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1.
A cyanobacterium ( Spirulina platensis) was co-cultured with black tiger shrimp ( Penaeus monodon) for water quality control. We evaluated the effects of: (1) three S. platensis trial conditions on inorganic nitrogen concentrations at one shrimp density ( S. platensis trial conditions included: absent, nonharvested and semicontinuous harvesting) and (2) two shrimp densities on inorganic nitrogen concentrations, with and without S. platensis. Semicontinuous harvesting of S. platensis at one shrimp density resulted in significantly reduced ( P<0.05) inorganic nitrogen concentrations (NH 4, NO 2 and NO 3). With S. platensis absent, ammonium and nitrite concentrations ranged from 0.5 to 0.6 mg l −1, while nitrate concentrations ranged from 16 to 18 mg l −1 by day 44. With nonharvested S. platensis, considerable variability occurred with nitrogen concentrations. Semicontinuous harvest of S. platensis reduced nitrate to 4 mg l −1, while ammonium and nitrite ranged from 0.0 to 0.15 mg l −1, respectively. The factorial evaluation of shrimp density versus presence and absence of S. platensis resulted in greatly reduced nitrogenous compounds with S. platensis present regardless of shrimp density, and only moderately increased nitrogen with greater shrimp density. Without S. platensis, all nitrogen compounds were substantially elevated and shrimp survived was significantly reduced at high shrimp density. 相似文献
2.
为利用种间竞争进行有益微藻共培养和构建池塘优良藻相,文章探究了不同温度 (10、15、20、25、30、35 ℃) 和起始密度比 [小皮舟形藻 ( Navicula pelliculosa)∶小球藻 ( Chlorella vulgaris) 分别为1∶10、1∶1、1∶0.1 ] 对2种藻类生长竞争的影响。结果显示,单种培养中,10~15 ℃小皮舟形藻的细胞密度呈先升高后降低的趋势,20~30 ℃呈逐渐升高的趋势,最大值为0.50×10 6个∙mL −1,35 ℃时停止生长,适宜生长温度为25~30 ℃;10~15 ℃小球藻生长缓慢甚至停止,20~35 ℃细胞生长迅速,最大值为14.15×10 6 个∙mL −1,适宜生长温度为35 ℃。混合培养中小皮舟形藻生长速率均高于单种培养,且随小球藻接种比例增加逐渐升高,在适宜温度下,混合培养的细胞峰值显著高于单种培养;混合培养中小球藻的接种密度越小生长速率则越大,1∶0.1组显著高于单种培养组,1∶10组则显著低于单种培养组。小球藻对小皮舟形藻的竞争抑制作用较小,混合培养中,小球藻对小皮舟形藻的竞争抑制参数( α)随温度升高和小球藻密度增加而增大,小皮舟形藻对小球藻的竞争抑制参数 ( β) 随温度和小皮舟形藻比重增加而增大。2种微藻能够稳定共存。 相似文献
3.
南极磷虾是南大洋生态系统食物网中的关键种,在南大洋中上层生态系统中起着至关重要的连接作用,其资源的养护和持续利用受到国际社会日益关注。磷虾研究已有90多年的历史,其生物量及其分布一直是研究的重点。生物量评估方法也在不断发展,从早期的浮游动物干重法、生产量与生物量比例系数转换法,到网具采样法以及现在流行的声学法,评估手段也变得更为高效。本文通过系统梳理磷虾生物量的主要评估方法,分析其优缺点,并着重从磷虾目标强度模型(TS)参数的海上实测、声学数据中磷虾信号的提取,磷虾单位平方海里声学反射系数(NASC)的计算,基于渔船声学数据修正磷虾渔业单位捕捞努力量渔获量(CPUE),基于渔船声学数据的磷虾集群、洄游和渔场形成机制研究等5个方面对现行生物量声学评估法提出改进建议,提高资源评估的精度,以期为磷虾生物资源的开发与管理提供科学依据。 相似文献
4.
