Laboratory observations on emergent patterns of juvenile Atlantic salmon, Salmo salar, relative to sediment loadings of test substrate

1986 ◽  
Vol 64 (6) ◽  
pp. 1331-1336 ◽  
Author(s):  
Hugh R. MacCrimmon ◽  
Barra L. Gots
Keyword(s):  
Particle Size ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Constant Temperature ◽  
Flow Rate ◽  
Sediment Loading ◽  
Vertical Flow ◽  
Loading Rates ◽  
Mean Particle Size ◽  
Stage Of Development

Effects of various loadings of a test gravel incubation substrate (32- to >4-mm pebble) with a single sediment mix (<0.25- to 4-mm sand) were examined in vertical flow incubators at a constant temperature (9.9 °C) and flow rate (200 mL min−1). Mean survival (75%) from ova burial to juvenile emergence was not influenced significantly by different sediment loadings. However, time to first and median emergence, duration of emergence, stage of development at emergence, and within-substrate behaviour were each correlated positively with mean particle size (r ≥ 0.72) and negatively with sediment loading rates (r ≥ −0.68).

Preparation and Research of Oil in Water Microemulsion

2020 ◽  
Vol 1001 ◽  
pp. 110-114
Author(s):  
Xiao Qi Chen ◽  
Meng Meng Zhou ◽  
Zheng Zheng Wang ◽  
Hai Jun Zhou ◽  
Shu Lan Yang ◽  
...  
Keyword(s):  
Particle Size ◽  
Constant Temperature ◽  
Polydispersity Index ◽  
Stable System ◽  
Mass Ratio ◽  
Drop Method ◽  
Mean Particle Size ◽  
Oil In Water ◽  
The Mean ◽  
The Stability

A series of oil in water (O/W) microemulsions were prepared through drop by drop method at constant temperature, taking Span80/Tween80 as a composite emulsifying system and Macol-52 as oil phase. Effects of the mass ratio of composite emulsifying system and oil/emulsifier ratio on the particle size were studied. Finally, the best technological conditions were selected and the stability of the microemulsion was also researched. Results showed that the most suitable Span80/Tween80 mass ratio was 1:1 and the oil/emulsifier ratio is 1:1. Under this condition, the mean particle size of the o/w microemulsion was 71.1 nm and the polydispersity index was 0.151. Moreover, the microemulsion maintain a bright and uniform stable system after 20minutes’ centrifugation at the speed of 4000r/min and the particle size increased slightly.

Effects of Low Environmental pH on Smolting of Atlantic Salmon (Salmo salar)

1983 ◽  
Vol 40 (8) ◽  
pp. 1203-1211 ◽  
Author(s):  
Richard L. Saunders ◽  
Eugene B. Henderson ◽  
Paul R. Harmon ◽  
C. Edward Johnston ◽  
J. Geoffrey Eales
Keyword(s):  
Atlantic Salmon ◽  
Atpase Activity ◽  
Salmo Salar ◽  
Constant Temperature ◽  
Water Hardness ◽  
Low Ph ◽  
Temperature Plasma ◽  
Atlantic Salmon Salmo Salar ◽  
Temperature Regimes ◽  
And Control

We reared Atlantic salmon (Salmo salar) in soft water (hardness 13 mg/L as CaCO3) at two pH levels, 6.4–6.7 and 4.2–4.7, from February to June, to assess the effect of low pH on survival, growth, and the smolting process under rising (4–8.5 °C) or relatively constant (9.5–10.5 °C) temperature. Survival was lower as a result of low pH (4.2–4.7) under both temperature regimes. Neither group exposed to low pH gained weight whereas both control groups gained weight during the experiment. Parr–smolt transformation, as indicated by salinity tolerance and gill Na+, K+ ATPase activity, was impaired as a result of low pH. The large (17–19 cm) parr used in this study were initially salinity tolerant and those at control pH (6.4–6.7) increased tolerance to 35‰ salinity between March and May; those in low pH became intolerant of high salinity. ATPase levels in salmon reared at low pH were significantly lower than those at normal pH levels under both temperature regimes. ATPase activity was significantly greater in fish reared at pH 6.4–6.7 with rising than with constant temperature. Plasma chloride and sodium levels were low in response to low pH, indicating impaired ionic regulation in freshwater. Plasma calcium levels were higher at low pH in both temperature regimes; higher levels were reached under constant temperature. Moisture content rose less sharply under low than under control pH in both temperature regimes. In the rising temperature regime, lipid levels reached similar, low levels under low and control pH conditions. Thyroid hormone (T3 and T4) levels gave no clear indication of effects of low pH on smolting. Smoltification did not proceed normally in our Atlantic salmon subjected to low pH levels.

