池塘网箱养鱼技术

网箱养鱼在江河、湖泊、水库以至近海等自然水域发展较快，而在精养成鱼塘正常养鱼的同时进行网箱养鱼较少。笔者通过1995～1996年在精养成鱼塘进行网箱养鱼的试验认为，开发池塘网箱养鱼具有广阔的前景，对于充分发挥池塘资源优势，提高池塘利用率和经济效益具有深远意义。1池塘网箱养鱼的可行性1．1池塘有网箱养鱼所需的水环境池塘虽为流水状态，但目前大部分精养鱼池排沙方便，且有的塘口还有增氧机械，与河、湖、库等自然水域一样，有着生活的基本条件，因而池塘水体可设置网箱养鱼。1．2池塘养鱼与网箱养鱼互无干扰池塘养鱼实际上是一…     

山区水库网箱养鱼应注意事项

水库网箱养鱼是节地型渔业,据统计,每平方米网箱年产鱼可达50-200公斤,10平方米网箱产量则相当于1亩高产鱼塘的产量。兴宁市属粤北山区,人多地少,水库多、面积大、水质好,发展水库网箱养鱼具有广阔的前景。     

黑龙滩水库网箱养鱼对水环境的影响

水库面积１６９３ｈａ，１９９３年伴随养鱼饲料进入水体的ＴＮ９６．２７ｔ，ＴＰ３４．０４ｔ，成为水库的污染源。一年沉积库底的残饵、粪便经推算为１６２５ｔ，构成内、荷二次污染源。对网箱区内外水体ＳＤ、ＴＮ、ＴＰ、Ｃｈｌａ，Ｈ２Ｓ、浮游植物和底栖动物的测定结果表明，网箱养鱼已促进了网箱区水质富营养化。ＤＯ减少、缺氧层增厚晃环境变化的一个重要标志，并直接影响网箱养鱼效果。为保证库多功能的正常发挥，在保持网     

洋河水库网箱养鱼对环境影响的初步研究

通过对网箱养鱼前后洋河水库不同区域总氮、总磷和化学耗氧量的监测,发现农业出水口位置的网箱养鱼并未对该区域水质造成影响,从而为农业出口位置的网箱养鱼提供了水环境依据,同时分析了网箱养鱼不影响该区域水质的原因和造成洋河水库富营养化的真正原因     

网箱养鱼对潘家口水库水质的影响分析

通过调查监测对比分析了网箱养鱼对潘家口水库水质产生的影响,对网箱养鱼增加的总氮和总磷的负荷进行了估算,最后,提出了降低网箱养鱼污染的途径和对策。     

池塘网箱养殖湘鲫及乌鳢鱼种试验

<正> 为寻求池塘养鱼增值新途径,笔者于1995～1996年进行了鱼塘网箱养名优鱼的试验,收到了良好效果,现综述如下。1 材料与方法1.1 鱼塘条件 1995年利用精养成鱼塘 1口,面积5803m~2,池深2.4m,蓄水深2m,水流畅通,排注方便,透明度20～30cm,     

网箱养鱼的冬春季管理

很多网箱养鱼者不注意气温较低的冬春季网箱管理工作,其结果是影响网箱养鱼的经济效益,乃至第二年网箱的整个生产。其实,网箱养鱼的冬春季管理是整个管理中的关键环节,加强这个时期的管理工作,对第二年的生产将起到很大的作用。     

大力发展网箱养鱼

在省水产局网箱养鱼会议精神的推动下,我区网箱养鱼生产发展快。局党委加强了对网箱养鱼生产的领导,组织网箱养鱼单位认真学习网箱养鱼先进经验,结合本地区的具体情况,对网箱养鱼生产进行研究。湘乡县溪口渔场党委对网箱养鱼生产很重视,认识到网箱养鱼这一新生事物的优点是密度大,生长快,成活率高,生产周期短,单位水体产量高。适应水库面积大,鱼池少,需要鱼种多的特点,能为水库培育数量多,质量妤的大规格鱼种,     

