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991.
通过分析中国对虾人工选育两个群体WSSV感染相关免疫与生化因子的变化,研究选育的两个中国对虾群体对WSSV的敏感性和抵抗力。结果表明,两个群体感染WSSV后,总细胞数(THC)在24h达到最大,随后呈下降趋势;两个群体血淋巴蛋白在感染初期和中期变化不同,但在后期均呈下降趋势;相比而言2'对虾群体比6'对虾群体血蛋白含量和THC下降幅度稍慢;2'对虾群体和6'对虾群体感染24h后酸性磷酸酶(ACP)稍有下降,随后保持较高的活性,而碱性磷酸酶(AKP)的变化除2'对虾群体在感染48h有显著增大外,6'对虾群体变化不明显;过氧化氢酶(CAT)、活性氧(ROS)、超氧化物歧化酶(SOD)与WSSV感染有密切的联系,两个群体抗氧化酶活性随WSSV增殖的变化略有不同;细胞内酚氧化酶(proPO)原变化趋势也表现出差异,斑点杂交结果显示6'对虾群体比2'对虾群体阳性反应较早,揭示不同群体间对WSSV感染的敏感性存在一些差异。 相似文献
992.
ABSTRACT: The diet shift of larval and juvenile Ryukyu-ayu Plecoglossus altivelis ryukyuensis was investigated for the landlocked population stocked in the Fukuji Reservoir, Okinawa Island. Gut contents of 274 specimens (5.1–31.4 mm in body length) including 31 yolk-sac larvae (5.7–8.0 mm) were examined. The diet of larval and juvenile landlocked P. a. ryukyuensis was mainly composed of zooplankton such as dinoflagellates, rotifers, copepods, and cladocerans. Feeding incidence was 48% in total and it gradually increased with growth. Diet analysis clearly demonstrated a diet shift during the larval and juvenile periods. For yolk-sac larvae and 5.0–19.9 mm fish, the diet was dominated by dinoflagellates Gymnodinium sp., and Peridinium sp., both numerically and by frequency, followed by rotifers that mainly consisted of Polyarthra spp. Diet breadth (Levin's standardized index BA ) diversified with growth, and feeding on copepods and cladocerans gradually increased in 10.0–14.9 mm fish. Diet overlap (Morisita's index: C) showed that diet drastically changed in 20.0–24.9 mm fish with a specialization on cladocerans Bosminopsis deitersi and Diaphanosoma brachyurum . This diet shift probably corresponded with an increase of feeding ability resulting from an enlargement of the mouth, increased swimming ability, and the development of sense organs. 相似文献
993.
用判别函数进行鱼类种群鉴别的计算机程序实现方法 总被引:1,自引:1,他引:1
用判别函数进行鱼类种群鉴别的计算机程序实现方法陈卫忠,李长松(东海水产研究所,上海200090)关键词判别函数,鱼类种群,鉴别,计算机程序ACOMPUTERIZEDAPPROACHTOIDENTIFICATIONOFFISHPOPULATIONBAS... 相似文献
994.
Remedies for pseudoreplication 总被引:1,自引:0,他引:1
Pseudoreplication is the failure of a statistical analysis to properly incorporate the true structure of randomness present in the data. It has been well documented and studied in the ecological literature but has received little attention in the fisheries literature. Avoiding pseudoreplication in analyses of fisheries data can be difficult due to the complexity of the statistical procedures required. However, recent developments in statistical methodology are decreasing the extent to which pseudoreplication has to be tolerated. Seven examples are given here, beginning with simple design-based remedies and progressing to more challenging examples including the model-based remedies of mixed-effects modelling, generalized linear mixed models, state-space models, and geostatistics. 相似文献
995.
996.
玛曲渔场几种裂腹鱼类脑的形态结构与真食性的相互关系 总被引:1,自引:0,他引:1
本文对极边扁咽齿鱼,黄河裸裂尻鱼、花斑裸鲤和厚唇重唇鱼进行了食性分析和脑的形态结构观察,并对脑结构和食性的关系作了初步探讨。认为这四种鱼类属于底层味觉食性鱼类,其中极边扁咽齿鱼和黄河裸裂尻鱼主要靠口腔、腭部味蕾觅食泥土和藻类,迷叶发达;厚唇重唇鱼主要靠触须寻找甲壳类为主的水底昆虫,面叶和小脑发达;花斑裸鲤的脑结构特征与其杂食性相适应。 相似文献
997.