文章以小新月菱形藻 (Nitzschia closterium f. minutissima)为研究对象,分析比较了小新月菱形藻在负压光生物反应器与开放式桶培养下,藻密度、pH、溶解氧及菌落结构的变化情况。结果表明,在负压光生物反应器培养下的藻密度可达到1.33×107个·mL–1,明显高于开放式培养的藻密度 (8.36×106个·mL–1)。藻液中pH随藻密度增加而升高,两者呈显著正相关 (P<0.01),在负压光生物反应器及开放式培养环境中pH最高值分别为10.3和9.3。溶解氧与pH变化趋势相反,在负压光生物反应器内溶解氧随藻密度增加而降低,最后稳定在6.5 mg·L–1,溶解氧的下降可能与玫瑰杆菌 (Roseobacter)成为优势细菌有关。利用16S rDNA基因的高通量测序技术,分析在培养过程中藻际菌群的结构变化,发现菌落的多样性显著下降 (P<0.05),培养前期主要以变形杆菌 (Proteobacteria)和拟杆菌 (Bacteroidetes)为优势细菌,在负压光生物反应器内培养后期主要以蓝细菌 (Cyanobacteria)与玫瑰杆菌为优势细菌,其菌落结构与开放式桶存在明显差异。 相似文献
5.
南极磷虾是南极海洋生态系统中的关键物种,具有重要的商业开发潜力,但其集群的类型与分布存在较大时空异质性,这增加了南极磷虾资源评估的难度,也对南极磷虾渔业的海上作业与企业生产安排带来了较大的挑战.为了探究布兰斯菲尔德海峡渔场内南极磷虾的集群分布和结构特征,提高渔船作业效率,基于渔船采集的声学数据,分析其时空分布特征,昼夜... 相似文献
6.
Growth, proximate composition and chlorophyll a content was estimated in static cultures of Isochrysis aff. galbana (clone T-Iso) to compare the quality and quantity of the biomass produced with an agricultural fertilizer medium versus f/2 medium. Culture of microalgae was done with controlled temperature, air flux of 4.5 l min −1, salinity of 33‰ and an irradiance of 110±3 μmol m −2 s −1. Daily samples from the cultures were taken to estimate cellular density, proximate composition and chlorophyll a content during 7 days. Mean cellular density from samples with f/2 medium and with agricultural fertilizer were similar (no significance at P≤0.05), and mean growth rates of 0.62 and 0.61 doubling per day, respectively. Maximum similar values of protein content of 7.3 and 7.6 pg per cell were estimated on the 5th day in f/2 and agricultural fertilizer medium, respectively. Carbohydrate and lipid content decreased during the first 5 days corresponding to the exponential growth in both experiments. Higher content of carbohydrate (no significance at P≤0.05) was found in both media during the first 2 days, after 4 days the carbohydrates reduced three times theirs concentrations. Generally lipid contents in the cultures with agricultural fertilizer were significantly higher ( P≤0.05) than f/2 medium. The chlorophyll a content increased exponentially during the culture, and its concentration was similar in both experiments. In conclusion, the cellular density and the biochemical constituents were similar when using either media. This fertilizer can be used in the production of I. galbana (T-Iso) employed in aquaculture. 相似文献
7.
太平洋磷虾是黄海生态系统中浮游动物的关键种。为准确评估太平洋磷虾的资源密度,基于2010年1月黄海渔业资源调查过程中采集的声学和生物学数据,利用SDWBA目标强度理论模型,研究了太平洋磷虾38和120 k Hz目标的回声散射特性,并根据2个频率平均体积散射强度的差值(简称频差技术),开展了太平洋磷虾回波映像识别及资源密度评估研究。结果显示,太平洋磷虾的目标强度与其倾角和体长密切相关;120k Hz的目标强度明显高于38 k Hz,且两个频率的有效平均目标强度之差随着磷虾体长的增加而减小。数据处理结果显示,两个频率回声数据的平均体积散射强度(MVBS)呈线性关系,120 k Hz的MVBS比38 k Hz高约14.1 d B,与理论仿真结果一致;回声散射层内太平洋磷虾的资源密度为1.8~2531.8尾/m3,均值为255.1尾/m3。本研究对利用渔业声学技术开展浮游动物资源评估具有借鉴意义,未来还需要进一步对太平洋磷虾目标强度模型参数及目标识别方法进行完善,以提高其资源密度声学评估的准确度。 相似文献
8.
