Quantitative description of habitat suitability for the juvenile common sole (Solea solea, L.) in the Bay of Biscay (France) and the contribution of different habitats to the adult population Olivier Le Pape a, * , Florence Chauvet a , Ste ´phanie Mahe ´vas b , Pascal Lazure c , Daniel Gue ´rault a , Yves De ´saunay a a IFREMER-DRV-RH-ECOHAL, rue de l’Ile d’Yeu, B.P. 21105, 44311 Nantes Cedex, France b IFREMER-DRV-RH-MAERHA, rue de l’Ile d’Yeu, B.P. 21105, 44311 Nantes Cedex, France c IFREMER-DEL-AO, B.P. 70, 29280 Brest, France Received 7 August 2002; accepted 17 March 2003 Abstract This study describes the spatial distribution of young-of-the-year sole based on autumnal beam trawl surveys conducted in the Bay of Biscay (France) during a 15-y period. Previous studies showed that habitat suitability for juvenile sole varies according to physical factors such as bathymetry, sediment structure and river plume influence. These factors, which are known exhaustively for the entire Bay of Biscay from static maps (bathymetry and granulometry) or temporal maps based on a hydrodynamic model (the river plume), were used as descriptors in a generalised linear model of habitat suitability in order to characterise the distribution of juvenile 0-group sole according to delta distribution. This model was used to identify the habitats in which juvenile 0-group sole are concentrated. The respective areas of these habitats were determined from a Geographic Information System (GIS), and their respective contribution to the sole population in the Bay of Biscay was calculated in terms of the estimated number of young fish (GIS area  density derived from the model). Despite the great variability of survey data, this quantitative approach emphasises the highly important role of restricted shallow, muddy estuarine areas as nursery grounds of sole in the Bay of Biscay and demonstrates the relation between interannual variations of nursery habitat capacity (with respect to estuarine extent) and sole recruitment. D 2003 Elsevier B.V. All rights reserved. Keywords: Solea solea; Nursery ground; Habitat suitability models; Geographic Information System; Bay of Biscay 1. Introduction Coastal zone systems are highly productive areas that serve as nursery grounds for many marine species of commercial importance (Costanza et al., 1997). However, habitat destruction is the most harmful means of slowing or preventing stock recoveries (Hall, 1998). Constant demands on the coastal zone from a wide range of human activities suggest that the continued function of natural communities may be threatened in some areas. The most environmentally sensitive coastal areas are those in which a resource (such as flatfish nursery areas) is mainly restricted to a few sites (Parrish et al., 1997). Thus, the identification 1385-1101/$ - see front matter D 2003 Elsevier B.V. All rights reserved. doi:10.1016/S1385-1101(03)00059-5 * Corresponding author. E-mail address: olepape@ifremer.fr (O. Le Pape). www.elsevier.com/locate/seares Journal of Sea Research 50 (2003) 139 – 149