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1.
有效氯对浮游植物生长的影响   总被引:3,自引:0,他引:3  
用0.5×10-6和1.0×10-6有效氯处理虾池浮游植物,用4.0×10-6、100×10-6和150×10-6有效氯处理叉鞭金藻、球等鞭金藻两个品种(9002、3011)、巴夫藻(3012)、塔胞藻和小新月硅藻,结果表明,0.5×10-6—1.0×10-6的有效氯对虾池浮游植物产氧有严重抑制,但对叶绿素含量无显著影响;金藻类用150×10-6有效氯处理1.5h仍可存活,但小新月和塔胞藻在有效氯为4.0×10-6时,短时间即可致死。  相似文献   

2.
等鞭金藻3011的半连续密封培养   总被引:3,自引:1,他引:2  
对等鞭金藻 3 0 1 1在不同的光照、温度和接种浓度条件下进行培养 ,分为两组 :实验组是用密封袋半连续培养 ,对照组是用大型玻璃缸槽进行培养。根据其相对生长常数K′、平均日增量X和平均倍增时间G ,筛选出最佳生长条件 :光照 6 0 0 0~ 80 0 0Lx ,水温 2 0℃ ,pH 8.2~ 8.6 ,接种浓度 3 0× 1 0 4个 mL。结果表明 ,在同样条件下 ,半连续密封培养等鞭金藻 3 0 1 1相比常规玻璃缸培养 ,达到 2 0 0× 1 0 4个 mL以上的收获浓度快 2~ 3d ,日增量和倍增时间均快 3倍左右  相似文献   

3.
本文用6种单细胞藻类培育西施舌面盘幼虫生长和成苗率的影响。观察结果:体长82μm的西施舌D形幼虫,2h后开始摄食湛江叉鞭金藻,体长136μm的壳顶幼虫才开始摄食扁藻。幼虫昼夜摄食率以上午6h—12h为最高,摄食小球藻、异胶藻、湛江叉鞭金藻的消化速率(H)为8—6h。用湛江叉鞭金藻为单一食料,投放密度以4—5×10~4ceⅡs/ml育苗效果较好。西施舌幼虫培育密度以2—5个/ml为适。  相似文献   

4.
通过投喂不同种类和不同浓度藻类对毛蚶浮游幼虫的生长进行了研究。结果表明在三种不同的单细胞藻类中湛江球等鞭金藻的效果最好,微绿球藻次之,而小球藻最差。在不同饵料浓度下,表明在初期投喂5×107L-1(cells/L)比较适宜,而后期以10×107L-1比较合适。  相似文献   

5.
笔者开展了不同饵料种类与密度对方斑东风螺面盘幼虫生长与成活率的影响的研究。实验结果:以单种单胞藻投喂方斑东风螺幼虫是牟氏角毛藻的效果最好;两种单胞藻混合投喂方斑东风螺幼虫是牟氏角毛藻+湛江叉鞭金藻组合效果最好;任何两种饵料组合均比这两种饵料的单种投喂幼虫生长速度快。牟氏角毛藻以4×104cells/mL的日投饵密度饲养幼虫效果最好;湛江叉鞭金藻和微绿球藻均是以6×104cells/mL日投饵密度饲养幼虫效果最好。  相似文献   

6.
为探究球等鞭金藻(Isochrysis galbana)的最优培养条件,采用实验生态学方法和响应面法,以球等鞭金藻的比生长速率为指标,设置不同温度、盐度、接种量单因素实验及Box-Benhnken(BBD)模型多因素交叉实验。结果表明:1)在一定温度、盐度及接种量范围内,球等鞭金藻的比生长速率随着各因素的增大,呈先升高后下降的趋势;2)通过响应面BBD模型优化出球等鞭金藻的最佳培养条件为:温度26.38℃、盐度26.61、接种量1.29×10~6个·mL~(-1),此时的球等鞭金藻的比生长速率最大,为0.44 d~(-1)。  相似文献   

7.
铜离子对湛江等鞭金藻生长的影响   总被引:1,自引:0,他引:1  
在不同的Cu离子浓度下分别培养了湛江等鞭金藻。结果显示,Cu离子浓度低于10-6mol/L时,有利于藻细胞的生长繁殖,其中在10-7mol/L时藻细胞的生长相对较快;叶绿素含量及可溶性蛋白含量相对较高;细胞膜透性、丙二醛(MDA)含量及O2-产生速率相对较低;而超氧化物歧化酶(SOD)活性相对较强。结果表明,在湛江等鞭金藻的培养液中加入浓度为10-7mol/L的Cu离子时最利于其生长,其细胞内各项生理生化指标处于最佳状态。  相似文献   

