title: An observer for a nonlinear age-structured model of a harvested fish population.
abstract: We consider an age-structured model of a harvested population. This model is a discrete-time system that includes a nonlinear stock-recruitment relationship. Our purpose is to estimate the stock state. To achieve this goal, we built an observer, which is an auxiliary system that uses the total number of fish caught over each season and gives a dynamical estimation of the number of fish by age class. We analyse the convergence of the observer and we show that the error estimation tends to zero with exponential speed if a condition on the fishing effort is satisfied. Moreover the constructed observer (dynamical estimator) does not depend on the poorly understood stock-recruitment relationship. This study shows how some tools from nonlinear control theory can help to deal with the state estimation problem in the field of renewable resource management.
authors.affiliation: Laboratoire d'Analyse Numérique et d'Informatique (LANI), UFR de Sciences Appliquées et de Technologie, Université Gaston Berger B.P. 234 Saint-Louis, Sénégal. ngom@univ-metz.fr
authors.forename: Diène
authors.initials: D
authors.lastname: Ngom
authors.forename: Abderrahman
authors.initials: A
authors.lastname: Iggidr
authors.forename: Aboudramane
authors.initials: A
authors.lastname: Guiro
authors.forename: Abderrahim
authors.initials: A
authors.lastname: Ouahbi
mesh_terms: D000465:Algorithms; D000818:Animals; D003198:Computer Simulation; D003247:Conservation of Natural Resources; D017753:Ecosystem; D005398:Fisheries; D005399:Fishes; D008433:Mathematics; D015233:Models, Statistical; D008962:Models, Theoretical; D009991:Oscillometry; D011157:Population Dynamics; D015203:Reproducibility of Results; D013997:Time Factors