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231.
LI Gang SHEN Yanbin LIU Yongqing Peter BENGTSON Helmut WILLEMS Hiramichi HIRANO 《《地质学报》英文版》2009,83(1):46-51
The diverse clam shrimp Nestoria-Keratestheria fauna is widely distributed in the Dabeigou Formation in northern Hebei and eastern Inner Mongolia of China. Its important component genus Magumbonia from the Dabeigou Formation in the Luanping Basin, northern Hebei, China, is revised on the basis of a scanning electron microscope (SEM) examination of the type species M. jingshangensis Wang, 1984, which revealed morphological features not recognized previously. These include coarse reticulation on the umbo and prominent growth lines ornamented with densely spaced, small tubercles and fine lirae. 相似文献
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234.
综述:对虾弧菌病及其免疫预防的研究进展 总被引:1,自引:0,他引:1
弧菌病是影响对虾养殖业最为常见、危害较重的一类疾病。其症状一般为红腿、黄鳃、烂尾、烂眼、甲壳溃疡、肌肉白浊等 ,常伴有败血症。副溶血弧菌Vibriopara haemolyticus是人们发现最早的对虾病原弧菌 ,随后溶藻弧菌V .alginolyticus,鳗弧菌V .anguillarum ,哈维氏弧菌V .harveyi,创伤弧菌V .vulnificus等十多种致病弧菌陆续被发现 ,但其致病机理仍未查清。多年来弧菌病主要采用抗生素治疗 ,但抗生素治疗带来一系列严重后果 ,主要是产生耐药菌株 ,造成水体污染 ,破坏虾体免疫力 ,因此探索新的治疗途径势在必行。以提高虾体自身免疫力的免疫预防研究是当前研究的热点之一 ,它以无毒无副作用 ,不会造成环境污染等优点而显示出广阔的前景。弧菌疫苗的研制已获初步成功 ,疫苗有灭活疫苗和减毒疫苗两种。免疫方式有浸泡、口服、注射和喷雾等 ,注射方式效果最佳但费时费力且易损伤虾体 ,浸泡疫苗需要量大 ,故探索一条好的免疫方式是当前工作的重点。要进行对虾的免疫预防研究 ,必须了解对虾的免疫机制 ,一般认为虾类的免疫主要以非特异性免疫为主 ,血细胞和酚氧化酶系统在其中起着重要作用。对弧菌病的病原、病理、诊断、对虾的免疫机制及免疫预防等方面的研究进展及趋势作一回顾 相似文献
235.
The deep-water giant red shrimp, Aristaeomorpha foliacea (Risso, 1827) (Decapoda, Aristeidae), represents a highly valuable resource for bottom trawling in the Mediterranean Sea. Recent assessments have described both a worsening of the status of the traditionally exploited stocks and low levels of annual-based instantaneous natural mortality (M 0.4–0.7 year−1) in the unexploited stocks. The mortality (M) figures, however, are in contrast with the longevity (Tmax) of 3–4-year males and 4–5-year females, estimated from classical length frequency distribution analysis. Reduced growth (after the onset of sexual maturity) and pile-up of older individuals in the larger size classes have been considered to be reasonable explanations for the contrast between M and Tmax. We propose that a discontinuity of the growth models could address this contrast. Because a clear discontinuity in sexual maturity is evident only in males, length frequency distribution data for different sets of males collected from the South of Sicily and the Maltese Islands deep bottoms (400–800 m) were fitted with both the classic (c) and double-phased (d) von Bertalanffy growth formula (VBGF). According to the dVBGF, adult males sharply reduce their growth rate after reaching an age between 1.2 and 1.5 year, which corresponds to the estimates of age at sexual maturity (tm between 1 and 1.5 years). The reduction in growth determines a higher Tmax (7.3–9.5 year) and lower M (0.4–0.6 year−1) than previously derived on the basis of cVBGF estimates (Tmax 3–4 years and M 1.2 year−1). The dVBGF results suggest that sexual dimorphism and length–sex segregation in giant red shrimps reflect an alternative life history strategy that is based mainly on growth reduction in adult males and it might be adopted for implementing more conservative assessments. 相似文献
236.
研究2005-2008年广东省湛江市英罗湾高桥3个红树林区(红坎、两头流、西村)虾类群落的变化特征,并分析虾类群落组成与水质指标(盐度,pH)和沉积物指标(pH、可溶性盐、有机质、黏土、粉砂、砂砾)的相关性。结果表明:3个区域捕获虾类13596尾,属3科5属9种,刀额新对虾是高桥虾类的优势种;虾类种类年际变化较大,年间相似度平均为70.4,区域间相似度平均为60.6;红坎虾类多样性较丰富,两头流虾类的优势种明显,各年优势度指数均达0.95以上;3个区域的主要生态因子年间差异不显著(P>0.05);红坎3个采样点的底质性状较复杂,其沉积物特性差异显著(P<0.05),两头流和西村的底质性状较为单一,其沉积物特性均差异不显著(P>0.05)。群落变化特征和沉积物性状有显著相关关系,表明高桥虾类的渔获量受人为因素影响,多样性和分布受环境影响。 相似文献
237.
