Study On The Effect Of PSB On The Evironmental Friendly Aquaculture Of Paddlefish (Polyodon Spathula)

This experiment was a practical productivity paddlefish fingerling breeding. Seven ponds was selected in Mei He to breed paddlefish fingerling and live through the winter .In one year culturecycle, firstly,we bought paddlefish fingerling from a good aquaculture farm that accorded with national standard, and we choosed strictly ponds, water source in according with Environmental Friendly Aquaculture norm. Secondly ,we used PSB(Photosynthesis bacteria) to adjust water quality and strengthen immunity, a favourable aquaculture enviroment and achieve ecological aquiculture was offered. Thirdly, we feed primarily nature feedstuff and feed auxilliarily compound feedstuff. We achieved obvious outcome in a year. The result show:Paddlefish fingerling and paddlefish can be bred entirely when breeding density was reasonal, paddlefish fingerling can grow paddlefish in one year. We can see from the breeding condition of paddlefish fingerling that we need not sprinkle PSB when zooplankton in ponds was abundant, wherease we must sprinkle PSB. Otherwise it would effect the growth of paddlefish fingerling. So and so only, paddlefish fingerling will grow speedly, yield highly.PSB effected hydrochemistry index—SD, DO, NH₄-N notabily. SD of comparison pond changed littlely,however, SD of experimental ponds had different degree after sprinkling PSB. But in total, the change was not very obviously, it was because that PSB,S period of validity was very short, it kept only present status of SD after its period of validity; DO of four experimental ponds was increasing and the ratio of increasing was great, it was because that phytoplankton produced greatly on account of PSB, phytoplankton may carry photosythesis to produce oxygen; NH4-N comparison pond had little change and NH4-N of experimental ponds had clearly change, the difference of experimental ponds was not distinctly, but the difference between comparison and experimental was distinctly. Because the nitrogen fixation of PSB , the use of small molecule organic and H₂S of PSB may eliminate organic and of ponds bottom. So PSB can keep water quality well.PSB had effect on phytoplankton and zooplankton. Microcystis of experimental ponds decreased greatly. It arrived at minimum at ninth day and then stabilized this level. There was a growth of profitable algaes after sprinkling PSB, for example greenalgae and euglenophyta. Microcystis of comparison pond had been disposed, such as affusion and dousing calcium oxide, so it changed obviouslessly. PSB is very small, it was feedstuff of zooplankton, so itcan cultivate zooplankton. Comparison pond was not fertilized or boused, so the quantity of zooplankton kept reducing. The zooplankton quantity of experimental stabilized in a level after a little increasing.we add 15 percent frostresisting dosage in compound feedstuff. It had affect on prophy lax and promoting growth and reducing conversion rate of food. But it only enhanced cost 0.05 yuan per j in.To sum up, we guarantee DO exceeding 3mg/l, its optimum is 5mg/l; PH :6-9, it optimum is 6.5-8.0; NH4-N<0.5mg/l; SD:20-40cm. In this condition ,paddlefish fingerling can grow regularly. At the same time, we should accomodate water quality according to measured value, such as affusion> drainage , sprinkling PSB. It was most important to adjust water quality and feed good feedstuff. Effective ecological measures and highquality feedstuff can aviod the harm of medicine, arrive at Environmental Friendly Aquaculture .The study has important practical value for paddlefish farming and the use of PSB in all kinds of water area.