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本文将小波分析用于波群结构和波群中波破碎的研究。实验结果表明,波群中波动的振幅不是关于波群中央对称的,而是波群前部波动的振幅较大。这种不对称性导致波群前部单个波的波陡较大,后部单个波的波陡较小,当谱宽度增大时波群前部与后部单个波的平均波陡之差增大。波群前部波陡较大导致波群前部的波动最容易发生破碎,而不是波群中央的波动最容易发生破碎,波群中波动最可能发生破碎的位置距波群中央的长度为波群长度的1/6。  相似文献   

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The Regularity of the Spawning Season of Some Fishes   总被引:3,自引:2,他引:1  
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黄海乳山湾的鱼类有40科69种,以暖温性底栖鱼类为主,并以底栖生物食性的鱼为最多.本文对黄海乳山湾13种主要经济鱼类的生物学特性加以说明,乳山湾5~9月为多种经济鱼类的产卵场,应严格执行有关法规,制定禁渔期和禁鱼区以保护鱼类资源.  相似文献   

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蚌、鱼养殖模式对水体富营养化控制作用的研究   总被引:11,自引:0,他引:11  
为了探索控制水体富营养化的新方法.在5~9月长江中下游地区水体富营养的发展期,通过野外规模性试验,即水体吊养珍珠蚌并搭养少量鱼类,然后定期测定4个主要富营养化指标,观察水生生物种群和数量。结果表明,养蚌育珠并搭养适量鱼类可以使20~40cm的水层形成附着丝状藻类、原生动物、腔肠动物、多孔动物和苔藓动物等多种附着生物,使N,P,COD和BOD5含量分别下降67.3%,73.2%,38.1%和15.5%,起到了明显控制富营养化的作用,同时还能收获珍珠、蚌肉和贝壳等产品。比其他控制方法具有更好的实际应用性。  相似文献   

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在实验室风浪槽中观测风浪,发现波群连长是影响波群中波高分布的重要因素,随着波群连长增大,波群中波高分布信息熵增大。当以平均波高无因次化,连长较大时波群中波高累积概率明显大于连长较小时情形。波群中波高分布受谱宽度影响。当谱宽度增大,波群中波高累积概率降低。谱宽度和波群连长对波群中波高累积概率的影响相当。引进体现波群特性的1个无因次化波高参量研究波群中波高累积概率。  相似文献   

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以3种海鱼(牙鲆、狭鳕、鲱鱼)为样本,针对海产品中主要的致病性寄生虫-异尖线虫,开展了酶消化检测技术的研究.根据鱼肉消化前后干物质的质量变化设计了胃蛋白酶消化效率的计算方法,并按照鱼肉:消化液=1:10 (g/mL)的反应比例,分别确定了酶水解鱼肉的最佳条件为:初始pH值为1.1,温度为37 ℃,酶活力为8 U/mL左右;消化后所得的虫体采用多重PCR方法替代传统的形态学观察进行种属鉴定,从而初步建立了基于酶水解-多重PCR的异尖线虫的酶消化检测体系.实际样本检测表明,该技术可以较为准确、快速地用于海产鱼类中简单异尖线虫(Anisakis simplex)和伪地新线虫(Pseudoterranova decipiens)的确证性检测.  相似文献   

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鳚亚目鱼类是鲈形目中较大的一个亚目,现知全世界有127属,700余种(Nelson,1994)。目前还不断有新种发现,多数为海洋鱼类,世界性分布。 鳚亚目鱼类大多体型较小,对它们的研究也少。随着科学技术的发展和研究方法的不断完善,人们对这一类群的认识也愈来愈深入,其种类、区系与动物地理学等方面的特点正逐渐为研究者所揭示。其中有些种类由于在海洋生态学、环境生物学和渔业生产上具有重要意义而吸引着许多鱼类学家和生态学家的注意和对其进行研究(Kotrschal,1992;Springer,1993;Stepien,1993)。 印度-西太平洋是鳚亚目鱼类种类最多的海区之一,中国及周边国家和地区在此领域已有一定的研究基础。日本学者Masuda等(1984)总结了日本沿岸鳚亚目鱼类有86属212种,菲律宾已知有36属80余种(Herre,1953)。中国是世界上海岸线最长的国家之一,适合于鳚亚目鱼类栖息的生境相当广泛,种类也相当丰富。作者根据目前已掌握的标本和文献资料,经初步分析得出中国海区现有鳚亚目鱼类33属78种。  相似文献   

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鲈亚目3总科53科239属840种.  相似文献   

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The investigation of female physiological reactions to different meteorological conditions and space weather is relevant, since there are little experimental findings in this field. The purpose of this work is to determine how the level of cerebral-cortex activity in women depends on the meteorological and cosmophysical parameters of weather and space processes. We studied electroencephalograms (EEGs) recorded at rest in the sitting position and with eyes closed. We performed four series of measurements of brain bioelectrical activity from February to June 2013. We found that the level of cortical activity recorded by EEG changed significantly during these 6 months. Significant differences were detected between the cortical activity and the parameters of weather and space processes; namely, an increase in the air temperature and a decrease in the wind speed and cosmic-ray energy result in a decrease in the activity rate of the right occipital lobe.  相似文献   

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鲈亚目 3 总科 53 科 239 属 840 种。  相似文献   

