This special volume includes sixteen papers on physical oceanography, geology, paleoceanography, planktonic, benthic and fisheries biology and ecology, and hydrographic and fisheries modelling from different Bay of Biscay areas. The papers were presented at the 8th International Symposium on Oceanography of the Bay of Biscay held at Xixón from 11 to 13 of April of 2002. This Symposium, familiarly known as the Colloque or Coloquio, which started as an informal meeting twenty years ago, has celebrated its 10th edition in 2006 as a consolidated scientific meeting. Every two years it gathers a representative amount of marine scientists, coming mostly from the various coasts facing the Bay of Biscay but also from other more distant countries, with the aim of advancing our current knowledge of every aspect of the oceanography of this sub-basin. We hope that the contributions collected in this truly multidisciplinary volume will encourage future cooperative research in this important region of the European north east Atlantic.