Factors Affecting Sea Lamprey Egg Survival

2009 ◽  
Vol 29 (4) ◽  
pp. 859-868 ◽  
Author(s):  
Stephen J. Smith ◽  
J. Ellen Marsden
Keyword(s):  
Sea Lamprey ◽  
Egg Survival ◽  
Factors Affecting

scholarly journals Rapid resistance to pesticide control is predicted to evolve in an invasive fish

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Mark R. Christie ◽  
Maria S. Sepúlveda ◽  
Erin S. Dunlop
Keyword(s):  
Genetic Model ◽  
Sea Lamprey ◽  
Control Agent ◽  
Native Fish ◽  
Primary Control ◽  
Factors Affecting ◽  
Natal Homing ◽  
Generation Times ◽  
Evolution Of Resistance ◽  
Near Future

AbstractXenobiotic resistance is commonly found in species with short generation times such as bacteria, annual plants, and insects. Nevertheless, the fundamental evolutionary principles that govern the spread of resistance alleles hold true for species with longer generation times. One such example could occur with sea lamprey (Petromyzon marinus), a parasitic invasive species in the Laurentian Great Lakes that decimated native fish populations prior to its control with the pesticide 3-trifluoromethyl-4-nitrophenol (TFM). Since the 1950s, tributaries have been treated annually with TFM, where treatments effectively remove most, but not all, larval sea lamprey. We developed an eco-genetic model of sea lamprey to examine factors affecting the evolution of resistance and found that resistance alleles rapidly rise to fixation after 40–80 years of treatment, despite the species’ relatively long generation time (4–7 years). The absence of natal homing allows resistant individuals to spread quickly throughout the entire system, but also makes the early detection of resistance challenging. High costs of resistance and density independent reproduction can delay, but not prevent, the onset of resistance. These results illustrate that sea lamprey have the potential to evolve resistance to their primary control agent in the near future, highlighting the urgent need for alternative controls.

Relationships between Alaskan salmon catch and North Pacific climate on interannual and interdecadal time scales

1998 ◽  
Vol 55 (10) ◽  
pp. 2255-2265 ◽  
Author(s):  
Mary W Downton ◽  
Kathleen A Miller
Keyword(s):  
Time Scales ◽  
North Pacific ◽  
Large Scale ◽  
Climatic Factors ◽  
Multivariate Time Series ◽  
Pink Salmon ◽  
Egg Survival ◽  
Commercial Catch ◽  
Factors Affecting ◽  
The North

Using multivariate time series models, Alaska's statewide commercial catch of three salmon species during 1925-1994 is shown to be related to surface temperatures in particular large regions of the eastern North Pacific. Previous research has indicated that interdecadal changes in Alaskan catch levels are related to large-scale changes in the climate regime of the North Pacific. The present work focuses on interannual variability by controlling for climatic shifts in the mid-1940s and mid-1970s. For sockeye (Oncorhynchus nerka) and chum (O. keta), relationships with temperature occur within a few months after ocean entry with warmer regional temperatures enhancing survival. For sockeye and pink salmon (O. gorbuscha), relationships with temperature occur at the time and location of the return migration, suggesting that colder ocean temperatures may enhance spawning success or egg survival. In addition, the models show a significant positive relationship of chum catch to pink catch 2 years earlier, suggesting a common influence on smolts of the two species. The results support the contention that climatic factors affecting the marine environment play a significant role in salmon production on interannual, as well as interdecadal, time scales.

scholarly journals Rapid resistance to pesticide control is predicted to evolve in an invasive fish

2019 ◽  
Author(s):  
Mark R. Christie ◽  
Maria S. Sepúlveda ◽  
Erin S. Dunlop
Keyword(s):  
Genetic Model ◽  
Sea Lamprey ◽  
Control Agent ◽  
Native Fish ◽  
Primary Control ◽  
Factors Affecting ◽  
Natal Homing ◽  
Generation Times ◽  
Evolution Of Resistance ◽  
Near Future

AbstractXenobiotic resistance is commonly found in species with short generation times such as bacteria, annual plants, and insects. Nevertheless, the fundamental evolutionary principles that govern the spread of resistance alleles hold true for species with longer generation times. One such example could occur with sea lamprey (Petromyzon marinus), a parasitic invasive species in the Laurentian Great Lakes that decimated native fish populations prior to its control with the pesticide 3-trifluoromethyl-4-nitrophenol (TFM). Since the 1950s, tributaries have been treated annually with TFM, where treatments effectively remove most, but not all, larval sea lamprey. We developed an eco-genetic model of sea lamprey to examine factors affecting the evolution of resistance and found that resistance alleles rapidly rise to fixation after 40-80 years of treatment, despite the species’ relatively long generation time (4-7 years). The absence of natal homing allows resistant individuals to spread quickly throughout the entire system, but also makes the early detection of resistance challenging. High costs of resistance and density independent reproduction can delay, but not prevent, the onset of resistance. These results illustrate that sea lamprey have the potential to evolve resistance to their primary control agent in the near future, highlighting the urgent need for alternative controls.

Factors Affecting Larval Sea Lamprey Growth and Length at Metamorphosis in Lampricide-Treated Streams

2001 ◽  
Vol 130 (2) ◽  
pp. 289-306 ◽  
Author(s):  
Ronald W. Griffiths ◽  
F. W. H. Beamish ◽  
B. J. Morrison ◽  
L. A. Barker
Keyword(s):  
Sea Lamprey ◽  
Factors Affecting

Factors Affecting Motility Characteristics and Fertilizing Ability of Sea Lamprey Spermatozoa

2002 ◽  
Vol 131 (2) ◽  
pp. 193-202 ◽  
Author(s):  
Andrzej Ciereszko ◽  
Konrad Dabrowski ◽  
Gregory P. Toth ◽  
Susan A. Christ ◽  
Jan Glogowski
Keyword(s):  
Sea Lamprey ◽  
Factors Affecting ◽  
Fertilizing Ability

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.

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