8.
通过考察乙酰甲喹对小新月菱形藻(Nitzschia closterium f.minutissima)、等鞭金藻(Isochrysis galbana Parke3011)的生长抑制和对叶绿素a、总超氧岐化酶(T-SOD)活性以及丙二醛(MDA)浓度的影响,研究了乙酰甲喹对2种微藻的毒性效应,为评价兽药乙酰甲喹的使用安全性和保护养殖环境提供基础数据。结果表明,乙酰甲喹对2种微藻的生长抑制作用随质量浓度的增加而增大,乙酰甲喹对小新月菱形藻的24 h-EC50(半数有效浓度)为4.73 mg·L~(-1)、对等鞭金藻3011的24 h-EC50为2.14 mg·L~(-1),乙酰甲喹对2种微藻均属于高毒物质,等鞭金藻3011更敏感。暴露24 h后,随着乙酰甲喹质量浓度的升高,小新月菱形藻叶绿素a浓度下降而等鞭金藻3011叶绿素a浓度基本不受影响;2种微藻的T-SOD活性随着乙酰甲喹质量浓度的升高均显著增加,各实验组MDA浓度也高于对照组,等鞭金藻3011更敏感,说明乙酰甲喹对2种微藻均能造成氧化胁迫,对细胞造成氧化损伤。  相似文献   

9.
太平洋牡蛎人工育苗的初步试验   总被引:3,自引:0,他引:3  
吕豪  魏若飞 《水产科学》1991,10(1):9-12
1990年6月,利用对虾育苗室,在45立方米水体中培育出太平洋牡蛎苗种1400万个,平均单位水体出苗33万个。卵孵化和幼虫培育所用海水均经次氯酸钠处理后使用。亲贝和幼虫培育均以等鞭金藻,叉鞭金藻,扁藻为饵料。幼虫培养每天换水2次,每次换1/3。每隔3天倒池1次。水温在21~25℃条件下培育14天,当幼虫壳长达280~300微米时出现眼点并开始附着。  相似文献   

10.
叉鞭金藻生物吸附Cu2+影响因素的研究   总被引:4,自引:0,他引:4  
对叉鞭金藻生物吸附Cu2 的影响因素进行了研究。发现叉鞭金藻对Cu2 的生物吸附主要经历了快速和缓慢吸附两个步骤。实验表明,藻细胞浓度一定时,在藻所耐受的毒性范围内,金属离子的去除率与金属离子的质量浓度呈正相关性;金属离子的去除率随着藻细胞的浓度的增加而增大;较佳的pH值为6~8。光照有利于藻体对金属离子的吸附;且叉鞭金藻干粉比新鲜藻能富集更多的Cu2 。  相似文献   

11.
An analysis of the food of 274 specimens of Tilapia aurea (Steindachner), which had been collected in Lake Kinneret, showed that this species is mainly a zooplankton consumer.A study of the quantitative dynamics of the food components in the course of a year has proved that the species in question feeds more intensely in spring, this being the time when zooplankton forms are more abundant in the water of the lake. Vegetable detritus, mixed with plankton and benthos forms, served as additional and alternative food.The lack of clearly positive degree of food component selectivity, as well as the low values of the intestine repletion index and of the condition coefficient, account for the slowness in growth of Tilapia aurea in Lake Kinneret.The low values of the growth and feeding indices are due, according to the authors, to the pressure brought to bear by the other local fish species, which are competitors for the same food.  相似文献   

12.
Analysis of the gut content of 329 specimens of T. zillii (Cichlidae) collected from Lake Kinneret, has shown great variation in the sorts of food.A study of seasonal dynamics has proved the prevalence in the food of Chironomida pupae (Diptera) in winter and spring and of zooplankton forms in summer and autumn. The additional food consisted of the various groups of algae, the most frequently found being Cyanophyta (100%) and Pyrrophyta (64.16%). An extremely voraceous species, it consumes — while searching for its preferred food — anything that comes its way in the water: algae, scraps of macrophytes, autochthonous and allochthonous insects, and forms of benthic origin, such as Nematoda, Ostracoda, Porifera and Chironomida (larvae).The satiation index is high (between 4.08 and 5.63), in contradiction to the low values of the coefficient of condition (between 3.05 and 3.51), and with the slow rate of growth in Lake Kinneret. The main food of Tilapia zillii, consists of arthropod species with a chitin content (which is eliminated unchanged) of more than 50% of the total weight, and this may account for the poor exploitation of the trophic base.This species of fish may be considered as being detrimental to others (i.e. commercially important species) because of its successful competition for food, and not, as is often incorrectly assumed, because it is an aggressive consumer of their spawn and fry.  相似文献   