网箱养鱼对水环境的影响

综述了网箱养鱼水体中污染的主要来源及对水体中理化因子和浮游生物的影响,以期为发展网箱养鱼提供参考。     

网箱养鱼规模及发展方向

本文根据网箱养鱼的条件，结合多年实践的经验教训，对网箱养鱼的规模在网箱养鱼中的重要性及其确定的原则进行了分析提出了网箱养鱼规模与水源条件、经济实力，社会总体供求的关系，同时对网箱养鱼发展方向进行了初步探索。     

Seasonal Changes in the Milt Quality of Waigieu Seaperch,Psammoperca waigiensis: Implications for Artificial Propagation

Milt quality of Waigieu seaperch was sampled at the beginning, the middle, and the end of the spawning season to assess if the sampling season has an effect on milt quality parameters. The milt volume and total sperm production were higher at the middle of the spawning season while the sperm concentration in milt was significantly higher at the beginning and the end of the spawning season. Sperm morphology and the major parameters of seminal plasma (pH, total protein, Mg²⁺, or Ca²⁺ concentrations) did not differ throughout the spawning season. The concentrations of Na⁺ and the osmolality increased throughout the spawning season. The percentage of motile cells did not differ during the spawning season while the duration of sperm motility (swimming duration) and velocity (swimming speed) were significantly different during the spawning season. The fertilization rate (75.7 ± 6.8%) and hatching rate (56.5 ± 3.1%) at the middle of the spawning season were higher than at the beginning and end periods. Results indicated that milt quality parameters and fertility success in the middle of the spawning season were higher compared to earlier and later sampling dates. Thus, we recommend collecting milt during this time for maximal fertilization and hatching success.     

珠江口南沙海域浮游植物群落结构特征

基于2015年4月(丰水期)和2015年11月(枯水期)珠江口南沙海域的调查资料,分析该海域浮游植物的种类组成、优势度、细胞丰度及多样性。共鉴定出浮游植物5门44属76种,硅藻为最主要优势种群。丰水期优势种有2种,分别为新月筒柱藻(Cylindrotheca closterium)和中肋骨条藻(Skeletonema costatum);枯水期优势种有3种,分别为萎软海链藻(Thalassiosira mala)、中肋骨条藻和有棘圆筛藻(Coscinodiscus spinosus)。丰水期和枯水期浮游植物细胞丰度分别为651.91×104个·L-1和129.21×104个·L-1,2个时期细胞丰度分布都表现为近岸向离岸递增的趋势。调查海区的浮游植物Shannon-Wiener多样性指数(H')和Pielou均匀度指数(J')的平均值在丰水期分别为1.64和0.40,而在枯水期分别为1.58和0.41,多样性总体处于较低水平。典范对应分析结果表明,丰水期影响浮游植物群落结构的主要环境因子为盐度、温度、总氮和p H,枯水期为温度、透明度、磷酸盐和盐度。     

秘鲁沿岸秘鲁鳀渔场及渔汛分析

秘鲁鳀(Engraulis ringens)是栖息于东南太平洋沿岸的小型中上层鱼类,了解秘鲁鳀渔场和渔汛的状况有助于渔情预报工作的开展进而实现资源的合理利用。利用2005~2014年秘鲁各港口的上岸量数据,以上岸量(landings)、总捕捞努力量(fishing effort)和单位捕捞努力量渔获量(CPUE)为指标分析秘鲁鳀渔场分布及渔汛;结合二因素方差分析(two-factor analysis of variance)探究渔场月份和纬度上的显著性差异;利用分位数的方法,找出各年的旺汛时间。研究表明,每年的4~6月和11~12月为秘鲁鳀的主汛期;主要的捕捞区域分布在7°S~13°S;渔汛的前中期,上岸量和捕捞努力量有着明显的年间差异,而CPUE在渔汛后期年间差异明显。方差分析表明,不同月份和不同纬度对捕捞努力量[ln(effort+1)]有极显著的影响(P0.01);5月为一年中最主要的捕捞阶段。旺汛期分析表明,第一渔汛阶段的旺汛一般在5月出现,而第二渔汛阶段的旺汛一般在11月出现。研究结果有助于对秘鲁沿岸秘鲁鳀渔场及渔汛的认识。     

