Getting cosy in freshwater: Assumed to be brackish pike are not so brackish after all     

Kim Birnie‐Gauvin  Lasse Birch Hjrup  Theis Kragh  Lene Jacobsen  Kim Aarestrup 《Ecology of Freshwater Fish》2019,28(3):376-384

Pike (Esox lucius) occupy coastal streams and rivers of the Baltic Sea, where they attain large sizes (>5 kg). These large sizes are perhaps due to the fact that they can tolerate relatively high salinities and can thus forage in the nearby more productive brackish environments. In an attempt to quantify the extent to which pike utilise brackish environments, and to provide some insight into the underlying causes for brackish water migrations, we tagged 30 pike from a western Baltic river with acoustic transmitters and were able to track 21 individuals for 1 year. Based on experienced from local anglers, this population was assumed to be brackish in nature, where individuals underwent freshwater migrations to spawn. Our findings however suggest that the smallest and most active individuals make short exits into brackish waters and do so on rare occasions. Our results further indicate that neither sex nor size is related to activity level. We suggest that these patterns reflect two distinct behaviours—active and passive—and that large pike can be supported by the food availability in the river, without the need to venture into coastal zones, thus defying the conventional view that Baltic pike are all brackish in nature.  相似文献   

南美白对虾淡水养殖试验报告   总被引：3，自引：0，他引：3  

陈德福  孟凡峰等 《齐鲁渔业》2002,19(4):15-16

采取人工调兑淡水盐度，定点投喂颗粒饲料，调节水质及病害预防措施，在667m^2淡水池塘中养殖南美白对虾，经107天的饲养管理，共产南美白对虾160．2kg，平均体长达13．5cm/尾，体重20g/尾，成活率达到80．1％，共获利润5732．5元，投入产出比1：2．47。  相似文献   

Ouabain-sensitive Na/K-ATPase activity increases during embryogenesis in the giant freshwater prawn Macrobrachium rosenbergii     

Marcy N Wilder  Do Thi Thanh Huong  Atsuro Okuno  Muharijadi Atmomarsono  Wei-Jun Yang 《Fisheries Science》2001,67(1):182-184

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Na/K-ATPase activity during larval development in the giant freshwater prawn Macrobrachium rosenbergii and the effects of salinity on survival rates     

Do Thi  Thanh HUONG  Vidya  JAYASANKAR  Safiah  JASMANI  Hisako  SAIDO-SAKANAKA  Andrew J.  WIGGINTON  Marcy N.  WILDER 《Fisheries Science》2004,70(3):518-520

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Chemical and Thermal Properties of Freshwater Prawn (Macrobrachium rosenbergii) Meat     

Chodsana Sriket  Wonnop Visessanguan  Hideki Kishimura  Kenji Hara  Asami Yoshida 《Journal Of Aquatic Food Product Technology》2013,22(2):137-145

Chemical compositions and thermal properties of cultured freshwater prawn meat (FPM) were studied. FPM contained 83.2% protein (dry basis), 62.7% of which was myofibrillar protein. Pepsin-soluble collagen (PSC) and insoluble collagen (ISC) contents were 0.63 and 0.32%, respectively. Both collagens were similar to type V collagen from porcine placenta. Glutamic acid/glutamine, arginine, aspartic acid/?asparagine, and lysine were abundant amino acids in FPM. Glycine, proline, hydroxyproline, and aspartic acid/?asparagine were predominant in both collagens. FPM exhibited thermal transition temperatures (T_max) of 48.3 and 64.7°C, whereas T_max of PSC and ISC were 43.0 and 46.0°C, respectively. Textural changes in FPM during post-mortem storage on ice are plausibly dependent upon its compositional and thermal properties.  相似文献   

五种蚌的形态变异与判别分析   总被引：30，自引：3，他引：30       下载免费PDF全文

魏开建 《水产学报》2003,27(1):13-18

运用多变量形态度量学方法，采用6个形态性状对褶纹冠蚌、三角帆蚌、圆背角无齿蚌、椭圆背角无齿蚌和球形无齿蚌5种蚌的种间以及地理种群间的形态变异进行了研究。主成分分析构建了2个主成分，第一主成分受4个性状的影响，贡献率为54.17%；第二主成分受1个性状的影响，贡献率为34.08%。主成分分析和聚类分析表明，褶纹冠蚌与三解帆蚌形态相近，随圆背角无齿蚌与球形无齿蚌外形相拟。方差分析和t检验表明，褶纹冠蚌和三解帆蚌的不同地理种群分别表现出形态上变异。建立了5种蚌的判别函数，三角帆蚌和圆背角无齿蚌的判别准确率均为100%，褶纹冠蚌、椭圆背角无齿蚌和球形无齿蚌的判别准确率依次为98.92%、86.36%和96.88%，总判别准确率为97.83%。  相似文献   

Median Lethal Concentration (LC50) of Piscicidal Plants and Their Utilization in Aquaculture     

S. N. Ramanujam  R. Dominic 《Journal Of Applied Aquaculture》2013,25(4):326-333

Aqueous and ethanol extracts of Acacia pennata (bark), Catunaregam uliginosa (fruit), Diospyros lenceofolia (fruit), and Sapindus mukorossi (fruit) were evaluated as piscicides on the freshwater fish Danio dangila, Danio rerio, and Puntius shalynius, and the air-breathing Heteropneustes fossilis. Catunaregam uliginosa (fruit) possessed relatively higher piscicidal potency followed by Sapindus mukorossi (fruit), Acacia pennata (bark), and lastly Diospyros lanceofolia (fruit). Catunaregam uliginosa can thus be used for eradicating unwanted wild fishes in a short time span at low concentrations so that the health of aquatic environment is maintained.  相似文献   

