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Activity : Environmental models
Sub-activity 1: Multi-oscillatory system approach
Work in progress as per 29th June, 2006 on Octopus Vulgaris.
From A. P. Solari (Universidad de
Currently, we are working on the dynamics of Octopus vulgaris (Cuvier, 1797) based on our new, non-linear framework [1-7] and discuss our results in relation to Â“classicalÂ” approaches such as those proposed by Beverton-Holt , Ricker  and the logistic equation.
We are using data from several sources:
(a) Population series are both from FAO (CECAF landings, years 1962-2001) and Spanish IEO (catch and effort from Moroccan areas, years 1976-1999);
series from localized geographical points (
descriptors such as NAO, pressure data from
The grounds for the modelling work on this case study have been put forward and discussed and, as far as our criteria are concerned, some of the results may be highly promising and contribute to determine sustainable catch ranges Â–at least- in the short term (4-8 years).
We (J. J.
Castro and A. P. Solari) have met up E. BalguerÃas twice at the IEO in
We are expecting some Moroccan catch and effort data with higher spatial resolution to further advance the tasks ahead.
also did an exploratory approach on the European sardine (put forward at the
 Solari, A. P., J. M. Martin-Gonzalez and C. Bas (1997). Stock and recruitment in Baltic cod (Gadus morhua): a new, non-linear approach. ICES Journal of Mar. Sc. 54:427-443.
 Bas, C., A. P. Solari and J. M.
Martin-Gonzalez (1999). Considerations
over a new recruitment model for exploited fish populations.
 Castro, J. J., A. P. Solari, J.
M. Martin-Gonzalez and C. Bas (1999). Recruitment to the fishery of the
skipjack tuna Katsuwonus pelamis in the
 Solari, A. P., J. J. Castro and
C. Bas (2003). On skipjack tuna
dynamics: similarity at several scales. In "Scales in Aquatic Ecology. Measurement, analyses and simulation".
Edited by Laurent Seuront (CNRS, France) and Peter G. Strutton (Monterey Bay
Aquarium Research Institute,
 Solari, A. P., J. J. Castro, S.
Souissi, E. BalguerÃas, V. HernÃ¡ndez-GarcÃa and C. Bas (2004). On the dynamics of the common Octopus
(Cuvier, 1797). Presented at the European CEPHSTOCK Workshop,
 Solari, A. P., J. J. Castro, S. Souissi, E. BalguerÃas, V. HernÃ¡ndez-GarcÃa and C. Bas (2004). On the dynamics of the common Octopus (Cuvier, 1797): towards a new framework.In review process.
 Castro, J.J., E. BalguerÃas, C. Bas y A. P. Solari (2006). Sobre la dinÃ¡mica del pulpo comÃºn, Octopus vulgaris (Cuvier, 1797): hacia un nuevo marco teÃ³rico. Report the Ministry of Education, Culture and Sports of the Canarian Autonomous Government. April, 2006.
 Beverton, R. J. and S. J. Holt,
1957. On the dynamics of exploited fish populations. Ministry of agriculture,
fisheries and food (
 Ricker, W. E., 1954. Stock and
recruitment. J. of the Fisheries Research Board of
Sub-activity 2: Environmental variability in production models
This activity aims at developing a Bayesian analysis of surplus biomass production models, accounting for environmental effects. Application will mainly concern the Mauritanian octopus stock (Octopus vulgaris). The flexibility of the Bayesian modelling framework (Meyer and Millar 1999; Millar and Meyer 2000; Rivot et al. 2004) will allow us to develop two axes:
a) To incorporate multiple sources of information and data in the model, and to simultaneously account for measurement errors and process uncertainty in the production function (in relation with the activity Â“data-poor modelsÂ”);
b) To model the influence of environmental fluctuations on the stock dynamics. In particular, it will be tested if the introduction of environmental covariates (i.e. upwelling index) may explain a significant part of the inter-annual variability of the production (FrÃ©on 1991) and improve the fitting of the model to the data and improve the predictions.
Application case study:Â Mauritanian octopus
Coordinator : Etienne Rivot
Meyer R. and Millar R.B. 1999. BUGS in bayesian stock assessments.
Millar R.B. and Meyer R. 2000. Non linear state-space modeling of fisheries biomass dynamic using Metropolis-Hastings within Gibbs sampling. J. R. Statist. Soc., SeryÂ C (Applied Statistics), 49: 327-342.
Rivot, E., PrÃ©vost, E., Parent, E., and BagliniÃ¨re, J.L.
Persons involved in the case studies