台风对工厂化虾池生态系统中COD的影响

根据2003年7月台风发生期间工厂化虾池生态系中的实测数据,重点分析了不同养成密度虾池生态系中COD的变化状况及其影响因素。结果表明:台风气候对虾池生态系中COD的影响较大,台风发生时COD含量相对较高,台风前后相对较低;台风气候对COD周日变化的影响以养成密度大的养殖池较为显著,养成密度小的养殖池则影响较小;COD与环境因子之间的相关性差异也较大,台风前,养成密度大的养殖池与NO2-呈显著正相关(r=0.668),与T和Chl.a呈负相关关系(r=-0.608或r=-0.633);台风后与PO4-P、NH4+和Chl.a之间则表现的显著正相关(r=0.907、0.832、0.846)。而养成密度低的养殖池,台风前COD与pH呈显著负相关(r=-0.732),台风后与PO4-P和NO2-分别呈显著正相关(r=0.720)和良好正相关(r=0.591)。但在台风发生时,二池均无此类相关性出现。     

Temporal and spatial distributions of dominant shrimp stocks and their relationship with the hydrological environment in the East China Sea

To provide a scientific and technological base for fishery administration, holding a moratorium on fishing, and combating habitat degradation, a shrimp stock survey was carried out in May, August, and November 1998 and in February 1999. The study was conducted in the area between 26o00′ N and 33o00′ N and to the west of 127o00′ E in the East China Sea using a multi-sac trawl-net, with 115 stations being sampled. Up to 2001, we had found 121 species, which belong to 63 genera under 22 families, and 41 species are of high economic value and in great abundance. Nine shrimp species were of great economic importance, whose stock accounted for 76.8% of the demersal total. They were Parapenaeus fissuroides, Metapenaeopsis philippi, Palaemon gravieri, Metapenaeopsis barbata, Solenocera koelbeli, Solenocera crassicornis, Trachypenaeus curvirostris, Solenocera melantho and Parapenaeopsis hardwickii (listed in stock order). The nine species belong to the eurythermal and eurysaline community and high thermal and high saline community, had different migration patterns and stocks, and their distribution patterns could be generally classified into three types:(1) dominating in the north or the south;(2) dominating to the north of and in the coast to the south of 30o00′ N;and (3) dominating to the east of 60 m isobath, which were related to six water masses in the ECS near two lines, i.e., the 60 m isobath and 30o00′N latitudinal lines. Densely habited shrimps were found in all four seasons due to temperature and salinity frontiers and upwelling. The general stock density index was relatively higher in spring, summer, and autumn, when it surpassed 10 kg/h, while in winter, it was only 6.8 kg/h which might be caused by overfishing. According to the spawning areas of the nine species and their distribution patterns, to attain sustainable development of the shrimp fishery in the ECS, it is imperative to protect fishing areas and to hold a moratorium on catching to the west of 60 m isobath from April through October, and between 60 m and 100 m isobaths and to the south of 30oN from June through August and to limit fishing in winter.     

中国对虾细胞色素P450基因CYP4原核表达条件优化

根据克隆得到的中国对虾（Fenneropenaeus chinensis）CYP4基因开放阅读框设计引物,构建了中国对虾CYP4基因原核表达载体p28a-CYP4,并对重组菌株Rosetta／28a-CYP4的原核表达条件进行了优化。结果表明：p28a—CYP4转化Rosetta后可实现CYP4基因的原核表达,SDS—PAGE分析显示其在56．0kDa处有显著诱导条带;通过对诱导温度、IPTG浓度、诱导时机（OD600）及诱导时间的优化表明,重组菌株Rosetta／p28a-CYP4的最佳诱导温度为37℃,最佳IPTG浓度为1．2mmol／L,最佳诱导时机及诱导时间分别为0．59和6h。     

东南亚养虾之现况与展望

东南亚是世界虾类养殖的重心地区,而白虾已成为世界养虾中最重要的虾种.中国为世界养虾产量最多的地区.在东南亚的养虾中,白虾的产量占总产量的比例从2004年的62%增加到2006年的76%,而草虾产量占总产量的比例则从38%减少到24%.但是印度、印度尼西亚与孟加拉国等地区的草虾产量不减反增,其中以印度为最,这与当地低密度的放养方式生产的较大体形的草虾有关.美国和日本的养虾产量由于供过于求,故虾价仍缓慢下跌,若养殖业者能把握虾价较高的季节(9月至次年1月)并生产大型虾类,则养殖利润仍高,越南的草虾即为一例.文中还提及白虾超高密度养殖的成功方法,许多地区的每季白虾生产可达40t·hm<'-2>以上;淡水区白虾养殖可不必加以禁养,因其对环境的危害影响仍不明显.本文最后还提出发展虾类养殖的科研重点,以供有识者参考.     

