Life‐history variation in a species complex of nonmigratory galaxiids          下载免费PDF全文

Peter E. Jones  Alistair Senior  Richard M. Allibone  Gerard P. Closs 《Ecology of Freshwater Fish》2016,25(2):174-189

Life‐history theory predicts that the optimal strategy in the trade‐off between egg size and number varies in relation to resource availability and environmental disturbance. We assessed interspecific differences in egg size, fecundity and other life‐history traits in a species complex of stream‐resident galaxiid fish, which are distributed across a range of contrasting habitat types on the South Island, New Zealand. Oocyte size, fecundity and reproductive effort were measured from gravid females collected immediately before spawning. Proxy measures of stream productivity, flow variability and predation pressure were extracted from modelled data sets. A suite of different egg sizes were identified across species within the Galaxias vulgaris complex, with mean oocyte volume differing by up to 133% between species. The species with the smallest eggs showed mean size‐relative fecundities 246% higher than the species with the largest eggs. A significant negative relationship was found between species’ mean egg size and size‐relative fecundity, suggesting a trade‐off between these traits. Species with larger eggs had larger maternal body size, lower reproductive effort and delayed maturity compared to ‘small‐egg’ species. Consistent with the predictions of life‐history theory, species with larger eggs, lower size‐relative fecundity, lower reproductive effort and delayed maturity were associated with low productivity, stable streams, whereas species exhibiting the opposite set of traits occurred in relatively productive but disturbed systems.  相似文献   

Treatment of a periradicular lesion in an alpaca (Vicugna pacos)     

Parker R  Hawkes C  Cox A  Barakzai SZ 《Journal of veterinary dentistry》2011,28(1):22-24

This case report describes the diagnosis and surgical treatment of a cyst-like periradicular lesion in an alpaca.  相似文献   

Molecular characterization of the uncultivatable hemotropic bacterium Mycoplasma haemofelis     

Barker EN  Darby AC  Helps CR  Peters IR  Heesom KJ  Arthur CJ  Crossett B  Hughes MA  Radford AD  Tasker S 《Veterinary research》2011,42(1):83

ABSTRACT: Mycoplasma haemofelis is a pathogenic feline hemoplasma. Despite its importance, little is known about its metabolic pathways or mechanism of pathogenicity due to it being uncultivatable. The recently sequenced M. haemofelis str. Langford 1 genome was analysed and compared to those of other available hemoplasma genomes.Analysis showed that in hemoplasmas genes involved in carbohydrate metabolism are limited to enzymes of the glycolytic pathway, with glucose appearing to be the sole energy source. The majority of the pentose phosphate pathway enzymes that catalyze the de novo synthesis of ribonucleotides were absent, as were cell division protein FtsZ and chaperonins GroEL/ES. Uncharacterized protein paralogs containing putative surface expression motifs, comprised 62% of M. haemofelis and 19% of Mycoplasma suis genome coverage respectively, the majority of which were present in a small number of unstructured islands. Limited mass spectrometry and immunoblot data matched a number of characterized proteins and uncharacterized paralogs, confirming their expression and immunogenicity in vivo.These data have allowed further characterization of these important pathogens, including their limited metabolic capabilities, which may contribute to their uncultivatable status. A number of immunogenic proteins, and a potential mechanism for host immune system evasion, have been identified.  相似文献   

Extralabel use of nonsteroidal anti-inflammatory drugs in cattle     

Smith GW  Davis JL  Tell LA  Webb AI  Riviere JE 《Journal of the American Veterinary Medical Association》2008,232(5):697-701

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Hematologic disorders of fish     

Tonya M Clauss  Alistair D M Dove  Jill E Arnold 《Veterinary Clinics of North America: Exotic Animal Practice》2008,11(3):445-462

Hematology can be a useful tool for monitoring health status, detecting illness, and following the progress of disease and response to therapy. Despite advances in fish medicine in recent years, interpretation of fish hematology often is hampered by a lack of meaningful reference values and the bewildering diversity of fish species. A multitude of intrinsic and extrinsic factors cause normal and abnormal variation in hematologic data. This article provides an overview of some of the hematologic abnormalities in fish induced by infectious agents and environmental, husbandry, and nutritional issues.  相似文献   

