The application of an age-structured model to the north Aegean anchovy fishery: An evaluation of different management measures

2012 ◽  
Vol 237 (1-2) ◽  
pp. 17-27 ◽  
Author(s):  
D.V. Politikos ◽  
D.E. Tzanetis ◽  
C.V. Nikolopoulos ◽  
C.D. Maravelias
Keyword(s):  
Structured Model ◽  
The North ◽  
Management Measures ◽  
North Aegean ◽  
Age Structured ◽  
Age Structured Model

STABILITY ANALYSIS OF A CONTINUOUS AGE-STRUCTURED MODEL WITH SPECIFIC REFERENCE TO NORTH SEA COD

2004 ◽  
Vol 12 (03) ◽  
pp. 249-260
Author(s):  
J. M. ANDREWS ◽  
S. P. BLYTHE ◽  
W. S. C. GURNEY
Keyword(s):  
Life History ◽  
Stability Analysis ◽  
North Sea ◽  
Specific Reference ◽  
Structured Model ◽  
The North ◽  
The North Sea ◽  
Age Structured ◽  
The Stability ◽  
Age Structured Model

We examine the stability of a class of continuous age-structured models. Stability borders are established for the different parameters in the model, including levels required for viability. Two examples are then given, the first is a simple model for which the analysis is straightforward. An example is then shown of the cod population in the North Sea, which involves more complicated life history structures making stability analysis more difficult. The model predicts that the North Sea population will go extinct if fishing levels remain high. We show, however, that if mortality was lowered it would eventually be possible for the population to reach a point where it was stable and within safe biological limits.

An Age-Structured Model of Fish Population Enhancement

2002 ◽  
pp. 376-394
Author(s):  
Richard Langton ◽  
James Lindholm ◽  
James Wilson ◽  
Sally Sherman
Keyword(s):  
Fish Population ◽  
Structured Model ◽  
Age Structured ◽  
Age Structured Model

scholarly journals Null Controllability of a Nonlinear Age Structured Model for a Two-Sex Population

2021 ◽  
Vol 2021 ◽  
pp. 1-20
Author(s):  
Amidou Traoré ◽  
Okana S. Sougué ◽  
Yacouba Simporé ◽  
Oumar Traoré
Keyword(s):  
Null Controllability ◽  
Auxiliary System ◽  
Time Interval ◽  
Observability Inequality ◽  
Controllability Problem ◽  
Structured Model ◽  
Male And Female ◽  
System A ◽  
Age Structured ◽  
Age Structured Model

This paper is devoted to study the null controllability properties of a nonlinear age and two-sex population dynamics structured model without spatial structure. Here, the nonlinearity and the couplage are at the birth level. In this work, we consider two cases of null controllability problem. The first problem is related to the extinction of male and female subpopulation density. The second case concerns the null controllability of male or female subpopulation individuals. In both cases, if A is the maximal age, a time interval of duration A after the extinction of males or females, one must get the total extinction of the population. Our method uses first an observability inequality related to the adjoint of an auxiliary system, a null controllability of the linear auxiliary system, and after Kakutani’s fixed-point theorem.

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