A digital atlas to link ontogenic shifts in fish spatial distribution to the environment of the eastern English Channel. Dab, Limanda limanda as a case-study

The eastern English Channel, which connects the Atlantic Ocean to the North Sea through the Dover Strait, is an area where numerous and often conflicting human activities take place. A cross-border multidisciplinary project called CHARM was initiated to provide knowledge and tools for planners and decision-makers to durably manage the shared marine living resources. One such tool was an atlas of fish spatial distributions and modelled habitats, which was used here to investigate ontogenic and seasonal shifts in fish spatial distribution and habitat through a case-study, the dab Limanda limanda. Survey data for several life-history stages (eggs, larvae, coastal nurseries, < and > 1 year old) and seasons were used to map spatial patterns (using geostatistics), and model potential habitats (using regression quantiles) based on environmental predictors. Habitat models were generally consistent with surveyed spatial patterns and helped explaining dab response to its environment. Dab response to hydrological parameters (e.g., temperature, salinity) was more variable (depending on the life stages and seasons considered) than response to physical parameters (e.g., depth, bed shear stress, seabed sediment type). The results of this work contribute to a better understanding of this species spatial ecology in the eastern English Channel.