Pathogenicity of halophilic Vibrio harveyi in giant freshwater prawns (Macrobrachium rosenbergii De Man)     

Wilailak Siripornadulsil  Mutjarin Thongserm  Surasak Siripornadulsil 《Aquaculture Research》2014,45(12):1979-1988

In this study, the phenotypic and pathogenic properties in freshwater host were characterized in 14 strains of halophilic Vibrio harveyi isolated from infected marine black tiger shrimp, Penaeus monodon. The lysogenic phenotype was assayed via prophage excision and mitomycin C induction. The bacteria were grouped into two types, corresponding to lysogenic and non‐lysogenic strains. The pathogenicity was determined via direct injection of bacterial cultures into post‐larval juvenile giant freshwater prawns, Macrobrachium rosenbergii De Man. All of the infected prawns showed similar symptoms and inflamed hepatopancreas. The V. harveyi isolates derived from the first‐injected infected prawns were re‐isolated and re‐injected into healthy giant freshwater prawns, in which they retained similar infectivity. Both lysogenic and non‐lysogenic Vibrio spp. showed identical virulence associated with 100% mortality within one day post‐injection. TEM micrographs showed hepatopancreatic nuclear deformation and lipid breakdown caused by lysogenic γ‐hemolytic VL19 and non‐lysogenic β‐hemolytic V33. However, the V33 strain was associated with severely disrupted mitochondria. None of the V. harveyi strains was able to produce a biofilm. Together, our findings indicate that the lysogenic and non‐lysogenic halophilic V. harveyi isolated from marine shrimps may use different virulence factors that are responsible for their pathogenicity in freshwater prawns.  相似文献   

Utilization of monounsaturated fatty acid (18:1n-9, oleic acid) by freshwater prawn Macrobrachium rosenbergii (de Man) juveniles     

B. V. L. Querijero  S. Teshima  S. Koshio  & M. Ishikawa 《Aquaculture Nutrition》1997,3(2):127-139

The utilization of oleic acid as an energy source and the effects of oleic acid levels and/or dietary soy bean lecithin (SBL) on oleic acid utilization, growth and survival, and lipid class and fatty acid compositions of freshwater prawn, Macrobrachium rosenbergii (de Man), juveniles were determined.
Increase in levels of dietary oleic acid from 10 to 80 g kg⁻¹ significantly ( P ≤ 0.05) reduced growth, survival and feed conversion efficiency of M. rosenbergii juveniles during the 40-day feeding period. Inclusion of 20 g kg⁻¹ SBL had no significant effect ( P ≥ 0.05) on growth and survival, nor was there any interactive effect between dietary SBL and oleic acid levels.
Body fatty acid profile of prawns reflected dietary fatty acid quantity. The fatty acid composition of prawns fed diets containing 80 g kg⁻¹ oleic acid had tremendously high proportions of oleic acid. Polar lipids, mostly phosphatidylcholine (PC), constituted the bulk of the extracted total lipids. Prawns fed with SBL had significantly ( P ≥ 0.05) higher PC content.
Oleic acid was metabolized for energy by M. rosenbergii juveniles at the same rate regardless of dietary level of SBL and/or oleic acid. Expired ¹⁴CO₂ accounted for half of the ingested radioactivity 48 h after feeding with labelled diets. No significant difference in the amount of ¹⁴CO₂ expired by prawns fed the labelled test diets was found. Per cent radioactivity ingested and absorbed into the body was also not significantly different in prawns of the different dietary treatments.  相似文献   

The On-Farm Trials of the Rotational Prawn-Rice Farming in a Semi-Deep Water Area     

Lam My Lan  Jean-Claude Micha  Duong Nhut Long  Tran Thanh Hai 《Journal Of Applied Aquaculture》2013,25(3):168-183

ABSTRACT

The on-farm trials of rotational rice-prawn farming in a semi-deep water area in the Mekong Delta of Vietnam was carried out in six rice fields (0.7–1.0 ha) to evaluate the production and economic efficiency of using low and high cost feed on prawn culture in paddies at different densities. Two stocking densities of 4 and 5 PL/m² were investigated. Two treatments of feed types (pellets only or a combination of pellets, trash fish, and snail meat) were applied at stocking 4 PL/m². At the treatment of 5 PL/m², prawns were fed a combination of pellets, trash fish, and snail meat. Prawns were stocked in the mid-April and harvested in mid‐November before the next dry season rice crop. Rice farming was started 3 to 5 days after prawn harvesting. By cull harvesting during the culture period, final mean weights of prawn ranged from 47.2 to 57.2 g/prawn and the male:female ratio at harvesting was 2.5:1.0. The prawn yield of treatment 5 PL/m² was highest (630 ± 22 kg/ha). Net profits in treatments using the combination of pellets, trash fish, and snail meat were 861 ± 193 US$/ha to 1,019 ± 25 US$/ha for the prawn crop and 1,393 ± 71 US$/ha to 1,576 ± 180 US$/ha for the whole system (prawn crop + dry rice crop) and significantly higher than in treatment using pellet only (P < 0.05). Prawns fed on pellets or a combination of pellets and snail meat both offer similar results in terms of production and economics. The dry rice crop offered high cost benefit ratio (2.29–2.33) with low operating cost (414–434 USD/ha) and it made a better use in sustainable rice fields through the rotational rice-prawn system.  相似文献