The total ammonia nitrogen (TAN) excretion of spiny lobsters Jasus edwardsii and Panulirus cygnus, was determined in relation to temperature, body weight, emersion, daily rhythm and feeding. Temperature and body weight had large influences on the rate of TAN excretion. Exponential relationships were found between temperature ( T) and TAN excretion of both species. These were described by the following equations: J. edwardsii Log 10 TAN=0.041 T−3.57 ( r2=0.979, F=143.2, P=0.001), P. cygnus Log 10 TAN=0.057 T−3.90 ( r2=0.987, F=302.2, P<0.001). TAN excretions of both species were positively correlated to body weight ( W), and the relationships were described by the following equations: J. edwardsii Log 10 TAN=0.473 log 10 W−1.704 ( r2=0.42, F=14.05, P=0.001), P. cygnus Log 10 TAN=0.499 log 10 W−1.346 ( r2=0.69, F=44.18, P<0.001). TAN excretion increased significantly when lobsters were re-immersed after a 30 min period of emersion. However, it returned to pre-emersion levels by the second hour of re-immersion. Daily rhythm resulted in a significantly higher nocturnal TAN excretion rate for J. edwardsii; no daily rhythm was observed for P. cygnus. Feeding had the largest influence on TAN excretion, with maximum increases of 6.28 ( J. edwardsii) and 5.60 ( P. cygnus) times the pre-feeding level. TAN excretion rates remained significantly higher than the pre-feeding levels for an extended period (26 h, J. edwardsii; 30 h, P. cygnus). Implications for the use of purging tanks in lobster holding facilities and for the design of biofiltration systems are discussed. 相似文献
9.
文章探讨了不同光照强度 (1 000、3 000、5 000、7 000和9 000 lx) 下琼枝藻 ( Betaphycus gelatinae) 的生长、光合色素及颜色变化,基于CSE-1成像色度检测分析系统,研究了琼枝藻颜色参数 L*a*b* (CIE 1976) 与光照强度、生长、光合色素的相关性。结果显示,琼枝藻的相对生长速率和增重率均随光照强度的增加显著增大,适宜生长的光照强度为7 000~9 000 lx,光照强度为1 000 lx时琼枝藻无明显生长。叶绿素 a (Chl- a)、类胡萝卜素 (Car)、藻红蛋白 (PE) 和藻蓝蛋白 (PC) 含量总体上随光照强度的增加呈下降趋势。随着光照强度的增加,琼枝藻的颜色由红褐色逐渐变为绿色,三刺激值 XYZ在CIE 1931色度图上呈现明显的分布差异。光照强度与明度 ( L*) 呈显著正相关 ( P<0.05),与红绿色度 ( a*) 呈极显著负相关 ( P<0.01);生长速率与 L*、黄蓝色度 ( b*) 均呈显著正相关 ( P<0.05);Chl- a与 L*呈显著负相关 ( P<0.05),与 a*呈显著正相关 ( P<0.05);PE和PC均与 a*呈显著正相关 ( P<0.05)。 相似文献
10.
This study was designed to test the possibility that Streptococcus iniae enters through the gills and causes infection in hybrid striped bass. To determine the dose response, four groups of fish were inoculated with S. iniae via the gills with a dose of 5.0×10 5, 2.6×10 6, 5.0×10 6, or 1.0×10 8 CFU/fish. One group of fish was inoculated with tryptic soy broth (TSB) via the gills to serve as controls. The cumulative percent mortality was 13%, 27%, 100% and 100% for 5.0×10 5, 2.6×10 6, 5.0×10 6 and 1.0×10 8 CFU/fish, respectively. We also examined the tissue dissemination of S. iniae at 0.5, 4, 8, 12, 24, 48 and 72 h after experimental gill inoculation. Fish were inoculated with 2.6×10 6 or 5.0×10 6 CFU/fish, which caused low and high mortality, respectively. Within 48 h, fish inoculated with the 2.6×10 6 dose were culture positive on the gill surface, blood of the first and second gill arches, blood of the third and fourth gill arches and the nares. However, for the dose of 5.0×10 6 CFU/fish, S. iniae was also isolated from the olfactory, optic and cerebellum regions of the brain, eye, head kidney, trunk kidney, spleen and liver at 48 h. For the 2.6×10 6 dose, S. iniae was not isolated until 48 h post-inoculation, but was isolated at 12 h for the 5.0×10 6 dose. The results of this study indicate that S. iniae can enter hybrid striped bass through the gills. However, mortality at similar S. iniae doses was lower than we previously observed by inoculation of the nares. 相似文献
11.