大水桥水库浮游植物群落结构特征研究

于2011年2月(枯水期)、5月(丰水初期)、8月(丰水末期)和11月(平水期)对大水桥水库的浮游植物群落结构进行研究.结果表明,浮游植物有6门、42种,丰度在6.6×106～3.7×108个/L,丰水期丰度最高,枯水期丰度最低,枯水期、丰水期和平水期第一优势种分别为蓝藻门的拟柱孢藻(Cylindrospermopsis rackiborskii)、湖泊假鱼腥藻(Pseudanabaena limnetica)和湖丝藻(Limnthriox redekei).浮游植物群落结构显示,水库处于中-富营养状态;丰水期水质较差,枯水期和平水期相对较好.浮游植物丰度与硝氮(r=-0.898,P＜0.01,n=12)、总氮(r=-0.894,P＜0.01,n=12)及透明度(r=-0.594,P＜0.05,n=12)表现出显著性负相关,与pH(r =0.676,P＜0.05,n=12)、总磷(r=0.703,P＜0.05,n=12)、水温(r=0.754,P＜0.01,n=12)表现出显著性正相关.     

Semi-Intensive Commercial Grow-Out of Penaeus vannamei Fed Diets Containing Differing Levels of Crude Protein During Wet and Dry Seasons in Honduras

Shrimp were grown under ideal management conditions during two distinct seasons of the year at stocking densities used most often in Honduras with the objective of evaluating the usefulness of high protein diets. A randomized design in 2 × 2 factorial arrangement was used to test a diet composed of either 20 or 40% crude protein in earthen ponds that were stocked with juvenile Penaeus vannamei at 5 to 11/m². The study was repeated during wet and dry seasons. Dietary protein level had no significant effect ( P > O .05) on survival, yield, or average weight of shrimp at either density during either season. Higher stocking rates yielded significantly greater shrimp production during both seasons. Mean shrimp weight in high density ponds was significantly lower than mean shrimp weight in low density ponds during the wet season, but there was no significant weight difference because of stocking density during the dry season. Mean survival was significantly lower at the higher stocking rate during the dry season. Net income was negative during the dry season, particularly at the high stocking density. Mean production was 240% greater in the wet season than in the dry season. Diets offered P. vannamei stocked at 5 to 11/m² should contain no more than 20% protein, regardless of season. Higher dietary protein levels increase costs and waste nitrogen without resulting in greater shrimp yields. The high stocking density might increase profitability in the wet season, but long term sustainable production may be more feasible at lower stocking rates because of reduced nutrient wastes.     

丰、枯水期里下河腹地典型水体浮游动物群落结构与水质评价

为了探究丰枯水期里下河腹地典型水体中浮游动物的群落结构特征,通过布设20个采样站点,于2014年丰水期(7月29日)和枯水期(12月24日)对里下河腹地典型水体进行了2次全面调查,并对水质状况进行了评价。结果表明,里下河腹地典型水体共鉴定出浮游动物21种(包括变种和变型),无节幼体1类;其中轮虫最多,共14种,占浮游动物总种数的66.6%;枝角类次之,共6种,占28.6%;桡足类最少,仅1种,占4.8%;各站点浮游动物种类组成和密度均以轮虫和枝角类为主,数量在5~15种,密度变化在9.8~102.2个/L。浮游动物相似性指数在0.18~0.55,平均为0.36,偏向于轻度相似,表明丰水期与枯水期的生境差异较大。优势种的优势度不高,在0.023~0.297;多样性指数在1.73~3.56,均匀度指数在0.67~0.95,表明丰、枯水期里下河腹地典型水体的浮游动物群落信息含量较大、群落结构处于较稳定状态。浮游动物多样性和水质监测结果均表明,枯水期水质优于丰水期,枯水期水质基本处于清洁状态,丰水期水质基本处于中度污染状态;污染源主要为面源污染,且串场河(6号)、新通扬运河(12号)、喜鹊湖(17号)、兴姜河(18号)受人类活动影响较大。     

