A Stochastic Age-Structured Population Model of Striped Bass (Morone saxatilis) in the Potomac River

1983 ◽  
Vol 40 (12) ◽  
pp. 2170-2183 ◽  
Author(s):  
Joel E. Cohen ◽  
Sigurd W. Christensen ◽  
C. Phillip Goodyear
Keyword(s):  
Growth Rate ◽  
Stochastic Model ◽  
Population Size ◽  
Striped Bass ◽  
Morone Saxatilis ◽  
Potomac River ◽  
Structured Population ◽  
Age Structured ◽  
Average Population Size ◽  
Age Structured Population

Deterministic age-structured models of fish populations neglect apparently stochastic fluctuations in the catch per unit effort of yearlings and of adult fish. We describe a model of an age-structured population in which the survival of eggs to yearlings fluctuates randomly, but all other age-specific rates of survival and of egg-laying are constant. For such a stochastic model, two measures of the long-term population growth rate are the average growth rate of the population size and the growth rate of the average population size. We compute both measures analytically for a simplified model representing only eggs and reproductive adults. For a model of the striped bass (Morone saxatilis) population spawning in the Potomac River, we compute both point and interval estimates of the growth rate of the average population size. We illustrate some statistical tests of the correctness of our stochastic model.

Stochastic modelling of age-structured population with time and size dependence of immigration rate

2018 ◽  
Vol 33 (5) ◽  
pp. 289-299 ◽  
Author(s):  
Boris J. Pichugin ◽  
Nikolai V. Pertsev ◽  
Valentin A. Topchii ◽  
Konstantin K. Loginov
Keyword(s):  
Population Size ◽  
Branching Processes ◽  
Stochastic Modelling ◽  
Random Variable ◽  
Structured Population Model ◽  
Immigration Rate ◽  
Structured Population ◽  
Mean And Variance ◽  
Age Structured ◽  
Age Structured Population

Abstract A stochastic age-structured population model with immigration of individuals is considered. We assume that the lifespan of each individual is a random variable with a distribution function which may differ fromthe exponential one. The immigration rate of individuals depends on the time and total population size. Upper estimates for the mean and variance of the population size are established based on the theory of branching processes with constant immigration rate. A Monte Carlo simulation algorithm of population dynamics is developed. The results of numerical experiments with the model are presented.

The Stochastic and Deterministic Model of the Spread of a Disease in Age-Structured Population

2020 ◽  
Vol 8 (12) ◽  
pp. 290-295
Author(s):  
Yardjouma Yéo
Keyword(s):  
Stochastic Model ◽  
Law Of Large Numbers ◽  
Deterministic Model ◽  
Characteristic Curve ◽  
Structured Population ◽  
The Central Limit Theorem ◽  
Large Numbers ◽  
The Law ◽  
Age Structured ◽  
Age Structured Population

We model the spread of an epidemic which depends on age and time. The behavior of the model obtained was the object of our studies.This studies shown that on each characteristic curve, the central limit theorem and the law of large numbers were satisfied. In this paper, we write a stochastic model to studie a disease which is begin in a population which is not large. we study overall the stochastic model obtained by varying the age and time together. We prove that the law of large numbers is satisfied.

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