DABS—C1柱前衍生高效液相色谱法测定对虾肌肉中18种游离氨基酸

建立一种以DABS-Cl为柱前衍生剂，利用反相高效液相色谱测定对虾肌肉中18种游离氨基酸的方法。结果表明，在50min内18种氨基酸得到完全分离，各氨基酸相关系数均大于0．997，氨基酸的回收率在86．60%-107．27％之间（胱氨酸除外），方法的检出限为0．18~o．66mg／L，相对标准偏差为3．53％-8．51％（天冬氨酸除外）。     

虾池浮游微藻的种类组成、数量和多样性变动

报道了在集约化养虾中应用有益微生物制剂对虾池浮游微藻的影响,分析了整个养虾周期浮游微藻的种类组成、生物量、优势种及多样性指数的周期变化情况。结果表明,早期虾池浮游微藻细胞数量维持在1×103~3×103mL-1的水平,养殖中期开始呈指数增长状态,后期达到顶峰,并维持在70×103~160×103mL-1的水平,生物量比自然海区高。优势种类明显,前期为中肋骨条藻和伏氏海毛藻等硅藻类,后期则为绿球藻和栅列藻等绿藻类,水色及藻相呈良好状态,而不施加芽孢杆菌制剂的对照池则在后期出现较大比例的有害的蓝藻。虾池藻类多样性指数、均匀度指数和种类丰度均呈现前期高后期低的趋势,而优势度指数则相反,呈现前期低后期高的趋势。浮游植物的多样性指数为0.60~3.80,平均为1.88,均匀度指数为0.14~0.83,平均为0.45;种类丰度为0.80~2.46,平均为1.38;优势度指数在0.17~0.85,平均为0.41。多样性指数和均匀度均比粤东海域低,但优势度则甚高。     

SELENIUM REQUIREMENT OF SHRIMP PENAEUS CHINENSIS

Penaeus chinensis were reared in fibreglass tanks for the study of their selenium requirements. The shrimp were fed semipurified diets containing graded levels of selenium, and weight gains, activities of glutathione peroxidase (GSH-Px) and selenium contents in muscle and hepatopancreas were determined. Weight gain and GSH-Px activity were the highest when the shrimp were fed diet containing 20 mg/kg selenium; Good linear correlation was found between GSH-Px activities and selenium contents in the diets, and the number of healthy shrimp. The experiment showed that 20 mg/kg selenium in the diet is optimal for the shrimp and that GSH-Px activity can be an important biochemical index of the selenium nutrition status of the animal.     

A comparative study of intensive Litopenaeus vannamei culture on four bottom substrates without water change

The effect of four bottom substrates, oyster shell powder (OP), sugarcane bagasse (SB), a mixture of OP and SB (OS) and fresh soil (FS), on the water quality and bacterial and zooplankton density of intensive shrimp (Litopenaeus vannamei) culture tanks without water change and the growth performance of cultured shrimp were compared in this study. At the end of a 110 days culturing trial, the total ammonium-N (TAN) of the water on SB and the nitrite nitrogen (NO₂-N) on OS was significantly lower than that on the other substrates (P<0.05), which coincided with the high density of ammonium- and nitrite-oxidizing bacteria in the water on SB and OS, respectively. The concentration of chlorophyll a (Chl a) increased slowly on OP, SB and OS but remained low on FS. The density of total bacteria on OP, SB and OS was one order of magnitude higher than that on FS, and the density of zooplankton on SB and OS was significantly higher than that on FS or OP (P<0.05). The improved water quality and increased density of bacteria and zooplankton on SB and OS may have had a synergistic effect on shrimp culture, improving its growth performance (high survival rate and yield and low feed conversion rate). SB and OS were more effective for improving the growth performance of intensively cultured L. vannamei without water change than OP and FS. To our knowledge, this study presents the first evidence regarding the effect of different bottom substrates on intensive shrimp culture.     

基于裤式拖网法的虾拖网网囊网目选择性试验与分析

为研究虾拖网网囊网目对主要渔获种类的选择性,于2017年9月在南海区采用裤式拖网法进行选择性试验。在SELECT模型框架下,使用极似然估算法,结合单网次和联合网次的数据,同时考虑网次间差异,估算网囊对主要渔获种类的平均选择性。共完成14网次作业,其中对照网囊之间的渔获性能比较试验4次,试验网囊的选择性试验10次。研究表明:对照网囊的位置对其渔获性能无显著影响;试验网囊对刀额新对虾(Metapenaeus ensis)的网次50%选择体长(L 50)为78.84~92.09 mm,平均为82.38 mm,网次选择范围(SR)为5.01~11.32 mm,平均为6.39 mm,网次相对作业强度(p)为0.44~0.71,平均为0.52;试验网囊对黄斑蓝子鱼(Siganus oramin)的网次L 50为59.20~76.80 mm,平均为71.17 mm,网次SR为5.30~16.87 mm,平均为14.20 mm,网次p为0.43~0.71,平均为0.63。试验网囊对刀额新对虾的网次和平均L 50值均大于其首次性成熟体长(80 mm),可见试验网囊对刀额新对虾的资源利用是合理的。本试验的裤式拖网法和数据处理方法可为今后拖网选择性研究提供参考。