Density-Dependent Growth of Age 1 English Sole (Parophrys vetuls) in Oregon and Washington Coastal Waters

1987 ◽  
Vol 44 (1) ◽  
pp. 48-53 ◽  
Author(s):  
Randall M. Peterman ◽  
Michael J. Bradford
Keyword(s):  
Coastal Waters ◽  
Time Trends ◽  
Annual Growth Rate ◽  
English Sole ◽  
Density Dependent ◽  
Stock Assessments ◽  
Negative Effect ◽  
Dependent Growth ◽  
Parophrys Vetulus ◽  
The Impact

We tested whether English sole (Parophrys vetulus) in Oregon and Washington waters show density-dependent growth. We found that there is a significant negative effect of cohort abundance on annual growth rate of age 1 fish, but not on growth of ages 2–7. Unlike most similar studies of density dependence, this result was not confounded by time trends in abundance and growth. The multiple regression of age 1 growth on cohort abundance and temperature accounted for 91% of the interannual variation in growth, which was a significant increase in r2 over that of the previously published relation with temperature alone. However, stock assessments which take into account only the previously published temperature effect on growth for this stock will probably not seriously overestimate the impact of management regulations which increase cohort abundance.

Optimal Thinning of a Year-Class with Density-Dependent Growth

1986 ◽  
Vol 43 (4) ◽  
pp. 889-892 ◽  
Author(s):  
Rögnvaldur Hannesson
Keyword(s):  
Density Dependence ◽  
Optimal Harvesting ◽  
Early Date ◽  
Density Dependent ◽  
Moderate Density ◽  
Class A ◽  
Dependent Growth ◽  
The Impact ◽  
Harvesting Costs

I consider the impact of density-dependent growth on the optimal harvesting of a year-class of fish. In general, density dependence makes "thinning" of the year-class a desirable strategy. Moderate density dependence implies that thinning should be gradual, even in the case of zero harvesting costs where the optimal harvesting strategy would otherwise be instantaneous harvesting. Strong density dependence calls for an immediate thinning at an early date, in the case of zero harvesting costs.

Factors of Macroeconomic Dynamics in the Transition to the Information Economy

2019 ◽  
Vol 7 (1) ◽  
pp. 25-30
Author(s):  
Леонид Басовский ◽  
Leonid Basovskiy ◽  
Елена Басовская ◽  
Elena Basovskaya
Keyword(s):  
Economic Growth ◽  
Factor Analysis ◽  
Growth Rates ◽  
Positive Impact ◽  
Principal Component ◽  
Developed Countries ◽  
Entire Period ◽  
Annual Growth Rate ◽  
Negative Effect ◽  
The Impact

The study was made of the relationship between GDP growth rates and individual components of its final use by combining factor analysis using the principal component method and regression analysis. The period from 1955 to 1980 was studied using data on the average annual growth rate of components over fiveyear periods in the countries of the non-socialist world. The growth rates of the various components of the use of GDP at different stages as the fourth technical and economic structure of the fourth dominates and the development of crisis phenomena in the economy has had a variable impact on economic growth. During the crisis period, the impact of the growth of all components of using GDP on economic growth has dropped sharply. The greatest role in this period was played by the growth of current expenditures of the state. Comparison of the structure of the use of GDP using factor analysis by the method of principal components was carried out by the average annual values for the period from 1950 to 1980. As the development crisis approaches, as the models show, the influence of factors of the structure of using GDP on economic growth decreases. During the entire period, high levels of government spending had a negative effect on economic growth. The impact of exports and imports was positive for the entire period studied. Overcoming the crisis in the economies of developed countries led to a transition to a positive impact of investment on economic growth.

Simulation Model of English Sole (Parophrys vetulus) Population Dynamics in Washington and Oregon Coastal Waters

1987 ◽  
Vol 44 (11) ◽  
pp. 1870-1878 ◽  
Author(s):  
Randall M. Peterman ◽  
Michael J. Bradford ◽  
Gordon H. Kruse
Keyword(s):  
Population Dynamics ◽  
Simulation Model ◽  
Larval Mortality ◽  
Early Life History ◽  
Fish Growth ◽  
English Sole ◽  
Egg Hatching ◽  
Density Dependent ◽  
Historical Variation ◽  
Parophrys Vetulus

