李维汉故居二十二年后的桂花香

我的曾祖父李灏余和李维汉的祖父李攀桂是亲兄弟。1852年，李灏余和李攀桂的父亲买下了这处前倚池塘后靠青山的屋场，共9栋13厅。     

海水养殖池塘浮游植物碳的计算机模拟

应用光学显微镜法对实验系统浮游植物进行了野外定量研究.测定了系统中浮游植物的种类组成和生物碳素变动,为模型有效性验证提供了野外数据;根据Ecopath能量平衡模型原理建立了海水养殖池塘浮游植物碳的计算机模型,初步确定了包括15个参数的浮游植物模块参数库,通过单因子分析法进行参数敏感性检验,确定了3个敏感性参数,并利用野外实际测定数据进行了模型验证.模拟结果表明本模型成功模拟了海水养殖系统浮游植物碳变动.在建模过程中,光限制因子与水温为影响浮游植物碳的主要内源因素,浮游动物捕食作用为外源影响因素.     

硝酸钠改良半咸水凡纳滨对虾(Litopenaeus vannamei)池塘底质和水质的研究

采用在8口土池开展半咸水养殖凡纳滨对虾施用NaNO3对比实验的方法,进行了硝酸钠对半咸水对虾养殖池塘底质和水质的改良效果、机理及应用前景的研究。结果表明,NaNO3处理组显著提高了池塘底泥表层的氧化还原电位,显著降低了底泥的BOD5和可利用磷的浓度;显著降低了池塘水中的蓝藻相对密度;处理组的养殖成活率、产量和饲料系数分别比对照组显著提高8.2%、10.1%和降低9.2%(P<0.05);处理组养殖效益明显高于对照组,每公顷池塘养虾净增加收入人民币9765元;NaNO3的施用起到了有效改良池塘底质和水质的作用。因此,NaNO3的应用可为半咸水对虾养殖池塘底质和水质的改良开辟一个新的途径,具有一定的应用前景。     

Bioaccumulation of polychlorinated biphenyls in prawns and a mud crab from mixed-aquaculture ponds

The bioaccumulation of ten polychlorinated biphenyl (PCB) congeners was investigated within different tissues in three prawns (Penaeusorientalis Kishinouce, Laomedia astacina de Haan and Penaeus vannamei Boone) and one mud crab (Scylla serrata Forsskal) from mixed-aquaculture ponds in Taizhou in April 2007. The average concentrations (wet mass) of Σ PCBs in muscle, head, and rind tissues for mean among these prawn species were 7.04, 21.16, and 11.47 ng/g, respectively. The average concentrations of Σ PCBs in muscle, branchia, and spawn in Scylla serrata were 6.49, 21.13, and 19.76 ng/g, respectively. The concentrations of CB28 were the highest in prawn tissues (2.40 ng/g), and accounted for 18.60% of Σ PCBs. The concentration of CB52 was the lowest. The application of principal component analysis (PCA) for the estimation of PCB sources of contamination resulted in first component main contributions of CB101, CB153 and CB28 in the muscle, head, and rind in combined prawn samples, respectively. The enrichment level of Σ PCBs for different tissues varied greatly. The accumulation coefficient of Σ PCBs in prawn muscle, head, and rind tissues were 396.35, 1 191.79, and 645.91, respectively. For the Scylla serrata, the accumulation coefficients were 365.81, 1 190.50, and 1 113.31 for muscle, branchia, and spawn tissues, respectively. For prawns, the accumulation coefficient of CB153 was the highest in muscle tissues, while CB155 had the highest coefficients in the head and rind tissues. The CB155 coefficient was the highest in spawn tissues of the mud crab.     

Optimization of stocking density for the sea cucumber, Apostichopus japonicus Selenka, under feed-supplement and non-feed-supplement regimes in pond culture

Optimal stocking densities were investigated for the sea cucumber Apostichopus japonicus Selenka under feed-supplement and non-feed-supplement regimes in net enclosures for 333 d. Substantial weight loss occurred during the aestivation phase (AE). Decreased growth rates were also observed during the winter phase (WT). In contrast, sea cucumbers showed rapid growth during the spring (SP) and autumn (AU) phases. Feeding regimes considerably influenced the growth performance, i.e., sea cucumbers grew faster under feed-supplement regime than under non-feed-supplement regime (P < 0.05). The average survival rates of sea cucumbers under feed-supplement regime were higher than those under non-feed-supplement regime for both the autumn phase and spring phase, but the differences were only significant for the latter phase (P < 0.05). The fitted B-N curves showed that the optimal stocking densities, in terms of net production, were 22.3 ind. m-2 for feed-supplement regime and 14.1 ind. m-2 for non-feed-supplement regime.     