基于GIS的考洲洋养殖水域水质状况分析

在GIS和数据库技术的支持下，据1999年2月(枯水期)和8月(丰水期)两个航次的调查数据。利用数据插值和栅格图形加权平均等处理手段，综台分析和评价了考洲洋水域的水质营养状况。结果显示，枯水期考洲洋的水质符合一类海水水质标准，整个水域未受明显有机污染，丰水期整个水域符合二类海水水质标准，湾西北部和吉隆河口附近水域受明显的有机污染，出现富营养化现象，应引起重视。两个调查航次初级生产力的分布趋势相似，均呈现湾口高，湾中部和湾西北部低的变化趋势。饵料生物的分布无明显的规律，在枯水期，饵料生物的分布较为均匀，大部分水域处于2～3级水平，其密集分布区出现在湾西北部、湾口和吉隆河口附近水域，而在丰水期，饵料生物的变化幅度较大，其密集分布区位于湾中部水域和望京洲沿岸水域。两个航次相比，丰水期的初级生产力水平和饵料生物水平均高于枯水期。     

Migration route of Pacific saury Cololabis saira inferred from the otolith hyaline zone

In order to establish the migration route of Pacific saury Cololabis saira, we measured the radius of otolith annual rings (ROA) in fish collected from areas off the Japanese coast up to 165°W in June and July (pre-fishing season) and from fishing grounds in August?CNovember (fishing season). The average ROA for six sea areas that each spanned 10° of longitude sampled during the pre-fishing season were compared with data obtained during each month of the fishing season. The average ROA decreased from west to east and also decreased monthly from August to November. The average ROA of fish caught after October at the peak of the fishing season was equivalent to that of the fish caught in the areas east of 160°E or 170°E. We conclude that Pacific saury caught by Japanese fishing vessels during the peak of the fishing season migrate from an area east of 160°E.     

呼伦湖蒙古油繁殖生物学的研究

对蒙古油(Hemiculter bleekeri warpachowskyi)的繁殖季节、繁殖习性、繁殖力、性比等繁殖生物学指标进行了研究。结果表明:蒙古油属敞水性产卵类型,粘性卵,为一次产卵类型。蒙古油初次性成熟年龄为1龄,繁殖季节为6月中旬至7月下旬,以7月中旬为产卵盛期。蒙古油个体绝对生殖力F为2021~15470粒,个体体长相对生殖力FL为230~1137粒/cm,个体体重相对生殖力FW为273~700粒/g;个体体长相对生殖力、个体体重相对生殖力分别和体长、体重成二次方程和三次方程关系。繁殖前期雌雄性比1∶0.83,繁殖期雌雄性比为1∶1.11。     

Fish assemblage dynamics in an intermittent river of the northern Australian wet–dry tropics

Intermittent rivers make up a large portion of the global river network and are the dominant river type in northern Australia. Increased pressure is being placed on such systems, and a better understanding of their ecology is needed. We examined, over a 7‐year period, the fish fauna of the intermittent Fergusson River, a major tributary of the Daly River of the northern Australia. Changes in habitat structure with the onset of the dry season involved contraction of the riffle/run/pool habitat to a single refugial pool, the size of which was determined by antecedent wet season hydrology. The fishes present comprised a subset of species present within the Daly River main channel and consisted of the most widely distributed of northern Australia's freshwater fishes. The Fergusson River provides suitable spawning habitat for species during the wet season (e.g. Hephaestus fuliginosus, Leiopotherapon unicolor and Neosilurus catfishes) and during the dry season for a different set of species (e.g. Amniataba percoides, Melanotaenia australis and Glossogobius aureus). Little year‐to‐year variation in assemblage structure was observed early in the dry season, whereas interannual variation in late dry season assemblages was substantial. Dry season recruitment imparted some of the interannual variability in assemblage structure recorded between late dry season samples. Piscivorous fishes were an important, but temporally variable, component of the assemblage present in the late dry season refugial habitat, and predation was potentially another important source of variation in assemblage structure.