13.
不同品系尼罗罗非鱼致死低温的研究   总被引:25,自引:1,他引:25  
在室内自然降温条件下,研究了三个品系尼罗罗非鱼(吉富品系,“78”品系,“88”品系)对低温的耐受力,计算得出每个品系的半致死低温,并对降温过程中尼罗罗非鱼行为活动的变化进行了观察。试验结果表明,在上海地区,当温度降低到11℃时,罗非鱼开始死亡,到7.4℃时,全部死亡。吉富罗非鱼死亡温度范围是11℃ ̄8.4℃,“78”品系是9.8 ̄7.4℃,“88”品系是11℃ ̄7.4℃。对三个品系半致死低温的研  相似文献   

14.
15.
The aims of this experiment were (1) toquantify the ability of grass carp to processduckweed and (2) to assess indirect changes inwater chemistry and phytoplankton community,caused by grass carp feeding. Yearling grass carp sized 126 ± 7.7 mm (TL) and19.6 g in weight were kept in 9 laminate tanksof 1 m3 for 14 days. Two stockingdensities (2 and 6 fish per m3) anda control without fish were used. Standard growthrate (SGR) of grass carp fed exclusively onduckweed was 0.70% body weight (BW) d–1and food conversion ratio (FCR) reached 2.0(average water temperature =21.1 ± 3.8 °C). Daily food intakewas 0.2 g of duckweed dry weight (DW), i.e.,1% of average BW of grass carp. SGR ofduckweed growing in 20 × 20 cm floatingenclosures, differed significantly[F(6,2) = 417.9; p = 0.002] between the twostocking densities of grass carp and thecontrol tanks (without fish). Mean SGR ofduckweed was 0.02 g g–1 day–1 and thehighest SGR was recorded in the control tanks.Both decrease in NH4-N and increase inNO2-N concentrations differedsignificantly between the treatments[F(2,2) = 45.3; p = 0.02 and F(2,2) = 19.2; p = 0.04 respectively]. Changes in other nitrogenand phosphorus components (NO3-N, TN, TPand PO4-P) caused by stocking of grasscarp were not significant. Biomass ofphytoplankton, dominated by filamentous algaeand blue-greens, increased proportionately tostocking density of grass carp. Althoughduckweed has a large potential for nutrientremoval, the most common pathway for thenutrients released through grass carp grazingif duckweed cover is loose is theirincorporation into phytoplankton biomass.  相似文献   

16.
叶尔羌高原鳅胚胎发育与胚后发育观察   总被引:1,自引:0,他引:1  
采用形态学和生态学方法,对叶尔羌高原鳅[Triplophysa(Hedinichthys)yarkandensis(Day)]胚胎发育和胚后发育阶段全过程进行观察、拍照并测量。结果显示:叶尔羌高原鳅,卵微黏性,略有沉性,受精卵呈卵圆形,卵径为(0.60±0.052)mm,在水温(20.0±1.0)℃下,历时65 h 34 min完成整个胚胎发育分为7个生理阶段过程;胚后发育主要根据卵黄囊、体色、鼓鳔和须的变化分为仔鱼期、稚鱼期、幼鱼期。初孵卵黄囊仔鱼全长(2.0±0.65)mm,出膜后7 d,卵黄囊吸收完毕,完全消失;初孵仔鱼继续培育至16日龄,仔鱼鳃盖后缘鼓鳔明显长出,须清晰可辨,体色加深,心脏红色素明显,体色与成体相似,标志后期仔鱼发育完全进入稚鱼期,此时鱼苗全长(8.0±0.45)mm;培育至30日龄,仔鱼鼓鳔完全,鳃盖张合明显,身体透明特征消失,稚鱼阶段完成发育进入幼鱼期,此时全长达(13.0±0.55)mm,其外部形态和生态习性均与成鱼相似。试验中,卵黄囊长度(LY)和出膜天数(D)的关系式:LY=0.0286D2–0.0636D+3.1196(R2=0.9050);用直线方程拟合卵黄囊长度(LY)和卵黄囊仔鱼全长(LT)的关系式:LY=–1.315LT+5.368(R2=0.8199);拟合卵黄囊仔鱼全长(LT)和出膜后仔稚鱼天数(D)的关系式:LT=–0.0263D2+0.5113D+1.6169(R2=0.9890)。本研究旨在通过了解叶尔羌高原鳅的早期发育特征为该物种的保护和增殖对策提供科学依据,并对其苗种生产提供理论指导。  相似文献   