该文基于CIE-L*a*b*颜色分析系统,采用全自动分光测色仪对热带普通小球藻 (Chlorella vulgaris) 生长过程中的颜色值变化进行监测,同时测定其细胞密度及色素的质量浓度变化并进行相关分析。结果显示,热带普通小球藻生长过程中细胞密度分为接种期、快速生长期、稳定期和衰亡期4个阶段,绿色素和黄色素质量浓度和颜色参数值黄度值(b*)、色差值(△E)和饱和度(C)均呈增加趋势,而颜色参数值明度值(L*)、红度值(a*)、相角(H°)呈降低趋势;颜色参数值与细胞密度、色素质量浓度具有较强的相关性,线性回归模型拟合度较高,在快速生长期尤为显著,其中b*和△E可作为较佳的指示指标。通过量化热带普通小球藻生长过程中的颜色参数变化,建立非接触性数量及质量动态变化预测模型,可快速准确预测,为提高养殖过程中精细操作及效率提供理论基础。 相似文献
12.
为研究 MAP2 K1 ( MEK1) 基因在三角帆蚌 ( Hyriopsis cumingii) 性别决定中的作用,采用cDNA末端快速克隆技术 (Rapid-amplification of cDNA ends, RACE) 克隆了 MAP2 K1基因序列,利用实时荧光定量分析比较 MAP2 K1基因在三角帆蚌6个组织 (性腺、闭壳肌、肝胰腺、鳃、外套膜、斧足)、早期发育阶段 (1—8月龄) 性腺和1—3龄雌雄性腺中的表达水平,利用原位杂交确定 MAP2 K1基因在2龄三角帆蚌性腺中的定位。结果显示, MAP2 K1基因开放阅读框 (ORF) 长度为1 194 bp,编码397个氨基酸。 MAP2 K1基因在卵巢中高表达;早期发育阶段在2月龄表达量最高;1—3龄的表达结果显示, MAP2 K1基因在卵巢中的表达量均高于同期精巢中的表达量 ( P<0.05)。原位杂交结果显示, MAP2 K1基因在雌性三角帆蚌的卵母细胞及卵子上有明显的杂交信号。RNAi结果显示,干扰 MAP2 K1基因的上游基因 C-MOS后,下游基因 MAP2 K1在雌性中的表达下降了82.31%,在雄性中的表达下降了73.60%。推测 MAP2 K1基因可能参与三角帆蚌的卵巢发育过程,在三角帆蚌中属于偏雌性基因,其表达受 C-MOS基因的影响。 相似文献
13.
The growth potential of wild juvenile Penaeus stylirostris was analyzed in experimental trials using chemical and organic fertilizers and pelleted feed in 0·25 ha earthen ponds. Shrimp were stocked at a low density (1·6 ind/m 2). After 103 days, final weight ranged from 9·5 to 26·0 g. The significance of differences in growth response was determined using a reparameterization of the von Bertalanffy growth curve. Maximum growth rates observed in the trials ranged from 0·06 to 0·33 g/day, averaging 0·22 g/day. Maximum rates were related to weight by the equation: (dw/dt)max=0·034w0·69 r2=0·9,P<0·05 Pelleted feed produced best growth, chemical fertilizers were acceptable, and organic fertilizers gave poor results. The high growth potential of the species stimulates future research in order to adapt a culture technology to the semi-arid conditions of northwest México, where the species is indigenous. 相似文献
14.
