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海产贝类在我国海水养殖中占有重要地位。我国贝类的主要养殖品种有牡蛎、贻贝,缢蛏、泥蚶、蛤仔和珍珠贝,近年来还试养扇贝和鲍。苗种生产以海区自然附苗为主。为提高天然采苗率,在我国有些海区对牡蛎、蚶、蛏进行过(或仍在进行)附苗预报,平畦预报工作,对生产发挥过一定作用,但没有设立专门的科研组织, 相似文献
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碧流河水库的底栖动物 总被引:2,自引:0,他引:2
关于碧流河水库的底栖动物,先后对6个断面14个采样点进行7次采样,经分析有4个类群。其中:软体动物2属;环节动物4属;水生昆虫双翅目幼虫6属,毛翅目幼虫、浮游目幼虫、蜻蜓目幼虫、鞘翅目幼虫、牛虻属幼虫和水蝇属幼虫;甲壳动物只有米虾属。以环节动物的寡毛类为主,水生昆虫居次。底栖动物现存生物量为1.62g/m,其鱼产潜力为0.54kg/亩. 相似文献
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根据池塘中养殖鲤鱼数量,规格对底栖动物数量的影响以及大伙房水库蓄水初期底栖动物的生物量,评述不考虑食底栖动物鱼类的现存量而以底栖动物的数量来估测底栖鱼类的鱼产力是不合理的。 相似文献
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为了解桑沟湾养殖区大型底栖动物的动态变化以及底栖生境的健康状况,于2019年5-9月采集了中国北方典型养殖海湾桑沟湾不同养殖区(藻类、贝类和网箱养殖区)大型底栖动物样品,分析了不同养殖区大型底栖动物的种类、组成、数量分布、群落结构及生物多样性等群落特征,运用多样性指数、AMBI和M-AMBI指数法评价了不同养殖区底栖生境健康状况的时空变化。调查共鉴定出大型底栖动物56种,其中多毛类31种,甲壳类10种,软体动物9种,棘皮动物4种,其他类2种,大型底栖动物的优势种主要为多毛类,以污染耐受种为主;调查期间,贝类养殖区和网箱养殖区的群落多样性指数H''呈现下降趋势,表明贝类养殖活动和网箱养殖活动已经造成沉积物中有机物颗粒过度积累。ABC曲线显示,7月桑沟湾养殖区开始受到干扰,8月和9月受到中等程度的干扰。AMBI和M-AMBI指数评价显示桑沟湾养殖区域底栖生态系统处于轻度或中度干扰状态,底栖生境健康状况处于高等或者良好的状态。 相似文献
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山东省沾化县海岸线长达170.5km,滩涂面积2.8万hm~2(42万亩),海岸带地势平缓,大部分底质为软泥质,水流缓慢,底栖硅藻丰富,适宜滩涂贝类生长。滩涂贝类养殖在沾化县已有百余年的历史,养殖品种有文蛤、杂色蛤、牡蛎、缢蛏、青蛤等。但是,近年来随着生产的发展和环境的变化,滩涂养殖也出现了一些不容忽视的问题:首先是滩涂底质老化。由于年复一年的不间断养殖,滩涂出现老化状态,使得滩涂生产能力大大降低。贝类死亡后贝壳大量沉积,对滩涂造成严重的污染,滩涂利用呈超负荷状态。 相似文献
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主要阐述了流式细胞仪在贝类血细胞分类、血细胞功能、染色体核型分析、倍性检测等研究中的应用,供研究贝类的科技工作者参考。 相似文献
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230日龄罗曼蛋鸡7400羽,随机分为2组,一组为有天窗的实验组,一组为对照组,试验天窗对产蛋率和破蛋率的影响。结果表明:有天窗的试验组的产蛋率极显著高于无天窗的对照组,试验组的破蛋率极显著低于对照组(p<0.01)。 相似文献
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ABSTRACT: A physical model of a soft shell underwater float with an openbottom was constructed and the float was subjected to sinusoidaloscillation in the vertical direction in order to investigate the relationsbetween the characteristic properties of the buoyancy and fluidforces in the movement of the float. No change in the fundamentalperiod of the float was seen in response to the imposed oscillation,but there was a lag in the phase of the float response of up toone-quarter wavelength. Various fluid force factors approached valuesreported for a globular buoy as the float was increasingly filledwith air, but hysteresis was very low. The drag coefficient showedmuch scatter. The dominant factor for control of vertical movementof a soft shell float with open bottom was buoyancy, not fluid resistanceforce. It was concluded that for the purposes of design and controlof these systems, only the float volumetric capacity and air capacitymust be considered. 相似文献
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为揭示南麂岛岩礁潮间带软体动物种类组成与数量分布及其演替状况,于2013年11月,2014年2月、5月、8月,共4次对南麂岛的潮间带7个断面进行了定量和定性调查,并对软体动物的种类、数量和优势种变化及物种多样性进行了研究。结果显示,共鉴定出软体动物种类63种,隶属于3纲113目34科52属,其平均栖息密度和生物量为506.5个/m2和801.54 g/m2;条纹隔贻贝(Septifer virgatus)是4个季节共有的且优势度最大的优势种;软体动物Shannon-Wiener多样性指数(H')平均值为冬季(1.73)春季(1.69)夏季(1.58)秋季(1.40);与历史资料对比发现,其物种数及生物量有一定程度的减少。研究表明,南麂岛岩礁潮间带的软体动物发育较好,栖息密度和生物量远高于邻近的其他岛屿,但与此前调查结果相比却有所降低。 相似文献
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In this study, predation of the trumpet shell, Charonia sp., on different invertebrate prey species, e.g. starfish, Asterina pectinifera and Asterias amurensis, abalone Haliotis discus hannai, clam Anadara broughtonii and Tapes phillipiarum, and sea urchin Hemicentrotus pulcherrimus and Anthocidaris crassispina, was measured in a laboratory experiment. Each prey species was placed in a tank with a trumpet shell; prey species were not combined. Each combination of prey and trumpet shell was replicated three times. Trumpet shells did not prey on economically important shellfishes, including Anadara broughtonii, Tapes phillipiarum and Haliotis discus hannai. Sea stars were most preferred by the trumpet shell. The following preference gradient from most to least preferred was found: sea stars > sea cucumber > sea urchin. In selected situations, trumpet shells may be a means of biological control of predators of economically important shellfish. 相似文献
