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新安江冷水区网箱培育虹鳟亲鱼及其人工繁殖试验初报 总被引:1,自引:1,他引:0
<正> 为了开发利用本县一万四千多亩冷水水面,发展虹鳟养殖,首先需要解决虹鳟的苗种来源问题。为此,我们根据当地冷水水面广、流量大的自然条件,进行了网箱培育虹鳟亲鱼及人工繁殖试验。1985年投入小批量生产,取得初步成功。现将试验情况报告如下。一、新安江冷水区的自然条件新安江是钱塘江主要支流。1959年电站大坝建成,由于高坝影响,使坝下23公里长,一万四千多亩江面形成常年水温偏低的冷水区。冷水区有以下特点。 (一) 流量稳。据资料,多年来,年径流量变动在28.4亿立方至148.4亿立方之间。 相似文献
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新安江电站的高坝尾水形成了坝下23公里长、14,000多亩水面的冷水区,水温常年在20℃以下(1986年1月至12月的月平均水温是10.9;10.0;10.0;11.4;12.8;12.513.6;14.4;15.9;17.0;16.7;13.9;),为发展网箱养鳟提供了优越自然条件。 1986年浙江省建德县水电局在新安江水电站坝下3公里处的建德县虹鳟养殖场进行了网箱培育虹鳟鱼种试验。网箱规格为2×2×1米~3,箱体网衣分为三级,一级箱采用16目聚乙烯网布制成;二级箱由3目无结节聚乙烯网片制成;三级箱由2×3聚乙烯丝编织成2目网片制成。均为六面体封闭式。箱留一边不缝作投饵孔。毛竹框架,漂 相似文献
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基于Kriging方法Argo数据重构太平洋温度场研究 总被引:7,自引:0,他引:7
采用Kriging算法,将2007年1~12月份期间获得的太平洋海域的Argo剖面浮标资料重新构成3°×3°的月平均海温场。重构的温度场能较好地揭示太平洋暖流区、西边界流系的季节性变化和西边界流系强温度锋面。将插值数据与同一时期的实测数据进行比较。结果表明Kriging算法得到的海表温度最大误差0.7℃,平均误差0.3℃,平均相对误差0.7%,平均标准误差0.06℃,计算结果令人满意。进一步利用重构的太平洋表层及水下4个断面的温度场分析了太平洋海域的温度分布格局及季节变化,赤道海区表层暖水占主体,随着水深增加,东部冷水迅速往东扩展,在200 m时冷水基本把北上的太平洋暖水切断。 相似文献
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北太平洋狭鳕资源声学评估调查研究 总被引:14,自引:0,他引:14
1993年夏季使用“北斗”号渔业调查船对北太平洋的狭鳕进行资源声学评估和渔场环境调查,调查覆盖面积达76万平方公里。调查结果表明:夏季白令海阿留申海盆区50-200m为冷水团占据,水温为1.3-4.9℃。狭鳕成鱼主要分布于海盆区东南部及公海区,主要栖息在175-225m层。在公海区东北部与陆架之间,首次发现大量狭鳕当生幼鱼,主要栖息在80-100m层。成鱼和幼鱼均有明显昼夜垂直移动。海盆区狭鳕平均 相似文献
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在阿村水库坝下冷水区内网箱培育虹鳟亲鱼,13尾三龄雌鱼共产卵28350粒,获发眼卵14638粒,卵出仔鱼12000尾,上浮稚鱼9546尾。试验证明了在该水域用网箱培育虹鳟亲鱼进行人工繁殖是可行的。 相似文献
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三峡水库蓄水后,将形成众多面积大小不等、形态各异的库湾及消落区,为我们进行渔业开发提供了巨大的空间。一、三峡水库工程建设的进度和三峡水库水位年度变化规律1、三峡水库工程建设分4个阶段。从施工准备(1993年)开始,至1997年11月为导流阶段,汛期20年一遇洪水坝前水位于78.2m;1997年11月至2003年6月15日前,20年一遇洪水坝前水位82.28m;2003年6月15日后坝前水位135m,这一水位一直将维持到2006年9月;至2006年8月,水库开始按初期蓄水位156m运行;至2009年8月,工程全部建成,坝前蓄水位175m。2、三峡水库水位年度变化。水库在汛期6~9月按防洪… 相似文献
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夏季白令海温跃层和中层冷水的分布特征 总被引:1,自引:0,他引:1
研究了夏季白令海阿留中海盆区温跃层和中层冷水的分布特点及形成机制。结果表明,(1)以水温为主要分析指标,调查海区自上而下(0~500m)层,可分为上匀和层、浊跃层、中居冷水和下匀和层(2)温跃层广泛分布于大部分调查海域,绝大多数测站其深度在25~50m,强度在0.10~0.16℃/m,其中东南部为一相对强温跃区(≥90.15℃/m);(3)中层冷水的上界深度在40~130m左右,下界深度在150~ 相似文献
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Liping Li Rui Wang Wanwen Liang Xi Gan Ting Huang Yan Huang Jian Li Yunliang Shi Honglin Luo Ming Chen 《广西水产科技》2014,(1)
Previously, we reported 10 PEGE types of 85 tilapia Streptococcus agalactiae(GBS), which shifted from Streptococcus iniae in China, by using PEGE method. Presently, larger and more representative tilapia GBS were isolated, for the ?rst time in China, to characterize their serotypes and genetic diversities more precisely than had done before. 168 GBS strains were distributed in ?ve provinces of China, in which Guangdong, Guangxi and Hainan were the major ones, holding36.9%(62/168), 37.5%(63/168) and 19.6%(33/168), respectively. Serotypes, Ia, Ib and III, were observed in these strains and the most predominant one was Ia(95.2%), which mainly distributed in Guangdong, Guangxi and Hainan. Ia initially occurred in 2009, it shoot up to 32.1% in 2010,but decreased to 16.1% in 2011 before went up to 45.2% in 2012. Ib sporadically occurred during2007–2011, III onlyoccurred in 2012. 14 different PFGE types, including 4 new types(N, O,P and Q), were observed, in which B, D, F and G were the predominant types, holding 83.9%(141/168) of the total GBS strains. Ia corresponded to 11 PFGE types(A–H, N–P), in which type D predominated(51%). Ib represented 3 genotypes(I, J and Q) and III harbored only 2genotypes(N and F). Type N and Fsynchronously presented in Ia and III. In summary, the genetic diversity of tilapia GBS varied by serotypes and changed with geographical locations and years.Although Iastillpredominated, new rareserotypeIII alreadyoccurred in China. 相似文献
