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1.
营养盐和光照对浮游植物群落结构的影响 总被引：3，自引：0，他引：3
2006年4月在沙埕港湾口处网箱养殖区,研究营养盐和光照对浮游植物类群及其优势种生长的影响。结果表明,微、小型浮游植物在100%自然光强下生长最快,微微型浮游植物在50%自然光强下生长最快。在各形态无机氮（N）、磷（P）营养盐存在的情况下,浮游植物会首先利用氨氮（NH4-N）,但培养后期NH4-N加富组的浮游植物丰度低于亚硝酸盐（NO2-N）加富组和硝酸盐（NO3-N）加富组。营养盐加富在短期内引起浮游植物数量的快速增加,当营养盐浓度达到一定水平后对浮游植物的生长不利,其抑制作用随浮游植物种类而异;随着营养盐消耗,浮游植物的数量和多样性均下降。微、小型浮游植物丰度与NO3-N、N/P呈显著相关,相关系数分别为-0.625、0.521;微微型浮游植物丰度与磷酸盐（PO4-P）呈显著相关,相关系数为0.530。 相似文献
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根据2001年5月、8月和11月对诏安湾网采浮游植物样品的分析鉴定结果,对浮游植物的种类组成和细胞数量等的平面分布和季节变化进行了分析研究,结果表明:诏安湾浮游植物种类丰富,共鉴定浮游植物5门58属172种,浮游植物的生态类群以广布种为主;浮游植物细胞数量的季节变动范围在2.03×106cell/m3～4.01×107cell/m3,数量高峰出现在11月,这与海水中无机氮和活性磷酸盐含量的明显上升有关.海水中活性磷酸盐为影响诏安湾浮游植物生长繁殖的限制因子之一. 相似文献
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三道河水库浮游植物群落结构特征及其渔产潜力分析 总被引：1，自引：0，他引：1
2007年8月-2008年4月调查并分析三道河水库浮游植物的群落结构及时空分布特征,并探讨水库的浮游植物多样性及渔产潜力.结果显示,该水库浮游植物有8门49属79种,主要由绿藻、硅藻和蓝藻组成;各采样点浮游植物种类数为43 ～56,但种类组成相似;不同季节浮游植物种类组成有很大差异,秋季种类数最多,冬季最少.浮游植物年平均细胞数量为20.33×104个/L,年平均生物量为0.21 mg/L.Shannon-Wiener多样性指数年均值为2.10,Pielou均匀度指数为0.85,且冬季最高,秋季最低.根据浮游植物水质评价标准,三道河水库为中营养型.据估算,三道河水库浮游植物渔产潜力9 072.45 kg,单产为22.68 kg/hm2. 相似文献
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浮游植物的初级生产力与黑白瓶测氧法 总被引：5，自引：0，他引：5
<正> 我国淡水渔业的主要养殖对象——鲢、鳙均能直接以浮游植物为食,浮游植物的生产量与鱼产量密切相关。众所周知,用个数或生物量所表示的浮游植物现存量(Standing crop或Standingstock)仅代表着某一采水时刻单位水体中存在的浮游植物总量,因而在评价水质“肥瘦”或生产性能时,只能作为一种指标加以应用。如欲用能量估算的方法探讨浮游植物与鱼产量之间的内在联系,仅有现存量的资料是不够的,还必须测定浮游植物的生产 相似文献
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根据2018年9月觉华岛近岸海域浮游植物调查资料,分析了该海域浮游植物种类组成、优势种和细胞数量平面分布,给出了2018年觉华岛近岸海域浮游植物名录。研究结果表明:该海域浮游植物群落组成为典型的北方海域种类组成,以硅藻为主,甲藻为辅,优势种明显,短角弯角藻和掌状冠盖藻是该海域本次调查的主要优势种。调查海域内浮游植物细胞数量属正常范围,其平面分布不是很均匀,觉华岛南部海域浮游植物细胞数量最大,北部海域浮游植物种类数量最大。 相似文献
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本文依据2009年罗源湾9个站位春、夏、秋、冬4个季度月浮游植物调查资料,结合环境参数对浮游植物的种类组成和群落结构进行多元分析,探讨浮游植物的群落结构和环境的影响因子。4个航次共鉴定浮游植物5门75属250种,其中,硅藻种类数占总种数的85％。四个航次浮游植物种类数比较显示：8月〉11月〉5月〉5月,丰度比较：8月〉5月〉11月〉3月。相关性分析表明,影响浮游植物分布的最主要环席因子为磷酸盐． 相似文献
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EdwardA．Laws RichardS．J．Weisburd 《江西水产科技》1992,(1):44-45
大多数封闭型养殖池塘中的氧气主要来源于浮游植物的光合作用，故池塘应保持一定的浮游植物产量。但是浮游植物量过大时，死亡细胞的分解会大大消耗氧气。在饮用水中，对健康无害的浮游植物过多，也会引起水质味道不佳。白鲢通常被认为是浮游植物食性的，因此白鲢常被用来控制湖泊和养殖池塘的水质，调节浮游植物丰盛度和周转率。然而对于这种做法也有不同看法。 相似文献
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We examine the claim in Christensen that Maximum Economic Yield (MEY) is equal to Maximum Sustainable Yield (MSY). The basis for this claim is that MEY considers only the ‘catching’ of fish and that when the full value‐chain is considered; it is the MSY level that maximizes economic value. We argue that to maximize society’s benefit from a given sector of an economy, resources need to be allocated across all sectors such that additional net