Effects of diel temperature fluctuation on the standard metabolic rate of juvenile Atlantic salmon (Salmo salar): influence of acclimation temperature and provenience

2015 ◽  
Vol 72 (9) ◽  
pp. 1306-1315 ◽  
Author(s):  
Hélène Oligny-Hébert ◽  
Caroline Senay ◽  
Eva C. Enders ◽  
Daniel Boisclair
Keyword(s):  
Atlantic Salmon ◽  
Metabolic Rate ◽  
Salmo Salar ◽  
Constant Temperature ◽  
Temperature Fluctuation ◽  
Standard Metabolic Rate ◽  
Acclimation Temperature ◽  
Atlantic Salmon Salmo Salar ◽  
Juvenile Atlantic Salmon ◽  
Thermal Regimes

We assessed the metabolic response of juvenile Atlantic salmon (Salmo salar; JAS) originating from two rivers with different natural thermal regimes to different acclimation temperature (15 or 20 °C) and diel temperature fluctuation (constant: ±0.5 °C; fluctuating: ±2.5 °C). Diel temperature fluctuation (15 ± 2.5 °C) near the thermal optimum (16 °C) for the species did not influence standard metabolic rate (SMR) compared with JAS acclimated to a constant temperature of 15 °C. Diel temperature fluctuation at 20 ± 2.5 °C increased SMR of JAS from the warmer river by 33.7% compared with the same fish acclimated to a constant temperature of 20 °C. SMR of JAS from the cooler river held at fluctuating conditions had SMR that were 8% lower than SMR at constant conditions. The results suggest that the mean temperature to which JAS is exposed may affect their responses to diel temperature fluctuation and that this response may vary between populations originating from rivers with different natural thermal regimes. Results were used to develop the first empirical SMR model for JAS subjected to diel temperature fluctuation using fish mass (3–36 g wet) and temperature (12.5–22.5 °C) as explanatory variables.

Lower lethal levels of pH for embryos and alevins of Atlantic salmon, Salmo salar L.

1977 ◽  
Vol 55 (9) ◽  
pp. 1504-1508 ◽  
Author(s):  
P. G. Daye ◽  
E. T. Garside
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Low Ph ◽  
Early Cleavage ◽  
Stages Of Development ◽  
Atlantic Salmon Salmo Salar ◽  
Stage Of Development ◽  
Ph Stress ◽  
Lethal Limit

Embryos and alevins of Atlantic salmon, Salmo salar L., at various stages of development were subjected to several levels of low pH ranging from 4.3 to 2.7, for maximum exposures of 10 000 min in static bioassays at 5 or 6 °C, after incubation from fertilization at pH 6.9–6.6 and 5.0–6.7 °C. Sensitivity of the embryos and alevins to pH stress was dependent on the stage of development. Embryos in early cleavage were more sensitive to low pH than older encapsulated embryos. Alevins were more sensitive to low pH than embryos. The lower lethal limit for embryos during early cleavage was about pH 3.6, while for older embryos in two sequential stages just before hatch it was about pH 3.0 and pH 3.1, successively. Alevins subjected to low pH levels at 7 days and at 28 days after median hatch had a lower lethal limit of about pH 4.0.

scholarly journals The influence factors of mean particle size and positive quality control of bacterial filtration efficiency system

2021 ◽  
Author(s):  
Yayi Yi
Keyword(s):  
Particle Size ◽  
Quality Control ◽  
Flow Rate ◽  
Influence Factors ◽  
Medium Thickness ◽  
Mean Particle Size ◽  
Control Value ◽  
Pump Flow ◽  
Bacterial Aerosols ◽  
Positive Quality

Summary Background The Coronavirus Disease 2019 (COVID-19) has swept the whole world with high mortality. Since aerosol transmission is the main route of transmission, wearing a mask serves as a crucial preventive measure. An important parameter to evaluate the performance of a mask is the bacteria filtration efficiency (BFE). Aerosol mean particle size (MPS) and positive quality control value are two key indexes of BFE system. Aim To study the major influence factors of the mean particle size of bacterial aerosols and positive quality control value of BFE system. Method and Results In this study, we investigated the influence of Anderson sampler, spray flow, medium thickness, and peristaltic pump flow on the MPS of bacterial aerosols and positive quality control value of BFE system, respectively. The results show that the machining accuracy of Anderson sampler has great influence on aerosol MPS and positive quality control value. With the increase of aerosol spray flow rate, the positive quality control value will increase gradually, but the effect on aerosol MPS is not a simple linear relationship. As the agar medium thickness increased, the positive quality control value and aerosol MPS increased gradually. With the increase of peristaltic pump flow, the positive quality control value increased gradually, while the aerosol MPS was basically in a downward trend. When the peristatic pump flow rate was 0.1mL/min, the spray flow rate was 7.2L/min, the agar plate thickness was 27mL, and the Anderson sampler of Beijing Mingjie was used for the experiment, the aerosol MPS and positive quality control value were both within the acceptable range and were the optimal parameters. Conclusions This study provides guidance for the manufacturers of the BFE system and improves the protective performance of masks, which is important for the human health, especially during the occurrence of viral pandemics such as "COVID-19".

Microstructure and texture of fresh and smoked Atlantic salmon, Salmo salar L., fillets from fish reared and slaughtered under different conditions

2001 ◽  
Vol 32 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Sjofn Sigurgisladottir ◽  
Margret S. Sigurdardottir ◽  
Helga Ingvarsdottir ◽  
Ole J. Torrissen ◽  
Hannes Hafsteinsson
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Atlantic Salmon Salmo Salar
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