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Association between the interannual variation in the oceanic environment and catch rates of bigeye tuna (Thunnus obesus) in the Atlantic Ocean 下载免费PDF全文
The environmental processes associated with variability in the catch rates of bigeye tuna in the Atlantic Ocean are largely unexplored. This study used generalized additive models (GAMs) fitted to Taiwanese longline fishery data from 1990 to 2009 and investigated the association between environmental variables and catch rates to identify the processes influencing bigeye tuna distribution in the Atlantic Ocean. The present findings reveal that the year (temporal factor), latitude and longitude (spatial factors), and major regular longline target species of albacore catches are significant for the standardization of bigeye tuna catch rates in the Atlantic Ocean. The standardized catch rates and distribution of bigeye tuna were found to be related to environmental and climatic variation. The model selection processes showed that the selected GAMs explained 70% of the cumulative deviance in the entire Atlantic Ocean. Regarding environmental factors, the depth of the 20 degree isotherm (D20) substantially contributed to the explained deviance; other important factors were sea surface temperature (SST) and sea surface height deviation (SSHD). The potential fishing grounds were observed with SSTs of 22–28°C, a D20 shallower than 150 m and negative SSHDs in the Atlantic Ocean. The higher predicted catch rates were increased in the positive northern tropical Atlantic and negative North Atlantic Oscillation events with a higher SST and shallow D20, suggesting that climatic oscillations affect the population abundance and distribution of bigeye tuna. 相似文献
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Growth hormone (GH) and reproduction: a review 总被引:5,自引:0,他引:5
Florence Le Gac Odile Blaise Alex Fostier Pierre-Yves Le Bail Maurice Loir Brigitte Mourot Claudine Weil 《Fish physiology and biochemistry》1993,11(1-6):219-232
Interaction between growth and reproduction occurs in many vertebrates and is particularly obvious at certain stages of the life cycle in fish. Endocrine interactions between the gonadotropic axis and the somatotropic axis are described, the potential role of GH being emphasised. A comparative analysis of these phenomena in mammals, amphibians and fish, suggests a specific role of GH in the physiology of puberty, gametogenesis and fertility. It also shows the original contribution made by studies on the fish model in this field of investigations. 相似文献
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Sandra García‐Garrido Ismael Hachero‐Cruzado Carlos Rosas Pedro Domingues 《Aquaculture Research》2013,44(11):1741-1751
Protein and amino acid composition of the mantle of juvenile O ctopus vulgaris (Cuvier, 1797) during fasting for 27 days were determined. Average protein content of octopus mantle was of 711.19 ± 46.80 g kg?1 DW, and it decreased with increasing fasting days. The non‐essential amino acids content was higher (486.18 ± 11.08 g kg?1 protein) than essential amino acids (425.82 ± 9.15 g kg?1 protein) at the start of the experiment (unstarved animals). The results suggest that the amino acid profile of the mantle where the most abundant amino acids are Arg, His, Lys, Gly, Leu and Pro could