scholarly journals Factors affecting the recruitment variability of the Norwegian spring-spawning herring (Clupea harengus L.)

2002 ◽  
Vol 59 (4) ◽  
pp. 725-736 ◽  
Author(s):  
R Sætre
Keyword(s):  
Clupea Harengus ◽  
Factors Affecting ◽  
Recruitment Variability

Fixation Shrinkage of Herring Larvae: Effects of Salinity, Formalin Concentration, and Other Factors

1982 ◽  
Vol 39 (8) ◽  
pp. 1138-1143 ◽  
Author(s):  
D. E. Hay
Keyword(s):  
Clupea Harengus ◽  
Pacific Herring ◽  
Larval Size ◽  
Factors Affecting ◽  
Clupea Harengus Pallasi

The most important factors affecting the degree of larval shrinkage of Pacific herring (Clupea harengus pallasi) larvae during fixation are the salinity and formalin concentrations and initial larval size. In low formalin concentrations (2–5% formalin) shrinkage increased from less than 2% shrinkage at low salinities to about 10% shrinkage in seawater formalin. In high formalin concentrations (20–30% formalin) shrinkage was fairly uniform, ranging from about 3% shrinkage in low salinities to about 5% in seawater. Shrinkage in fixatives stored at 0, 5, 10, 20, and 30 °C was slightly higher (1–2%) at the higher temperatures. Buffering agents and starvation had no effect on shrinkage. Small, young larvae shrank relatively more than larger older larvae.Key words: herring larvae, fixation, shrinkage, formalin, salinity

Oceanographic factors affecting interannual recruitment variability of Pacific saury (Cololabis saira ) in the central and western North Pacific

2018 ◽  
Vol 27 (5) ◽  
pp. 445-457 ◽  
Author(s):  
Taro Ichii ◽  
Haruka Nishikawa ◽  
Kedarnath Mahapatra ◽  
Hiroshi Okamura ◽  
Hiromichi Igarashi ◽  
...  
Keyword(s):  
North Pacific ◽  
Western North Pacific ◽  
Pacific Saury ◽  
Factors Affecting ◽  
Cololabis Saira ◽  
Recruitment Variability

Factors Affecting the Distribution, Abundance, and Measurement of Pacific Herring (Clupea harengus pallasi) Spawn

1987 ◽  
Vol 44 (6) ◽  
pp. 1181-1194 ◽  
Author(s):  
D. E. Hay ◽  
A. R. Kronlund
Keyword(s):  
Survey Methods ◽  
Abiotic Factors ◽  
Early Years ◽  
Clupea Harengus ◽  
Pacific Herring ◽  
Biological Factors ◽  
Factors Affecting ◽  
Clupea Harengus Pallasi ◽  
The Mean ◽  
Stock Abundance

Records of the date, location, and magnitude of Pacific herring (Clupea harengus pallasi) spawnings in British Columbia, collected since 1928, were compiled and analysed. In the early years of spawn surveys, adjacent spawnings were often reported as single events. Gradually, this practice has changed so that each spawning has a separate record. As a consequence of this change in methods, the mean length of spawnings has decreased in recent years but the total numbers of records has increased. Estimates of mean spawning width and intensity have also changed, partly due to changing survey methods as well as changing spawning distributions. A spawn abundance index is developed to account for these temporal changes. Abiotic factors affecting the distribution and abundance of spawn deposition include sea surface temperatures and the fishery. Biological factors affecting spawn distribution and abundance are not as well defined, but it is shown that in some situations, spawn dimensions may change as a function of stock abundance.

Consideration of the Stable Age Distribution Assumption in "Analytical" Yield Models

1983 ◽  
Vol 40 (1) ◽  
pp. 95-101 ◽  
Author(s):  
M. Sinclair ◽  
R. O'Boyle ◽  
T. D. Iles
Keyword(s):  
Analytical Model ◽  
Growth Rates ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Age Distribution ◽  
Clupea Harengus ◽  
Melanogrammus Aeglefinus ◽  
Yield Model ◽  
Stable Age Distribution ◽  
Recruitment Variability

