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黄海北部发现的中华白海豚Ⅱ.脊柱、肋骨、胸骨和肢带骨测定结果 总被引：3，自引：0，他引：3
前文初步报告了对2003年5月在黄海北部(北纬39°35′01″;东经122°51′50″)误捕的中华白海豚的外形和内脏器官测定结果,本文则报告了对该中华白海豚的脊柱、肋骨、胸骨和肢带骨的测定结果,此中华白海豚脊椎式为:C7 T12 L10 Ca22,与中国沿海其他海区的中华白海豚的骨骼测定结果基本相似。脊椎骨测定结果体现了海豚流线型曲线特点,但样本的第八和第十腰椎的脊突出现了分叉。另外,左第九、十肋骨上也出现了病灶。 相似文献
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珠江口是中华白海豚的重要栖息地之一，是唯一一个国家级中华白海豚保护区。近年来，由于水环境的恶化和其它因素，死亡、受伤的白海豚经常出现于珠海海域。本记录分析了2001年以来死亡、受伤于珠海海域及港澳的鲸豚类情况，提出了加强保护白海豚的建议。 相似文献
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2005年3-5月我县民主乡山上的一个村相继发生牛羊不明原因死亡,共死亡牛15头、羊20余头,当地群众不知所措,认为有人投毒,报案后始终未找到线索.后经笔者对该村牛羊死亡情况进行流行病学调查、病理解剖和实验室检查,诊断为牛羊肝片吸虫病. 相似文献
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珠江口中华白海豚(Sousa chinensis)种群从伶仃洋一直连续分布至上川岛海域。为探究上川岛以西海域是否也有中华白海豚分布,于2013-2015年采用船基截线法在上川岛至海陵岛海域进行了8个航次的考察。结果显示各个航次均有中华白海豚的目击记录,考察期共目击到78群次(约623头次),部分个体有重复目击记录,证实了该海域常年栖息着一定数量的中华白海豚。海豚的目击分布以下川岛、漭洲岛周围水域,以及东平港至庙湾角近岸水域较为集中。海豚的平均目击率与珠江东部河口(伶仃洋)和珠江西部河口区处于同一水平,海豚聚群规模较大并发现有大于30头的超大规模聚群,整体的年龄组成较为年轻化,表明上川岛至海陵岛海域是中华白海豚的重要栖息地,具有较好的保护潜力。 相似文献
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中华白海豚(Sousa chinensis)隶属于白海豚属,为国家一级重点保护动物。为详细了解中华白海豚骨骼的特征,对2009年2月广东阳江闸坡海边搁浅死亡的1头中华白海豚,经多步骤处理制成骨骼标本,对其骨骼数据进行全面测量和相关统计分析。结果显示,其胸椎质量与椎体高度、椎体长度之间存在显著的二次函数关系(R~2=0.919 2;R~2=0.840 5);尾椎的椎体质量与椎体高度、椎体长度、椎体宽度之间均存在显著的幂函数关系(R~2=0.955 0;R~2=0.928 6;R~2=0.866 4);幂函数能很好地拟合V型骨质量与最大高、最大厚、最大宽之间的数学关系(R~2=0.950 3;R~2=0.917 4;R~2=0.89)。 相似文献
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2017年2月,某猪场哺乳仔猪出现腹泻、呕吐等症状,且病死率高,为查明病因,送检发病死亡仔猪2头于贵州大学生物技术中心实验室进行诊断。通过临床症状观察、病理解剖及PCR/RT-PCR诊断,确诊发病死亡仔猪为PEDV和PCV2双重感染,从发病情况、剖检症状及防治措施进行阐述。 相似文献
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珠江口中华白海豚观察报告 总被引：1，自引：0，他引：1
被喻为“水上大熊猫”的中华白海豚Sou sa chinensis因被选定为香港回归祖国的吉祥物而蜚声中外，海内外海洋、水产专家对中华白海豚的研究亦随之进入实质性的阶段。1997年1月莲花山镇渔科站属下的番渔科07001、07002号科研调查船承担了广东省海洋与水产厅资源环境处下达的课题，对珠江口水域中华白海豚进行观察，现将7个月来在珠江口水域观测的情况报告如下。 相似文献
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1 发现情况 1999年10月21日上午，我市太山乡某村养牛大记，突发一头牛死亡，至10月26日共有7头牛发病，死亡4头；2000年6月上旬，我市烧锅镇某村养牛大户，突然发病共计5头，死亡一头，发病特点是：发病急，死亡快，如及时诊治可以控制疫情的蔓延。 相似文献
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Osmoregulatory ability of anadromous Arctic char, Salvelinus alpinus (L.), migrating towards the sea
Abstract. Hypoosmoregulatory capacity was examined in anadromous Arctic char, Salvelinus alpinus (L.), caught whilst migrating towards the sea in the river Å-elva, northern Norway (69°04′N and 17°00′E). Metacercariae of the marine digenean Cryptocotyle lingua (Creplin) were found on 47% of the fish investigated, demonstrating that they had been in brackish or sea water on at least one previous occasion. The fish were randomly divided into three groups, and exposed to sea water (35 ppt salinity at 5–6°C) for 7 days- one group immediately after capture, and the other two groups after 16 days of acclimation in fresh water and brackish water (15–17ppt), respectively. Blood plasma osmolality, Na+ and Mg2+ levels showed only a small and transient rise during seawater exposure, and there were only minor changes in muscle water content, irrespective of prior treatment. A slight, but insignificant, reduction in hypoosmoregulatory capacity appeared to occur in the groups retained in fresh water or brackish water for 16 days prior to seawater exposure. The results did not indicate that the fish show any improvement of hypoosmoregulatory capacity following a period of acclimation in brackish water. The hypoosmoregulatory capacity of seaward-migrating Arctic char is well developed before they enter the sea, and may be comparable to that seen in salmonids which undergo a parr-smolt transformation. There was a negative correlation between blood plasma electrolyte levels and both body length and weight, indicating that hypoosmoregulatory capacity was affected by the size of the fish. The effects of body size upon the development of hypoosmoregulatory capacity are discussed with respect to estuarine residence and the constraints placed upon the survival of small fish in full-strength sea water. 相似文献
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将体重为（65．26±4．37）g的刺参分成3组（A组为室内低温养殖,B组为夏眠30d后室内低温养殖,C组为夏眠60d后室内低温养殖）,在不同温度条件下养殖120d,期间多次取样分析和比较刺参生长状况和体壁成分的变化。刺参夏眠期体质量显著下降,夏眠后体重增加明显。A、B、c三组刺参的特定生长率分别为-0．03％、0．27％、0．32％/d,存活率分别为91．67％、71．43％、53．57％,说明低温度夏虽然不能促进生长,但成活率高。刺参体壁主要营养成分含量由高到低依次为水分、粗蛋白、灰分、总糖和粗脂肪。养殖30d后,夏眠组与室内低温组相比,粗蛋白和粗脂肪含量增加,水分、灰分和总糖含量减少。实验结束时,A、C两组刺参体壁各营养成分与实验开始时无显著性差异（P〉0．05）;B组除粗脂肪含量显著低于实验开始时（P〈0．05）外,其他体壁营养成分无显著性差异（P〉O．05）。研究表明,高温季节低温饲育并不能解除所有刺参夏眠;刺参经历夏眠蛰伏后有一个体重快速增长期;刺参在体重快速增长的同时,体壁营养成分含量无显著性变化。 相似文献
