综合养鱼高产池塘的浮游植物

根据对综合养鱼不同养殖结构类型、不同产量水平的高产池塘浮游植物定性定量的连续观测：查明了浮游植物丰度及其季节变化；分析了浮游植物群落组成类型及其季节变化；讨论了各型鱼池浮游植物群落组成上的差异性、共同性及浮游植物水华类型与养鱼水质的生物等级。得出结论：综合养鱼高产池塘里主要是隐藻、膝口藻、蓝裸甲藻、角甲藻、裸藻、空球藻、衣藻、棕鞭藻等鞭毛藻类和硅藻、大型绿球藻等优势属种交替形成水华，它们是滤食性鱼类的充足的优质适口饵料，这１０种水华都是一等水质。     

珠三角地区密养淡水鱼塘水体叶绿素a及水环境动态研究

于2012年5月—12月调查了珠三角地区主养笋壳鱼(Oxyeleotris marmoratus)、草鱼 (Ctenopharyngodon idellus)、加州鲈(Micropterus salmoides)和乌鳢(Channa argus)四个品种池塘水体中的叶绿素a(Chl a)含量和水环境因子动态变化。通过方差分析和多重比较方法研究池塘间水质因子的差异,使用逐步回归方法分析池塘中Chl a含量变化的影响因子,使用自组织神经网络(SOM)分析方法探讨池塘水质状况。研究结果显示：池塘水体TN、TP和化学耗氧量(Chemical Oxygen Demand,COD_Mn)变化范围分别为1.52~22.76 mg/L、0.20~4.82 mg/L和3.71~50.76 mg/L,呈现出严重富营养化和有机污染状况;池塘间Chl a含量差异显著（P<0.05）,从高到低顺序为：草鱼（均值）>乌鳢>加州鲈>笋壳鱼,各池塘Chl a含量的影响因子差异较大;乌鳢池塘中盐度（Sal）、电导率(Cond)、总可溶性固体(TDS)、TP、PO₄^3--P、TN、NO₃^--N和COD_Mn等因子显著高于其他品种(P<0.05);整个采样期池塘水质状况可分为5大类,并呈现出一定的时序和空间特征,池塘水质优劣顺序为笋壳鱼>加州鲈>草鱼>乌鳢。     

Use of Fishpond Recommendations in the Rural Niger Delta of Nigeria

Application of fishpond production recommendations by rural beneficiaries of the Green River Project in the Niger Delta region of Nigeria was examined in this study. A sample size of 270 beneficiaries of the Project was selected through stratified and random sampling methods. Data elicited through the questionnaire and interview schedule were analyzed with frequencies, percentages, analysis of variance, and means separation. Results indicated a high (73.78%) mean rate of application. Interstocking of catfish with tilapia was the most (77%) applied recommendation. The highest rate of application was in Bayelsa State with 80.93%, followed by Rivers State with 77.42% and, lastly, by Imo State with 63.07%. Bayelsa and Rivers State application rates varied significantly from that of Imo State. The study recommends a more intensive agricultural extension effort by the Project in Imo State.     

主养青鱼高产池塘的浮游植物和有机碎屑

本文报道了主养青鱼净产１１．２５、１５吨／公顷·年两个产量级池塘的浮游植物和有机碎屑组成、现存量的研究结果：浮游植物丰度为２０－６０ｍｇ／Ｌ，有机碎屑丰度为３０－７０ｍｇ／Ｌ；浮游植物群落由７种优势种群交替组成，它们分别是隐藻（Ｃｒｙｐｔｏｍｏｎａｓ．ｓｐｐ）、蓝裸甲藻（Ｇｙｍｎｏｄｉｎｕｍｃｙａｎｅｕｍ）、裸藻（Ｅｕｇｌｅｎａｓｐｐ）、针杆藻（Ｓｙｎｅｄｒａｓｐ．）和菱形藻（Ｎｉｔｚｓｃｈｉａｓｐ．）、尖头藻（ＲａｐｈｉｄｉｏｐｓｉｓｓＰＰ）、裂面藻（Ｍｅｒｉｓｍｏｐｅｄｉａｓｐｐ．）、绿球藻类（Ｃｈｌｏｒｅｌｌａｃｅａｅｓｐｐ．），隐藻为主的鞭毛藻类占优势。文中还探讨了浮游植物与鱼池水质净化、浮游植物有机碎屑丰度与鱼产量的关系。     