The implications on the "analytical" yield model of deviations from the stable age distribution were investigated for stocks of five species with a range of life history characteristics, these being Atlantic cod (Gadus morhua), haddock (Melanogrammus aeglefinus), pollock (Pollachius virens), Atlantic herring (Clupea harengus harengus), and Atlantic mackerel (Scomber scrombus). Recruitment variability for the stocks considered ranged from 21% for pollock to 104% for haddock. The comparison of the growth rates at age for the five species showed the expected continuum in relative growth rates from cod to mackerel. With the population in a stable age distribution without fishing there is also a continuum from cod to mackerel in the manner in which age-specific production decreases through the life span. It is thus to be expected that deviations from the stable age distributions for mackerel would have a much greater impact on population production than would a similar deviation for cod. Also, species whose growth rates decrease more rapidly with age tend to have a higher recruitment variability. To demonstrate the implications of deviations from the stable age distribution on the accuracy of model output, MSY yields (that would have been generated given historical estimates of population numbers-at-age) were compared to estimates of annual population production. Cod and pollock production deviate relatively little from the "analytical" model predictions. In contrast, annual production for haddock, herring, and mackerel deviate markedly from MSY yields as the age composition deviates in each direction from the stable age distribution. The analysis suggests that for some species the "analytical" model may contribute to growth overfishing.Key words: "analytical" yield models, stable age distribution, growth overfishing

Progress In The Practical Application Of Automated Image Analysis To Tem Negatives

1977 ◽  
Vol 35 ◽  
pp. 214-217
Author(s):  
F. A. Heckman ◽  
E. Redman ◽  
J.E. Connolly
Keyword(s):  
Image Analysis ◽  
Image Quality ◽  
Exposure Time ◽  
Image Contrast ◽  
Automated Image Analysis ◽  
Practical Application ◽  
Factors Affecting ◽  
High Image Quality ◽  
Qualitative Evidence ◽  
Comprehensive Study

In our initial publication on this subject1) we reported results demonstrating that contrast is the most important factor in producing the high image quality required for reliable image analysis. We also listed the factors which enhance contrast in order of the experimentally determined magnitude of their effect. The two most powerful factors affecting image contrast attainable with sheet film are beam intensity and KV. At that time we had only qualitative evidence for the ranking of enhancing factors. Later we carried out the densitometric measurements which led to the results outlined below.Meaningful evaluations of the cause-effect relationships among the considerable number of variables in preparing EM negatives depend on doing things in a systematic way, varying only one parameter at a time. Unless otherwise noted, we adhered to the following procedure evolved during our comprehensive study:Philips EM-300; 30μ objective aperature; magnification 7000- 12000X, exposure time 1 second, anti-contamination device operating.

Factors affecting microstructural scale in liquid crystalline polymers

1990 ◽  
Vol 48 (4) ◽  
pp. 220-221
Author(s):  
Christine M. Dannels ◽  
Christopher Viney
Keyword(s):  
Liquid Crystalline ◽  
Liquid Crystalline Polymers ◽  
Factors Affecting ◽  
Crystalline Polymers ◽  
Thermal Expansion Coefficients ◽  
Low Thermal Expansion ◽  
Lower Viscosity ◽  
Fine Microstructure ◽  
Planar Orientation ◽  
Strength And Stiffness

Processing polymers from the liquid crystalline state offers several advantages compared to processing from conventional fluids. These include: better axial strength and stiffness in fibers, better planar orientation in films, lower viscosity during processing, low solidification shrinkage of injection moldings (thermotropic processing), and low thermal expansion coefficients. However, the compressive strength of the solid is disappointing. Previous efforts to improve this property have focussed on synthesizing stiffer molecules. The effect of microstructural scale has been overlooked, even though its relevance to the mechanical and physical properties of more traditional materials is well established. By analogy with the behavior of metals and ceramics, one would expect a fine microstructure (i..e. a high density of orientational defects) to be desirable.Also, because much microstructural detail in liquid crystalline polymers occurs on a scale close to the wavelength of light, light is scattered on passing through these materials.

Factors affecting dentist participation in a state Medicaid program

1990 ◽  
Vol 54 (11) ◽  
pp. 638-643 ◽  
Author(s):  
PC Damiano ◽  
ER Brown ◽  
JD Johnson ◽  
JP Scheetz
Keyword(s):  
Medicaid Program ◽  
Factors Affecting
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