1. Department of Fisheries, Wildlife, and Conservation Biology; University of Minnesota; 135 Skok Hall 2003 Upper Buford Circle St Paul MN 55108 USA
2. Centre for Environment, Fisheries & Aquaculture Science; Pakefield Road Lowestoft Suffolk NR33 0HT UK
3. DTU AQUA; Section of Inland Fisheries and Ecology; Technical University of Denmark; Vejlsøvej 39 8600 Silkeborg Denmark