微生物制剂在水产养殖中应用的研究

实验研究了2种微生物制剂对养殖水体的理化指标、藻类和浮游动物的种群结构等生态因子的影响。结果表明,微生物制剂不仅能够提高鱼的抗病能力,防治鱼病,而且能够促进鱼的生长发育,提高饵料的效率。微生物制剂影响藻类种群的组成、数量和生物量,不仅能够使藻相比较复杂,而且使鱼类易于消化吸收的藻类增加,而使代表水体富营养化的藻类降低;微生物制剂还具有影响养殖水的理化环境,改善池塘底泥等作用。     

珠江三角洲地区精养淡水鱼塘浮游植物功能群特征

分别于养殖前期(5月)、中期(9月)和后期(12月),对珠江三角洲地区主养草鱼(Ctenopharyngodon idellus)、大口黑鲈(Micropterus salmoides)、云斑尖塘鳢(Oxyeleotris marmoratus)和乌鳢(Channa argus)4个品种池塘中的浮游植物功能群进行研究。结果表明,采样池塘浮游植物丰度、物种多样性指数较高,密度均值达1.32×10~8 cell/L,最大值为3.00×10~8 cell/L,生物量均值为168.17 mg/L,最大值为345.41 mg/L;共鉴定到196种(含变种变型)藻类,分属于绿藻(91种)、裸藻(40种)、硅藻(27种)、蓝藻(23种)、甲藻(7种)、隐藻(4种)、黄藻(3种)、金藻(1种)等8大藻门;采样池塘藻类可划分出A、B、C、D、F、G、G_2、H1、J、K、L_1、L_M、L_0、M、MP、N、P、S1、S2、T、T_D、W1、W2、W_S、X1、X2、X_(Ph)、Y等28个功能群;频率分析发现C、F、J、MP、N、P、W1、X2、Y、K、L0、M、W2等主要优势功能群在精养池塘中出现频率高,生物量比重大,说明池塘浮游植物群落稳定,整个养殖过程水体的生态功能比较单一;对环境因子与主要优势功能群进行冗余分析(RDA),得到池塘浮游植物功能群分布状况的首要影响因素是有机质含量(COD_(Mn)),其次为营养物质含量水平(TP和N:P),最后为水体物理环境,包括透明度(SD)、pH、溶解氧(DO)、总可溶性固体(TDS)和水温(WT)。研究发现,池塘水体浮游植物功能群数养殖中期多于前期和末期,并在养殖中期水体交换量大的大口黑鲈和云斑尖塘鳢池塘较为突出,表明在高密度精养池塘中,进行充足的水体交换是高温时期防控水质恶化的重要措施。基于传统的物种多样性指数方法,判定池塘水质状况为洁净,但以浮游植物功能群生境特征判定水体污染严重,且与水体理化环境测定结果和现场水体表观相符,说明功能群比多样性指数能更好地反应池塘水质的真实状况。     

高产肥水鱼池浮游生物研究

对重庆市6口高产肥水鱼池的测定表明,浮游植物生物量为19.84～61.03mg/l。其中,69个样品高于20mg/1,平均为32.69～44.08mg/l,符合肥水鱼池水质标淮.浮游动物生物量为2.74～31.09mg/l.其中,61个样品在5～10mg/1之间,各平均为4.47～11.60mg/l,低于正常水质标准.鞭毛藻类是浮游植物群落的优势类群,隐藻属(Cryptomonas)尤为突出;轮虫是浮游动物群落的优势类群。池塘浮游生物的种类组成有利于鱼类生长.     

Abundance and culture trials of Ruditapes philippinarum (Adam and Reeve, 1850), and abundance of Tellina (Quidnipagus) palatum (Iredale, 1929) at two sites in Kāne'ohe Bay,O'ahu,Hawai'i

Abundance, length‐frequencies and distribution of Ruditapes philippinarum (Manila Clams) and Tellina (Quidnipagus) palatum were measured at two beaches in Kāne'ohe Bay, O'ahu, Hawai'i in June, 2010. Abundances had decreased from 866.2 m^?2 to 3.4 m^?2 for Ruditapes and from 75.5 m^?2 to 1.5 m^?2 for T. palatum since 1977. Distribution of both species was patchy, but both were most commonly found >40 m from shore. Size frequencies of live clams compared with empty shells suggest that few Ruditapes survive to sexual maturity. A similar trend was not detected for T. palatum. Aquaculture trials of R. philippinarum were conducted at the He'eia and Moli'i traditional Hawaiian fishponds in the same bay. The clams failed to thrive, although triploid and diploid Crassostrea gigas performed well in concurrent trials in the same fishponds. Current lower abundances for wild R. philippinarum could be due to factors related to predation or nutrient limitations. Previously, two large sewage outfalls existed at the surveyed clam bed areas which may have temporarily increased nutrient availability for both wild and cultured clams. Current nutrient levels may inhibit Manila clam growth and recruitment in Kāne'ohe Bay.