对虾封闭式工厂化养殖水环境要素的变化特征及其相互关系   总被引：4，自引：0，他引：4  

童万平  韦蔓新  何本茂 《台湾海峡》2004,23(1):19-23

根据2002年8月7～8日对虾工厂化养成中后期A、B代表池的实测数据，分析讨论了该时期养殖水体中环境要素的变化特征及其相互关系．结果表明：研究水体水温、盐度和溶解氧含量适宜．日变化幅度不大．但pH值略为偏低，而COD值明显偏高．与该时期投饵量大，残饵及排泄物明显增加有关．但对A池来说，生物作用的影响占主导地位，而对B池而言．则以化学过程影响为主．  相似文献   

基于ASTER影像的近海水产养殖信息自动提取方法   总被引：5，自引：1，他引：5  

周小成  汪小钦  向天梁  江洪 《湿地科学》2006,4(1):64-68

水产养殖地已经成为海洋环境监测的热点目标之一。采用具有高光谱分辨率和较高空间分辨率(15m)的ASTER遥感影像,以九龙江河口地区为研究示范区,进行近海水产养殖信息的自动提取方法研究。结果表明,利用ASTER影像的光谱信息和水产养殖地的纹理结构信息,可以实现近海水产养殖地的自动提取。先利用监督分类方法提取混淆有其他水体的水产养殖信息,采用邻域分析来增强水产养殖地的空间纹理信息。通过综合监督分类和水产养殖地空间纹理增强的结果,在专家决策分类器中建立决策规则,进行水产养殖地的自动提取,提取的精度达93%。  相似文献   

Sustainable management of a coastal lagoonal system (Ria Formosa, Portugal): An ecological model for extensive aquaculture     

S. Gamito 《International Journal of Salt Lake Research》1997,6(2):145-173

The Ria Formosa lies in southern Portugal, extending for about 55 km. It is a true barrier island system, comprising mainland, backbarrier lagoons, inlet deltas, barrier islands, barrier platforms and shoreface. Of the Ria Formosa system, which covers a total area of 163 km², 20 km² are occupied by salinas and aquaculture ponds. The main water reservoir of thesalinas and the extensive aquaculture ponds behave like small lagoons where there are one or more openings to a tidal channel. These small lagoons have the advantage of being easy to study and to model. An ecological model was developed to estimate the potential production of the gilthead seabream in the Ria Formosa, in an extensive aquaculture regime. This model was based on information concerning chemical and physical factors (forcing functions) and secondary production estimates from four sites in the Ria Formosa with different environmental conditions, where extensive aquaculture is practised. Published information on optimal growth parameters of the gilthead was used to build the model, which was based on some assumptions concerning the detrimental effect of an excessive increase of salinity and other environmental factors both on gilthead growth (one state variable) and on prey production (divided into two state variables), which is essentially benthic macrofauna. Reservoirs with low water renewal undergo large environmental fluctuations. The growth of gilthead or other fish can be difficult, not only because of the adverse environmental conditions but also because of the low secondary production. The maximum yield of fish is predicted to be less than 6 g m⁻². In reservoirs where the water exchanges on almost every tide, the maximum yield of gilthead can be in excess of 22–25 g m⁻². Nevertheless, the high productivity of these sites in terms of secondary production of benthos and fish, as well as primary production, can lead to oxygen depletion during the night or at day-break. An attempt to further improve fish production by fertilisation or by adding food could provoke a rapid deterioration of the water quality and endanger all production.  相似文献   