Reply     

Dr.  John Innes  Dr.  Margaret Costello  Dr.  Heike Rudorf  Dr.  Frances Barr  Dr.  Alistair Barr 《Veterinary radiology & ultrasound》2004,45(4):368-369

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Modelling the Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) site index from site factors in Portugal   总被引：1，自引：0，他引：1  

Fontes  Luis; Tome  Margarida; Thompson  Frank; Yeomans  Alistair; Luis  Jaime Sales; Savill  Peter 《Forestry》2003,76(5):491-507

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Current update on drugs for game bird species     

Needham ML  Webb AI  Baynes RE  Riviere JE  Craigmill AL  Tell LA 《Journal of the American Veterinary Medical Association》2007,231(10):1506-1508

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The protein and energy requirements of farmed South African abalone Haliotis midae L. cultured at optimal and elevated water temperatures     

Alistair J Green  Clifford L W Jones  Peter J Britz 《Aquaculture Research》2011,42(11):1653-1663

Formulated abalone feeds used by the culture industry are believed to be unsuitable for use at elevated water temperatures (>20 °C). The aim of this study was to develop a feed that could safely be fed to abalone cultured at elevated water temperatures by optimizing dietary protein/energy levels. Abalone (54.90 ± 0.08 mm; 28.99 ± 0.16 g) were cultured at either 18, 22 or 24 °C, and fed diets containing graded levels of protein (18–26%) and energy (11.6–16.2 MJ kg^?1). Abalone growth was temperature dependent, declining from 4.33 g month^?1 at 18 °C to 0.77 g month^?1 at 24 °C. Shell length and weight gain were independent of dietary protein, provided that the digestible energy content of the diet was not lower than 13.5 MJ kg^?1. Dietary energy levels below 13.5MJ kg^‐1 resulted in significant reductions in shell growth, weight gain and increased mortality from 5% to 27%. Feed consumption of the 22% and 26% protein diets with 11.6 MJ kg^?1 was significantly higher (0.53 ± 0.04 and 0.55 ± 0.04% bd. wt. day^?1 respectively) compared with abalone fed the 16.2 MJ kg^?1 diets at the same protein levels (combined mean of 0.45 ± 0.04% bd. wt. day^?1) indicating that consumption was linked to energy requirement. The growth and mortality results suggest that abalone cultured at these temperatures have a dietary digestible energy requirement of at least 13.5 MJ kg^?1.  相似文献   

Topographic preferences and habitat partitioning by pelagic fishes off southern Western Australia     

Alistair J. Hobday  Geoff Campbell 《Fisheries Research》2009,95(2-3):332-340

Pelagic fishes are typically considered mobile and wide-ranging open ocean foragers. However, many species have also been recorded in association with nearshore topographic structures. The relative abundance of four pelagic species at and away from topographic features on the continental shelf, as inferred from fine-scale catch data collected over a 7-year period, was examined for southern Western Australia. A total of 1056 captures were recorded from 890 h of trolling over 102 days: the top four species accounted for 97.5% of all captures. Eight distinct topographic features received 13.7% of the total trolling effort and produced 43.8% of captures. The percentage of all captures within 1 km of these features were 80% for yellowtail kingfish (Seriola lalandi, YTK), 50% for bonito (Sarda australia, BON), 27% for southern bluefin tuna (Thunnus maccoyii, SBT), and less than 5% for skipjack tuna (Katsuwonus pelamis, SKJ). Catch rates were 26, 6.59, and 2.47 times higher than catch rates away from the topographic features for YTK, BON, and SBT, respectively. In contrast, SKJ catch rates were 1/3rd lower at topographic features, indicating avoidance rather than preference. The mean distance at which species were captured from the center of each feature differed significantly, with YTK closest (303 m), followed by SBT (442 m), BON (493 m), and SKJ (539 m). These findings indicate habitat partitioning in pelagic fishes at topographic features and offer a way to increase catch of a targeted species, or reduce the capture of unwanted or quota-limited species.  相似文献