盐碱池塘浮游动物的群落演替和多样性

于1997年4月5日至1998年9月1日对山东高青赵店乡渔场34个盐碱池浮游动物群落演替及其多样性进行了研究,采集了389个浮游动物定量水样。结果表明,轮虫主要是在夏秋高温季节占主导地位,桡足类在春季和秋末冬初在大部分养鱼池和所有无鱼对照池中占绝对优势,原生动物在养鱼池浮游动物中占相当比重,浮游动物生物量的冬季变动一般都有放养早期的春季生物量峰值和盛夏至初秋的生物量高峰,浮游动物多样性指数的季节变动形式与浮游动物生物量的季节变动不尽相同,其季节变动的总趋势是,冬季最低,春季开始上扬,夏季最高,秋季又开始下降;浮游动物多样性指数在浮游动物生物量峰值时多是低谷,而生物量下降时多样性指数又上升,无鱼对照池和新挖池塘的浮游动物多样性指数和生物量均较一般养鱼池塘的高。     

光合细菌对盐碱地池塘浮游生物的影响

初步研究了在低洼盐碱地池塘中光合细菌（PSB）施用后对浮游生物的影响。研究结果表明：（1）光合细菌的施入,促进了浮游植物中蓝藻门、绿藻门、隐藻门、裸藻门的数量和生物量的增长;硅藻门总体上有所下降,但小型种属增加;（2）光合细菌的施入,促进了浮游生物中枝角类、轮虫,尤其小型轮虫的增长,而桡足类和原生动物却表现出下降趋势;（3）浮游生物总体上表现为数量增加而生物量下降,但绝大部分种属均有不同程度的增加,而且浮游生物种类趋向于小型化,从而增加了鱼类有效的天然饵料,因而光合细菌的施入,可以调整并优化盐碱地池塘的浮游生物的群落结构。     

线纹尖塘鳢仔幼鱼的生长发育与池塘育苗研究

线纹尖塘鳢的胚后发育大致分为仔鱼、稚鱼、幼鱼和成鱼期。初孵仔鱼仅2.875mm。前期仔鱼混合营养期短,仅2～3d。后期仔鱼为器官发育、奇鳍条基本形成期,历时10d,平均全长从4.31mm增至8.97mm。稚鱼为器官分化完毕,奇偶鳍条分节、鳞被形成期,历时27～29d,长至平均全长27.79mm。早期幼鱼鳞被等发育完善,进入生长时期。仔鱼开口饵料为150～200μm轮虫,其摄饵大小与口宽呈正相关。15mm后稚鱼可驯饵摄食人工混合料。对仔、稚、幼鱼的生长测定结果显示,全长与日龄呈线性关系L=0.5289t-0.7354(r2=0.9720),体重与日龄呈指数函数关系,W=0.8236e0.1267t(r2=0.9611),全长与体重呈幂函数关系,曲线回归方程W=0.0045L3.2527,b=3.2527,属匀速生长型。采用池塘培水,添加外源饵料生物系列,稚鱼全长15mm时开始驯饵。2002-2005年共培育全长2.2～3.4cm早期幼鱼523.7万尾,仔鱼培育成15mm稚鱼的成活率为26.8%,培育成早期幼鱼的成活率为75.7%。     

多营养层次养殖的海水池塘水体理化因子变化与富营养状况评价

2020年10月至2021年4月,在漳浦县佛昙湾垦区对“鱼-虾-贝”多营养层次养殖的海水池塘水体进行采样分析。研究结果显示,养殖过程中,各池塘水温变动范围为17.8～25.5℃;盐度变动范围为33.1～35.2,偏高且较为稳定;pH值变动范围为7.94～9.46,先下降后趋稳;溶解氧变动范围为7.46～10.43 mg/L,水体溶解氧充足;化学需氧量变动范围为0.57～4.57 mg/L,总体呈上升趋势。无机氮含量变动范围为0.03～0.18 mg/L,均处于低值;活性磷酸盐含量变动范围为0.009～0.208 mg/L,在养殖后期剧增;氮磷比变动范围为0.68～17.22,呈先升后剧降趋势。养殖水体营养状况从初期的贫营养状态演变为后期的氮限制潜在性富营养化。