Conservation of freshwater fish in the British Isles: the status of fish in national nature reserves     

Alex A. Lyle  Peter S. Maitland 《水产资源保护:海洋与淡水生态系统》1992,2(1):19-34

1. To consider fully the conservation management of freshwater fish, it was important to know which fish were already in the protected environment of National Nature Reserves (NNRs) — the principal sites for nature conservation in Great Britain. For this reason, 235 NNRs declared by the Nature Conservancy Council (NCC) were surveyed for freshwater fish between 1987 and 1990 by questionnaires to the wardens, by compiling data from other sources, and, where necessary, by field sampling. The presence of fresh waters (as lakes, ponds, rivers and streams) was also recorded. The survey was organized to follow the country and regional structure by which nature conservation was administered by the NCC so that the results could be considered accordingly. 2. Seventy five percent of NNRs contain fresh waters and, of these, just over 20% have no fish. Of the 51 fish species available 37 (73%) were recorded in NNRs. NCC regions with most fish species are: SW Scotland, West Midlands and East Anglia, but NW Scotland has the highest total of species occurrences in NNRs. In terms of both the numbers of species and their frequency of occurrence, NW and NE England are notably the lowest. The most common fish in NNRs are Eels, Brown Trout and Three-spined Sticklebacks. 3. The results for species and for sites (NNRs) are discussed from the viewpoint of fish conservation. The majority of fish in NNRs are those most common in Great Britain. Two of the species recorded (Powan and Smelt) are currently important for conservation, but several of those most threatened do not occur in NNRs. A number of NNRs have diverse fish communities, but only six have significant fish conservation value, of which Loch Lomond NNR is outstanding. 4. There is considerable scope through NNR management to improve fish conservation and it is suggested that the acquisition of new reserves for threatened species should be considered.  相似文献   

Conservation of freshwater fish in the British Isles: Proposals for management     

Peter S. Maitland  Alex A. Lyle 《水产资源保护:海洋与淡水生态系统》1992,2(2):165-183

1. Recent checklists of the freshwater fish of the British Isles have included 42 native and 13 introduced species. Of the former, however, two are extinct now and eight are threatened in various ways. In addition there are several important stocks of common native species under threat. 2. Protection for British fish exists mainly through legislation and protected sites of various designations. The legislation is inadequate in some respects and very few of the protected sites were actually established for their fish interest. Nevertheless, in Great Britain, 37 species of fish occur in National Nature Reserves. The overall status of fish in Sites of Special Scientific Interest is unknown. 3. The main conservation options for managing freshwater fish resources are habitat restoration, stock transfer to new sites, captive breeding and cryopreservation. The first two of these are regarded as the most useful for the long-term conservation of threatened species. Improved legislation would also help, especially in relation to preventing the import and transfer of potentially harmful species. 4. As well as the implementation of conservation management programmes for rare fish, research and monitoring studies are also needed in order to aid management and maintain a watch on populations of important species. In addition, national fish databases and registers of important stocks are an important background for overall fish conservation and management.  相似文献   

The growth of young cattle and sheep managed on a preference and follower herd basis within a rotational grazing system on veld     

A.D. Lyle  G.M. Brockett  S.F. Lesch 《African Journal of Range and Forage Science》2013,30(1):46-47

The trial was carried out at the Kokstad Research Station in the summer rainfall area on the Eastern sea board of South Africa. Growing cattle and sheep in the first season and cattle only in the second were run on a preference and follower herd basis within a rotational grazing system on veld. This resulted in better mass gains in the preference cattle which reached statistical significance in both seasons. The cattle and sheep in the preference herd selected a diet higher in crude protein than the follower herd. The sheep selected samples which were higher in crude protein than those selected by the cattle.  相似文献   

伪狂犬病病毒吉林分离株感染BHK-21细胞的超微结构变化   总被引：1，自引：0，他引：1  

初小辉  常灵竹  骆艳秋  贺文琦  陈克研  高丰 《中国兽医学报》2010,30(12)

