Affiliation: | 1. Fjord&2. B?lt and University of Southern Denmark , Margrethes Plads 1, DK-5300 , Kerteminde , Denmark E-mail: magnus@fjord-baelt.dk;3. Department of Biology , Aarhus University , 8000 , Aarhus C , Denmark;4. Centre for Fish and Fisheries Research , Murdoch University , Murdoch , 6160 , Western Australia , Australia |