Potassium, sodium, magnesium and iodine requirements of shrimp,Penaeus chinensis were studied. Orthogonal design was employed in this experiment. The composition of the basal diet consisted of fish meal,
peanut cake, corn meal, soybean cake, wheat bran, vitamin mix and mineral mix, and supplementations of potassium, sodium,
magnesium and iodine in the basal diet were made according to the L9(34) orthogonal table. The results indicated that iodine supplementation improved growth of the shrimp significantly and raised
survival very significantly, iodine requirement of the shrimp was 0.003%; sodium requirement was 0.87% or less; and that 1.1–1.3%
potassium and 0.18–0.38% magnesium in the diet were proper nutrition supplements for the shrimp.
Contribution No. 2342 from the Institute of Oceanology, Chinese Academy of Sciences. 相似文献
238.
April to October, 1997 comparative studios on the nitrogen budgets of closed shrimp polyculture systems showed that, in all the studied polyculture systems, nitrogen from feeds and fertilizers were the main input items, which comprised 70.7% - 83.9% of the total input nitrogen, 3.2% - 7.4% of which was provided by nitrogen fixation. It was in monoculture enclosures (Y-4, Y-11 and Y-12) that the percentage reached the maximum value. The output nitrogen in harvested products comprised 10.8% - 24.6% of total input nitrogen, and the highest percentage, 24.6%, was found in shrimp-fish-tagelus polyculture systems. In shrimp monoculture and shrimp-fish polyculture systems, they were 19.1% and 21.9%, respectively. The nitrogen utilization efficiency was different and varied from 12.2% to 20.1%. The highest, 20.1%, was found in shrimp-fish-tagelus polycultttre systems, and the average of 20.0% was found in shrimp-tagelus polyculture systems. The lowest, 12.2%, was found in shrimp monoculture systems.All the nitrogen utilization efficiencies in shrimp-fish systems or shrimp-scallop systems seemed to be higher than that of the monoculture system, but they showed little statistical difference. The main outputs of nitrngen were found in sediment mud, and comprised 48.2% -60.8% of the total input, the lowest percentage was found in shrimp-fish-tagelus polyculture systems, and the highost percentage in shrimp-scallop systems.During the experiment, nitrogen lost through denitrification and ammonia volatilization comprised 1.9% - 6.2%, averaged 2.8%, of the total input, and the loss through seepage comprised 5.9% - 8.9% of the total.The estimated nitrogen attached to the enclosure wall comprised 3.7% - 13.3% of the total, and was highest in shrimp monoculture systems. Compared with the classic shrimp farming industry, the closed shrimp polycul-ture systems may improve the nitrogen utilization efficiency, and hence reduce the environmental impacts on coastal waters. The nitrogen discharging rates for all the studied polyculture systems ranged from 3.0% to 6.0% of total input nitrogen. 相似文献
239.
为研究高位虾池养殖导致的环境影响,用电感耦合等离子体质谱仪ICP-MS(Agilent7700x型)对海口市东营镇3种类型养殖虾池及其外围沟渠底质中的Cr、Ni、Cu、Zn、As、Cd和Pb质量分数进行检测,用Vario TOC对底质中的TN(总氮)和TOC(有机碳)质量分数进行检测,并对所检测的数值采用单因子污染指数、地积累指数和综合潜在生态风险指数等方法进行分析及评价。结果表明:1)未清洗的虾池底质重金属质量分数呈现L1层向L4层明显递增的规律;2)虾池L1层底质中Cd呈现明显的累积(污染)现象,其质量分数是海南省土壤背景值5.47~35.18倍;3)地积累指数( )的评价表明,各样地底质中均有2种及以上重金属达到轻度—中等及以上污染程度;4)综合潜在生态风险指数(RI)结果表明,底质RI范围值为176.97~1 090.87,各样地综合潜在生态风险程度均达到中等及以上生态风险,其中Cd是主要的贡献因子;5)Pearson相关分析显示,虾池底质中的饵料残留物及对虾排泄物所含的Cr、Ni、Cu、As、Cd、TOC相互之间具有极显著相关性,相关系数高达0.9以上,表明农户所使用的饵料不同程度地含有以上重金属,同时有机碳是影响底质中重金属富集的重要因素。 相似文献
240.
为了探明南海北部虾拖网副渔获的种类组成、优势种类和幼鱼比例等情况,2012年8月1~5日作者于湛江近海进行了虾拖网副渔获调查。结果表明:湛江近海虾拖网副渔获种类极多,副渔获物与虾类的质量比为3.9:1;副渔获物的主要种类为蟹类和鱼类;蟹类副渔获物的优势种类分别为红星梭子蟹(Portunus sanguinolentus)、三疣梭子蟹(Portunus trituberculatus)和远海梭子蟹(Portunus pelagicus),其相对重要性(IRI)分别为7558.72、6540.72和2826.41;鱼类优势副渔获物的种类分别为褐斑三线舌鳎(Cynoglossus trigrammus)、少鳞鱚(Sillago japonica)、多齿蛇鲻(Saurida tumbil)和六带石斑鱼(Epinephelus sexfasciatus),其IRI分别为3158.94、1755.57、1294.44和1058.46;副渔获物的幼鱼比极高。最后,作者结合相关研究,对如何从技术层面解决南海区虾拖网严重的副渔获问题进行了探讨,以促进南海区虾拖网渔业的可持续发展。 相似文献