Evaluations On Ecological Health Status And Culture Efficiency Of Pelteobagrus Fulvidraco Culture Ponds Based On Three Culture Capacities

This paper aimed at 6 productive ponds of an aquaculture company in Nanning,Guangxi,to elucidate the effects of three different culture capacities（15000 tails/mu in group A,10000 tails/mu in group B and 5000 tails/mu in group C）on the ecological health statuses and culture efficiencies of ponds.This study mainly discussed the relationships between different culture capacities and plankton,main physical and chemical factors and culture efficiency in culture ponds through the regular determination and analysis of biological,physical and chemical factors in culture water,as well as the evaluations of ecological health status and the culture efficiencies of culture ponds.It provided theoretical support for the establishment of high-efficiency ecological culture technology model of large-scale pond of Pelteobagrus fulvidraco.The experimental period was 180 days（19 July 2019 to 19 December 2019）.The main findings were as follows:（1）Water environment assessment based on plankton diversity,the water health status of group C was better than that of group B than that of group A.Water environment stability:group B（culture capacity 10000 tails/mu）﹥group C（culture capacity 5000 tails/mu）﹥group A（culture capacity 15000 tails/mu）.That was,the water environment health conditions of medium and low culture capacities（groups of B and C）were better.（2）The pond culture capacity of P.fulvidraco had a direct influence on culture water environment factors,among which the effects of high and medium culture capacities（groups of A and B）on SD、NO₂-N、NH₃-N、WT and p H were more obvious,and those of low culture capacity（group C）on DO、TP、BOD₅and SD were more obvious.（3）In three different capacity ponds of P.fulvidraco,the F value of the comprehensive score expression of water environmental（principal component analysis）of high capacity group（group A）was the highest,and the pollution was more serious.The F values of medium capacity group（group B）and low capacity group（group C）were ranked lower,and the quality of water environment was relatively good.The evaluation of the water health of different culture capacity ponds and the view of"appropriate yield"of P.fulvidraco based on principal component analysis,the culture capacity of P.fulvidraco 10000tails/mu（group B）was suitable,and the ecological health status of the water body was better.（4）On the dynamic changes of water environment factors in different culture capacity ponds,TN and DO contents were positively correlated with culture capacity,and the COD_Mn and NH₃-N contents were inversely correlated with culture capacity.The water environmental pressure of culture ponds was the largest in group A,slightly smaller in group B and the smallest in group C.In general,there was a positive relationship between the pressure of water environment and the size of culture capacity.（5）The WGR,LCR and SGR of P.fulvidraco in different culture capacity groups were inversely related to culture capacity.The feed energy consumption level,the medium capacity group（group B）was decreased by 42.15%and0.77%compared with the high capacity group（group A）and the low capacity group（group C）.In terms of production per unit area,group B（10000 tails/mu）was increased by 19.82%and 62.36%compared with group A（15000 tails/mu）and group C（5000 tails/mu）.Based on the perspective of fast growth,low feed energy consumption and"suitable yield",group B（10000 tails/mu）was suitable for the selection of pond aquiculture capacity model of P.fulvidraco.（6）At the CF level,the group C was increased by 9.12%and 1.13%compared with groups A and B.At the level of the VSI level,the group B was increased by 3.64%and 2.13%compared with groups A and C.At the HIS level,the group A was increased by 19.76%and 59.82%compared with groups B and C.In the shell rate level,the group A was increased by 0.50%and 0.20%compared with groups B and C.On the whole,the physical quality indexes of group B P.fulvidraco（culture capacity of 10000 tails/mu）were better than those of groups A and C.（7）Antioxidant enzymes（SOD and CAT）showed the ability of P.fulvidraco to resist environmental stress.The digestive enzymes（LPS、TPS and AMS）mainly showed the feeding ability and the digestion and absorption ability of the food.The activity of SOD in group B increased by 5.63%and3.42%compared with groups A and C,and the activity of CAT increased by5.55%and 1.24%compared with groups A and C.The LPS activity of group C was increased by 12.91%and 34.83%,the TPS activity was increased by 9.25%and 11.30%,and the AMS activity was increased by 32.29%and 28.37%,compared with groups A and B.