Search results for "Salmon"

La remontée du saumon pour le frai dans le fleuve Tornionjoki, suivie au moyen d'un sonar à double faisceau horizontal.

2000

Fixed location split-beam horizontal echosounding was used to assess the size and timing of the Atlantic salmon (Salmo salar) spawning run in the River Tornionjoki. Four transducers, two on each river bank, were mounted across the river at the study site 4 km upstream from the river mouth. Net weirs were used on both shores to direct the passage of fish through the acoustic beams. Hydroacoustic monitoring covered 40-50% of the river cross-sectional area. Also test fishing and yearly catch statistics of salmon were used as an indication of the size of the spawning run in the river. Altogether, 7 700, 5 300 and 4 300 salmon-sized targets (target strength, TS ≥ -29 dB) moving upstream were det…

Attenuated Carbohydrate and Gill Na+ , K+-ATPase Stress Responses in Whitefish Caged near Bleached Kraft Mill Discharges

2002

Exposure to biologically treated bleached kraft mill effluent (BKME) is demonstrated to greatly modify the acute physiological stress response in fish and, accordingly, to lead to inconsistencies in data interpretation due to dissimilar effects of handling procedures on reference and exposed fish. To consider this phenomenon, juvenile whitefish (Coregonus lavaretus) were caged for 30 days in four reference sites and in three areas influenced by different BKME discharges. After exposure, fish were subjected to the impacts of low-level handling by raising the cages to the water surface, serially handnetting the fish, and transferring ( approximately 10 min) the submerged cages to the research…

Nocturnal drift of mayfly nymphs as a post-contact antipredator mechanism

2000

SUMMARY 1. The predominantly nocturnal constrained drift of stream invertebrates is commonly regarded as a behaviour that avoids encounters with visually foraging fish in the water column. The alternative explanation, that drift peaks are caused by bottom-feeding, nocturnal predators, has rarely been tested. 2. We examined these hypotheses by collecting invertebrate drift in five streams in northern Finland: one with brown trout (Salmo trutta, a drift-feeding fish), one with alpine bullhead (Cottus poecilopus, a benthic fish), one with both species, and two fishless streams. 3. Drift by Baetis mayflies was aperiodic or slightly diurnal in both fishless streams on all sampling occasions. In …

rDNA fingerprinting as a tool in epidemiological analysis of Salmonella typhi infections

1991

SUMMARYCharacterization of 169 strainsof Salmonella typhiof phage types C1, C4, D1and D9isolated in 1975–88 was carried out by rDNA gene restriction pattern analysis. Twenty-four isolates had been recovered during four large waterbone outbreaks in the last 20 years in Sicily; 145 strains, isolated from apparently sporadic cases of infection in Southern Italy in the same period of time, were also examined.Application of rRNA–DNA hybridization technique after digestion of chromosomal DNA withClaI showed the identity of patterns of the epidemic strains of phage types C1and D1, confirming attribution of the outbreaks to single bacterial clones. Patterns of the two available strains of lysotype …

High prevalence of integron-mediated resistance in clinical isolates of Salmonella enterica

2010

Salmonella enterica has become progressively resistant to antimicrobial agents worldwide as a result of genes carried on different classes of integrons. The aim of the current study was to investigate the molecular diversity of these integrons and their association with antimicrobial resistance in clinical S. enterica isolates from Tehran, Iran. Antimicrobial susceptibility testing was performed according to the Clinical and Laboratory Standards Institute. The presence of integrons was investigated by PCR using specific primers. Integrons were detected in 65 (47.1%) strains, with classes 1 and 2 being observed in 54 (39%) and 11 (8%) strains, respectively. Integron-positive isolates belonge…

The variable food webs in cold-water lakes

2022

TiO2 Supported over Hβ and HZSM-5 Photocatalysts for Salmonelle and Escherichia Coli Disinfection

2008

Comparing RADseq and microsatellites for estimating genetic diversity and relatedness : Implications for brown trout conservation

2019

The conservation and management of endangered species requires information on their genetic diversity, relatedness and population structure. The main genetic markers applied for these questions are microsatellites and single nucleotide polymorphisms (SNPs), the latter of which remain the more resource demanding approach in most cases. Here, we compare the performance of two approaches, SNPs obtained by restriction-site-associated DNA sequencing (RADseq) and 16 DNA microsatellite loci, for estimating genetic diversity, relatedness and genetic differentiation of three, small, geographically close wild brown trout (Salmo trutta) populations and a regionally used hatchery strain. The genetic di…

Novel silver-based nanoclay as an antimicrobial in polylactic acid food packaging coatings.

2010

This paper presents a comprehensive performance study of polylactic acid (PLA) biocomposites, obtained by solvent casting, containing a novel silver-based antimicrobial layered silicate additive for use in active food packaging applications. The silver-based nanoclay showed strong antimicrobial activity against Gram-negative Salmonella spp. Despite the fact that no exfoliation of the silver-based nanoclay in PLA was observed, as suggested by transmission electron microscopy (TEM) and wide angle X-ray scattering (WAXS) experiments, the additive dispersed nicely throughout the PLA matrix to a nanoscale, yielding nanobiocomposites. The films were highly transparent with enhanced water barrier …

Incidence of microbial flora in lettuce, meat and Spanish potato omelette from restaurants

2001

A total of 370 samples including lettuce, meats (beef, pork and chicken) and Spanish potato omelette from restaurants were studied to evaluate the incidence of Escherichia coli, E. coli O157:H7,Staphylococcus aureus, Salmonella spp.,Yersinia enterocolitica, enterococci and some micro-organisms that can cause spoilage orcan be usedas indicators for food safety. Escherichia coliand enterococci were harboured with the highest incidence in lettuce, whereas incidence of Staphylococcus aureus was higherin meat than in the other foods studied. Enterobacter cloacae and Klebsiella pneumoniaewere isolated from the three food groups. Chryseomonas luteola, Enterobacter sakazakii, Klebsiella ozaenae, Mo…