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R. GREGORY LOUGH 《Fisheries Oceanography》2010,19(2):159-181
The demersal settlement of pelagic juvenile fish has been considered a critical period in which the final adjustment is made to the size of a year class. Distribution patterns of pelagic and recently settled juvenile cod (Gadus morhua) were examined from nine surveys on Georges Bank during the summer over 5 years, 1984–1989, to relate juvenile survival to the sedimentary environment. Pelagic juveniles were widespread across Georges Bank in June, and by mid‐July they occurred on all bottom types from sand to gravel on eastern Georges Bank. However, by late July‐early August they were mostly abundant on the northeastern edge gravel deposit, which with its complex relief, provides abundant prey and refuge from predators. A bank‐wide estimate of pelagic juvenile abundance in 1986 and 1987 was used to assess mortality of the recently settled juveniles and to evaluate the relative importance of survivors from the northeastern edge gravel area to recruitment of the Georges Bank population. Settlement mortality rates over 1–2 months on the northeastern gravel area ranged from 3 to 8% day?1, which compared reasonably with other studies. The seasonal abundance of the pelagic juveniles was almost an order of magnitude higher in 1987 than 1986; however, recruitment at age 1 was similar, indicating that a high mortality of the demersal juveniles occurred in 1987. The limited northeastern gravel area on Georges Bank may represent a survival bottleneck depending on the variability in the distribution and abundance of juvenile cod settlement in relation to that of their predators. 相似文献
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厚壳贻贝的模型拟合与壳体曲面分析 总被引:1,自引:0,他引:1
以长度85~110 mm的野生厚壳贻贝作为研究对象,探究贻贝壳体模型特征。利用光学扫描仪得到相应的样本点云文件,通过geomagic wrap软件处理优化点云数据,得到质量优良的三维样本模型;利用Matlab软件拟合三维样本模型,得到最佳的拟合模型——标准模型,并将标准模型数字化,得到标准模型壳体外曲面(W)和壳体内曲面(N)的数学函数关系式。检验数字化模型、标准模型、样本模型之间的误差,得出三者间的平均误差均不超过0.06 mm。因此,可以使用数字化贻贝模型替代样本模型来指导贻贝定向、固定装置零部件的设计,规划最佳的贝肉剥离路线,为打造现代化贻贝加工流水线提供理论基础。 相似文献
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Distribution and intensity of bottom trawl fisheries in the Patagonian Shelf Large Marine Ecosystem and its relationship with marine fronts 下载免费PDF全文
Trawling is a major concern worldwide and there is considerable debate about its impact on marine ecosystems. The Patagonian Shelf Large Marine Ecosystem (PSLME) is an important fishing area in the Southwest Atlantic where bottom trawling is the dominant fishing method. We investigated the distribution of bottom trawl fishing within this region, defining the areas of highest trawling intensity (hotspots) and evaluating their relationship with marine fronts. We focused on the three main oceanographic fronts, the shelf‐break front, the southern Patagonia front and the mid‐shelf front. To estimate fishing effort and trawled areas, we used VMS data from 2006 to 2012. Despite being almost a fully trawlable shelf, we found that the spatial distribution of trawling activity is patchy and trawling hotspots were small, comprising annually <5% of the shelf extension or <7% of the total trawlable area. Contrary to what is believed worldwide, our findings suggest that over the PSLME the magnitude of habitat effects as a result of bottom trawling is relatively small. Regarding the three frontal systems studied, only the shelf‐break front showed a positive relationship with trawl fishing activity. Although trawling hotspots did not overlap with marine fronts, the shelf‐break front receives more trawling effort than expected. We hypothesize that this pattern is due to aggregation of species near or at the front taking advantage of the opportunities provided by this area. 相似文献