indicate a prolonged fasting condition (>20 days) or poor nutrition of O . vulgaris. This study supports the idea of using mantle for metabolic needs of starved O . vulgaris suggesting that the degradation pathway of amino acids to pyruvate and tricarboxylic acid cycle intermediates was favoured contrary to the degradation pathway of ketogenic amino acids. Special considerations should be taken concerning Thr, Ile, Ser, Ala, Asx (Asp, Asn), Glx (Glu, Gln) (because of their fast intake) and Lys and His (due to their stable contents) during a prolonged period of fasting. 相似文献
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In this experiment, a feeding trial was performed to determine the effects of fructooligosaccharide (FOS) on growth performance, digestive enzyme activity and immune response of Japanese sea bass, Lateolabrax japonicus juveniles (initial weight 38.3 ± 0.5 g), and the fish were examined following feeding with six levels of FOS (0, 0.5, 1, 2, 4 and 6 g/kg) for 28 days. Significant enhancement of weight gain (WG) and specific growth rate (SGR) was found in fish fed 1 g/kg FOS incorporated diets (p < .05), while the feed conversion ratio (FCR) in the 1, 2 g/kg FOS groups reduced significantly compared with the control (p < .05). Besides, the crude lipid in the 4, 6 g/kg FOS groups increased significantly compared with the control (p < .05). On the other hand, the erepsin and lipase activities significantly elevated in intestine of fish fed 2 g/kg FOS (p < .05) and the lysozyme activity in serum of fish fed 2 g/kg FOS were significantly higher than that in the control (p < .05). Moreover, the alkaline phosphatase activities in serum of fish fed 0.5, 1, 2 g/kg FOS were significantly higher than in control (p < .05). Regression analysis showed that the relationships between dietary FOS levels and either SGR, FCR, erepsin or lysozyme activities were best expressed by regression equations, and the optimal inclusion levels are 1.37, 1.80, 3.06, 3.11, 1.93 and 1.80 g/kg for SGR, FCR, erepsin, lipase, lysozyme and total superoxide dismutase activities, respectively. Overall, this study revealed that FOS incorporated diets could beneficial for L. japonicus culture in terms of increasing the growth, digestion and immune activities. Under the present experimental condition, the optimal supplementary level of FOS in the diet of L. japonicus is 1–3 g/kg. 相似文献
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The endemic, anadromous cyprinidChalcalburnus tarichi is the only fish species known to occur in alkaline Lake Van (Eastern Anatolia, Turkey). EightC. tarichi were maintained individually in Lake Van water (17 – 19°C; pH 9.8; 153 mEq·I–1 total alkalinity; 22 total salinity) and tank water samples analyzed for 24 h in 2 to 4 h intervals. At zero time, < 1µM ammonia was present and urea was undetectable in the tank water; at 24 h, total ammonia and urea made up 114±32 and 35±25µM, respectively. Over the experimental period, ammonia-N and urea-N excretion averaged 1041±494 and 607±169moles·kg–1 fish·h–1, respectively. The extent of urea excretion was highly variable between specimens. Uric acid excretion was not detectable.Urea was present at high concentrations in all tissues and plasma (25 – 35moles·g–1·ml–1) of freshly caughtC. tarichi; total ammonia content of the tissues was by a factor of 1.9 (liver) to 3.0 (brain) lower. High arginase activity (2.4±0.2 U·min–1·g–1) was detected in the liver ofC. tarichi but ornithine carbamoylphosphate transferase, a key enzyme of the ornithine-urea-cycle, was absent. Ureagenesis is likely through degradation of arginine and/or uricolysis. High glutamine synthetase activity (11±0.6 U·min–1·g–1) and low ammonia content in brain suggest that, like other teleosts,C. tarichi has an efficient ammonia detoxification in the brain, but in no other tissue.Nitrogenous waste excretion at alkaline pH is discussed. The ability ofC. tarichi to excrete high levels of ammonia at extremely alkaline pH is unique among teleosts studied so far. The mechanism of ammonia excretion under Lake Van conditions remains to be elucidated. 相似文献