以猪伪狂犬病病毒(PRV)吉林分离株PRV-JL感染体外培养的BHK-21细胞为模型,通过透射电镜对PRV的形态发生学和宿主细胞超微结构的动态变化规律进行研究。结果显示,PRV能导致BHK-21细胞圆缩,并发生细胞融合,形成合胞体;电镜观察到的病毒粒子呈球形或椭圆形,成熟的病毒粒子直径大小为140~210 nm,未成熟病毒粒子直径为90~150 nm,多呈中空状,部分呈致密核芯。病毒吸附于细胞后以膜融合的方式进入细胞,在胞核内复制,装配好的病毒粒子以出芽的方式离开细胞核,获得最初的囊膜,进入胞浆;在胞浆内的病毒粒子又利用高尔基体的膜结构合成第2层囊膜,形成完整的病毒粒子;最后包裹有完整病毒粒子的高尔基囊泡与细胞膜发生融合,将病毒粒子释放到细胞外。感染细胞超微结构变化主要表现为:细胞胞浆空泡增多,内质网扩张,线粒体增生、嵴肿胀、脱落,最后空泡化,整个细胞裂解、破碎。  相似文献   

Episodic collapse in the horse     

C. H. Lyle  J. A. Keen 《Equine Veterinary Education》2010,22(11):576-586

The term ‘collapse’ can be used to describe a variety of incidents in which a horse loses postural tone with or without progression to recumbency and with or without loss of consciousness. Depending on the aetiology of the condition the episode may be self‐limiting and may or may not recur. Alternatively the collapse may be secondary to serious injury or disease and require veterinary intervention. This article mainly discusses investigation of the former scenario of self‐limiting single or multiple episodes of collapse in apparently healthy horses. An overview of the various causes of collapse is followed by a suggested approach to the diagnosis of these challenging cases.  相似文献   

Reproduction,larviculture and early development of the Bluebanded goby,Lythrypnus dalli,an emerging model organism for studies in evolutionary developmental biology and sexual plasticity          下载免费PDF全文

Sophie Archambeault  Eric Ng  Lyle Rapp  David Cerino  Bradford Bourque  Tessa Solomon‐Lane  Matthew S Grober  Andrew Rhyne  Karen Crow 《Aquaculture Research》2016,47(6):1899-1916

The Bluebanded goby, Lythrypnus dalli, is a popular ornamental aquarium species and a key organism for the study of several fundamental biological questions, most notably reversible sex change in adults. To maximize the tractability of this species as an emerging model system, it is essential to have an optimized propagation system and a detailed developmental staging scheme. One limitation to the larviculture of L. dalli is the relatively small size of the larvae, which makes the transition from yolk to feeding challenging. We developed a protocol and successfully reared three generations of L. dalli in the laboratory. The protocol contains several key innovations for the rearing of diminutive fish larvae, including tank design and co‐culturing of microalgae (Isochrysis galbana) with copepods (Parvocalanus sp.) in the larval rearing tanks. In addition, we describe the embryonic and larval development of L. dalli under controlled conditions and in comparison with the model organism Danio rerio. We found that at 21°C L. dalli larvae hatch in 4 days, reach flexion in 18–25 days and are sexually mature by 3 months. Overall, the embryonic development of L. dalli is remarkably similar to D. rerio with several striking differences, including the position and shape of the blastomere, size of the neuromasts and corresponding cupula, and relative timing of pigmentation and brain subdivision. The ability to rear this species in captivity is a valuable tool that could be utilized for a variety of similarly diminutive species and to address a greater breadth and depth of biological questions.  相似文献   

Risk factors for race-associated sudden death in Thoroughbred racehorses in the UK (2000-2007)     

Lyle CH  Blissitt KJ  Kennedy RN  Mc Gorum BC  Newton JR  Parkin TD  Stirk A  Boden LA 《Equine veterinary journal》2012,44(4):459-465