Anna Maria Addamo Karen J. Miller Vreni Häussermann Marco Taviani Annie Machordom 《水产资源保护:海洋与淡水生态系统》2021,31(1):1-14
- 1. When considering widely distributed marine organisms with low dispersal capabilities, there is often an implication that the distribution of cosmopolitan species is an artefact of taxonomy, constrained by the absence of characters for delimiting either sibling or cryptic species. Few studies have assessed the relationship among populations across the global range of the species' distribution, and the presence of oceanographic barriers that might influence gene flow among populations are underestimated.
- 2. In this study, evolutionary and ecological drivers of connectivity patterns have been inferred among populations of the cold-water coral Desmophyllum dianthus, a common and widespread solitary scleractinian species, whose reproduction strategy and larval dispersal are still poorly unknown.
- 3. The genetic structure of D. dianthus was explored using 30 microsatellites in 347 specimens from 13 localities distributed in the Mediterranean Sea and Atlantic and Pacific Oceans.
- 4. Results clearly reveal genetically differentiated populations in the Northern and Southern Hemispheres (FST = 0.16, FSC = 0.01, FCT = 0.15, P-values highly significant), and Chilean and New Zealand populations with independent genetic profiles.
- 5. Marine connectivity patterns at different spatial scales are discussed to characterize larval dispersal and gene flow through the Northern and Southern Hemispheres.
998.
Hitoshi Kubota Takahide Doi Shoichiro Yamamoto Seiichi Watanabe 《Fisheries Science》2007,73(2):270-284
ABSTRACT: Stocking of exogenous, hatchery-reared white-spotted charr Salvelinus leucomaenis has been conducted throughout much of their range in Honshu Island, Japan, to increase angling opportunities. Although the native charr populations are thought to have declined because of hybridization with introduced fish, their distribution and genetic status have been uncertain. Fine population structures of charr in the upper Tone River drainage were examined using mitochondrial DNA and microsatellite analyses so as to clarify the presence of native populations. One common mtDNA haplotype was detected in all populations in the Ohashi River and Watarase River, and four and one tributary populations were monomorphic for such haplotypes, respectively. However, several haplotypes, considered to have originated from stocked hatchery fish, were observed in the stocked and the remaining populations. Judging from the genetic integrity over a fine geographic scale, the former were considered as indicative of native populations and the latter as admixtures with hatchery fish. Comparisons of genetic diversity, deviations from the Hardy–Weinberg equilibrium, principal component analysis, and relatedness estimations based on microsatellite DNA can also provide evidence for distinguishing native populations from those influenced by hatchery fish. 相似文献
999.
海南中部山区植被演变阶段植物物种多样性与群落结构多样性变化规律 总被引:2,自引:0,他引:2
以海南中部山区的草地、灌丛、次生林和原始林为演替系列,研究植被演替过程中群落结构多样性与物种多样性的变化规律。结果表明,群落演替过程中植物科属种数、总体Shannon-Wiener指数和Margalef指数、乔灌木层的Shannon-Wiener指数和Margalef指数及垂直结构多样性指数都显著增大;群落结构多样性指数分别与群落植物科属种数、总体alpha物种多样性指数、灌木层和乔木层物种alpha多样性指数都显著正相关。通过恢复演替,植被复杂性和质量都呈增大趋势。 相似文献
1000.
利用S1家系密植鉴定改良方法对中综6群、瑞德群、黄改群、先玉335群进行1~2轮改良,获得9份群体。以9份群体为父本,自交系丹598、郑58、吉853为测验种,配制27份杂交组合,进行产量配合力比较试验,从单株产量、穗部性状和配合力角度分析群体改良的效果。结果表明,改良群体单株平均产量均有增加,穗部性状向有利于高产的方向发展。中综6群经过两轮改良后,一般配合力效应从C0的-4.44增加到C2的3.84;瑞德群经过一轮改良后一般配合力效应从C0的-1.44增加到C1的2.9;黄改群从C0的-2.83增加到C1的1.93,一般配合力效应均达到极显著水平。特殊配合力排前两位的杂交组合为郑58×黄改群、丹598×瑞德群。 相似文献