为了探究南极磷虾致敏问题,从南极磷虾中筛选、鉴定、分离纯化其主要过敏原,并对过敏原的性质进行研究,实验通过缓冲盐溶液提取南极磷虾蛋白;采用SDS-PAGE和Western blot(WB)筛选南极磷虾过敏原;使用高效液相色谱-串联质谱鉴定过敏蛋白;通过等电点沉淀、硫酸铵盐析、阴离子交换柱层析分离纯化过敏原;采用SDS-... 相似文献
15.
近年来,南极磷虾渔业过于集中于布兰斯菲尔德海峡,这也使得该海区磷虾资源状况及其生态学特征日益受到关注。南极磷虾群具有较为明显的昼夜垂直移动特征,开展此方面的研究可为探索其渔场形成机制提供基础数据,并为磷虾渔业反馈式管理提供参考。基于磷虾渔船上Simrad EK80记录的相关声学数据,使用Echoview软件判别声学数据中的磷虾群体,对2016年秋季布兰斯菲尔德海峡南极磷虾群昼夜垂直移动特征进行分析,并进一步分析影响磷虾群昼夜垂直移动的因素。结果显示,3月和4月磷虾群深度基本维持在250 m以浅,虾群最大深度出现在日升时分的频次最高(22.9%),而最浅深度出现在夜间时分的频次最高(36.0%),同时在日升时分,虾群厚度达到最大值;白天磷虾群多集中在较深水层,夜间会上浮到较浅水层。随着月份的推移,磷虾群平均深度总体呈现加深的趋势。光强和海底深度是影响磷虾群深度变化的2个主要因素。 相似文献
16.
南极磷虾( Euphausia superba)为南大洋中上层生态系统的关键种,对其生物量的研究有助于更准确地掌握磷虾的生态和分布信息。基于2017年我国南极磷虾声学调查采集的断面回波映像,应用声学回波后处理软件(Echoview),评估了南奥克尼群岛周边水域的磷虾生物量。该海域磷虾体长范围为25.50~49.21 mm,平均体长为(33.01±4.06)mm;其中雌性平均体长为(33.15±3.90)mm,雄性平均体长为(32.68±4.43)mm,雌、雄磷虾体长无显著性差异。本海域声学映像可分为1338个积分单元,最大单元磷虾密度为554.07 g/m 2,最小单元密度值为0 g/m 2。调查海域磷虾分布不均匀,87.90%的积分单元无磷虾生物量。磷虾平均密度为71.01 g/m 2,总生物量为1.77×10 6 t,密度差异系数为97.4%。磷虾主要分布在水深<200 m的南奥克尼群岛大陆架海域,群岛东侧磷虾生物量多于西侧。积分单元中磷虾密度大于450 g/m 2但小于600 g/m 2的有2个,群岛东西两侧各1个;密度值大于300 g/m 2但小于450 g/m 2的积分单元有6个,5个位于群岛东侧。远离群岛的2个断面(1,9)和调查海域中心的2个断面(5,6)磷虾生物量较少。本海域磷虾的昼夜垂直移动对磷虾生物量评估也无影响。磷虾白天聚集在60~180 m水层,随着时间推移,磷虾逐渐向上或向下移动。光照强度是触发磷虾白天下沉、夜晚上浮的因素之一。 相似文献
17.
The nutritional response of Litopenaeus schmitti larvae to substitution of Chaetoceros muelleri by Spirulina platensis meal (SPM) was evaluated. The substitution levels (S) were 0%, 25%, 50%, 75% and 100%, dry weight basis. Final larval length (FL) ranged from 1.98 to 3.16 mm for the different substitution levels. There was a significant relationship between S and FL, described by the following quadratic equation: FL = 2.853 + 0.01598 S − 0.000233 S2. The substitution level ( S) yielding maximum FL was 34.2%. Development index (DI) values ranged from 2.84 to 3.93 and were dependent on substitution level. The corresponding equation was DI = 3.799 + 0.00945 S − 0.000189 S2 ( P < 0.01). Maximum DI was obtained at 25.0% substitution. Survival was high (82–87%) and no significant differences were found between treatments. Protein digestibility of either microalgae was high, with 92% for SPM and 94% for C. muelleri, with no significant differences between them. The results in this study indicate that an adequate balance of nutrients in relation to the requirements of the species is critical. To simultaneously improve FL and DI, a 30% substitution of C. muelleri by SPM is suggested. This is equivalent to feeding 0.15 mg larvae − 1 day − 1 dry weight basis of a 70% C. muelleri/30% SPM diet, representing 0.078 mg protein larvae − 1 day − 1, 0.026 mg lipids larvae − 1 day − 1 and 2.732 J larvae − 1 day − 1. 相似文献
18.
