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31.
海洋环境因子对澳洲鲐亲体补充量关系的影响——基于贝叶斯模型平均法的研究 总被引:1,自引:1,他引:0
澳洲鲐(Scomber australasicus)是西北太平洋重要的中上层经济鱼类,生命周期相对较短,资源量受补充量影响明显,了解澳洲鲐太平洋群系补充量状况对掌握其资源量及确保其可持续利用具有重要的意义。本文利用产卵场1(30°~32°N,130°~132°E)海表面温度(sea surface temperature,SST1)、产卵场2(34°~35°N,138°~141°E)海表面温度(SST2)、索饵场(35°~45°N,140°~160°E)海表面温度(SST3)、潮位差(tidal range,TR)、太平洋年代际涛动(Pacific decadal oscillation,PDO)和亲体量(spawning stock biomass,SSB)6个影响因子任意组合与补充量构建多个模型,运用贝叶斯模型平均法(Bayesian model averaging,BMA)分析各个环境因子对资源补充量的解释能力,并预测其补充量的变化。结果表明,SSB对补充量具有最长期且稳定的解释能力,其次是SST3,PDO、TR、SST2、SST1也对补充量模型具有一定的解释能力。SST3是环境因子中影响最大的因子,可能是由于补充群体在索饵场内生活时间较长,索饵场温度对仔鱼或鱼卵的生长存活有较大的影响。研究认为,基于BMA的组合预报综合考虑了各个模型的优势,优于单一模型,可用于澳洲鲐资源补充量的预测。 相似文献
32.
从东江调水后契爷石水库的水质和浮游植物群落结构特征 总被引:4,自引:3,他引:1
本文比较了太湖梅梁湾敞水区2004年秋季渔汛期刀鲚(Coilia ectenes)和间下鱵(Hyporhamphus intermedius)的食性,同时对不同食物的重要性、选择性以及两种鱼类食物的重叠进行了分析.结果表明,秋季刀鲚、间下鱵的食物主要由浮游甲壳动物、鱼和昆虫等组成.镖水蚤中的指状许水蚤(Schmackeria inopinus)是刀鲚最重要的食物,而间下鱵最重要的食物是裸腹溞(Moina sp.),而且摄食鱼和昆虫的比例远高于刀鲚.刀鲚和间下鱵对个体较大的指状许水蚤的选择性都比较高,对个体较小、而在太湖密度很高的象鼻溞(Bosmina spp.)都表现出主动回避.刀鲚与间下鱵的食物重叠系数较高,表明对竞争比较激烈,但要完全了解这两种鱼类的竞争关系,还要对它们在太湖的分布,不同发育阶段和不同季节的摄食情况进行详细的调查研究. 相似文献
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以乌鳢(Ophiocephalus argus)为研究对象,采用不同日粮饲喂,试验W1组饲喂冰鲜鱼,试验W2组饲喂畜禽内脏。12周后,取肠道内容物,利用16S rDNA技术研究投喂不同饲粮的乌鳢肠道生物群落结构差异和微生物多样性,分别获得W1组和W2组乌鳢肠道细菌有效序列51124和39298条。结果分析表明;W1组和W2组物种注释(operational taxonomic unit,OTU)数目分别为2631和4114条,分类地位明确的细菌种类分别隶属5个属和49个属,W1组和W2组乌鳢肠道细菌种类差异很大。W1组乌鳢肠道细菌的优势类群是邻单胞菌属(Plesiomonas)、狭义梭菌属(Clostridium sensu stricto)、鲸蜡菌属(Cetobacterium);W2组乌鳢肠道细菌的优势类群是狭义梭菌属(Clostridium sensu stricto)、邻单胞菌属(Plesiomonas)、Spartobacteria、甲基副球菌属(Methyloparacoccus)、杆菌属(Alsobacter)、Saccharibacteria、分支杆菌属(Mycobacterium)。W2组乌鳢肠道细菌香农指数高于W1组乌鳢肠道细菌,表明前者肠道细菌多样性大于后者。本实验揭示了畜禽内脏饲喂乌鳢肠道细菌的群落种类多样性、OTU丰富度和物种总数均高于冰鲜鱼饲喂乌鳢;W1组肠道有益菌OTU丰富度大于W2组,且W2组还存在一些潜在致病菌。本研究为乌鳢的健康养殖和后续肠道微生物资源的挖掘提供了理论依据。 相似文献
35.
