wide adaptability,strong disease resistance,and could growth in both seawater and freshwater.Although there are study showing that the shrimp could grow faster under low-salinity conditions,the shrimp in high-salt condition has better taste and quality,etc.,which make L vannamei become a potential species for high-saline aquaculture.At present,the research on the effects of salinity on shrimps is more focused on the growth,survival,bait utilization,and enzyme activities in low-salt condition,and the research on the effect of high-salt condition on shrimp is limited.In particular,there is a lack of study on the characteristic of water quality and maricultural performance of shrimp L vannamei in large water body pond of high salinity.There are still many problem in the high-salt aquaculture of L.vannamei,which caused higher mortality rate,lower yield and unstable in the production.It is urgent to strengthen the research on the effects of high salt on L.vannamei and high-salt water culture technology.In this paper,the environmental characteristic of large water body pond of high salinity and the culture efficiency of shrimp were monitored.The effects of salinity and temperature on the physiology and ecological characteristics of L.vannamei were studied.The parameters of individual dynamic energy budget model were miasured.The main results were as follows1.The experiment was conducted in Binhai,Binzhou City,Shandong Province from April to July 2018.The water quality of large water body ponds and the growth and output benefits of L.vannamei under different salinity?30,45,55?conditions were monitored and analyzed.The results showed that:?1?the nutrient and COD concentrations of the ponds in the three salinity groups were within the national second-class water quality range;the chlorophyll a concentrations in the high-salinity group were significantly lower than those in the other groups?P<0.05?.?2?There were significant differences in body length and weight of shrimps in the three salinity groups?P<0.05?.Among them,the medium salt group was significantly higher than the low salt group?P<0.05?.The specific growth rates of shrimp body weight in the three salinity groups are 7.37?%/d?,7.77?%/d?,and 7.53?%/d?,respectively.The yield per mu and profit are both in the order:medium salt group>high salt Group>low salt group2.The influence of temperature and salinity on the oxygen consumption rate?RR?of shrimp L.vannamei were studied,the results showed:?1?Within the temperature range of 10??35?,RR increased with temperature increasing.The relationship of RR and temperature was as follows:RR=-0.023T²+0.2968T-0.1822?R²=0.9689?Temperature had an extremely significant effect on RR?ANOVA,P<0.01??2?The RR was linearly related to salinity?S?,and the relationship was as follows:RR=0.084S+0.2575?R²=0.8519?.The salinity 31,35 and 40 and salinity 55 were significantly different?P<0.01?3.The effects of salinity and Artemia concentration on the feeding rate of L vannamei were studied.The results showed:?1?The experimental concentration of Artemia was in the range of 62.5?312.5 ind./L.The highest feeding rate was happeded in the Artemia concentration of 250 ind./L.The relationship between feeding rate FR and Artemia Concentration?C?was as follows:FR=-0.5786C2+4.3014C+3.6?R²=0.6255?.?2?Under the range of salinity?35?60?,the feeding rate of L.vannamei to Artemia was in the range of 10.44?15.94 ind./?tail·h?.The relationship between the feeding rate FR and the salinity was:FR=-1.2344S2+4.5031S+12.422?R²=0.9426??3?The feeding rate has a significant relationship with the shrimp body length L?cm?:FR=0.5887L^1.8478?R²=0.9457?.4.The effect of salinity and microalgae concentration on Artemia feeding rate were studied.The results showed:?1?within the experimental concentration of microalgae?10³?10⁶ cell/ml?,the microalgael concentration had significant influence on the feeding rate of Artemia?P<0.05?,the relationship was inverted bell-shaped.The feeding rate got the peak value when the concentration was 10⁵ cell/ml.?2?in the range of 35?60,the feeding rate of Artemia ingestion of microalgae under different salinity conditions was significantly different?ANOVA,P<0.01?.5.Parameters of Dynamic Energy Budget model of L.vannamei were estimated.5 basic parameters,such as shape coefficient??m?,Arrhenius temperature?T_A?,Volume-specific maintenance costs per unit of time?[???_M]?,Volume-specific costs for growth[E_G]and Maximum storage density?[E_M]?were measured and calculated in this paper.The regression relationship between shell length?SL?and soft part wet weight?WW?was:WW=0.0062L3.0743?R²=0.9795?.According to the formula V=??_mL?³,the soft tissue wet weight of the cube root and shell length linear regression,the slope is the shape coefficient.?m value was 0.1925.TA was calculated on experiments on oxygen consumption as function of temperature.The mean value of T_A was 6483 K.According to the starvation experiment,[???_M],[E_G]and[E_M])were estimated to be 93.9 J cm^-3 d^-1,4339.5 J cm^-3 and 3230.8 J cm^-3,respectively.These results lay the foundation for the construction of the DEB model of shrimp L.vannamei.