Part of this work was financed by the FAO Partnership Programme for Visiting Experts from Academic and Research Institutions and the Norwegian Research Council. Some of the results presented were obtained thanks to the financial support of the Norwegian Research Council. We are also grateful to Dr Carmen Gonzalez Sotelo (Instituto de Investigaciones Marinas, CSIC, Vigo, Spain), Dr David Axelson (Mri_Consulting, Ontario, Canada) and Dr Marit Aursand (SINTEF Fisheries and Aquaculture AS, Trondheim, Norway) for allowing us to use some of their original unpublished results and figures.
