International eel symposium, 2003 - Quebec August 11, 2003
Oral Presentation

Eel Population Modeling and Its Application to Conservation Management

De Leo, G.A.* Dipartimento di Scienze Ambientali, Università degli Studi di Parma, 43100 Parma, giulio.deleo@unipr.it
Gatto, G. Dipartimento di Elettronica ed Informazione, Politecnico di Milano, Via Ponzio 34/5, 20131 Milano, Italy, gatto@elet.polimi.it
Melià, P. Dipartimento di Elettronica ed Informazione, Politecnico di Milano, Via Ponzio 34/5, 20131 Milano, Italy, melia@elet.polimi.it
Crivelli, A. Station Biologique de la Tour du Valat, Le Sambuc, Arles, F-13200, France, a.crivelli@tour-du-valat.com

Presenter email address: giulio.deleo AT unipr.it

Abstract Text: The aim of the present work is to present a critical review of population dynamics models developed for the European eel in the last twenty years. Specifically, we will briefly analyze the input-output regression model developed by Vøllestad and Jonsson in 1986 for Norwegian rivers, the age structured model developed by Gatto and Rossi in 1979 for the eel fishery in the Comacchio lagoons (North Adriatic Sea, Italy), and a more complex sex, size and age structured models developed by De Leo and Gatto between 1999 and 2001. Moreover, we will illustrate more recent development of population modeling that the authors are developing for the Camargue eel fishery in France. The models will be discussed in terms of mathematical complexity and usability, data requirement for calibration, realism in the description eel life cycle and demographic parameters, possibility of analyzing different management strategies for the populations that are commercially exploited. Particular emphasis will be given to the issue of how to treat uncertainty and environmental variability by using bootstrapping techniques and MonteCarlo simulations. Finally, we will briefly address the problem of how population models can be built and applied to conservation-based eel management in larger geographic areas when data are scanty.