WATER QUALITY STUDIES IN MALAYSIAN DISUSED MAN MADE LAKFS FOR SUITABILITY OF AN AQUACULTURE PROJECT     

Azma Hanim Ismail Mashhor Mansor Wan Maznah W O 《湿地科学》2005,3(4):258-268

A study has been conducted on the status of water quality in two disused man made lakes, which have potential for cage aquaculture project. This study highlights the quality of water analyzed with reference to various physical - chemical parameters in two selected lakes and their suitability for fish farming. A number of parameters were measured including the amount of NH3 - N, NO3 - N, NO2 - N and total phosphorus while in - situ measurement including DO, pH, temperature, conductivity, TDS and Secchi disk visibility. Beside the physical -chemical of water, the location, morphometry and climate conditions were also investigated. The chemical data analyzed for six months indicated that Lake A and Lake B are characterized by relatively high DO, slightly neutral pH and low TSS. The concentration of NH3 -N and NO2 -N was very low （0. 058 mg/L and 0. 04 mg/L, respectively） and total phosphorus was usually in low concentration and sometimes would seem negligible. Besides, NO3 - N occurred in slightly higher concentration （1.75 mg/L）. Results obtained indicated that the study site has high potentiality for development of inland fisheries practices.  相似文献   

Effects of Enclosure on Plant and Soil Nutrients in Different Types of Alpine Grassland     

WANG Fang  HE Yongtao  FU Gang  NIU Ben  ZHANG Haorui  LI Meng  WANG Zhipeng  WANG Xiangtao  ZHANG Xianzhou 《资源与生态学报(英文版)》2020,11(3):290-297

Enclosure is one of the most widely used management tools for degraded alpine grassland on the northern Tibetan Plateau, but the responses of different types of grassland to enclosure may vary, and research on these responses can provide a scientific basis for improving ecological conservation. This study took one site for each of three grassland types (alpine meadow, alpine steppe and alpine desert) on the northern Tibetan Plateau as examples, and explored the effects of enclosure on plant and soil nutrients by comparing differences in plant community biomass, leaf-soil nutrient content and their stoichiometry between samples from inside and outside the fence. The results showed that enclosure can significantly increase all aboveground biomass in these three grassland types, but it only increased the 10-20 cm underground biomass in the alpine desert. Enclosure also significantly increased the leaf nutrient content of the dominant plants and contents of total nitrogen (N), total potassium (K), and organic carbon (C) in 10-20 cm soil in alpine desert, thus changing the stoichiometry between C, N and P (phosphorus). However, enclosure significantly increased only the N content of dominant plant leaves in alpine steppe, while other nutrients and stoichiometries of both plant leaves and soil did not show significant differences in alpine meadow and alpine steppe. These results suggested that enclosure has differential effects on these three types of alpine grasslands on the northern Tibetan Plateau, and the alpine desert showed the most active ecological conservation in the responses of its soil and plant nutrients.  相似文献   

牡蛎对浮游植物群落下行控制作用的围隔实验研究     

王兆慧  张光涛 《海洋科学》2020,44(9):47-53

牡蛎的滤食作用不但能控制浮游植物丰度，还能通过摄食选择性影响群落结构。通过在较高营养水体的围隔实验表明，牡蛎养殖在持续磷限制条件下，促使浮游植物群落由甲藻向小型硅藻优势转变。实验结束时对照组中浮游植物群落由扁压原甲藻主导，占总丰度的77%；而牡蛎养殖组新月柱鞘藻丰度占比达到93%。牡蛎养殖组中，甲藻去除速率随养殖密度增长，但是硅藻最终丰度在高密度牡蛎组最高。研究结果说明大量的贝类养殖能够提升小型链状硅藻的优势度，增加此类赤潮发生风险。  相似文献   

适宜浓度的维生素E促进半滑舌鳎生长激素基因的表达     

王蔚芳  向玲  王琳  黄滨  李会涛 《海洋科学》2020,44(2):113-119

本实验旨在探究维生素E对半滑舌鳎垂体组织中生长激素基因表达的影响。作者在每千克等氮等能的基础饲料中分别添加0、400和1 600mg的DL-α-生育酚乙酸酯(维生素E)投喂半滑舌鳎(Cynoglossus semilaevis)成鱼(464±2.6) g,进行为期8周的养殖实验;另外,在L-15培养基中添加0、18和54μmol/L的维生素E,对半滑舌鳎成鱼(464±2.6) g的垂体细胞进行为期3 d的体外原代培养实验。分别取垂体组织和原代细胞,通过荧光实时定量PCR分析其gh mRNA的相对表达量。实验结果表明:垂体组织中gh mRNA的相对表达量随着饲料中维生素E含量的增加而呈现先升高后下降的变化趋势,在400 mg/kg组时显著高于其他各组(P0.05);随着细胞培养液中维生素E浓度的升高, gh mRNA的相对表达量显著增加(P0.05)。由此可见,适宜浓度的维生素E能够促进半滑舌鳎垂体组织中生长激素基因的表达。  相似文献   