We constructed an empirically based simulation model of population dynamics for English sole (Parophrys vetulus) occupying waters off the Washington and Oregon coast. While the original purpose for developing this model was to provide a tool for analysis of management questions, we also found it useful in evaluating hypotheses about biological processes in the early life history of sole. By comparing the ability of alternative sets of model hypotheses to reflect historical variation in abundance of age 4 recruits, we found some combinations of hypothesized mechanisms to be better than others. Approximately 61% of the interannual variation in recruitment was accounted for by a model which included (1) the effect of ocean temperatures on spawning timing, egg hatching, and fish growth, (2) density-dependent larval mortality, (3) age-dependent mortality of fish younger than age 4 yr, and (4) density-dependent growth of age 1 fish. This model explained more variation in recruitment than previous models of this population and emphasized the importance of timing of spawning on the subsequent abundance of the cohort.

scholarly journals Implications of late-in-life density-dependent growth for fishery size-at-entry leading to maximum sustainable yield

2018 ◽  
Vol 75 (4) ◽  
pp. 1296-1305 ◽  
Author(s):  
Rob van Gemert ◽  
Ken H Andersen
Keyword(s):  
Density Dependence ◽  
Maximum Sustainable Yield ◽  
Sustainable Yield ◽  
Fish Stocks ◽  
Density Dependent ◽  
Large Size ◽  
Adult Growth ◽  
Stock Assessments ◽  
Stock Recruitment ◽  
Dependent Growth

Abstract Currently applied fisheries models and stock assessments rely on the assumption that density-dependent regulation only affects processes early in life, as described by stock–recruitment relationships. However, many fish stocks also experience density-dependent processes late in life, such as density-dependent adult growth. Theoretical studies have found that, for stocks which experience strong late-in-life density dependence, maximum sustainable yield (MSY) is obtained with a small fishery size-at-entry that also targets juveniles. This goes against common fisheries advice, which dictates that primarily adults should be fished. This study aims to examine whether the strength of density-dependent growth in actual fish stocks is sufficiently strong to reduce optimal fishery size-at-entry to below size-at-maturity. A size-structured model is fitted to three stocks that have shown indications of late-in-life density-dependent growth: North Sea plaice (Pleuronectes platessa), Northeast Atlantic (NEA) mackerel (Scomber scombrus), and Baltic sprat (Sprattus sprattus balticus). For all stocks, the model predicts exploitation at MSY with a large size-at-entry into the fishery, indicating that late-in-life density dependence in fish stocks is generally not strong enough to warrant the targeting of juveniles. This result lends credibility to the practise of predominantly targeting adults in spite of the presence of late-in-life density-dependent growth.

scholarly journals Density-dependent growth in ‘catch-and-wait’ fisheries has implications for fisheries management and Marine Protected Areas

AMBIO ◽  
2019 ◽  
Vol 49 (1) ◽  
pp. 107-117 ◽  
Author(s):  
Julian Merder ◽  
Patricia Browne ◽  
Jan A. Freund ◽  
Liam Fullbrook ◽  
Conor Graham ◽  
...  
Keyword(s):  
Fisheries Management ◽  
Marine Protected Areas ◽  
Marine Reserve ◽  
Growth Patterns ◽  
Fundamental Issue ◽  
Catch Per Unit Effort ◽  
Density Dependent ◽  
Negative Effect ◽  
Dependent Growth ◽  
Fisheries Enhancement

Abstract Stock enhancement activities provide an opportunity to examine density-dependent suppression of population biomass which is a fundamental issue for resource management and design of no-take-zones. We document ‘catch-and-wait’ fisheries enhancement where all but the largest lobsters are thrown back, recapturing them later after they have grown to a larger size. The residency, rate of return, and potential negative density-dependent effects of this activity are described using a combination of tagging and v-notching and by relating spatial growth patterns to population density defined with Catch Per Unit Effort. The results successfully demonstrated the concept of catch-and-wait practices. However, a density-dependent suppression of growth (in body size) was observed in male lobsters. This demonstrates a mechanism to explain differences in lobster sizes previously observed across EU fishing grounds with different stock densities. This negative effect of density could also affect individual biomass production in marine reserve or no-take zones.