Ten species of microalgae were tested for ingestion and digestion in Pteria sterna larvae using epifluorescence microscopy to choose an appropriate diet. An experiment was conducted using 2, 4, 5 (straight-hinge) 10 and 22 (umbo stage) day old larvae. Larvae were stocked in 150 ml flasks at 30 ml −1 and fed 100,000 algal cells ml −1 of each species individually. Larvae were fed for 1 h and then were observed under the microscope to detect ingestion; larvae were then sieved and placed in flasks containing filtered seawater and were observed after 1 and 2 h to analyse digestion for the microalgae ingested. Out of the 10 species administered, only Nannochloris sp., Pavlova lutheri and Isochrysis aff. galbana (T-ISO) were ingested, and only the last two species were digested. No ingestion of Phaeodactylum tricornutum, Chaetoceros muelleri, Ch. calcitrans, Thalassiosira weisflogii, Dunaliella salina, Tetraselmis tetrathele and T. suecica was evident at any stage of larval development tested. Only T-ISO and P. lutheri should be used for larval rearing of P. sterna until other species are identified as suitable (ingested and digested) for this species. 相似文献
19.
Mobile hydroacoustic surveys are increasingly used to assess the distribution and abundance of freshwater fish; yet, fish may avoid moving vessels, potentially introducing bias in these assessments. In this study, avoidance in boreal lakes and reservoirs was quantified by developing a simple method based on paired drift:drift (D:D) and drift:motor (D:M) transects. Two systems in eastern Manitoba, Canada were studied: Lac du Bonnet reservoir and Nopiming. Acoustic data were collected using a digital DTX echosounder (BioSonics, Seattle, WA, USA), with a downward facing 200‐kHz split‐beam transducer, deployed from 5.5‐m vessels (Boston Whalers) modified for acoustic research. An avoidance coefficient ( Ac) was developed based on comparisons of acoustic fish densities while the vessel moved over the same transects by drifting, and by motoring at survey speeds. Ac did not differ significantly from 1 (no avoidance) at Nopiming (median of 0.81, n = 13), but did at Lac du Bonnet (median of 0.51, n = 31, P < 0.05). Variability in Ac was as high in transect pairs and was unrelated to fish depth (mean 6.9 m at Lac du Bonnet; 13.1 m at Nopiming) or survey speed (up to 3.70 m·s ?1, 7 knots). Results indicated that fishes did not dive in the presence of the motoring vessel, nor was avoidance size‐based. We did not detect any evidence of fish attraction to our drifting vessel. Our results suggest that boat avoidance during acoustic surveys of shallow boreal lakes may vary in relatively similar water bodies but can be quantified experimentally. 相似文献
20.
针对中国毛虾 ( Acetes chinensis) 产量逐年锐减问题,中国开始对近海海域实施毛虾限额捕捞措施,采用视频监控技术辅助捕捞管理。提出一种基于3-2D融和模型的毛虾捕捞渔船行为识别方法,为限额捕捞管理提供新的解决方案。通过在毛虾渔船上4个固定位置安装高清摄像设备,并记录捕捞作业全过程,共获取600余个视频监控数据作为初始数据;从初始数据中筛选有效的视频数据,同时对视频数据进行5种行为的划分和标记。为了提高网络训练的效率,对视频数据进行压缩和帧数分割等预处理;最后,通过搭建3-2D融合的卷积神经网络来训练模型,实现渔船行为特征的提取和分类。结果表明,捕捞渔船行为识别方法的分类精度为95.35%,召回率为94.50%,平均精确度为96.60%,模型整体得分达93.32%,平均检测时间为35.46 ms·帧 −1,可用于毛虾渔船捕捞视频的实时分析。 相似文献
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