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1999年 8～ 10月广东沿海网箱养殖的眼斑拟石首鱼 (Sciaenopocellatus)流行一种暴发性传染病 ,经抗菌药或杀虫剂处理均无效。为查明病因 ,取病鱼镜检 ,未发现寄生虫 ,也分离不到细菌。电镜观察 ,可见病鱼的脾脏细胞内有截面为六边形、直径约 15 0nm的病毒颗粒 ,且脾、肝、肾都有一定程度的病变 ;用 2对日本所报道的虹彩病毒特异引物进行PCR扩增 ,在病鱼的脾脏样品中扩增出 2条大小与所报道的虹彩病毒扩增产物吻合的特征带 ,故初步认定虹彩病毒是眼斑拟石首鱼暴发性传染病的主要致病原 相似文献
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E. M. Olsen H. Knutsen J. H. Simonsen B. Jonsson J. A. Knutsen 《Ecology of Freshwater Fish》2006,15(4):446-452
Abstract – Sea trout ( Salmo trutta ) originating from small coastal streams can be found at sea throughout the year, in contrast to conspecifics from larger rivers, which typically spend the autumn and winter in fresh water. Such an extended marine stay has been observed in coastal Skagerrak. We studied the seasonal variation in marine growth of Skagerrak sea trout based on scale increment patterns and body lengths of 563 individuals captured at sea. Growth, measured as increased body length, was rapid during summer while there was no evidence for continued growth during autumn and winter. Growth decreased with increasing age of the fish. Our results suggest that coastal Skagerrak is an important feeding area for sea trout during summer, and that an extended marine stay during autumn and winter may have trade-off benefits other than somatic growth. Alternative benefits might be increased winter survival and decreased migratory costs of juvenile fish. 相似文献
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Juraj Hol&#;ik 《Ecology of Freshwater Fish》1995,4(4):175-179
Abstract– In the anadromous cyprinid kutum, Rutilus frisii (Nordmann, 1840) from the Anzali Lagoon, Iran, the following hitherto unrecorded characters were found. The complex life-style of juvenile kutum is reflected directly in their body size and preferred habitat, and indirectly in their growth rate and the formation of scale annuli. The early juveniles did not move downstream to the feeding grounds in the sea as they are supposed to do in populations inhabiting the Caucasian coast of the Caspian sea, but most of them spend one or two years in fresh or brackish water. Moreover, most kutum scales carried one or two juvenile marks. It appears that the time spent in fresh water is inversely proportional to the age of the kutum. On average about 43% of fish 2 years old and older, spent their first year in fresh or brackish water, while 57% spent two years there. The rate of growth in length is substantially different in both groups. Fish that enter the sea in their second year of life grew faster but their life span seems to be shorter than those which spent two years in fresh or brackish water. 相似文献
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The sea trout population of the River North Esk was sampled by means of a stationary trap situated on Kinnaber Mill Lade which drains its water from the main river. Commencing in 1971 the number of trout taken in the trap was noted daily, and from 1976 all stages of trout caught in the trap were tagged. The peak of the sea trout smolt migration was usually in May or June, and over the period of study exhibited a tendency to occur later each season. Two-year-old smolts comprised the largest age class in the smolt samples with 3-year-old fish being the other substantial age class. Samples of smolts taken for sex determination were found to be predominantly female. In 1979 and 1980 the sea trout smolt production of the North Esk was estimated from a mark-recapture experiment to be 51,969 and 78,208 respectively. A proportion of finnock (post-smolts) returned to fresh water in the year of their smolt migration and were taken moving upstream into the trap from July onwards, with a peak of movement occurring in the autumn. The main run of adult sea trout into the trap was found to take place at any time between July and October. The adult sea trout sampled were predominantly maiden spawners of ages 2.1+ and 3.1+ years. Both finnock and adult sea trout samples exhibited a similar freshwater age composition to that of the smolts. 相似文献