我国大黄鱼养殖产业发展研究          下载免费PDF全文

杨卫  王春苗 《海洋开发与管理》2020,37(5):71-75

文章对我国大黄鱼养殖产量及分布、养殖模式、投入产出情况、收购价格变动和进出口情况进行分析，总结了几项产业中存在的问题，包括：养殖结构亟待调整、关键养殖技术欠缺、鱼苗成活率偏低、市场中存在逆向选择。在此基础上，提出积极调整养殖结构与养殖密度、提升合作社与试验站职能、加强养殖技术与鱼药研发力度、培育推广优质大黄鱼苗种、促进可追溯体系建设的产业发展建议。  相似文献   

苏北浅滩养殖筏架附生绿藻入海过程在黄海绿潮形成中的作用   总被引：3，自引：0，他引：3  

张清春  孔凡洲  颜天  于仁成  胡晓坤  苗辉  周名江 《海洋与湖沼》2018,49(5):1014-1020

本研究采用现场定量观测为主的研究方法,在2017年5月期间对苏北浅滩竹根沙收紫菜养殖筏架作业过程进行跟踪调查;对养殖筏架绠绳附生绿藻自然脱落和收筏架作业过程人为刮落附生绿藻,以及收筏架作业前后入海的漂浮绿藻生物量进行定量观测。结果表明:筏架绳附生绿藻自然脱落率低,为3.58%±0.78%;收筏架作业过程中绠绳上刮落绿藻生物量为(12±3)kg湿重/根,由此估算2017年整个苏北浅滩刮落的生物量估算可达到万吨湿重;收筏架作业后海域漂浮绿藻生物量是作业前的7.6倍。研究结果进一步明确了收筏架作业过程中人为刮落绿藻是目前筏架附生绿藻最主要的入海方式。刮落绿藻是海水中漂浮绿藻的主要来源,其生物量对南黄海绿潮的规模大小有重要的影响。研究结果为绿潮防控措施的制定和实施提供科学依据。  相似文献   

Landsat长时间序列的阳澄湖湖面围网时空变化     

计璐艳  尹丹艳  宫鹏 《遥感学报》2019,23(4):717-729

准确提取湖泊围网区域的时空分布信息对湖泊的保护和可持续发展具有重要意义。本文以阳澄湖为研究区域,收集该地区1984年—2017年所有的Landsat 5和Landsat 8影像(共计396景),提出了结合光谱和纹理特征的围网提取新算法,同时利用时间序列滤波消除年际间因数据不一致造成的偏差。以高清影像人工解译作为参考,阳澄湖围网提取结果的生产者精度在72.57%—88.53%,用户者精度在79.79%—98.10%,围网面积变化与文献记录吻合。结果表明,阳澄湖围网经历了"无围网期"(1984年—1994年)、"快速增长期"(1994年—1998年)、"巅峰期"(1999年—2002年)、"快速下降期"(2003年—2006年)和"稳定期"(2007年—2017年)5个阶段,最高达到100 km2,目前稳定在30 km2;通过研究围网区植被指数发现,2002年之后围网区浮水植物的种植面积增大;通过对比水质数据发现,2002年至今持续15年的围网拆除并未使阳澄湖恢复到80年代无围网养殖时期的II类水,其水质依然处于Ⅲ—Ⅳ类。因此在湖泊养殖开发过程中,政府应该坚持可持续发展道路,在不破坏湖泊水质的基础上发展湖泊经济。  相似文献