Reasons for performing study: Sudden death adversely affects racehorse welfare, jockey safety and the public perception of horseracing. Objective: To describe the risk of racing‐associated sudden death in Thoroughbred racehorses in the UK from 2000 to 2007, to identify whether there were risk factors uniquely associated with sudden death and to improve the understanding of the pathogenesis of racing‐associated sudden death by identification of risk factors for such cases. Methods: A sudden death was defined as an acute collapse and death, in an apparently healthy Thoroughbred racehorse, during or immediately after racing, in the absence of clinical data indicative of a catastrophic orthopaedic injury. The retrospective study included 201 case race starts and 705,712 control race starts. Univariable and multivariable logistic regression were used to identify risk factors for sudden death at any one start. Results: In the multivariable model, age, distance, race type, season and number of starts in the 60 days prior to the race were associated with sudden death. Conclusions: The risk factors identified in this study are not uniquely associated with sudden death and have been also been identified in studies using all causes of fatality as the outcome. These data suggest that a generic approach to reduce fatal musculoskeletal injury and sudden death may be possible. Potential relevance: The identification of risk factors allows speculation on the underlying mechanisms of sudden death in racing. This may stimulate hypothesis‐led investigations into the pathogenesis of exercise‐related arrhythmias, exercise‐induced pulmonary haemorrhage and blood vessel rupture. See also correspondence by Cook  相似文献   

Factors associated with outcome in 94 hospitalised foals diagnosed with neonatal encephalopathy          下载免费PDF全文

J. Lyle‐Dugas  S. Giguère  M. F. Mallicote  R. J. Mackay  L. C. Sanchez 《Equine veterinary journal》2017,49(2):207-210

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Influences of Follicular Size on Parthenogenetic Activation and in Vitro Heat Shock on the Cytoskeleton in Cattle Oocytes     

JK Tseng  CH Chen  PC Chou  SP Yeh  JC Ju 《Reproduction in domestic animals》2004,39(3):146-153

The availability of cow ovaries from the slaughterhouse has been very limited in Taiwan. To maximize the use of cow ovaries for research purposes, whole ovary dissection was performed and the developmental competence of the oocytes derived from different sizes of follicles was assessed by the rates of in vitro maturation (IVM) and parthenogenetic activation of the oocytes in Experiment 1 (Exp 1). Cumulus-oocyte complexes (COCs) derived from small (1-2 mm) and large (3-8 mm) follicles were subjected to standard IVM culture for 24 h. Mature oocytes were selected and then parthenogenetically activated using A23187 (5 microm, 5 min) or thimerosal (200 microm, 10 min) alone or combined with 6-dimethylaminopurine (2.5 mm and 3.5 h, respectively). Activation rates of the oocytes, neither from the large nor small follicles, were affected by different activation treatments (single or combined stimuli). Whereas maturation rates for the oocytes from large follicles were superior to those from small follicles in both the single (59% vs 45%) and combined treatments (76% vs 40%; p < 0.05). To understand how prolonged heat shock (HS) influences cytoskeletal configurations of mature bovine oocytes, in Experiment 2 (Exp 2), matured oocytes derived from large follicles were randomly allocated to different durations of HS treatments at 41.5 degrees C for 0 (C0h, control, n = 12), 1 (HS1h, n = 28), 2 (HS2h, n = 31), and 4 h (HS4h, n = 30). An additional control group was cultured for 4 h without HS (38.5 degrees C, 4 h, n = 35). Alterations in nuclear structures, microtubules (MTs), and microfilaments (MFs) of the oocytes were examined. Abnormalities in the chromosomes, spindle MTs and the percentages of oocytes with cytoplasmic MTs increased with time of HS treatment. The intensity of the MF distribution in the HS oocytes was also altered. Significant changes in the cytoskeleton after HS may be associated with the reduced development under hyperthermia and, perhaps, with the low pregnancy rates of the animals during hot seasons.  相似文献   

Abstracts of papers presented at     

R. Or  G. Fishler  M. Kehat  CH. Chen  Z. Klein  E. Dunkelblum  S. Gothilf  LEA Muszkat  VENEZIA Melamed-madjar  SHOSHANA Yathom  J. Halperin  Z. Mendel  O. Bonneh  NITZA Saphir  Y. Golan  Z. Madar  I. Moore  R. Snir  I. Harpaz  MICHAL Mazor  D. Becker  T. Kimmel  R. Cyjon  A. Cosse  M. Wysoki  A. Hefetz  D. Graur  DALIA La-france  A. Shani  U. Ravid  RUT Ideses  VICTORIA Soroker  ADA Rafaeli  E. Nevo  G. Heth  A. Beiles  J. C. Auffray 《Phytoparasitica》1987,15(2):155-164

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