17.
In this study, the embryonic development of the eggs in the Mastacembelus mastacembelus (Bank & Solender, 1794) was examined. At the same time, possibilities of artificial breeding through artificial insemination were investigated. Artificial insemination was achieved by mixing the eggs of the mature female and sperm of the mature male samples caught with gill nets (22 × 22) in Ataturk Dam Lake in Turkey. To this end, first in a Petri dish (100 × 20), the testes were cut into small pieces with a lancet and the mixture of sperm–testes‐tissue was obtained. The fertilization rate of the eggs was found to be 80%. The diameter of the eggs ranged from 2.015to 1.147 mm. The perivitelline space formed 0.5 h after insemination. The first cleavage occurred at the animal pool 4 h after insemination. The oil droplets had fused to a single droplet 19 h after insemination. The blastoderm became an embryonic shield 30 h after insemination. The blastoderm covered almost half the egg 40 h after insemination and embryonic body was formed. The blastoderm covered almost the whole egg 50 h after insemination. Some somites were discernible 59 h after insemination. The embryonic body reached two‐third of the circumference of the egg 70 h after insemination. The tail bud began to separate from the yolk 77 h after insemination. A newly hatched larva was observed at 85 h after insemination.  相似文献   

18.
Dendronereis spp. (Peters) (Nereididae) is a common polychaete in shrimp ponds built on intertidal land and is natural food for shrimp in traditionally managed ponds in Indonesia. White spot syndrome virus (WSSV), an important viral pathogen of the shrimp, can replicate in this polychaete (Desrina et al. 2013); therefore, it is a potential propagative vector for virus transmission. The major aim of this study was to determine whether WSSV can be transmitted from naturally infected Dendronereis spp. to specific pathogen‐free (SPF) Pacific white shrimp Litopenaeus vannamei (Boone) through feeding. WSSV was detected in naturally infected Dendronereis spp. and Penaeus monodon Fabricius from a traditional shrimp pond, and the positive animals were used in the current experiment. WSSV‐infected Dendronereis spp. and P. monodon in a pond had a point prevalence of 90% and 80%, respectively, as measured by PCR. WSSV was detected in the head, gills, blood and mid‐body of Dendronereis spp. WSSV from naturally infected Dendronereis spp was transmitted to SPF L. vannamei and subsequently from this shrimp to new naïve‐SPF L. vannamei to cause transient infection. Our findings support the contention that Dendronereis spp, upon feeding, can be a source of WSSV infection of shrimp in ponds.  相似文献   

19.
Substitution effect of sea tangle (ST) with tunic of sea squirt (SS) in diet on growth and carcass composition of juvenile abalone was determined. One thousand four hundred and seventy abalones were distributed into 21 containers. Six formulated diets in triplicate were prepared. A 200 g/kg ST was included into the ST0 diet. The 200, 400, 600, 800 and 1000 g/kg of ST were substituted with the same amount of tunic of SS, referred to as the ST200, ST400, ST600, ST800 and ST1000 diets, respectively. Finally, Undaria was prepared to compare effect of the formulated diets on performance of abalone. The experimental diets were fed to abalone for 16 weeks. Weight gain of abalone fed the ST400 diet was higher than that of abalone fed the ST0, ST600, ST800 and ST1000 diets and Undaria. Weight gain of abalone fed the formulated diets was higher than that of abalone fed the Undaria. The chemical composition of the carcass of abalone was affected by dietary substitution of ST with tunic of SS. In conclusion, ST could be completely substituted with tunic of SS without retardation in performance of abalone. Abalone fed the ST400 diet substituting 400 g/kg ST with tunic of SS achieved the best growth.  相似文献   

20.
Daphnia lumholtzi (Sars) was found in Lake Kinneret until the late nineteen-fifties. Lake Kinneret was the northern-most limit of the distribution of this species. It is suggested that fingerlings of grey mullets and Sarotherodon aureus that were introduced into Lake Kinneret caused the extinction of D. lumholtzi.  相似文献   

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