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   

Factors Affecting the use of Dreissena polymorpha as a Bioindicator: the PCB Pollution in Lake Como (N. Italy)     

A. Binelli  S. Galassi  A. Provini 《Water, air, and soil pollution》2001,125(1):19-32

The aim of this study was to assess the PCB pollutionof the South-Western branch of Lake Como by using thezebra mussel (Dreissena polymorpha) as abioindicator since its recent reintroduction. Someenvironmental and physiological variables influencingaccumulation processes of organochlorine compounds inDreissena were investigated because climaticfactors may affect life cycle, reproductive stage andage. PCB levels were highest in the soft tissues ofDreissena close to the industrialized area ofComo (2298 ng g^-1 of lipids) and slowly decrease goingnorth, reaching approximately half this value at theclosing section of the lake branch. Nonetheless, thePCB concentrations are well below the dangerous levelsfor the aquatic environment.  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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珠江三角洲地区生鲜农产品冷链网络化运输技术     

曾艳英  李旭东 《湖南农机》2015,(3):92-93

文章主要是对我国的珠江三角洲地区的生鲜农产品冷链的物流方式进行探究,结合现在我国的生鲜农产品冷链运输技术的现状和发展前景进行大胆的预测,并提出我国的珠江三角洲地区的生鲜农产品冷链的运输技术的网络化的建议。  相似文献   

Environmental correlates of body size distribution in Cyprinidae (Actinopterygians) depend on phylogenetic scale          下载免费PDF全文

Gaël P.J. Denys  Pablo A. Tedesco  Thierry Oberdorff  Philippe Gaubert 《Ecology of Freshwater Fish》2016,25(1):125-132

The pattern of increasing species body size with increasing latitude has been noticed in different groups of animals. Here, we used seven key environmental factors and independent contrasts to assess body size latitudinal clines in Cyprinidae at two phylogenetic levels (inter‐ and intragenera), which were defined using a genus‐level supertree. Model selection procedures revealed that environmental factors shaping body size variation in Cyprinidae differed according to the phylogenetic scale considered. At the higher phylogenetic level, we found that both temperature (negative effect) and habitat availability (positive effect of drainage basin surface area) constituted mechanistic explanations of large‐scale body size distribution. No temperature‐related body size cline was observed at the intragenus level. Instead, competitive interaction (negative effect of species richness), habitat availability (positive effect of drainage basin surface area), migration ability and available energy (positive effects of glacial coverage and actual evapotranspiration) constitute alternative explanations at this lower phylogenetic scale. We conclude that (i) at the intergenus level, cyprinids do show a tendency to be smaller at high temperatures and larger at low temperatures, (ii) this tendency no longer exists at the intragenus level, (iii) latitude per se is a weak predictor of body size clines whatever the taxonomic level analysed, (iv) generalising geographical body size patterns may be rendered difficult by the superimposition of a series of mechanisms across different taxonomic scales, and (v) habitat size, here acting positively at both taxonomic scales, may play a major role in shaping riverine species body size clines.  相似文献   

黑珍珠樱桃在黔北地区的生物学特性及栽培技术   总被引：2，自引：2，他引：0  

金方伦  向青云  敖学熙  韩成敏 《贵州农业科学》2010,38(3)

历经7年(2003-2009年)对黔北地区黑珍株樱桃进行了引种观察和栽培试验。结果表明:定植后第2年部分植株开花结果,第3年大部分植株开花结果,第4年植株普遍开花结果,第5～6年以后进入盛果期。植株抗病、抗虫性较强,同时抗低温、抗旱、抗裂果较强。在海拨800～1200m,平地、山地和坡地栽植生长结果均良好。并提出了采用高标准建园、配方施肥、合理修剪、保花保果、合理疏花疏果、有效防治病虫害和合理采收等配套的栽培措施。  相似文献   

Environmental assessment of boreal rivers using fish data – a contribution to the Water Framework Directive     

T. VEHANEN  T. SUTELA  H. KORHONEN 《Fisheries Management and Ecology》2010,17(2):165-175

Abstract A fish‐based assessment method was developed to estimate the ecological status of boreal rivers. Electric fishing data were collected from 902 rapids, together with information on the land use, channel modification and water chemistry. Discriminant function analysis was used to select fish variables that most correctly classified the undisturbed reference sites and human impacted sites into exact classes. The relationship between the level of human alteration and fish metrics was examined. Five metrics were selected for the index: the number of fish species, proportion of sensitive species, proportion of tolerant species, density of cyprinid individuals and the density of age‐0+ salmonids. The value for each metric (between 0 and 1) was calculated according to a point estimate for classical probability. The index is used to estimate the ecological classification of rivers according to the EU Water Framework Directive.  相似文献   

Blood chemistry values of juvenile red pacu (Piaractus brachypomus)     

Sakamoto K  Lewbart GA  Smith TM 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2001,30(2):50-52

Abstract: Blood samples were collected from 29 juvenile red pacu ( Piaractus brachypomus ), ornamental freshwater fish, to establish baseline blood chemistry values. Mean (minimum-maximum) values, obtained by automated bichromatic analysis and ion selective electrode analysis, were as follows: sodium, 150.4 (146–159) mmol/L; potassium, 3.93 (2.7–5.0) mmol/L; chloride, 138.7 (128–150) mmol/L; total CO₂, 7.5 (6–10) mmol/L; albumin, 0.86 (0.5–1.0) g/dL; lactate dehydrogenase, 237.8 (65–692) IU/L; aspartate aminotransferase, 49.1 (0–125) IU/L; creatinine, 0.31 (0.2–0.4) mg/dL; calcium, 10.80 (9.5–12.5) mg/dL; anion gap, 6.89 (1.2–12.5) mmol/L; and phosphorus, 7.29 (4.1–8.9) mg/dL.  相似文献