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养殖对虾病毒性疾病的细菌并发症防治研究 总被引:1,自引:0,他引:1
本文研究报道了发病对虾肝胰腺分离菌物敏感性,采用防台细菌人工感染方法进行药物饲料的筛选,在实验室及养殖池中进行药物饲料的防治效果试验。结果表明,在对虾病毒流行期间,采用药物饲料可有效防止对虾爆发性大量死亡,提高对虾存活率。 相似文献
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赤点石斑鱼人工配合饵料中蛋白质最适含量的研究 总被引:11,自引:1,他引:11
本文探讨了不同蛋白质含量的配合饵料对赤点石斑鱼(Epinephelusakaara)生长的影响。通过60d度验得出:在各配合饵料组中,蛋白质含量为49.52%的试验的相对增重率(46.84%)体长相对增长率(15.96%)、蛋白质效率(60.35%)和饵料转化率(29.85%)等均为最佳。配合饵料组鱼体肌肉营养成分(蛋白质、脂肪、氨基酸和鲜味氨基酸)也均优于对照组,而更接近野生鱼。经回归方程分析,赤点石斑鱼人工配合饵料中蛋白质最适含量为48.37%~49.24%。 相似文献
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We investigated whether trochophore larvae of the polychaete Hesiocaeca methanicola, which lives on exposed ice‐like methane hydrates between 500 and 600 m, could consume near‐bottom picoplankton. In laboratory trials larvae significantly reduced the growth rates of all types of picoplankton, including heterotrophic bacteria, Prochlorococcus sp., Synechococcus‐type cyanobacteria and phototrophic eucaryotes <3 μm. Our findings suggest that these types of plankton may be important food sources for deep‐sea planktotrophic larvae. 相似文献
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On the basis of the data of oceanographic survey in the East China Sea in four seasons during 1997-2000 (23°30'~33°00'N, 118°30'-128°E), the variation of total biomass and diet biomass of zooplankton and their spatial-temporal distribution and relationship with the fishing ground of Engraulis japonicus are approached and analyzed. The results show that the average biomass is 65.32 mg/m3 in four seasons, autumn (86.18 mg/m3) being greater than summer (69.18 mg/m3) greater than spring (55.67 mg/m3) greater than winter (50.33 mg/m3). The average value of diet zooplankton biomass is 40.9 mg/m3. The trends of horizontal distribution both in the total biomass and the diet biomass of zooplankton are similar. The high biomass region (250-500 mg/m3) is very limited, only accounting for 1% of the investigation area. Seasonal variation of the biomass is very remarkable in the west and north parts of East China Sea coastal waters ( 29°30'N,125°E). The horizontal distribution of diet zooplankton depends on the 相似文献
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E. Cocheret de la Morinire B. J. A. Pollux I. Nagelkerken G. van der Velde 《Estuarine, Coastal and Shelf Science》2003,57(5-6):1079-1089
The spatial size distribution of grunts and snappers have previously indicated the separation of juveniles in nursery habitats from the adults on the coral reef. This implies life cycle migrations from nursery habitats (such as seagrass beds and mangroves) to the coral reef. If diet shifts are related to such migrations, then the diets of these fish must change before or around the fish size at which such migrations take place. A wide size range of juveniles of two grunt species (Haemulon sciurus and Haemulon flavolineatum) and of two snapper species (Lutjanus apodus and Ocyurus chrysurus) were caught in seagrass beds and mangroves, and their gut contents identified and quantified. Regression analysis between fish size and dietary importance of small crustaceans showed a negative relationship in all four species. Positive relations were found for H. sciurus, L. apodus and O. chrysurus between fish length and the dietary importance of decapods, and for L. apodusand O. chrysurus between fish length and prey fish importance. Critical changes in the fish diets with fish size were examined by application of a Canonical Correspondence Analysis (CCA). The CCA yielded three clusters of size-classes of fishes with similar diets, and application of a Mantel test showed that each of these clusters had significantly different diets, and that each cluster diet was significantly specialised. The size at which a fish species ‘switched’ from one cluster to another was compared with size-at-maturity data and with the typical size at which these species migrate from the nursery habitats to the coral reef. H. sciurus and H. flavolineatum may be prompted to migrate from the nursery habitats to coral reef habitats because of dietary changes, or because of the development of the gonads. For L. apodus and O. chrysurus, a dietary changeover forms a more likely explanation for nursery-to-reef migrations than does sexual maturation because these species reach maturity at sizes much larger than the maximum size of individuals found in nursery habitats. Although other factors may theoretically initiate or promote the migration patterns, the results of this study indicate that ontogenetic dietary changes may crucially influence the nursery-to-coral reef migrations of these reef fish species. 相似文献
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