本文设计大棚高效养殖池塘养殖南美白对虾.对同一大棚内4口池塘的养殖效果和养殖水体中部分理化因子、浮游藻类进行监测.结果表明:理化因子方面,水温在16.85～31.75℃之间波动,整体呈上升趋势;pH在7.41～9.36之间波动,峰值出现在养殖初期,之后逐渐下降到一个稳定水平;溶解氧保持在5 mg/L以上;氨氮含量在0.20～6.56 mg/L之间,峰值出现在5月下旬至6月上旬;亚硝酸盐氮含量在0.002～29.5 mg/L之间,在5月底至6月初出现爆发性增加;浮游藻类方面,养殖池溏出现的浮游藻类6门36种(属),其中绿藻门13种(属),甲藻门6种(属),硅藻门6种(属),金藻门6种(属),裸藻门3种(属),蓝藻门2种(属).优势种共9种(属),绿藻门的优势种为拟衣藻、卵囊藻、球衣藻,硅藻门的优势种为小环藻、菱形藻,甲藻门的优势种为裸甲藻,金藻门的优势种为小土栖藻,蓝藻门的优势种为色球藻、颤藻,其中色球藻的优势度指数明显高于其他优势种,整个养殖周期中浮游藻类的细胞总数在3.07×106～729.44×106 cell/L之间;养殖效果方面,4口池塘平均产量为1335±25.5 kg/667 m2,平均成活率为77.88％±1.49％,平均饵料系数为1.51±0.04.

三疣梭子蟹(Portunus trituberculatus)隶属于甲壳纲、十足目、梭子蟹科、梭子蟹属,俗称梭子蟹、枪蟹、门蟹等,是一种重要的海洋经济蟹类,广泛分布在中国、日本、韩国及南亚各国近岸海域,是重要的渔业产品之一[1,2],由于其生长速度快、经济价值较高,我国沿海地区梭子蟹人工养殖十分广泛.目前,其养殖方式以围塘养殖为主,投饵量通常根据经验定量投喂,投饵方式基本采用抛撒式,因而在养殖过程中,往往会出现投饵不足或者过量的情况.饵料不足不仅影响梭子蟹生长,且会造成梭子蟹互相残杀;而饵料过量不仅会浪费成本,且会污染水体,影响水质,更可能致使梭子蟹疾病多发甚至死亡,养殖效益降低.

Acute toxicity of triazophos acephate and phoxim on juveniles Acanthopagrus schlegel from Zhoushan Sanxin Mariculture Co LTD was done from July to August 2008.The weight and length of the juvenile was(5.09±0.71) cm and(2.09±0.66) g respectively.The result indicated that the orders of the toxicity of these three pesticides on juveniles Acanthopagrus schlegel was triazophos>phoxim>acephate.We found that the median-lethal concentrations(LC50) in 24 h,48 h,72 h,96 h to juveniles Acanthopagrus schlegel were 30.11 mg/L,21.83 mg/L,17.30 mg/L and 14.07 mg/L for acephate respectively;0.68 mg/L,0.49mg/L,0.34 mg/L and 0.30 mg/L for phoxim,respectively ;0.068 mg/L,0.060 mg/L,0.054 mg/L and 0.051 mg/L for triazophos respectively.And the safe mass-concertrations of acephate,triazophos and phoxim to juveniles Acanthopagrus schlegel was 1.41 mg/L,0.005 mg/L and 0.03 mg/L respectively.Finally,the thesis discussed the characters of acute toxicity,the effects and the saf-concentration of these pesticides to juveniles Acanthopagrus schlegel.

Juveniles Sparus macrocephalus,with length of 5.09±0.71 cm and weight of 2.09±0.66 g,have been chosen as the subjects of our experiment which has been done to investigate the influences of acute toxicity of four kinds of heavy metal on juveniles Sparus macrocephalus.The experiment is done with water temperature(28.8±1.6) ℃ and pH 8.24.The results of the experiment indicate that the median-lethal concentrations(LC50) in 24 h,48 h,72 h,96 h to juveniles Sparus macrocephalus are 11.53 mg/L,10.15 mg/L,6.56 mg/L,6.09 mg/L for Zn2+ respectively;31.48 mg/L,24.31 mg/L,23.01 mg/L,23.01 mg/L for Cr6+ respectively;2.75 mg/L,1.55 mg/L,1.30 mg/L,1.06 mg/L for Cu2+ respectively and 0.098 8 mg/L,0.098 1 mg/L,0.089 2 mg/L,0.074 2 mg/L for Hg2+ respectively.The degrees of the intensity of the toxicity of these four kinds of heavy metal on juveniles Sparus macrocephalus are Hg2+Cu2+Zn2+Cr6+ succesively.Finally,this paper has discussed the poisoning features of ions of heavy metals,the impact of acute toxicity of heavy metal on juveniles Sparus macrocephalus in the stage of their early growth,toxicity evaluation,as well as the control of the ions of heavy metals in water.

全人工养殖已成为海水养殖业发展的一个新的热点.但由于各地客观条件的差异,养殖技术各有不同,以致养殖产量及效益丰歉悬殊.200 3年,结合当地的实际条件,利用改建后的5.87ha的对虾养殖池塘,对三疣梭子蟹不同苗种来源、放养密度以及日常管理技术进行探索试验,为进一步完善、规范三疣梭子蟹全人工养殖技术奠定了基础.

近年来,每年的5月-6月,浙江沿海对虾和梭子蟹养殖的池塘中,经常会出现大量芽口枝管水母(Proboscidatyla ornata Mccrady)等海洋水母类生物.水母类生物捕食池塘中的浮游生物,破坏了池塘微生态环境和养殖生物的饵料结构;同时水母也捕食虾、蟹幼苗,造成养殖品种单位水体的密度下降;而且其分泌的有害毒素更危及养殖品种的生长,严重时将造成养殖生产的失败.2002-2003年试验组筛选出茶籽饼作为杀灭水母的药物,经试验和生产性应用,低浓度茶籽饼浸出液12h内能有效地杀灭水母,而且对甲壳类等养殖生物无明显影响.同时在浙江省岱山县栲门围塘养殖基地大面积发生水母的池塘中进行了推广应用,取得了明显的效果.该方法为国内首创.现将试验结果报告如下.

一、材料和方法 (一)亲鱼 1.亲鱼来源:亲鱼一部分取自人工养殖,一部分取自野生捕捞,要求体质健壮,无损伤,无疾病,雌鱼体重100克以上,腹部饱满,生殖突红润且较突出的;雄鱼体重120克以上,生殖突浅红色的.共收购亲鱼600尾,约90千克.