A Study On The Breeding Character Of Jiangsu Hard Clam And The Relationship Between The Sulfuret And The COD In The Hard Clam Farming Area

Abstract: Asiatic hard clams (Meretrix meretrix ) were collected two or three times every month from the stations: DongLing, DaFeng, XinGang, LvSi etc. Every time, the growth of the hard clams and the temperature of the seawater were all measured, in the same time, we observed the situation of developing gonad of the hard clams straightly and made the microscopical sections of the hard clams' gonad, through these, we can study the developing character of the clams' gonad. Through the observation, it showed that the gonad of Jiangsu clams were all composed of three parts: follicle, generative pipeline, generative duct. And the gonad's developing time can be cut into five periods: the period of forming, the period of growth, the period of maturity, the period of ovulation and the period of exhausting. The period of forming is from March to April, the temperature of seawater is from 10.5 degree to 16.5 degree; The period of growth is from April to May, the temperature of seawater is from 18 degree to 20.5 degree; The period of maturity is from May to June, the temperature of seawater is from 24 degree to 25 degree; The period of ovulation is from June to August, the temperature of seawater is from 24 degree to 32 degree; The period of exhausting is after September, up to November, the temperature of seawater decline from about 24 degree to lower 10 degree. When the temperature of seawater is lower than 10 degree, the developing gonad of the hard clams are stopped, this period is from November up to the next year's early of March.samples were collected respectively at 4 stations: Dong Sha, Dong Ling, Xin Gang and Lv Si. Samples had been taken from the holes which had been dug into the depth of 15cm in every station were the effusion water and the sediments, sulphuret in the sediments and COD in the effusive water were all analyzed in the lab in time, finally, the relationship between the concentrations of sulphuret in the sediments and the COD in the effusion water was discussed. The results is : the range of sulphuret in the sediments collected from every station is from 32.90mg/kg(sediments) to 131.06mg/kg(sediments), its average is 81.71mg/kg(sediments); the range of COD in the effusion water collected from every station is from 1.54 mg/L(effusive water) to 20.59mg/L(effusive water), its average is 4.13mg/L(effusion water). Regressive analysis showed that the sulphuret and the COD have a obviously positive correlativity in the middle ten days of July among the 4 stations; There has a pertinence transition of the sulphuret and the COD between the middle ten days of June and the first ten days of July in Dong Sha and Dong Ling respectively, that is, before or after the transition, between the sulphuret and the COD has a obviously positive correlativity, similarity, there has a transition between the first ten days of June...