1. The North Sea Research Center, Section for Aquaculture; Technical University of Denmark; Hirtshals DK-9850 Denmark
2. Department of Animal and Aquacultural Sciences; Norwegian University of Life Science; Aas N-1432 Norway
3. Centro de Ciências do Mar (CCMar); Universidade do Algarve; Campus de Gambelas Faro 8005-139 Portugal