benefits from employing one more unit of society’s resources are equalized across all sectors of the economy. In this way, the opportunity cost of employing society’s resources across all economic sectors is minimized. In an economy where all resources are fully utilized, further value added in the value chain for fish is an additional cost and has the effect of reducing fishing effort and optimum yield rather than the opposite. In a less developed economy or a developed one in recession where all resources are not fully used, the multiplier effect could be important, and if it is high for fisheries it would be an argument to maximize sustainable yield and effort. We show, using current input‐output data, that this is not the case. Furthermore, from a simple principle of optimization, we know that to optimize a sector that consists of many segments through time, one has to optimize every portion of the chain through time. 相似文献
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1994年5月到10月和1996年5月到10月对关门山水库进行了鱼产力的调查。水库的饵料生物量分别是：浮游植物3．23mg/L;浮游动物0．95mg/L;水生高等植物450g/m2水生底栖动物40,3g/m2。水库的鱼产力为217．29kg/hm2,其中浮游植物鱼产力129kg/hm;浮游动物鱼产力58．2kg/hm2;水生植物鱼产力18kg/hm2;底栖动物鱼产力12．09kg／hm2。毛初级生产量48．01卡／m2·日;净初级生产量11．79卡／m2·日。合理利用途径是：充分利用水域自然饵料和优越的水质条件,突出本地区冷水鱼类的优势,以养为主,增殖、养殖捕捞相结合,提高鱼产量,增加经济效益,以达到合理利用水域资源形成高产、高效的良性循环。 相似文献
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从感染白斑综合症病毒(Whitespotsyndromevirus,WSSV)的对虾中提取和纯化WSSV,对其蛋白酶活力进行分析。结果表明,WSSV蛋白酶具广泛的pH稳定性,当pH达7.5时,蛋白酶活性最大;pH高于10 0时,酶活力很低,其蛋白酶偏碱性。丝氨酸蛋白酶抑制剂苯甲基磺酰氟(PMSF)对酶活性有抑制作用。Ca2 、Mn2 、Fe2 和Cu2 可降低WSSV蛋白酶活性,但Mg2 有轻微的激活作用。胰蛋白酶抑制剂在浓度为12.5～25.0mg/L时,对WSSV蛋白酶活性无影响。Leupeptin使蛋白酶活性降低12.29%。Chymostatin在质量浓度为12.5～25.0mg/L时,对WSSV蛋白酶活性有强烈的抑制作用,表明WSSV蛋白酶类属胰凝乳蛋白酶。蛋白质修饰剂对WSSV蛋白酶活性影响的研究结果表明,组氨酸残基为WSSV蛋白酶活性基团,而巯基为非必需基团,说明WSSV蛋白酶为非巯基依赖型的蛋白酶。 相似文献
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许氏平鮋消化道中部分消化酶的研究 总被引：1，自引：0，他引：1
对许氏平 (Sebastesschlegeli)消化道内的 5种与消化吸收有关的酶进行分布和活性测定。结果表明 ,(1)肠道各段均具很高碱性磷酸酶活性 ,最适 pH为 9.7。食道和胃几乎没有碱性磷酸酶活性。 (2 )消化道各部位均含酸性磷酸酶 ,肠道活性最高 ,自幽门盲囊起依次递降。食道和胃酸性磷酸酶活性明显低于肠 ,胃和肠酸性磷酸酶的最适 pH均为 5 .3。 (3)肠道中羧酸酯酶活性明显高于胃 ,且 2者羧酸酯酶最适 pH差别较大 ,分别为 8.4和 6 .8。(4)胃蛋白酶活性明显高于肠道 ,胃蛋白酶最适pH为 2 .6 ,肠蛋白酶最适 pH为 9.4。 (5 )胃淀粉酶活性明显低于肠道 ,胃淀粉酶最适 pH为 4 .6 ,肠道淀粉酶最适pH为 7.0。这表明许氏平对蛋白质的初步消化在胃中进行 ,在肠中进一步消化和吸收 ,而对糖类和脂类的消化和吸收主要在肠道进行 相似文献
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松浦银鲫主要形态学性状：体高／体长比为42．6％，头长／ 体长比为26．7％，体厚／体长比为20．3％，尾柄长／体长比为12．7％，尾柄高／体长比为16．8％，背吻距／体长比为49．9％，背尾距／体长比为56．2％，体厚／头长比为76．4％。侧线鳞数和侧线至背鳍基部及侧线至腹鳍基部的鳞片数为327／7，第一鳃弓左鳃耙数为50．5个，体背部青灰色，体侧淡绿色，腹部姜黄色。上述指数除头长／体长比外，都与方正银鲫明显不同，而细胞遗传学特征与方正银鲫相同，群体中雄性极少，为雌核发育群体。松浦银鲫个体较大，生长较快，一龄鱼稍快于方正银鲫，体重30克以上；二龄鱼体重约160克。群体生产力，在与鲤、链等鱼混养情况下，亩产30－45公斤。由于松浦银鲫体高较高，1－3龄鱼的肥满系数明显高于方正银鲫，鱼肉营养成份中，粗脂肪在鲜肉（3．6％）和干肉（14．8％）中都明显低于正方银鲫， 这是松浦银鲫的一个极有价值的指标。松浦银鲫和方正银鲫一样繁殖力极强，2龄极能成熟和繁殖，因此其生产能力很大。 相似文献
