中华绒螯蟹高密度育苗水质及调控方法探讨

Characteristics and Control of Water Quality in Intensive Artificial Breeding of Chinese Crab Eriocheir sinensis

报道了在中华绒螯蟹育苗期间二级海水沉淀池和幼体培育池中水温、ｐＨ、ＤＯ、ＮＨ＋４－Ｎ、ＣＯＤＭｎ的昼夜变化，以及幼体不同发育期水温、ｐＨ、ＤＯ、ＮＨ＋４－Ｎ、ＣＯＤＭｎ、ＮＯ－２－Ｎ、硫化物的检测结果。提出氵蚤状幼体最佳换水时间为每日凌晨３：００时。培育池ＣＯＤＭｎ控制范围Ｚ１～Ｚ３期为１０～２０ｍｇ／Ｌ，Ｚ４～Ｍ期为１５～２５ｍｇ／Ｌ。试验期间用漂白粉能有效控制培育池水中的ＮＯ－２－Ｎ。Ｚ１～Ｚ３期采用换水时吸底、Ｚ４～Ｍ期换水时使用推耙来控制ＣＯＤＭｎ、ＮＨ＋４－Ｎ、硫化物含量。检测发现，五月中旬当地沉淀池水ｐＨ普遍偏高，进入氨氮含量高的培育池后使ＮＨ３大幅度增加。因此幼体氨中毒是导致Ｍ期幼体大批死亡的主要原因。

Diural changes in water temperature, pH, DO, NH + 4 N, COD Mn and sulphide were reported in sea water reprecipitating tanks and in larva rearing tanks during artificial reproduction of Chinese crab ( Eriocheir sinensis ) from April to May, 1997. The high water quality for zoea rearing was as follows: COD Mn 10￣20 mg/L during period from Z 1 to Z 3 and 15￣25 mg/L from Z 3 to megalopa and draining and refilling at 3:00. Content of NO - 2 N was controlced by bleaching powder. It was found that pH in the reprecipitating tank was high in mid May, which resulted in increasing level of NH 3 and high mortality in larva rearing tanks. This was one of the main reasons of heavy loss of megalopae.