FCRR 2009, Vol. 17(4) 60 pp

Impact de la pêche sur l'écosystème marin de Guinée - modélisation EwE 1985/2005 (Fishing impact on the marine Guinean ecosystem: a 1985/2005 model using EwE)

Fisheries Centre Research Reports 17(4) 2009

By Didier Gascuel, Sylvie Guénette, Ibrahima Diallo and Aboubacar Sidibé

Download this report: Full Report

DIRECTOR’S FOREWORD

This report constitutes a new step forward, in an already long and profitable collaboration between the following three institutes: • the Pôle halieutique Agrocampus Ouest in Rennes (France), • the Centre National des Sciences Halieutiques de Boussoura (CNSHB) in Conakry (Guinée), and • the Fisheries Centre, the University of British Columbia in Vancouver (Canada). This collaboration started in 2000, under the framework of the "Fisheries Information and Analyses System" project (FIAS-UncoDev), funded by the European Commission and devoted to the assessment of fishing impacts on marine resources and ecosystems in North Western African waters. It was especially based on a strong partnership between fisheries labs from the developed world (Europe and Canada) and fisheries research institutes from Cape Verde, Mauritania, Senegal, Gambia, Sierra Leone and Guinea. Within the FIAS project, and in partnership with these African institutes, the UBC Fisheries Centre was in charge of developing ecosystem models. This was not an easy task, notably due to lack of data or knowledge for many compartments of the considered ecosystems. But this approach, led by the former director of the Fisheries Centre, Daniel Pauly, was a success and resulted in the first global overview of the dynamics of ecosystems in North West African waters. In this context, Guénette and Diallo (2004) published a first version of an Ecopath model for the Guinean ecosystem. During the same FIAS project, and under the supervision of its director Didier Gascuel, the Pôle Halieutique Agrocampus Ouest was more involved in the training and sharing of knowledge with African scientists in the use of conventional stock assessment methods. For many important stocks, assessment models were used for the first time, leading to stocks status diagnoses and to estimation of time series regarding catch or biomass. This was notably the case in Guinea, where stock assessments focused on the coastal sciaenids species (Sidibé 2003) and the sparidae community (Laurans 2005). The ecosystem and single-species approaches both gave clear and convergent insights on the impacts of fishing on marine resources and ecosystems. In particular, the international symposium organised in Dakar at the end of the FIAS project clearly illustrated the urgent necessity for a more efficient regulation of North Western African Fisheries (Chavance et al. 2004). Didier Gascuel was hosted at the UBC Fisheries Centre during the 2006/07 academic year. He worked mainly on the development of an ecosystem trophic level based model called EcoTroph (see FCRR17(1)) during his stay with us. He also studied specific ecosystems and started to develop a new version of the Guinean Ecopath model, incorporating all the results obtained from the FIAS and other research projects. The present report is the result of this work, based on the collaboration between scientists from the three institutes. It proposes a completely revised and actualised version of the Guinean Ecopath model, for 1985 and 2004, as well as an Ecosim model fitted on the catch and biomass time series. The authors wanted to make a useful work for African scientists and stakeholders, who are more familiar with French than English, and thus this report was written in French. English speaking readers will find, in the following pages, an extended English abstract referring to the main graphs and results of the reports. Of course, there is no end to science and this report is just one more step—a step towards fruitful international collaborations between fisheries institutes in Canada, France and African countries. Rashid Sumaila Director, UBC Fisheries Centre