共查询到20条相似文献，搜索用时 62 毫秒
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在水温保持约28℃条件下,方斑东风螺日均摄食率、日均体重增长率,随其生长逐渐下降,而日均体重生长量逐渐上升。在密度300~1500个/m2范围内、小换水量(30%/d)试验条件下,当体重为1~2g、壳高15~20mm时,不同密度组方斑东风螺生长无明显差异,适宜的密度在1500个/m2以内;当体重3~4g、壳高25mm左右时,密度1500个/m2,方斑东风螺生长速度明显低于其他组,认为适宜的密度为900个/m2左右;当体重4~5g、壳高25~30mm时,适宜密度应为600~900个/m2。 相似文献
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方斑东风螺水泥池养殖不同底质的生长与存活试验 总被引：1，自引：0，他引：1
为了解方斑东风螺水泥池养殖适宜的底质,水泥池底铺设不同底质进行对比试验。结果表明：在池底铺沙情况下,添加10%海泥或添加1%的贝壳,不影响方斑东风螺的正常生长与存活,体重、壳高生长速度分别是23.7～25.1mg/d和105.3～110.4μm/d,不同池生长、存活无明显差异;底沙添加海泥达到30%时,初期东风螺的生长受到不良影响,但随着换水次数的增加,逐渐趋于正常;池底不铺沙时体重生长速度为10.0mg/d,仅为其他池的39.8～42.2%,存活率仅为其他池的65.1～67.6%。认为东风螺水泥池养殖必须铺沙,底沙可适当含泥,含泥量不高于10%。 相似文献
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2种东风螺繁殖及苗种生长发育的比较 总被引：2，自引：0，他引：2
对方斑东风螺Babylonia areolata(Link)和台湾东风螺B·formosae(Sowerby)进行人工繁育试验,结果表明:在水温23·6±1·1℃和充气条件下,方斑东风螺的孵化时间为8d,台湾东风螺的孵化时间为7d;刚孵出幼体壳长方斑东风螺为482·7±10·6μm,台湾东风螺为398·2±10·3μm。在水温25·2±0·9℃、培育密度为0·1~0·2ind·mL-1左右时,方斑东风螺幼体壳长增长速度可达33·6μm·d-1,约在第18天开始进入附着变态,变态时壳高为1323·9±118·6μm;台湾东风螺幼体壳长增长速度为25·3μm·d-1,约在第16天开始进入附着变态,变态时壳高为955·5±74·4μm。在水温26·5±0·7℃、培育密度为2100ind·m-2左右时,方斑东风螺和台湾东风螺的稚贝壳高增长速度分别为0·21和0·20mm·d-1。 相似文献
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为营造东风螺水泥池养殖经济、高效的底质环境，进行了水泥池两种铺沙方式东风螺养殖效果的比较试验。结果表明，在不同年份的相同季节，养殖水温无明显差异，养殖密度大致相同的情况下，同一铺沙方式方斑东风螺（B.aerolataLink）和波部东风螺（B．formosaehabei）的生长无明显差异。而离底铺沙，方斑东风螺和波部东... 相似文献
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集约化养殖(盐碱水)中白斑狗鱼的生长及耗氧率研究 总被引：1，自引：0，他引：1
对肉食性凶猛的白斑狗鱼在中国西部甘肃省酒泉市盐碱水域设施集约化养殖中的生物学特性和耗氧率进行了研究。平均体长12·3±1·36cm、平均体重22±1·85g的白斑狗鱼经362d养殖后,平均体长和体重分别达到54·2±0·5cm和1776±6·5g;日均增长和日均增重为1·183mm/d和4·89g/d;特定增长率和特定增重率平均为0·41%和1·186%。水温在15·4~26·3℃时,特定增长率保持在0·5%/d以上,水温21·1℃时,特定增长率为最高0·728%/d;在水温13·8~26·3℃时,特定增重率保持在1·0%/d以上,水温23·7℃时,特定增重率达到最高(2·286%/d)。在一定水温范围内,随着水温升高,耗氧量、耗氧率和窒息点随之增大,呈正相关性。33±2·54g和81±5·34g体重白斑狗鱼水温与耗氧量关系式分别为:y=0·416x-0·2833,(R2=0·988);y=0·6963x-2·902,(R2=0·8871)。在水温20℃时,白斑狗鱼耗氧量随其体重增加而升高,但耗氧率和窒息点却随体重增加而下降。拟合白斑狗鱼体长与体重的关系为:W=0·0098L3·0299(R2=0·9989),其中b接近于3,表明白斑狗鱼的体长和体重处于等速生长。 相似文献
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方斑东风螺对海水温度、条件比重适应性的研究 总被引：2，自引：0，他引：2
进行了方斑东风螺对海水温度、条件比重适应性试验。结果表明：方斑东风螺所适应的海水的条件比重为1．014以上;其适应的水温为14℃以上,当养殖水温在24℃以上时,方斑东风螺可获得较快的生长速度。 相似文献
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报道了在人工养殖条件下,大海马(Hippocampus
kuda Bleeker)的体长与体重的相对生长率、生长比率及生长速度与饵料、水温等环境因子的关系。结果表明，大海马生长高峰期为5～11月，群体体长月平均增长率为12.20％，体长特定增长率为15.92％；体重月平均增重率为15.87％，体重特定增重率为27.70％，群体增重倍数为13.8。大海马体长呈逻辑斯蒂曲线增长，关系式为L＝192.3460／(1＋e 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 
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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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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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Iciar Martinez Amaya Velasco Ricardo Pérez-Martín Eskil Forås Michiaki Yamashita Carmen G. Sotelo 《Journal Of Aquatic Food Product Technology》2013,22(4):289-297
The purpose of this work was to evaluate the suitability of a method based on the presence of two restriction sites (for Hae III and Hindf I) in the mitochondrial NADH dehydrogenase subunit 5 (mt ND5) gene to identify Scomber species. The evaluation was performed on 144 reference and market samples by sequencing of the entire 505-bp fragment of the mt ND5 gene and of a 464-bp fragment of the Kocher fragment of the cytochrome b gene (mt Cytb). Sequence analysis of any of the two fragments allows the identification of each of the four Scomber species, but S. japonicus and S. colias had the same restriction sites at the ND5 amplicon and would not have been differentiated by this analysis. Similarly, loss of the Hae III site in some S. scombrus individuals would have misidentified them as not being Scomber. All the market products were correctly labeled except one acquired in Spain labeled as originating in the Atlantic and containing S. japonicus. 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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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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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
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
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