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Abstract – From both a modern and a historical perspective there is little doubt that the Arctic charr, Salvelinus alpinus , in Britain and Ireland (as well as elsewhere) is a 'difficult' species. Historically 15 separate species have been recognised from populations in Britain and Ireland and there have been recent attempts to reassert these specific names. Here we review the evidence for the status of these 'species'. We conclude that the evidence for these 15 being afforded full species status is poor. However, both historical and contemporary data show that Salvelinus alpinus (Linnaeus 1758) in Britain and Ireland exhibits levels of variability in form that is much greater than in other species. We argue that a comprehensive genotypic and phenotypic survey of charr populations in Britain and Ireland is required to determine the full extent of variability and the status of populations with a view of providing suitable protection. 相似文献
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Coastal zones are productive areas that serve as nursery grounds for a large number of marine species. However, the processes involved in survival success during the juvenile phase are not well‐known. Some authors suggest that the availability of prey is important to support the production of pre‐recruit fish whose fitness is enhanced through optimal feeding conditions. Accordingly, recruitment is limited by the carrying capacity of the nursery habitat. In contrast, other authors state that the carrying capacity of the nursery grounds is not fully exploited, suggesting that there is no effect of food limitation. This study combines an overview of the literature, focused on flatfish that are especially dependent on coastal and estuarine nursery grounds, an extension to other marine fishes and a modelling approach on growth and survival of juvenile fish to explore the controversy of food limitation in their nursery grounds. We demonstrate that the relative lack of growth limitation observed for young marine fishes at the individual scale is related to an observational bias: fish have been affected by size‐selective mortality linked to food limitation, but only surviving individuals are observed. As the population is skewed towards the faster‐growing juveniles, the growth of survivors remains close to optimal, even when food resources are limited. Food limitation is of major influence in determining the carrying capacity of the nursery habitat. To sustain marine fish populations and related fisheries, management action is needed to protect coastal and estuarine areas and maintain or restore nursery productivity. 相似文献
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2011年西南大西洋拖网渔获物阿根廷滑柔鱼生物学分析 总被引：3，自引：0，他引：3