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The development of the offshore industry on a world-wide basis has given rise to thegrowing demand for a good knowledge and understanding of the ocean wave environment.In addition to the accepted probabilistic and spectral methods of defining wave climate,attention has recently focussed on wave groups-a series of waves on enhanced amplitudeoccurring in close sequence. Such an occurrence is important in a range of offshore andcoastal engineering problems, particularly in the dynamic response of compliant offshore sys-tems and the stability of breakwaters. The paper presents a brief review of the previous work on wave groups, followed by  相似文献   

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为调查新冠肺炎对我国水产品(海水鱼)流通环节的影响因素和市场信心预期,文章通过发放调查问卷,对水产品(海水鱼)流通环节的经营者和个体从业人员进行数据采集并做描述性统计分析。研究结果表明:鲜活状态的海水鱼受疫情影响最大;多数受访者预测消费者对水产品质量安全的信心会增强;疫情造成的订单减少和农贸市场关停是水产品流通不畅的主要原因,亟须尽快有序恢复水产批发市场,疏通“无接触”物流渠道,做好拉动生产、促进消费和保障民生等工作。  相似文献   

15.
Multivariate principal components analysis and cluster analysis were performed on data representing presence or absence of 498 species of juvenile and adult fish species in twenty-four coastal marine systems (bays, coastal lagoons, estuaries and coastal zones) distributed from southeast to southern Brazil. Five groups of coastal systems were identified based on fish assemblage similarity: estuaries and bays of the southeast area; an estuary of the southern area; coastal lagoons; rocky coastal zones; and the continental platform. Species assemblages for each zone were identified and used as surrogate habitat indicators to compare and contrast the groups. Stepwise multiple regression of environmental and physical variables as predictors of the number of species indicated that only ‘ area ’ was included in the model as the most important variable explaining the variation of the number of species in these data sets. The total number of fish species increased as surface area increased.  相似文献   

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海洋鱼类生化组成及能量含量的研究   总被引:2,自引:0,他引:2  
随着海洋生态系统动力学研究的深入,海洋鱼类生化组成及能量含量的研究越来越显现出它的重要性和必要性。建立生化组成与能量含量与鱼体某个易于测定的指标(如水分含量、体重、体长、肥满度等)之间显著的相关关系,则可以较方便、准确地对有关指标进行间接估计。本文对国内外此领域研究现状进行分析、评述,以期进一步探讨饵料营养质量变化对食物产出的影响。  相似文献   

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The global trade in aquatic wildlife destined for home aquaria not only has the potential to be a positive force for conservation, but also has a number of potential risks. The greatest and most documented risk is the potential to translocate species that will become invasive in a new habitat. Although propagule pressure can influence species invasiveness, a high percentage of documented marine aquarium fish that are invasive in the US are uncommon in the trade. Here, the covariation of size with species invasiveness was assessed using a web scraper to collect size, price, life history characteristics, and behavior data from five internet retail stores for 775 species of fish. Fish that routinely exceed 100 cm in total length are traded, nevertheless are typically sold at sizes much smaller than their theoretical maximum. No economic benefit from the sale of species that will outgrow tanks and have a high risk of being released was found. Large fish, including groupers that can achieve weights of 800 pounds, will continue to enter the trade because the growth of aquaculture for commercial food markets is making it easier to acquire these species that also have appealing small life stages, making it easier and less expensive to bring these species into the aquarium trade. The entire trade should consider taking concerted action to limit the trade in fish that are likely to become invasive.  相似文献   

18.
广西两港湾红树林鱼类生态的比较研究   总被引:10,自引:1,他引:10  
何斌源 《海洋通报》1999,18(1):28-35
研究了广西英罗港和珍珠港夏季红树林鱼类生态的异同,结果表明两港湾鱼类在分布、区系、适温性方面较一致,但在生态类型上差别较大,群落相似性低;渔获的个体数组成和鲜重组成的优势种亦有差异,但在相对重要值上则均以大眼青鳞鱼最大;英罗港鱼类生物多样性较珍珠港的低。  相似文献   

19.
Species compositions of deep-sea demersal fishes were compared during the day and at night in two cruises of KT-01-8 and KT-02-5. A total of 742 individuals belonging to 28 species were collected in four day and four night hauls in KT-01-8, and in KT-02- 5 128 individuals belonging to 33 species were sampled in three night and four day hauls. Principal Component Analysis (PCA) revealed that there were two distinct groups corresponding to sampling time in both cruises, although in KT-02-5 the species composition from the first haul sampled after sunrise was similar to those found in night hauls. This suggests that the species composition of deep-sea demersal fishes changes between day and night. The existence of a time lag between the sea surface and the sea floor was also suggested, lag being 2–4 hr at 500 m depths in the study area. There may be two possible explanations for the change in deep-sea demersal fish composition between daytime and nighttime: the artificial effect of successive sampling design, and actual fish migration. Since the artificial effect would not be sufficient to explain the change of demersal fish composition, the vertical or horizontal movements of deep-sea demersal fishes would contribute to the faunal change between daytime and nighttime in the study areas.  相似文献   

20.
Don Maurer 《Marine Ecology》1983,4(3):263-274
Abstract. Animal-animal interactions are recognized as critical in benthic invertebrate recruitment. The hypothesis tested was that benthic recruitment is more successful in low densities of infaunal suspension feeders than in high densities. Densities of young hard clams Mercenaria mercenaria (L.) ranging from 82.5 to 330m-2 were placed in defaunated boxes of sand. The mean number of species, mean number of individuals, mean wet weight biomass, mean species richness and mean dominance index per sample were calculated per density of hard clams from May to October. The experiment did not support the hypothesis. It was concluded that feeding behaviour of dense populations of M. mercenaria did not preclude successful recruitment of other benthic species.  相似文献   

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