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Abstract. Samples of Atlantic salmon, Salmo salar L., held in sea cages and tanks with running water were examined for presence of sea lice, Lepeophtheirus salmonis. The number of lice, their sex stage (only post-chalimus stages) and location on the fish body were recorded. A new method has been used to express parasitic intensity in fish of different size. Effects of different factors on the degree and character of infestation (structure of the lice population), such as fish size, habitat and chemical treatment, have been studied. Different lice categories have shown different susceptibility to delousing with dichlorvos. Second pre-adults are most susceptible, and males generally more than females. Running water has been found to'flush out'the lice from the fish body. Pre-adults are flushed out easier than adults, and males generally easier than females. Adult males show high tolerance to water of lowered salinity and great mobility manifested in occasional transfer between hosts. The higher activity level of adult males may partly explain a drop in proportion of males after delousing and in running water. Frequency of mating has been found to increase with parasitic intensity. 相似文献
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The migrations of North Esk sea trout were studied by tagging all stages of sea trout taken in a stationary trap situated on Kinnaber Mill Lade which drains its water from the main river. The majority of recaptures were reported from the Montrose area, and evidence of a great deal of intermixing between the sea trout of the North Esk and neighbouring rivers was found. After their initial migration as smolts a proportion of the tagged sea trout returned to fresh water within the same year. Some tagged fish undertook several journeys back and forth between sea water and fresh water during (his period. Numerous examples of tagged sea trout travelling appreciable distances (>100 km) along the coast were obtained. In addition four tagged fish were recaptured in excess of 500 km from the North Esk, three off the Scandinavian coast and one in the River Barvas, North West Lewis. 相似文献
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The worldwide demand for sea cucumber is outpacing the sustainable harvest capabilities of fisheries. Sea cucumber ranches and farms are striving to supplement wild harvest, but variable temperature and salinity conditions in pond culture systems make sea cucumber production challenging. In this study, we evaluated how water temperature, salinity and body size affected the energy budget of pond-cultured sea cucumber Apostichopus japonicus Selenka. An orthogonal design was used to identify the most suitable conditions for energy consumption and scope for growth (SFG). After the 42-day experimental period, we found that water temperature, salinity and body size significantly influenced energy consumption, while salinity and body size were the main influencing factors on SFG. Based on these results, we suggest that a water temperature of 16 °C and a salinity of 30 g L?1 are optimal conditions for stocking sea cucumber A. japonicus with a body size of 37.34 ± 4.63 g. As such, the optimum stocking seasons for sea cucumber A. japonicus may be April in the spring and October in the autumn. 相似文献
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Lo Persson Anders Kagervall Kjell Leonardsson Mansour Royan Anders Alanr 《Ecology of Freshwater Fish》2019,28(2):190-199
Hydropower development has negatively influenced Atlantic salmon (Salmo salar) populations. Compensatory hatchery‐rearing programmes exist, but released fish suffer from high mortality that may be related to the lack of experience from natural environments in hatchery‐reared smolts and their large body size and high energetic state. Here, we used acoustic telemetry to test how body size, energetic state, and the environmental conditions of the river affect migration in hatchery‐reared smolts. The study was conducted in three consecutive years between 2011 and 2013 in the lower part of the River Umeälven, Sweden. For individual fish, there was no effect of body size but the energetic state of the fish had a negative effect on sea entry. The most important factor affecting sea entry rate was the water discharge in the old river bed that differed among years. Smolts were more likely to enter the sea in years when the discharge was high or when the discharge increased substantially shortly after release. Hatchery‐reared fish had higher migration speed at a slower flowing section compared with a faster flowing section, which was likely a result of large hesitation to enter the rapid section. The increase in water discharge led to an increase in fish migration speed disproportional to the increase in water velocity. Our results highlight the importance of water discharge for the smolts during smolt migration, and we argue that concern should be given to migrating fish when managing regulated rivers. 相似文献