Qi-Kang Bo Yun-Zhao Lu Hui-Jing Mi Yan-Guang Yu De-Xian Gu Hong-Zheng You Shuang Hao 《Marine Ecology》2020,41(4):e12594
Bohai Bay, a representative semi-enclosed bay of China, has been severely impacted in recent decades by rapid human development. Although the mantis shrimp Oratosquilla oratoria plays an important role in the Bohai Bay ecosystem and fishery, its feeding ecology and the impact of habitat changes on its feeding habits are poorly known. In this study, we sought to identify its feeding strategy through the separation of stomach contents, and to describe its trophic ecology during maturation in the Tianjin coastal zone of Bohai Bay by the DNA barcoding method using a fragment (about 690 bp) of the mitochondrial cytochrome oxidase I (CO I) gene. A total of 594 specimens were collected from March to July 2018, and 347 (58.42%) stomachs were found to have food remains. More than half of the O. oratoria individuals had poor feeding activity, and the degree of feeding of females was higher than that of males, but there was no significant difference in the visual fullness index and the fullness weight index (FWI) between sexes for each month. In addition, the feeding activity of O. oratoria was consistent across the months, suggesting in artificial breeding programs it is not worried too much about the accessional diet supplied to the female bloodstocks except maintaining their normal food. A total of 167 retrieved prey items yielded 187 readable sequences; 86.63% of these sequences could be assigned to the species level. Consequently, 25 different prey taxa covering all readable sequences were identified, showing O. oratoria is a generalist predator. In terms of percent composition by frequency of occurrences (%N), crustaceans and fishes accounted for the same and highest percentage (35.83%) in the mantis shrimp diet, followed by mollusks (24.59%) and the remaining marine organisms (3.73%) including Polychaeta (2.67%), Sagittoidea (0.53%), and Chromadorea (0.53%). The result shows the benthic fish Oxudercidae (family) appears to be an especially important food supply for O. oratoria during maturation. The degree of cannibalism decreased with an increase in diet species and the frequencies of cannibalism in this study was noticeably higher than that in previous studies, suggesting that cannibalism may be a significant feeding strategy in the mantis shrimp O. oratoria in the Tianjin coastal zone of Bohai Bay, and because of the frequently cannibalistic behavior, the high stocking density of broodstocks should be avoided. 相似文献
36.
微塑料污染目前成为海洋污染普遍关注的一个研究热点。本文在实验室内将青岛近海常见的海洋桡足类猛水蚤暴露于不同浓度的微塑料尼龙6中,研究了猛水蚤的摄食、排泄以及生殖的变化。研究结果表明,微塑料尼龙6对猛水蚤的摄食、排泄、生殖均产生不利的影响,并且存在剂量-效应关系。微塑料尼龙6对猛水蚤摄食率、滤水率、排粪率的24 h·EC 50分别为67.7、62.2、84.1 mg·L^-1,对猛水蚤抱卵率的144 h·EC 50为30.3 mg·L^-1。“饱食感”造成猛水蚤摄食率降低,从而能量和营养摄入不足可能是导致猛水蚤抱卵率降低的原因。猛水蚤对微塑料的摄食,导致猛水蚤排泄的粪便颗粒小型化,由长椭球体变为短小椭球体,可能与其粘度或物理结构的改变有关。暴露于尼龙6的猛水蚤的粪便体积和沉降速率显著低于未暴露微塑料的对照组。本实验结果对于研究微塑料对海洋桡足类以及滤食性浮游动物的生态毒理影响具有一定的帮助。 相似文献
37.
鱼类摄食生态研究的理论及方法 总被引:21,自引:1,他引:21
综合分析了鱼类摄食生态研究的理论,方法及其应用中的诸多问题:胃含物分析法,营养生境及食物重叠,食物链与食物网,营养结构与营养级,摄食器官的形态特征与摄食行为的关系,食物选择以及生理生太因子对鱼类摄食的影响;提出了食物排序的概念、优势度指数D及其判定公式,并以此比较客观地建立了摄食生态相似的鱼类群落主次食物的划分标准。 相似文献
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Macrofauna Communities in the Eastern Mediterranean Deep Sea 总被引:1,自引:0,他引:1
Abstract. During two expeditions with RV ‘Meteor’ in summer 1993 and winter 1997/98 the structural and functional diversity of the benthic system of the highly oligotrophic eastern Mediterranean deep sea was investigated. The macrofauna communities were dominated by polychaetes even at the deepest stations. The fauna at shallow stations was dominated by surface deposit feeders, whereas subsurface deposit feeders and predators generally increased with depth. A high percentage of suspension‐feeding Porifera was found in the Levantine Basin. Mean abundance and number of taxa of both expeditions were significantly correlated to depth and distance to the nearest coast as well as to the total organic carbon (TOC) content in sediments. Numbers of taxa and abundance decreased generally with depth, although lowest numbers were not found at the deepest stations but in the extremely oligotrophic Levantine and Ierapetra Basin. Biomass measured during the second cruise was extremely low in the Ierapetra Basin and comparable to other extreme oligotrophic seas. The significant correlations found for TOC contents and macrofauna with distance to coast during both expeditions apparently reflect the role of hydrographically governed transport of organic matter produced in coastal regions into greater and extreme depths of the Mediterranean Sea. Seasonal differences in macrofauna communities due to seasonal differences in food supply were not found. However, recent large‐scale hydrographic changes (Eastern Mediterranean Transient, EMT) might change the oligotrophy and, thus, the structure of the benthic communities in the Eastern Mediterranean deep sea. 相似文献