Trends in Dietary Intake of Vitamins A, C, and E in German Children and Adolescents – Results of the DONALD Study

2003 ◽  
Vol 73 (5) ◽  
pp. 335-342 ◽  
Author(s):  
Alexy ◽  
Kersting ◽  
Sichert-Hellert
Keyword(s):  
Vitamin E ◽  
Nutrition Education ◽  
Time Trends ◽  
Nutrient Intake ◽  
Age Groups ◽  
Food Groups ◽  
Fortified Food ◽  
Vitamin Intake ◽  
Dietary Records ◽  
The Impact

Intake of vitamins A, C, and E was evaluated and age and time trends were assessed on the basis of 3-day weighed dietary records (n = 5121) of 2- to 18-year old boys (n = 417) and girls (n = 425) enrolled in the DONALD Study (Dortmund Nutritional and Anthropometric Longitudinally Designed Study) 1986–2001. Intake of vitamin A remains stable over time, intake of vitamin C increases linearly, and intake of vitamin E follows a nonlinear trend. Age trends of vitamins A and C (per MJ) were nonlinear with a minimum at the beginning adolescence, while intake of vitamin E (per MJ) increased linearly. Girls had higher nutrient densities but lower intakes expressed as percent of reference values. Fortified food in total had a higher impact on time trends of nutrient intake than other single food groups defined here. Our results point to the impact of the food industry on long-term nutrient intake, but also underline the necessity of nutrition education even in young age groups to improve vitamin intake.

The Transnational Women's Rights Movement and the World Economy

2020 ◽  
Vol 6 (2) ◽  
pp. 145-173 ◽  
Author(s):  
Heidi E. Rademacher
Keyword(s):  
Women's Rights ◽  
Small Body ◽  
World System ◽  
World Society ◽  
Women’S Rights ◽  
Social Movement Organizations ◽  
Global Movement ◽  
Negative Effect ◽  
Society Perspective ◽  
The Impact

Promoting the ratification of the Convention on the Elimination of All Forms of Discrimination against Women (CEDAW) was a key objective of the transnational women's movement of the 1980s and 1990s. Yet, few studies examine what factors contribute to ratification. The small body of literature on this topic comes from a world-society perspective, which suggests that CEDAW represented a global shift toward women's rights and that ratification increased as international NGOs proliferated. However, this framing fails to consider whether diffusion varies in a stratified world-system. I combine world-society and world-systems approaches, adding to the literature by examining the impact of women's and human rights transnational social movement organizations on CEDAW ratification at varied world-system positions. The findings illustrate the complex strengths and limitations of a global movement, with such organizations having a negative effect on ratification among core nations, a positive effect in the semiperiphery, and no effect among periphery nations. This suggests that the impact of mobilization was neither a universal application of global scripts nor simply representative of the broad domination of core nations, but a complex and diverse result of civil society actors embedded in a politically stratified world.

The Impact of Competitive Quasi-Market on Service Delivery in Benue State University, Makurdi Nigeria

GIS Business ◽  
2019 ◽  
Vol 14 (4) ◽  
pp. 85-98
Author(s):  
Idoko Peter
Keyword(s):  
Service Delivery ◽  
A Priori ◽  
Least Square ◽  
Secondary Source ◽  
State University ◽  
Ordinary Least Square ◽  
Negative Effect ◽  
The Impact ◽  
The Relationship

This research the impact of competitive quasi market on service delivery in Benue State University, Makurdi Nigeria. Both primary and secondary source of data and information were used for the study and questionnaire was used to extract information from the purposively selected respondents. The population for this study is one hundred and seventy three (173) administrative staff of Benue State University selected at random. The statistical tools employed was the classical ordinary least square (OLS) and the probability value of the estimates was used to tests hypotheses of the study. The result of the study indicates that a positive relationship exist between Competitive quasi marketing in Benue State University, Makurdi Nigeria (CQM) and Transparency in the service delivery (TRSP) and the relationship is statistically significant (p<0.05). Competitive quasi marketing (CQM) has a negative effect on Observe Competence in Benue State University, Makurdi Nigeria (OBCP) and the relationship is not statistically significant (p>0.05). Competitive quasi marketing (CQM) has a positive effect on Innovation in Benue State University, Makurdi Nigeria (INVO) and the relationship is statistically significant (p<0.05) and in line with a priori expectation. This means that a unit increases in Competitive quasi marketing (CQM) will result to a corresponding increase in innovation in Benue State University, Makurdi Nigeria (INVO) by a margin of 22.5%. It was concluded that government monopoly in the provision of certain types of services has greatly affected the quality of service experience in the institution. It was recommended among others that the stakeholders in the market has to be transparent so that the system will be productive to serve the society effectively

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