根据2011年1月～4月双拖网船在西南大两洋作业时采集的901尾阿根廷滑柔鱼（lllex argentinus）样本,对其渔获群体组成、摄食等级、胴长-体质量关系以及性腺发育等进行了分析。结果表明,样本个体大小随采样时间的推移有明显增大趋势;小胴长组阿根廷滑柔鱼的摄食能力较大胴长组弱,摄食等级的高低与其繁殖高峰期有关。阿根廷滑柔鱼雌、雄初次性成熟胴长分别为191．6mm和182．6mm,性腺成熟度为Ⅴ期个体的平均胴长小于处于Ⅲ、Ⅳ期个体的平均胴长。综合分析推测,该研究采集的901尾样本为南部巴塔哥尼亚群体和夏季产卵群体的混合样本,在拖网作业后期,渔场补充了部分大个体的夏季群体。 相似文献
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利用放射化学方法测定了克氏原螯虾大颚器中甲基法尼酯合成速率。结果发现，同一尾克氏原螯虾的左、右侧大颚器中甲基法尼酯的合成速率无明显差异(P＞0.05)；雄螯虾甲基法尼酯的合成速率比雌螯虾大(P＜0.05)；处于精巢发育期的雄螯虾甲基法尼酯合成速率明显大于发育前期的雄螯虾(P＜0.05)；在雌螯虾卵巢发育周期中，甲基法尼酯的合成速率依次为次级卵黄发生期＞初级卵黄发生期＞成熟期＞卵黄发生前期＞恢复期，表明大颚器合成甲基法尼酯与促进卵黄发生密切相关。 相似文献
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Elizabeth A Fulton Anthony D M Smith David C Smith Ingrid E van Putten 《Fish and Fisheries》2011,12(1):2-17
There is broad consensus that the main problem facing fisheries globally is too many boats chasing too few fish. Unfortunately it is also possible to argue that there are too many proposed solutions and not enough practical answers to improving fisheries management. There is a deepening divide between those who propose alternative regulatory controls on fishers, including establishing large areas permanently closed to fishing, and those who argue for better alignment of incentives combined with broad participation of resource users in fishery management decisions (in simple terms, between top down and bottom up systems of governance). However despite the choice of policy instruments used, a consistent outcome is that resource users behave in a manner that is often unintended by the designers of the management system. Hence whilst uncertainty is broadly recognized as a pervasive feature of fisheries management, to date most of the attention has focussed on only part of that uncertainty – scientific uncertainty about the status of exploited resources. The effect of uncertainty generated on the human side of fisheries science and management has received much less attention. However, the uncertainty generated by unexpected resource user behaviour is critical as it has unplanned consequences and leads to unintended management outcomes. Using empirical evidence of unexpected resource user behaviour and reviewing current responses to unexpected management outcomes, we identify different approaches that both improve prediction of human behaviour in fisheries systems and identify management measures that are more robust to these sources of uncertainty. However, unless the micro scale drivers of human behaviour that contribute to macro scale implementation uncertainty are communicated effectively to managers and considered more regularly and in greater depth, unanticipated responses to management actions will continue to undermine management systems and threaten the sustainability of fisheries. 相似文献