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Two gonadotropins (GtH; Qa and Qb) were purified by gel filtration and ion exchange chromatography from the pituitaries of Indian walking catfish (Clarias batrachus). The presence of GtH during purification was assessed by in vitro oocyte maturation and in vivo steroidogenic activity, and their identities were determined by elution profiles, molecular weight, biological activities and yield. The molecular weights of Qa and Qb were 37 and 42 kDa, respectively, and composed of distinct subunits (Qa: 20 and 14 kDa and Qb: 26 and 18 kDa). Polyclonal antibodies raised against Qa immunostained Qa, Qb and pituitary GtH cells. A competitive Qa‐ELISA was developed whose sensitivity was 6.25 ng mL?1 (1.25 ng well?1) with intra‐ (3.5%) and inter‐ (12.4%) assay coefficients of variation. Displacement curves parallel to the standard were obtained with plasma and pituitary extracts of catfish, Qb and carp GtHII. The assay was validated by measuring the plasma Qa levels after LHRH treatment and in relation to ovarian growth in the female catfish during different reproductive phases. Based on the results, Qa and Qb corresponded to fish LH and FSH respectively. The findings will increase the knowledge of the mechanisms controlling fish reproduction and identification of sensitive phases in fish in captivity for hormonal manipulation. 相似文献
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Controlled infection of Poecilia reticulata Peters (guppy) with Tetrahymena by immersion and intraperitoneal injection 下载免费PDF全文
G Sharon M Pimenta‐Leibowitz M C L Vilchis N Isakov D Zilberg 《Journal of fish diseases》2015,38(1):67-74
Tetrahymena is a protozoan parasite, which infects guppy, Poecilia reticulata Peters, and causes substantial economical losses in commercial farms worldwide. Studies of guppy infected by Tetrahymena require standardized infection protocols. The LD50 for Tetrahymena infection of guppies by intraperitoneal (IP) injection was calibrated, and the level obtained was 946 parasites per fish. Guppy infection with Tetrahymena by immersion, imitating the natural route of infection via the integument, was studied under normal or stress conditions. Exposure to cold and netting (CNI) and to cold only (CI) followed by immersion exposure to 10 000 Tetrahymena per mL resulted in 22.5% and 19.2% mortality, respectively, as compared to 14.2% and 10% in groups that were netted only (NI) or non‐stressed (I). Histopathology revealed that immersion infection resulted in a systemic infection. Lysozyme levels, measured 3 weeks after infection, were significantly higher in the CNI group (288 μg per mg protein) compared with CI‐, NI‐ and I‐treated groups (94.5, 64 and 62.3 μg mg?1, respectively). There was no evident parasite immobilization activity in body homogenates, suggesting no development of acquired immunity. Re‐infection by IP injection revealed no increase in protection in any of the treatment groups, mortality range of 56.3–75%, higher than in the non‐exposed control (40.6% mortality). 相似文献