Impact of fishing activities on the population dynamics of European whitefish in four peri-alpine lakes

International audienceOur study introduces the first Bayesian Delay-Difference model adapted to whitefish fisheries in peri-alpine lakes. By analyzing various data, the model accurately estimates annual biomass, recruitment, stage structure of landings, and fishing mortality. These insights are invaluable for comprehending the historical trends and impacts of fishing activities on these stocks

Expertise collective sur les tempêtes, la sensibilité des forêts et sur leur reconstitution

[TR1_IRSTEA]33 - CEMAFOR / FOSFORNational audienceThe gale of December 1999 had a huge impact on forest in France, at a level never reached in the past. A group of scientific experts was set up at the instigation of Cemagref and INRA to understand the reasons of such a damage and to give advises for forest restoration. This paper includes a synthesis of the deliberations of this expect group. Firstly, the authors address the climatic storm hazard and the factors related to the vulnerability or resistance of forest. After discussing the rareness of such an event, the evolution of forest is considered. The vulnerability is studied at the tree and the stand level, including the influence of tree species and silvicultural parameters. In a second part, the authors consider the main factors or risks deriving from forest damages (fire, ungulate populations, pests and diseases,_), before suggesting alternatives possibilities of forest restoration.Les tempêtes de la fin 1999 ont frappé profondément et assez durablement le secteur forestier. Face à cette catastrophe, l'INRA et le Cemagref ont pris l'initiative, en concertation avec la DERF de mettre sur pied un groupe d'expertise scientifique avec pour objectif : produire une expertise collective sur l'aléa tempête et la sensibilité de la forêt et proposer des orientations pour la reconstitution des forêts endommagées. Affiner les conclusions de ce rapport après interprétation des premières évaluations des dégâts par l'inventaire forestier national. Encadrer des projets de recherche et élaborer de nouveaux programmes de recherche

Dégâts des tempêtes aux forêts: facteurs de sensibilité ou de résistance

National audienc

Modelling the recruitment of European eel (Anguilla anguilla) throughout its European range

European eel (Anguilla anguilla) recruitment has been declining at least since the early 1980s at the scale of its distribution area. Since the population is panmictic, its stock assessment should be carried out on a range-wide basis. However, assessing the overall stock during the continental phase remains difficult given its widespread distribution among heterogeneous and separate river catchments. Hence, it is currently considered by the International Council for the Exploration of the Sea (ICES) more feasible to use glass eel recruitment data to assess the status of the overall population. In this study, we used Glass Eel Recruitment Estimation Model (GEREM) to estimate annual recruitment (i) at the river catchment level, a scale for which data are available, (ii) at an intermediate scale (6 European regions), and (iii) at a larger scale (Europe). This study provides an estimate of the glass eel recruitment trend through a single index, which gathers all recruitment time-series available at the European scale. Results confirmed an overall recruitment decline to dramatically low levels in 2009 (3.5% of the 1960-1979 recruitment average) and highlighted a more pronounced decline in the North Sea area compared to elsewhere in Europe